This page has been archived and kept as a reference. Content on this page may be out of date.

CReefs - The Australian Node

 Lizard Island 2010
 

by Rebecca Leech

 

Farewell to Lizard Island
14 September 2010

 

The CReefs Lizard Island 2010 expedition has come to a close. Although the work will continue back at the museums and universities, the field trip is over.

The expedition has given Australian and international marine scientists the opportunity to contribute significantly to our knowledge of the plants and animals that live on coral reefs, and the wider picture of what lives in the world's oceans.

Many of the scientists who participated in the Lizard Island expedition, as well as some new participants, will visit Heron Island for three weeks in November this year for the final expedition of the CReefs Australia project.
 

 The team on the CReefs Lizard Island 2010 expedition.

The team on the CReefs Lizard Island 2010 expedition.
Image: Gary Cranitch*.


 

CReefs builds networks of experts
14 September 2010

 

The CReefs Australia project is not just making new scientific discoveries, it is also building new professional networks, according to Dr Rob Adlard of the Queensland Museum.

Dr Adlard is one of a team of scientists studying parasites in fishes on the CReefs expedition to Lizard Island this month. He is focusing on microscopic parasites known as Myxozoa, which can be found in various tissues, including the gall bladder, brain, muscle and heart of fish. His particular interest is in myxozoans of the genus Kudoa.

"We are trying to map parasite species to their host groups or to the tissues they infect. Are all the species found in brains related? Is there a geographical link – are the species on the Great Barrier Reef more closely related to each other than to than those found, for example, on the pacific coast of North America?" he says.

"The closest correlation we're getting is the association with the tissue in which they are found, so the species found in brain tissue appear more closely related to each other than they are to those that live in the muscle or in the wall of the intestine.

"Lizard Island is very rich in myxozoans compared with what we've seen at Heron Island, which is the other place we've sampled the best. We've also done some limited sampling in French Polynesia, and it seems to be depauperate: parasites aren't present at the same levels there as they are on the Great Barrier Reef," he explains.
 

Dr Rob Adlard in the research lab

Dr Rob Adlard in the research lab. Image: Gary Cranitch.

"We're not sure whether that's related to the structure of the reef, the host species, the water temperature or some other factor, although it looks as though diversity decreases as you move east across the Pacific," he says.

Dr Adlard has studied parasites in fishes on the Great Barrier Reef for many years, but this is his first CReefs field trip.

"This trip is important because it gives us another opportunity to sample biodiversity, but also because it provides an opportunity to interact with experts in related fields," he says.

Parasites can have two, three or even four hosts within a life-cycle. They have been found in polychaetes, a group of marine worms, and also in bryozoans, tiny invertebrate organisms that create colonies on rocks or dead coral in coral reefs.

"Parasites have been recorded from polychaetes and bryozoans, and on this trip we've got polychaete specialist Dr Pat Hutchings and bryozoan authority Phil Bock. It is great to work with the experts in the field and to compare notes," Dr Adlard says.

"Parasitology clearly has a central focus on the interaction between species, so in this system we are interested in the fish, the parasite and the invertebrate intermediate host – now that is what makes it fascinating to us."

 

Back to top

 

A question of environment
13 September 2010

 

Hundreds of thousands of tiny crustaceans called isopods live on tropical reefs, yet they have barely been studied in Australia at all. The CReefs Australia project is helping to change that picture.

Museum of Tropical Queensland researchers Chad Buxton and Dr Niel Bruce have been collecting isopods from the reefs directly around Lizard Island on CReefs expedition over the last three years, and they are still finding new cryptic species.

Scientists are beginning to understand the abundance and diversity of the species found here – but, Chad says, much work still needs to be done to describe the many new species and resolve their phylogeny and evolutionary history.

Different families of isopods can be found in deep ocean, in freshwater and on land, but Chad is focusing on isopods of the family Stenetriidae, which are free-living on coral reefs among other places.
 

 Chad Buxton collecting rubble to examine for isopods.

Chad Buxton collecting rubble to examine for isopods.
Image: Gary Cranitch.

"Stenetriidae haven't been particularly well-described in Australia, and no Stenetriidae species have been described on Australian coral reefs, so virtually all of the species that we find here are new to science," he says. "It is exciting work because you never know what you will discover next."

Chad estimates that through the CReefs project at least 30 new isopod species have been discovered in this family alone, and that there are many more to be described among other isopod taxa as laboratory work continues.

Chad has found some interesting patterns in the distribution of Stenetriidae directly around Lizard Island.

"Often, it's not a question of distance, it's a question of environment. I am currently examining micro-habitats, such as different beds of algae, different types of coral rubble, sand, and exposed outer-reef habitats to reveal patterns of species distribution," he says.

"I find different isopods on MacGillivray Reef – a sandy cay reef exposed to winds and currents, less than five kilometres from Lizard Island – than I find on the protected, inshore reefs around the island itself. I find different species in shallow areas than I find on the same reef at depths below 20 metres," Chad says.

"A more striking difference is found between the inner reefs and the outside of the barrier reefs. Basically, all reefs are not created equal to an isopod!"

Part of Chad's research will study the phylogeny of the Stenetriidae – the evolutional history and development of species over time – and the biogeography – the patterns of species distribution and abundance over geographical areas over time.

Chad is working on an Australian Biological Resources Study grant to study isopods at the Museum of Tropical Queensland in Townsville and is currently pursuing his PhD at James Cook University.

 

Back to top

 

Of worms, fish and people
13 September 2010

 

"Have you ever gone to a fish market in Melbourne and bought a couta fillet? You should. They're a tasty fish, and really cheap.

"Do you know why they're so cheap? Because they're full of worms."

So says University of Melbourne Professor of Veterinary Parasitology Ian Beveridge, who, on this CReefs trip, is examining fish, sharks and rays for trypanorynch cestodes, an order of tapeworms, and anisakid nematodes, a group of roundworms.

"When you think about tapeworms, you tend to be a bit anthropogenic, and think about human tapeworms and dog and cat tapeworms, but in fact the greatest diversity of tapeworms is in elasmobranchs, that is, sharks and rays," Professor Beveridge explains.

Trypanorynch cestodes and anisakid nematodes, found in fish and marine animals, are considered parasites, although Dr Beveridge says they do not seem to cause any harm to their hosts, and they only very rarely cause nuisance for humans.

People can eat fish with adult cestodes in the flesh, such as couta, worms and all, without consequence. In fact, cooking or freezing will kill any parasites. The only human problems ever associated with these groups of tapeworms and roundworms have been reported from people eating raw fish and squid.

 

Professor Ian Beveridge boating off Lizard Island.

Professor Ian Beveridge boating off Lizard Island.
 Image: Gary Cranitch.

"Some of the tapeworm larval stages occur in squid, and if a larva gets into a human mouth, it can put out its hooked tentacles and grab onto the tonsils. It's very painful, but it can be treated: the tapeworm can be pulled off the tonsils with a pair of forceps," Professor Beveridge explains.

"Some of the roundworm larval stages occur in fish. If larvae survive on a piece of raw fish and make it into a human stomach, they will do what they normally do in any other host: they come out and try to burrow into your stomach wall," he says.

Professor Beveridge is one of a team of scientists, drawn from the University of Melbourne, RMIT and Charles Sturt University, awarded an Australian Biological Resources Study grant to study anasakid nematodes. One of the team is concentrating on interactions between nematodes and people. Professor Beveridge is focusing on the biodiversity of species and their life cycles.

 

Back to top

 

Bright and beautiful
12 September 2010

 

The Octocorallia, or soft corals, are not only diverse in their taxonomy – there are approximately 3000 species known in the oceans worldwide – they are also diverse ecologically.

Sea pens, of the octocoral order Pennatulacea, for example, have a feathery structure, grow up to two metres tall, feed primarily on plankton, and are found in deep tropical or temperate waters, sometimes at depths of 2000 metres. Some species are bioluminescent – when touched they can emit a greenish light.

Octocorals of the order Gorgonacea, however, can be fanlike or bushy, brightly coloured, often red or purple, and are found in tropical waters. Some gorgonian species gain energy through a combination of photosynthesis through creating symbiotic relationships with algae and feeding on plankton.
 


Drs Ekins and Schlacher-Hoenlinger examining soft corals.

Drs Ekins and Schlacher-Hoenlinger examining soft corals.
Image: Gary Cranitch.

And blue corals, of the order Helioporacea, produce massive skeletons of aragonite, a carbonate mineral, and the polyps live in tubes within the skeleton. They occur largely on shallow coral reefs in the Indo-Pacific.

Among the great diversity of soft corals, octocoral expert Dr Monika Schlacher-Hoenlinger and Collection Manager Dr Merrick Ekins of the Queensland Museum have some favourites.

"I like the huge fans, candelabras and whips of the gorgonians," Dr Schlacher-Hoenlinger says.

Dr Ekins agrees the gorgonians are "stunning" but adds to the list.

"I like the Sarcophytons: they are mushroom-shaped corals. Xenias are also very pretty: the polyps look like little flowers and you can see them open and close," he says.

Drs Schlacher-Hoenlinger and Ekins are focusing on soft corals during the CReefs expedition. They take small pieces of corals for identification using morphology (the study of the shapes, structure and anatomy), microscopy of the sclerites, and molecular biology (DNA analyses).

This is their second CReefs trip to Lizard Island, and they believe they have now collected examples of many of the shallow-water genera known in Australia.

"Lizard Island is very diverse for soft corals. Last year we sampled widely and collected about 400 specimens. This time we tried to find specimens that we didn't find before," Dr Schlacher-Hoenlinger says.

"We have a piece of Paraminabea, which is uncommon. They usually live deeper than 30 metres, but can be found in shallower waters in caves and under overhangs. They like the dark. We haven't seen one with its polyps out; they may only come out at night," Dr Ekins says.

Drs Schlacher-Hoenlinger and Ekins have also collected pieces of corals of the genus Chondronephthya and the genus Siphonogorgia, which are not commonly found.

While the rare species might be more exciting to find, Drs Schlacher-Hoenlinger and Ekins say there is also still more to be learnt about common genera. They have collected many specimens of the widespread genera Lobophytum and Sinularia around Lizard Island, but say that further laboratory study will be needed to identify some species.

"Often, two specimens of the same species can have different morphology depending on their location on the reef, the turbidity, current and other factors," Dr Schlacher-Hoenlinger explains.

Dr Schlacher-Hoenlinger and Ekins are contributing subsamples of DNA from every specimen they collect to Dr Abigail Fusaro, a representative of the Ocean Genome Legacy on the CReefs Australia project.

"One of the advantages of being in the CReefs project is that the Ocean Genome Legacy is going to sequence our samples, and this will assist us to identify samples of corals in the future," Dr Ekins says.

 

Back to top

 

The diverse life of (and inside) fish
12 September 2010

 

"This fish," says Dr Terrence Miller, examining the body cavity of an emperor he has just opened, "has trypanorhynch cestodes."

He points out the numerous and relatively large cysts of the tapeworm larvae, which are extraordinarily concentrated around the throat region in this individual.

"Each fish may be host to a range of internal and external parasitic species – some individuals we examine host up to 10 or more different species of parasites – so we will systematically search through each of the tissues and organs of this fish to see what else is here," he says.

 

Dr Terrence Miller spearfishing for target species off Mangrove Beach at Lizard Island.

Dr Terrence Miller spearfishing for target species off Mangrove
Beach at Lizard Island. Image: Gary Cranitch.

Dr Miller, a researcher with the University of Queensland and the Queensland Museum, is working with a team of parasitologists on the CReefs trip to Lizard Island. Other members of the team are focusing on cestodes (tapeworms), nematodes (roundworms), and microscopic parasites of the class Myxosporea, but Dr Miller's main focus on this trip are parasitic flatworms of the subclass Digenea, which belong to the phylum Platyhelminthes.

Digeneans are internal parasites commonly known as flukes or trematodes, which are primarily found in the intestines and stomach of their final fish host (where the worm develops into an adult), but may also be found in most tissues including the gills, body cavity, liver, spleen, and urinary bladder.

"The diversity of trematodes in marine fish is staggering," Dr Miler says, while picking out another unusual parasite species from the flesh of the emperor.

"On some of the previous CReefs trips we have observed fish species hosting up to 12 different trematode species. What is also interesting about this is that many of these parasites are very host specific, in that they only infect a single fish species or a small group of closely related hosts. And these are just the trematodes. When you include all of other internal metazoan and protozoan parasites, the diversity and richness of living creatures within a fish is quite fascinating. Lizard Island is home to fish that harbour a diverse range of Platyhelminthes, so every day we're discovering something new."

These CReefs expeditions have not only allowed Dr Miller to explore trematode species diversity in coral reef fishes, but are also helping to inform us of their life-cycles, evolutionary relationships and biogeography.

"While discovering and documenting new species of parasites is in itself really exciting, we are now starting to see some interesting patterns in the evolution and biogeography of some species. For example, some species of parasites have relatively restricted biogeographic distributions, while others are distributed almost Indo-Pacific wide. How these parasites have evolved and dispersed so widely in the various small reef-associated or larger pelagic reef-associated fish families is a key question these expeditions are allowing us to explore."

 

Back to top

 

Shrimp on film
11 September 2010

 

Dr Zdeněk Ďuriš is interested in shrimp. As he tells me this, we are watching a tiny shrimp, less than a centimetre long, in exquisite detail as it goes about its business of cleaning a piece of coral.

"This is a Dasycaris zanzibarica. Its host, the sea whip, is a gorgonian coral. Corals have very delicate tissue and polyps which produce mucus. The mucus contains a lot of nutrients which are eaten by the symbiotic shrimps in the process of cleaning the host, and this stimulates the host to produce new portions of mucus," Dr Ďuriš explains.

Dr Ďuriš is videoing the shrimp through his microscope; the footage, he says, is an important tool in his work to describe and understand shrimp species.

Dr Ďuriš, an Associate Professor at the University of Ostrava in the Czech Republic, specialises in symbiotic shrimp of the Palaemonidae family. On the CReefs expedition to Lizard Island, he is looking for specimens of the subfamily Pontoniinae, which are usually found in marine habitats such as coral reefs.

"Some species are free-living on the reef, while others form strong relationships with host animals. This suggests a complex history of evolution from free-living forms to different kinds to hosts, host switching, and leaving hosts and living freely again on the bottom of the reefs," Dr Ďuriš explains.

 

Dr Zdeněk Ďuriš filming shrimp habitat.

Dr Zdeněk Ďuriš filming shrimp habitat. Image: Gary Cranitch.

Almost all species of Pontoniinae form relationships with hosts, usually larger marine invertebrates including sponges, molluscs, cnidarians (such as corals, anemones and jellyfish), molluscs (mainly bivalves), echinoderms (like sea urchins, sea stars, feather stars or sea cucumbers), as well as with sea squirts, and some are also fish cleaners.

These relationships are often considered to be commensal, that is, benefiting the shrimp but not affecting the host, or mutual, benefiting both the shrimp and the host. But, says Dr Ďuriš, sometimes the relationships are parasitic, benefiting the shrimp but causing some harm to the host.

"Most so-called symbionts may in some cases cause harm to their hosts. For example, some shrimp living on the sea anemones may, in periods of starvation, nip at the tentacles of the sea anemones," he says.

It probably doesn't happen very often, he says – but then again, research on the stomach contents of shrimps living in sponge hosts found ‘a lot' of sponge tissue.

"It would not be in the interest of the shrimp to kill its host, because in many cases the shrimp are unable to move to another host – instead the shrimp may feed on their host's body in very small quantities with the host being able to renew its tissues," he says.

To understand these relationships better, Dr Ďuriš is trying to observe and record the interaction between the shrimp and its host.

"I use underwater video of the shrimp habitats and video through the microscope of the feeding and cleaning behaviour of the shrimp," he explains.

"I can observe shrimp behaviour on the different hosts in a various habitats. In this way, I can see adaptation of colours, morphology, the way it moves on its host, and what it is doing with its mouth and other appendages," he says.

Dr Ďuriš refers to the videos when describing species. He has also provided footage for television documentaries in Poland and the Czech Republic, and may make his collection available to the scientific community in the future.

 

Back to top

 

Spore Heart
13 September 2010

 

Three-quarters of the threadfin cardinalfish examined in the waters around Lizard Island have myxosporean cysts around their hearts, according to Holly Heiniger.

Holly, a PhD student and researcher at the University of Queensland and the Queensland Museum, is focusing on myxosporean parasites found in fish of the family Apogonidae, or cardinalfish.

The Myxosporea are a class of microscopic parasites. They have a two-stage life cycle, usually involving an invertebrate, such as a polychaete worm, and a vertebrate, such as a fish, reptile, amphibian or mammal. The parasite releases a different type of spore from each host, and species identification is usually based on the size and shape of the spores released by vertebrate hosts.

Holly is particularly interested in the biology and species richness of species from two genera of myxosporeans, Myxidium and Zschokkella. She will study the morphology (the shapes, structure and anatomy), ecology and phylogenetics (the evolutionary relationships between species) of specimens she finds on the CReefs trip to Lizard Island.

"Specimens from these two genera can appear similar based on morphology, and there's been some contention over which species belong to which genera. My work will focus on revising these two genera, so that the taxonomy accurately reflects the species' phylogenetics," Holly explains.

 

Holly Heiniger collecting apogonids.

Holly Heiniger collecting apogonids. Image: Gary Cranitch.

"We're focusing on parasites in apogonids, or cardinalfish, because they are one of the most diverse fish families on the reef, occupying different behavioural and ecological niches; for example, some species are solitary, while others form schools, and different species have different feeding behaviours," she says.

Many reef fish have a pelagic larval stage: that is, young fish live for a time in the water column of coastal and oceanic waters, some distance from shallow coral reefs. Some apogonids, however, do not have a pelagic stage, because they are mouth brooders – the male fish holds the eggs in his mouth to incubate them.

"We're looking at how mouth brooding behaviour in apogonids affects parasite ecology, compared to fish that have pelagic larval stages," Holly explains.

Holly is working with the team of parasitologists on Lizard Island to catch apogonids, and examine specimens through microscope work, taking measurements of all the morphological characters. Samples of the parasites' genetic material will also be analysed, using small subunit of the ribosomal DNA to assist in identifying parasite species.

"On this trip, we've found a number of Myxidium and Zschokkella species in apogonids' gall bladders," Holly says.

"We've also found a high prevalence of myxosporean parasites of the genus Kudoa in the threadfin cardinalfish, Apogon leptacanthus. Approximately 75 to 80 per cent of these fish are infected with cysts surrounding their hearts caused by a species of Kudoa; that's quite a high infection rate."

Holly's work is not, for the moment, concerned with the pathology caused by the myxosporeans, but is focusing on their host-parasite relationships, diversity and biogeography in marine fish.

 

Back to top

 

Sands of time
10 September 2010

 

A little-known species of marine animal could provide a clue to the evolution of coral reefs over millions of years, says Associate Professor James Reimer of Japan's University of Ryukyus.

Professor Reimer is studying marine life on the CReefs field expedition to Lizard Island on the Great Barrier Reef this month.

His interest is Zoantharia, an order of colonial animals related to corals and sea anemones.

Zoanthids form colonies of polyps on the ocean floor or on other reef structures. Unlike hard corals, zoanthids do not grow skeletons, but many incorporate small pieces of sediment, sand and rock into the tissue of their body walls and the button-like, tentacled disc atop each polyp. There are some species that do not incorporate sand at all.

Professor Reimer is particularly looking for an unusual group of zoanthids, the genus Neozoanthus, which incorporate large, irregular particles of sand into their body walls, but do not have sand in the disc tissue.

Specimens of these zoanthids were found by scientists in Madagascar in 1973. Professor Reimer found similar species on the CReefs expedition to Heron Island last year, and more recently in Okinawa in Japan. He expects to find related species at Lizard Island.

The study of these species could provide insight into the evolution of coral reefs.
 

 Dr James Reimer collecting zoanthids.

Dr James Reimer collecting zoanthids. Image: Gary Cranitch.

"Evolution doesn't always take the simplest route," Professor Reimer says.

"This group of zoanthids looks like an intermediate stage between zoanthids that don't use sand and those that do, but our DNA analysis suggests that's not the case at all.

"It seems that most zoanthids had sand, then one group lost sand, and some species, the ones I'm looking for, partially regained it.

"This suggests that the zoanthids' use of sand might not be a particularly complex characteristic, but rather something they can turn on or off rather quickly, like a switch," he says.

Of course, this ‘quick switch' still takes place over several million years, but in the 600-million-year history of coral reefs, this is a relatively short time.

"My theory is that at one point in time, when corals couldn't build skeletons well, perhaps due to ocean acidification or other natural environmental disturbances, the zoanthids evolved. The sand provides structural strength to the zoanthids, an alternative to the way hard corals build skeletons, but with a similar outcome," Professor Reimer says.

"Zoanthids are found in a range of environments throughout the oceans, in Australia, Japan, Singapore, the Arctic, the Antarctic, Canada, and even at depths to 5600 metres – but the species that don't have sand are only found in coral reefs in shallow waters in warmer areas, and they all have symbiotic relationships with single-celled algae, so that may be significant," he says.

Professor Reimer will study the diversity of species of zoanthids found around Lizard Island, and compare this to Japan, Heron Island and Ningaloo Reef.

 

Back to top

 

What we need to know
12 September  2010

 

"Zoanthid research is a poster child for the good and the bad points of coral reef science," says Associate Professor James Reimer of Japan's University of Ryukyus.

Professor Reimer is studying the colonial anemones known as zoanthids on the CReefs expedition to Lizard Island. Zoanthids are related to other anemones and to hard corals.

"Zoanthids are everywhere in oceans around the world, so there is a great opportunity to learn more about them – but they are not a well-studied group, and there are very few scientists working on them, so most biodiversity surveys just ignore them," he says.

A zoanthid of the species Zoanthus sansibaricus.

A zoanthid of the species Zoanthus sansibaricus. Image: Gary Cranitch.

"They produce chemicals, which may have commercial or medical applications, and they produce palytoxin, one of the most toxic substances known in nature," he says.

The palytoxin produced by zoanthids can be absorbed through intact skin, and even in small quantities, can be fatal to humans if it is ingested or enters the blood stream.

It has been reported, for example, that a home aquarist was poisoned when he accidentally brushed an open cut on his finger against a Parazoanthus species. He was lucky to recover: his zoanthid was found to contain more than two milligrams of palytoxin per gram, enough to kill 125 grown men.

Despite these unusual characteristics, as yet very little work has been done to investigate zoanthids.

"Essentially, the example of the zoanthids shows how little we know about coral reefs," he says.

According to Professor Reimer, zoanthids are common on coral reefs, but they are not as big as many corals – most zoanthids polyps are less than three centimetres across – and unlike hard corals, zoanthids don't form skeletons, so they don't leave any trace behind them when they die.

Professor Reimer suggests this makes zoanthids more cryptic than corals; that is, they are less obvious and a little harder to study.

Professor Reimer will compare the zoanthids he finds at Lizard Island with specimens found on other CReefs trips to Heron Island and Ningaloo Reef, and those found in Japan, Singapore, Madagascar, the Indian Ocean and elsewhere.

He will also compare recent information to those few studies that have been conducted in the past.

"I'm excited to join the CReefs expedition to Lizard Island. We can learn a lot from this project," he says.

"Through this research, we can start to get a better global picture. We can start to get an understanding about the common species, at least. Then groups that have previously not been well-studied, such as zoanthids, can be included in biodiversity surveys, and can be considered in planning for the management and conservation of marine areas," he says.

 

Back to top

 


 

The evolution of worms

9 September 2010

 

Research undertaken on the CReefs Lizard Island expedition could contribute to new discoveries about the 600-million-year history of evolution of the most common and widespread group of marine invertebrates.

Dr Pat Hutchings, a Senior Principal Research Scientist at the Australian Museum in Sydney, is part of a team of researchers focusing on the segmented, invertebrate marine worms known as polychaetes, as part of the CReefs project.

She has been studying polychaetes for more than 40 years, and the CReefs project ties into ongoing research.

The researchers are working to establish a baseline for the diversity of the group and describe new genera and species, as well as to better understand the evolution, distribution and biodiversity of these animals.

"Our research is looking at the relationships between the different polychaete families, and where the polychaetes came from," says Dr Hutchings.

"Polychaetes are segmented, as are crustaceans, and for a long time science assumed the two groups were closely related. We have since discovered that polychaetes are much more closely related, in the evolutionary sense, to molluscs than to crustaceans," she says.

The polychaete research team uses a combination of morphology (the study of shape, colours, structure and anatomy) and molecular biology, including DNA analyses, to classify species.



 



Dr Patricia Hutchings collecting polychaetes. Image: Gary Cranitch.


The researchers also consider the fossil record of polychaetes.

"Not all polychaetes leave fossils, because they are soft-bodied, but there are examples dating back to the Cambrian period 600 million years ago," Dr Hutchings says.

"There are 80-odd families and, in evolutionary terms, they seem to form clusters. We're trying to work out how the clusters are related to each other, bearing in mind that there may have been families that had evolved that have since died out," she explains.

Polychaetes as currently constituted are not a monophyletic group, , meaning that within this group there are a number of independent evolutionary lineages and the relationships among these lineages is still being explored

Groups that may be descended from the polychaetes include earthworms, leeches, sipunculans, also known as peanut worms, and echiurans, also known as spoon worms.

Dr Hutchings' work on the CReefs expedition to Lizard Island is funded by an Australian Biological Resources Study/CReefs grant. The research team is drawn from the Australian Museum, Museum Victoria, the Museum and Art Gallery of the Northern Territory and Charles Darwin University.

 

 

Back to top


 

BHP Billiton enviros to get a taste of salt water
8 September 2010

 

BHP Billiton employees Darren Niejalke and Kim Boyall are gaining a broader understanding of their employer's valuable investment in scientific research this week on the CReefs expedition.

Both came to Lizard Island as part of the BHP Billiton Employee Engagement Program, which sends employees on each of the CReefs expeditions to gain first-hand experience of marine field work.

Darren is a Principal Sustainability Advisor for BHP Billiton, working on projects in South Australia and Western Australia. Kim is a Graduate Environment Officer for Illawarra Coal in Wollongong in New South Wales.

BHP Billiton is the major sponsor of the CReefs Australia expeditions.

"BHP Billiton has a policy of investing one per cent of pre-tax profits, around $200 million a year, in various community programs around the globe. The company then encourages employees to get out into the field and see the impact of this quite significant investment," Darren says.

"Participating in the CReefs trip is a great opportunity for us to gain an appreciation of the wider scope of the company's community involvement, and then when we go back to the office, to tell others about the importance of this work," he says.



Darren Niejalke examining specimens under a microscope.
 

Darren Niejalke examining specimens under a microscope. Image: Gary Cranitch.

Kim agrees. "My role with BHP Billiton involves environmental management of three mine sites in New South Wales, but it's important to learn about the latest research across other branches of the scientific community as well.

"I've always been interested in marine science, and the CReefs trip has given me a chance to learn more about what a research field expedition involves –just to get a taste of what marine biologists do," she says.

Darren and Kim have had the chance to snorkel with the scientists at several reef sites around Lizard Island, to observe how they collect samples, and to assist them in the research lab. They have worked with the polychaete team to look for worms in coral rubble that has been collected, and with the parasitology team to dissect fish to search for internal parasites. They have also helped to classify species and process samples for several of the researchers.

"This is valuable experience for my role with BHP Billiton," says Darren.

"My work involves preparing environmental impact statements for new mining projects. I have been working with a small team of marine scientists on one of our upcoming projects, so this is a good opportunity for me to see how other marine researchers apply their trade. Hopefully, I can add a bit of value to the CReefs project, too," he says.

Darren and Kim are visiting the Lizard Island Research Station from 26 August to 1 September.

 

Kim Boyall snorkelling.

Kim Boyall snorkelling. Image: Gary Cranitch.

Back to top

 

Introductions all around
7 September 2010

 

The research conducted by Dr Maria Capa as part of the CReefs project could contribute to understanding which marine animals pose a danger to coral reefs, as well as which geographical areas are richest in marine life and in most need of protection.

Dr Capa, a post-doctoral researcher with the Australian Museum in Sydney, is one of a team of scientists studying the diversity and biogeography of polychaete worms on the CReefs expeditions to Lizard Island and Heron Island on the Great Barrier Reef, and Ninglaoo Reef in Western Australia.

"There seem to be several species that have Indo-Pacific distributions, so they were found all around the coast of northern Australia. We're now looking at the genetics of populations to confirm this," Dr Capa says.

A polychaete of the family Sabellidae genus

A polychaete of the family Sabellidae genus Notaulax. Image: Gary Cranitch.


"We are trying to discover if there are connections between these populations, or if there are geographical boundaries, perhaps due to currents or geology or habitat," she says.

So far, there don't seem to be significant differences in most species between Lizard Island, Heron Island and Ningaloo Reef, but the polychaete team has made some interesting discoveries, particularly about introduced species.

Many polychaete species are endemic, or native, to Australia, but there are 10 species that have been identified as introduced. Polychaetes can live in substrate attached to the hulls of ships, and planktonic polychaete larvae can live in ballast water for up to a month, and so can be transported around the world.

"One species is unusual because we have found it at Cairns and Heron Island, rather than in cities with large ports. It has some identical genes to specimens found in Hawaii, so we think they are the same species, but we don't know whether if they've gone from Heron Island to Hawaii or the other way around," Dr Capa says.

Introduced species could potentially threaten marine ecosystems.

"One species of the group I am working with, for instance, Sabella spallanzanii, is a tube worm that measures about 20 centimetres long and has a large fan of branch-like tentacles. In its native habitat in the Mediterranean, these worms are widely dispersed in seagrass beds, but in southern Western Australia and in Port Philip Bay in Melbourne, they cover some areas in very high densities. They modify the environment below them, because they capture most of the small particles of food from the water, and are probably competing with native species," Dr Capa says.

She says that understanding the biogeography of endemic and introduced species could have important applications for conservation.

"For instance, if a species lives in several places in northern Australia and we want to preserve it, we might choose, for example, an area in Western Australia to preserve, and say that is a representative population of that fauna. But if there are different species in different locations, we might need to preserve an area in Western Australia, another in the Northern Territory and another in Queensland," she explains.

"CReefs is an important project because it allows us to conduct population studies, which will help us to resolve the biogeographical boundaries of the species," she says.

 

Back to top

 

Worms provide early warning
7 September 2010

 

If you ever thought worms were unattractive or dirty, think again, says Dr Pat Hutchings of the Australian Museum. Not only are many of the marine worms she studies brightly-coloured, delicate and quite beautiful, they also play an essential role in keeping marine environments clean, and can be used to monitor the health of coral reef ecosystems.

Dr Hutchings is one of a team of researchers focusing on polychaetes on the CReefs field trip to Lizard Island this month.

Polychaetes, or segmented worms, are amongst the most common and widespread invertebrates found in the oceans. They provide a food source for fish and crustaceans, but perhaps most importantly, polychaetes' own feeding patterns act as a filtering system for ocean sediment.

"They are a bit like the earthworms in your compost bin," explains Dr Hutchings.

"They are very good at breaking down organic matter. A good population of worms helps to ensure a healthy marine environment," she says.

Polychaetes are also very good monitoring devices for pollution.

Because they tend to be widespread and appear in large numbers throughout the oceans, tracking changes in polychaete biodiversity on coral reefs could provide scientists with an early warning system of potential degradations to these ecosystems.

 

A polychaete of the family Terebellidae, genus Reteterebella.

A polychaete of the family Terebellidae, genus Reteterebella.
Image: Gary Cranitch.

 

"There are some worms that can live in heavily contaminated sediment, but a lot can't. If a sample of mud has no worms in it, I know that it's heavily contaminated. It's not a healthy situation," Dr Hutchings says.

The polychaete research team is working to establish a baseline for the diversity and abundance of polychaetes in Australian waters. This information is being used in the management and conservation of marine areas.

"How do you decide which areas need to be conserved, which are the richest in biodiversity?" Dr Hutchings asks.

 

A polychaete of the family Terebellidae, genus Lanicedes.

A polychaete of the family Terebellidae, genus Lanicedes.
Image: Gary Cranitch.

"Until recently, proxies were used, such as sediment, depth, presence of seagrass beds or mangroves, and the abundance and diversity of fish. These are important considerations, but we also need to monitor the invertebrate creatures living in the sediment.

"There are 80 or more families of polychaetes; more than can be studied by the few researchers in Australia. Our team has targeted five families, each with many species, and each with different reproductive and feeding strategies. These can reasonably be used as surrogates for the biodiversity of other polychaete families," she says.

"Through CReefs field trips and other research, we now have thousands of records of polychaete populations around the coast of Australia. We are beginning to see patterns of which species are present in which environments. Where species are absent, we can consider the reasons why this may be the case, including whether the habitat is degraded due to pollution," she says.

 

Back to top

 

BHP Billiton enviro broadens his horizons
6 September 2010

 

Participating in the CReefs project is a rewarding professional and personal experience, says BHP Billiton employee Matthew Jones.

Matthew, an Environmental Superintendant for a BHP Billiton Mitsubishi Alliance (BMA) coal mine in the Bowen Basin in central Queensland, is visiting Lizard Island as part of the BHP Billiton Employee Engagement Program, which sends employees on each of the CReefs expeditions to gain first-hand experience of marine field work.

BHP Billiton is the major sponsor of the CReefs Australia expeditions.

Matthew has long had an interest in fisheries and oceans management and policy. After working in the fishing industry while still at school, Matthew followed his fisheries passion into a role as a research scientist for the fisheries section of the Northern Territory Department of Resources. His goal in the coming years is to undertake a higher research degree in marine science, and believes his participation in the CReefs expedition is providing valuable insight into this area of research.

"When the opportunity came up to be part of the CReefs project, I leapt at it," Matthew says.

"BHP Billiton wants its employees to be able to broaden their horizons. This trip is a great way for me to learn about what is happening in a field of science outside my immediate areas of expertise – and what a fantastic experience!" he says.

Matthew has participated in a range of research activities on this field trip, including scuba diving at a number of sites, both on reefs around Lizard Island and outer shelf reefs such as Day and Yonge Reefs.

He has dived with the soft coral research team, assisted with collecting samples and with setting out transects: measuring a straight 20-metre line underwater and recording the numbers and species found within half a metre either side of the line, to establish the diversity and abundance of soft corals in different environments.
 

He has also been spear fishing and line fishing with the parasite research team, and then back at the research station, observing how each fish is dissected and examined for internal parasites in the organs and muscles.

Matthew says learning more about each team's research has been "eye-opening".

"I've spent time with the researchers, discussing what they are looking for, what they've found so far, and other projects that they've been involved in. As an environmental scientist working in an industrial context, I'm particularly interested in how this research can be applied to monitor and improve the health of ecosystems," Matthew explains.

"I want to know, for example, if the fish infected with parasites are in a worse state than those that aren't, and what impact that might have on fisheries. I want to know more about how macroalgae accumulate significant amounts of heavy metals, and how this could be applied for use in industrial clean-up.

"This sort of research could assist industry to more accurately assess, and where possible reduce, impacts on local ecosystems, ultimately ensuring the long-term health of our environment," he says.

Matthew is taking notes to document his participation in the CReefs project, and plans to spread the word about the importance of the research to other BHP Billiton employees when he returns to work.

Matthew is visiting the Lizard Island Research Station from 6 to 12 September.

 

Matthew Jones scuba diving.

Matthew Jones scuba diving. Image: Gary Cranitch.

Back to top

 

Spawn and die happy
5 September 2010

 

The diversity of parasite life can be a significant indicator in the overall health of an ecosystem – but parasites don't care about that, says Dr Rob Adlard of Queensland Museum.

Dr Adlard is one of a team of scientists studying parasites in fishes on the CReefs expedition to Lizard Island this month. His particular interest is in myxozoans of the genus Kudoa.

Myxozoans typically have two hosts within a life cycle. One life stage occurs in segmented worms (annelids), during which the parasite transmits spores into fish. A second developmental stage in the fish produces spores that are transmitted back into the annelid worms.

"If they can pass on their genetic material in this way, they have successfully completed their life cycle within that system," Dr Adlard says.

It's tempting to say that myxozoans procreate then die happy, but Dr Adlard warns against the tendency to anthropomorphise parasites.

He relates an anecdote in which he was speaking at conference and a participant demanded to know the purpose of such ‘disgusting' creatures as parasites.

As it happens, parasites play an important role in marine environments. Infected fish may be smaller or weaker than other fish, or may adopt erratic behaviour. This makes them easy targets for predators, and ultimately functions as a form of population control.

"Parasites have the ability to regulate host populations, and to change the inter-specific and intra-specific competition for resources," Dr Adlard explains.
 

For the parasites themselves, however, ‘the point' is simply existence, and any human perception of ‘purpose' is not their concern.

Parasites, by definition, are organisms that live in intimate association with their host and from which they derive benefit but also cause harm during the process.

This becomes of more importance to us when, for example, parasites hitch a ride on ships from around the world and are introduced into Australian waters.

In some environments, the absence of parasites may suggest high levels of pollution, that is, they are sensitive indicators. In others, the opposite may be the case: human interaction has introduced parasites or created conditions in which existing parasite populations have flourished, to the detriment of other marine life.

To understand these dynamics and put them to use is necessary to build a baseline against which we can compare – a central goal of the CReefs project.

 



Dr Rob Adlard preparing to spearfish.

Dr Rob Adlard preparing to spearfish. Image: Gary Cranitch.  

Back to top

 

Tidy towns
4 September 2010

 

The family of shrimp studied by Dr Ivan Marin may be the clean freaks of the marine world.

Dr Marin, a scientific researcher at the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, is looking for shrimp of the family Palaemonidae on the CReefs expedition to Lizard Island this month.

The Palaemonidae are divided into two subfamilies: Palaemoninae are usually found in freshwater environments, while Pontoniinae are usually found in marine habitats such as coral reefs.

Shy, delicate, only half a centimetre long, and mainly transparent or cryptic coloured, pontonines are not easy to find, and until recently, little research has been devoted to them. Dr Marin's work, however, has found that pontonines play an important role in coral reefs.
 

"They clean coral reefs. They extract hard pieces such as stones, sand particles, or sediment from the body of the coral or from the sponges, wherever they are living, and move the detritus away from their hosts," Dr Marin explains.

Almost all pontonines establish symbiotic relationships with larger marine invertebrates including sponges, molluscs, cnidarians, such as corals, anemones and jellyfish, and echinoderms, such as sea stars, sea urchins and sea cucumbers. Different Pontoniinae species have preferences for different hosts; for example Coralliocaris live on hard corals of the genus Acropora while Anchistioides always live inside sponges.

"These relationships are of a kind called mutualism, in which both animals benefit. The shrimp live inside a coral, for instance: the coral protects the shrimp and the shrimp clean the coral," Dr Marin explains.

The shrimp may also eat mucus produced by corals and eat scraps of food left from the meals of their hosts.

"The shrimp play a very important role. There have been experiments by others scientists who have removed the worms, shrimp, crabs and other tiny crustaceans from colonies of coral. The coral died because it couldn't clean itself," Dr Marin says.

Research into the role of symbiotic relationships in coral reefs may have significant implications for conservation.

"Scientists have tried to understand, for example, what causes coral bleaching, which may be related to warm or cold waters in coral reefs. Maybe changes in water temperature killed the symbiotic assemblage, and the coral died because the symbiotic relationships were destroyed," he says.



 

Dr Ivan Marin collecting shrimp.

Dr Ivan Marin collecting shrimp. Image: Gary Cranitch.

Back to top

 

Eternal life
4 September 2010

 

The tiny invertebrate organisms being studied by Phil Bock can, theoretically, live forever.

Phil, a Museum Victoria honorary associate, is collecting bryozoans on the CReefs field trip to Lizard Island this month.

Bryozoans, also known as moss animals or lace corals, are tiny creatures, typically about 0.5 millimetres across. Individual bryozoans, called zooids, cannot survive independently, but instead grow in colonies on dead corals or the underside of rocks in coral reefs.

They do this by cloning.

"A larva released from an existing colony will settle down on a rock and almost instantly start budding. It does this by a process of cloning, repeating itself over and over. Then some of the cloned zooids will bud into more clones, and so on," Phil explains.

"Each colony is made up of thousands or even millions of these zooids," he says.

Colony members are genetically identical and co-operate for the good of the colony as a whole. Different zooids within a colony will have different tasks, "a bit like an ant colony," says Phil. The key players are the autozooids, which are responsible for feeding the colony, but various types of specialist heterozooids are responsible for defence, cleaning, breeding and structure.

Phil describes the structure of each zooid as "a kind of box with organs in it" – an exoskeleton and body wall protecting the gut, nervous system and feeding apparatus such as the mouth and tentacles, or in heterozoids, specialised organs such as the reproductive system.

In addition to asexual reproduction through cloning, bryozoans reproduce sexually, with cross-fertilisation occurring between colonies.
 

"Some species have separate male zooids and female zooids, but in many colonies, each reproductive zooid has both male and female organs. Colonies release sperm into the water, which floats to other colonies to fertilise the eggs held in the brood chamber of reproductive zooids there," Phil explains.

"Fertilised eggs are released into the water, and each one tries to float to a new place to settle down, begin budding, and begin a new colony," he says.

Although little is known yet about the life spans of zooids, it does seem that each dies after fulfilling its task.

"It can do some feeding or do some breeding, and then it dies back, leaving behind a little dark spot in the colony. But then, another zooid can bud again – so the same hole is occupied by a new set of tentacles, but it is all the same clone," Phil says.

"This cycle of death and rebirth can be as short as a few weeks. Some colonies die back after only a few months," he says.

"There are others, though, that, as far as we know, live for tens of years on the undersides of great shelves of coral. Parts of the earlier forms of zooids will die, be broken off or wash away, while the colony is still growing at the edges. A colony that lives for a decade may have completely renewed itself hundreds of times over – they appear to have an almost infinite life."

Scanning electron micrograph of part of a bryozoan colony showing male and female brooding zooids and feeding autozooids.

Scanning electron micrograph of part of a bryozoan colony showing male and female brooding zooids and feeding autozooids. Image: Phil Bock.

Back to top

 

Next of kin unknown
3 September 2010

 

If you've ever puzzled over your own family's genealogy, spare a thought for the task of Dr Maria Capa of the Australian Museum, who is one of a small team of scientists working to understand the evolution of polychaetes, a group of segmented, invertebrate marine worms.

Dr Capa is focusing on several families of polychaetes, including the sabellids, sabellariids and oweniids. She uses morphology (the study of shape, form and colour) and molecular biology, including DNA analyses, to better understand the specimens she finds.

Polychaetes are a very old lineage that diversified very rapidly during the Ordovician period. The group is now highly diverse, with more than 13,000 polychaete species currently described worldwide, and with polychaetes found in all marine realms. This rapid diversification, however, has caused its own problems for taxonomists in trying to figure out the evolutionary relationships among these species. For example, polychaetes belong to the only phylum of animals for which its closest relative is not known, and there is still considerable uncertainty within the phylum how to classify the many forms.
 

 "We understand, more or less, each family tree. What we don't understand is the relationships between the families," Dr Capa explains.

Until recently, many polychaete groups were thought to be related because their morphological features shared some resemblance, but DNA analyses have shown that this is not necessarily the case.

Advancements in DNA technology over the last decade have also made identifying new species easier, especially in those cases where there are few morphological differences.

 

Dr Capa has found at least five new species during the CReefs project. She will study the morphology of these specimens, compare them to existing species, and define where they are found geographically, before each is described as a new species.

A polychaete of the family Sabellidae.

A polychaete of the family Sabellidae. Image: Gary Cranitch.

Back to top

 

Always twirling, twirling, twirling towards freedom
3 September  2010

 

The parasites studied by Dr Rob Adlard can cause changes in fish behaviour – and have impacts in commercial aquaculture.

Dr Adlard, of the Queensland Museum, is an expert in myxozoan parasites of the genus Kudoa.

"We are starting to get an idea of the patterns of the diversity of these parasites: which fish have which parasites and what proportion of each population is infected," Dr Adlard explains.

"We're finding that some species of parasites are commonly found in a particular species of host fish. If we catch trevally, for example, we would expect a certain proportion of these fish to host Kudoa quadricornis. Some of the fish populations on the Great Barrier Reef have surprisingly high prevalences of these parasites," he says.

Dr Adlard is targeting certain species of fish in the waters off Lizard Island. Each fish is dissected and examined for parasites in the brain, muscle, heart, gall bladder, urinary bladder and intestines. The team examines each parasite specimen under a high-powered microscope, and samples are prepared for DNA analyses and histology, which involves staining and examining sections of tissue.

Dr Adlard says that this work for CReefs is concerned with establishing a baseline of the biodiversity of fish parasites and identifying new species, but that he is also interested in the impact of the parasite on the host.

"It can be difficult to monitor the effects of parasites. If a parasite kills a fish on the reef, you won't find a body: detritus is cleaned from the ecosystem very quickly. Largely, though, the parasite won't kill fish directly, but it can lead to pathology or maybe preferential predation on that infected fish," Dr Adlard says.

"The brain parasite Myxobolus cerebralis, for example, causes whirling disease in juvenile salmon; it gets into their cartilage before the bones harden, or ossify," he explains.

The disease causes fish to ‘whirl' in corkscrew pattern instead of swimming normally. It is difficult for infected fish to feed and they are vulnerable to predators. Most juveniles die, releasing the parasite back into the water. Those fish that survive to adulthood suffer from skeletal deformation and neurological damage.

"This is a problem for commercial salmon aquaculture in North America," Dr Adlard says.

The Myxobolus cerebralis is not the only parasite causing problems in commercial fishing and aquaculture.

"Other myxozoans can form obvious white cysts in the flesh of fish, rendering it unmarketable. Some species, such as Kudoa thrysites, have a pretty cute trick of releasing enzymes that break down the muscle in a fish," Dr Adlard says.

Perhaps this is not surprising, given that the word ‘myxozoan', translated from its Greek etymology, means ‘slime animal'.

Kudoa thyrsites has been found in more than 35 different fish species worldwide, including farmed eating fish such as species of hake, salmon, trout, mackerel and anchovies. This post-mortem ‘myoliquefaction' causes the fish flesh to become soft, mushy and pretty unappetising.

Eating the softened flesh does not cause parasitic infections in humans, although some studies are investigating a potential link between Kudoa infection in fish and human seafood allergies.
 

Currently, there is no way for aquaculturists to prevent parasite infection in their fish, or even to determine if fish are infected without killing the fish. Dr Adlard's research, however, may provide a clue to locating the sources of infection or of disrupting the parasitic life cycle to reduce the prevalence of infection in commercial sea-pens.

"Little is known about the life cycles of fish parasites worldwide. If we can better understand this aspect of biology, this information can then be applied to the management of disease in aquaculture. If, for example, we find that a marine worm acts as a host for Kudoa, and that worm is living in the pipes of an aquaculture system, aquaculturists can target that to reduce the infection levels," Dr Adlard says.

Dr Adlard's work will contribute to knowledge of the biodiversity and biogeography of parasites in marine fish, and the understanding of host-parasite relationships.
 


Dr Rob Adlard and his team scuba diving to catch fish.Image: Gary Cranitch.

Back to top

 

Gut feeling
28 August 2010

 

The crustaceans studied by Dr Viatcheslav "Slava" Ivanenko are no more than two millimetres long – and to identify their species, he needs to dissect them.

Approximately half of the 13,000 known species of tiny, semitransparent, one-eyed crustaceans of the subclass Copepoda form symbiotic relationships: they live on or in – and potentially cause harm to – other animals in the oceans.

Dr Ivanenko, of the Moscow State University, hopes the specimens he collects on the CReefs trip to Lizard Island will provide more clues about which species of copepods are found on which animals, and how the copepods interact with their hosts.

He is focusing on copepods that live on hard corals at depths of five to 30 metres (the maximum depth allowed for scuba diving on the CReefs expedition), as hard corals from these habitats have not been well-studied for copepods.

"The diversity of symbiotic copepods in Australia is very high and very little studied," Dr Ivanenko says.

"There are more than 300 species of hard corals around Lizard Island, and during this trip I aim to inspect at least 100 colonies of as many species as possible. I have found that almost every colony of coral has at least one host-specific species of copepod, usually more. Sometimes I find up to 1000 individuals of up to five species of copepods on one little piece of coral," he says.

 

Dr Slava Ivanenko photographing copepods' coral habitats.

Dr Slava Ivanenko photographing copepods' coral habitats. Image: Gary Cranitch.

An example, says Dr Ivanenko, is the family Xarifidae. Xarifid copepods live in large numbers on different scleractinian corals, also called stony corals, which are like sea anemones but which build hard skeletons.

"I have noticed a lot of specimens of this family around Lizard Island as well as on Ningaloo Reef. They are highly-modified, caterpillar-like animals that have quite strange relationships with their hosts. They live inside coral polyps, and somehow alter the shape of the polyps. It is not clear whether they eat the tissues of the polyp, or just use it as a house, or both," Dr Ivanenko explains.

The problem, he says, is that the copepods are too small to observe interacting with their hosts underwater with the naked eye.

"Crustacean copepods are very small animals, so it's not so easy to see directly how they feed or do damage to their hosts; however, observing the structure and shape of the feeding apparatus in the laboratory can tell us a lot about the ways they may be feeding. Sometimes we can look at the contents of the gut – but this is not always possible, because sometimes even the adult copepods are only one-fifth of a millimetre in diameter and the food of these creatures often has no visually distinguishable features," he explains.

A copepod of the family Xarifidae.

A copepod of the family Xarifidae. Image: Slava Ivanenko.

 


Dr Ivanenko uses very sharp, fine needles to dissect the animals under a microscope to examine, for example, the contents of their digestive systems, or the details of their legs, which can help to identify the species to which they belong. To put this into perspective: if you're reading this blog in about 10-point font, some copepods are smaller than a full stop.

Dr Ivanenko will also analyse the genetic material from copepods and their hosts.

He is one of very few marine biologists to focus on symbiotic copepod biodiversity, especially in the deeper areas of the oceans. His work has discovered copepods living near hydrothermal vents and cold seeps, and in other less known chemosynthetic environments on the ocean floor, such as wood-falls.

Copepods are thought to be among the most ecologically important animals in the world, as they make up a large part of the biomass of the oceans, and so contribute significantly to the oceans' status as the world's largest carbon sink. It is estimated that the oceans absorb approximately two billion tons of carbon each year.

 

Back to top

 

 
New order
27 August 2010

 

Takuma Fujii, of Japan's University of the Ryukyus, believes he may have discovered a new order of marine life, and is searching for specimens during the CReefs expedition to Lizard Island.

Takuma is focusing on zoanthids,

an order of colonial animals related to hexacorals, such as stony corals, also called scleractinia, and sea anemones.

Individual zoanthids polyps look like small buttons, and feature two rows of weak tentacles. The polyps form colonies, which appear as a mat on the ocean floor or on other reef structures in deep sea environments and fringe habitats, such as intertidal, back reef and other shallow areas over dead corals.

Zoanthids do not grow skeletons, but some incorporate small pieces of sediment, sand and rock into their tissue, although there are some species that do not incorporate sand at all.

Zoanthids

gain energy through a combination of photosynthesis through creating symbiotic relationships with algae and feeding on plankton.

Takuma is particularly looking for one tiny, undescribed species of zoanthid. Just two millimetres across, it is found in very hard to reach habitats, such as under stones and inside small cracks in rocks and corals.

"This undescribed species is very, very different from all the known zoanthids species. It may be not just a new species or genus, but a new order," Takuma says.

Takuma Fujii diving for zoanthids

Takuma Fujii diving for zoanthids. Image: Gary Cranitch.

"I think it is very important for the discussion of evolution of hexacorals and zoanthids," he says.

Takuma has found the undescribed zoanthid in the waters around Okinawa in Japan, and has found several specimens of what seems to be the same zoanthid here at Lizard Island.

"They look the same, but zoanthids do not have hard tissues such as skeletons of sclerites, so it's difficult to observe morphological characters – so I won't know for sure until DNA analyses have been done," he says.

Takuma is collecting specimens and establishing the diversity and abundance of zoanthids found around Lizard Island, along with his supervisor, Associate Professor James Reimer, who has participated in several CReefs expeditions.

 

Back to top

 

Clams and snails and DNA tales
27 August 2010

 

Clams and snails are some of what Dr Abigail Fusaro's scientific samples are made of on this CReefs field trip.

Dr Fusaro, staff scientist with the Ocean Genome Legacy in Massachusetts, United States, is an expert in the genetic identification of marine species.

Working with all the researchers on the CReefs expedition, Dr Fusaro

takes tissue samples of much of what is collected. Back at the Ocean Genome Legacy, researchers break open the cells and extract the DNA. Part of this DNA is stored for perpetuity; part of it is made available for researchers to request for their own research projects; a small fraction is sequenced for DNA barcoding; and the sequences are made available through the public online Barcode of Life Database.

 

Takuma Fujii diving for zoanthids

Shipworms collected by Dr Abigail Fusaro. Image: Gary Cranitch.

In addition to sampling other researchers' specimens, Dr Fusaro has been snorkelling at various sites around Lizard Island to gather her own. She is largely targeting snails, also known as gastropods.

The CReefs Australia project deliberately focuses on groups that are not yet well understood by science. Dr Fusaro is the only researcher collecting snails on this field trip.

"Shells tend to be pretty and catch your eye, just like fishes and corals – and so, like fishes and corals, many aspects of snails have been well studied already," Dr Fusaro says.

"However, while the morphology, identification and distribution of these groups are well known, this is the first time we have taken material from this region for DNA sequencing and archiving.

"It is important that we include genetic data from a diverse

range of species at all three coral reefs targeted for study by the CReefs Australia project," she explains.

Dr Fusaro is also collecting specimens of shipworms, which are modified clams that burrow into driftwood and host symbiotic bacteria in their gills. The clams are of particular interest to a research group at the Ocean Genome Legacy.

Between her own specimens and the hundreds of samples she has taken from specimens collected by other researchers, Dr Fusaro estimates that this field trip will supply DNA material from at least 50 species new to the Ocean Genome Resource collection, and there will likely be many more.

Dr Fusaro's work on the CReefs project contributes to the international scientific community's understanding of the genetic make-up of marine biodiversity, and ensures that scientists who don't have the opportunity to participate in field research due to a lack of funding, time or resources can still gain access to the materials they need to conduct important research into marine life.

 

Back to top


 

The cycle of life
27 August 2010

 

Advances in DNA sequencing technology could help parasitologist Professor Ian Beveridge learn more about the life cycles of marine tapeworms and roundworms as they develop from larvae to adults and pass through a series of hosts.

"If we catch a coral trout and open up its abdominal cavity, we're likely to find big black cysts containing tapeworm larvae. We might then find the adult stage of the same species in a shark or a ray. This tells us a lot about the patterns of tapeworm life cycles," Professor Beveridge says.

On this CReefs trip, Professor Beveridge, of the University of Melbourne, is focusing on trypanorhynch cestodes, an order of tapeworms with adult stages found mostly in sharks and rays.

 


Professor Ian Beveridge (far right) with the parasites team at the Lizard Island Research Station.

Professor Ian Beveridge (far right) with the parasites team at the Lizard Island Research Station. Image: Gary Cranitch.

He will also collect the larval stages of anasakid nematodes for his work with a team of scientists awarded an Australian Biological Resources Study grant to study this particular group of roundworms.

His interest is in establishing a baseline for biodiversity, identifying new species, and learning more about the life cycles of these groups.

Back at this own laboratory after the field trip, Professor Beveridge will prepare the specimens of tapeworms and roundworms he has collected here. He stains the cestodes to highlight different types of anatomical structures; dehydrates and mounts them on slides on resin; and then views the slides under a compound microscope. Nematodes can be cleared in a fluid called lactophenol for examination under a compound microscope.

"The adult tapeworms are difficult to identify to species level. Each has four long tentacles, extending from the front of the body, covered in hooks that grab onto a shark's intestine. All the identification is based on the shape, size and distribution patterns of these hooks," Professor Beveridge explains.

It is complicated and time-intensive work – but recent advances in DNA technology have allowed parasitologists to combine histology with analyses of parasites' genetic material, which is making species identification a little easier.

"One of the major obstacles, up until now, has been that the nematode larvae are almost featureless. We could identify which genus they were from, but not which species. Now, however, members of the ABRS team have developed molecular techniques for identifying the larvae," Professor Beveridge explains.

To barcode the DNA, researchers break open the cells and extract the genetic material, focusing on a nucleotide sequence of about 650 letters in the chain of DNA. To identify cestodes, researchers look specifically for a subunit of the mitochondrial DNA called cytochrome oxidase 1 (COI). For many marine organisms, COI is found in a predictable spot and is unique to the species – essentially a quick molecular ID or fingerprint of a species.

For the nematodes, the COI sequence isn't unique between species, and researchers must look at the spaces between genes, particularly the internal transcribed spacer 2 (ITS2), to differentiate one species from another.

"The DNA sequences of adult parasites found in larger hosts have been barcoded, and now the larvae can be barcoded as well. This allows us to match the DNA sequences of the larvae with those of the adults, so we can be sure which larvae species we have found in which host," Professor Beveridge says.

"This tells us a lot about the life cycles. We think nematode eggs, for example, float in the ocean and are eaten by tiny crustaceans called copepods. A copepod may then be eaten by a small fish, and the worms develop in the mesentery, in the abdominal cavity. This fish may be eaten by a bird, such as a noddy, a tern, a cormorant or a penguin, or by a bigger fish, a shark, a dolphin or a seal. The worms work their way up the food chain, develop into adults in the guts of these larger animals, and then lay their eggs out to sea to complete the cycle."

 

Back to top

 

Invading forces
26 August 2010

 

Species of tropical macroalgae can become invasive pests in temperate climates, says University of Adelaide PhD student Gareth Belton.

Caulerpa taxifolia, a green alga native to tropical waters of the Indo-Pacific, has become established in the warm calm waters of Port Adelaide in South Australia, and in many other regions on earth, including the Mediterranean and California. Eradication efforts have been unsuccessful in most instances, including in Port Adelaide, and Caulerpa taxifolia is now one of the top 100 invasive species in the world.

Macroalgae of the genus Caulerpa.

Macroalgae of the genus Caulerpa. Image: Gary Cranitch.

Gareth is collecting specimens of algae of the Caulerpa genus during the CReefs field expedition to Lizard Island.

"Of the 90 or so Caulerpa species worldwide, the majority occur in the tropics, but in Australia the reverse is true. Caulerpa is remarkably diverse in temperate Australia, with 19 species known, compared to the 14 or so known from tropical Australia," Gareth says.

Furthermore, of the 19 Caulerpa species known from southern Australia, 11 are endemic, native to the area.

"We have a unique pattern of diversity here in Australia. During my project I willundertake an extensive taxonomic survey of the Caulerpa genus in Australia, to better understand the relationship between the southern Australian endemics and tropical species," Gareth says.

This has been difficult in the past as many Caulerpa species are highly "plastic" in their morphology: individuals of the same species can look very different. Because of this, species boundaries and relationships within Caulerpa are uncertain. The advent of DNA sequencing and phylogeny (the study of evolutionary relatedness among various groups of organisms) over the past 20 years has revolutionised taxonomy and is now a reliable and widely-used technique to investigate phylogenetic relationships. Gareth will use these DNA sequencing and phylogenetic methods, as well as traditional morphological methods (the study of the shapes, structure and anatomy), in his PhD project.

Gareth is working with his supervisor Dr Carlos Frederico "Fred" Gurgel, who has been awarded a significant Australian Research Council grant to study the Caulerpa genus. They will compile a DNA barcode database of the approximately 35 Caulerpa species found in Australia plus species from other countries so that any new introductions can be identified promptly and before populations become invasive.

Samples of the algae Gareth collects on the CReefs Ningaloo expedition will also be pressed for herbarium collections, deposited and curated at the State Herbarium of South Australia, and samples will be taken for DNA analysis to better understand the genetic diversity and evolution of marine macroalgae.

Back to top

 

Cryptic chrysopetalids  
26 August  2010

 

 
Identification of cryptic species – species that look very similar but are genetically distinct – is becoming more common as biodiversity studies, such as the CReefs Australia project, investigate previously under-studied areas, and as relatively fast and inexpensive DNA sequencing technology becomes readily accessible to scientists.

As a result, estimates of the number of species living in the world's oceans may be revised dramatically – meaning that there may even be more yet to be discovered than we had thought.

Studying cryptic species with pan-tropical distributions helps scientists better understand how and when polychaetes spread throughout the world's oceans.

 

A polychaete of a new species of the genus Treptopale.

A polychaete of a new species of the genus Treptopale. Image: Charlotte Watson.

 

The cryptic species studied by Charlotte Watson of the Museum and Art Gallery of the Northern Territory provide an interesting example. Charlotte's focus is on the tiny, segmented, invertebrate marine worms, or polychaetes, of the family Chrysopetalidae. While on CReefs trips to Heron & Lizard Islands and Ningaloo, she has found specimens belonging to a cryptic species complex of the genus Treptopale. After morphological and preliminary DNA analysis, she is in the process of describing two new species.On the east coast of Australia, from Heron Island to New Guinea, Treptopale new species 1 is found in large numbers, while new species 2 is found in the same areas but in very small numbers. Around the north coast of Australia the opposite is true, while in Western Australia both species coexist in moderately similar numbers. An interesting pattern of these same two Treptopale species is also found across the Indo-Pacific from the Seychelles to Hawaii.

The species look almost exactly alike: the difference between the two comes down to the shape of a single hair on the side of their bodies and the degree of ornamentation on the fan of bristly hairs on their backs (and this is on an animal less than a centimetre long).

Polychaetes have a long fossil record. Chrysopetalid-like fossils are recorded in the Burgess Shales from 600 million years ago. As the majority of chrysopetalid genera have pan-tropical distributions, Charlotte believes that chrysopetalids, including Treptopale, have been around for a very long time.

"The question is around the timing of the split between the two Treptopale species – is what we are seeing evidence of a very old pattern or of a comparatively recent event? There is a possibility that Treptopale new species 1, found on the east coast, is the ancestral species, and that the new species 2 has evolved from it quite recently," Charlotte explains.

"The Indo-Pacific through flow between the Torres Straits halted during the last ice age with a dramatic drop in sea levels around 18,000 years ago. The ancestral populations of Treptopale species 1 would have been cut in half and isolated, with perhaps a second species evolving in the turbid, silty environments of northern and western Australia and western Indonesia," she says.

Charlotte has found another single specimen of Treptopale new species 2 on Day Reef near Lizard Island on this expedition, and is hoping that DNA analyses will tell her more about the evolution and speciation of the Treptopale.

 

Back to top

 

Slip another shrimp under the camera lucida
26 August 2010

 

"I think it was just in me when I was born," says Dr Ivan Marin of his passion for the tiny Palaemonidae shrimp he is studying on the CReefs Australia field trip to Lizard Island.

Dr Marin is focusing on Pontoniinae, a subfamily of the Palaemonidae family of shrimp.

Most pontoniines inhabit coral reefs, where they form symbiotic relationships with marine invertebrates such as corals, sponges, anemones, sea stars and molluscs.

Pontoniines are often very brightly coloured or transparent with vivid spots, banding or mottling.

 

A shrimp of the family Palamonidae, Exocliminella maldivensis, collected by Dr Marin's colleague, Dr Zdeněk Ďuriš.

A shrimp of the family Palamonidae, Exocliminella maldivensis, collected by
Dr Marin's colleague, Dr Zdeněk Ďuriš. Image: Gary Cranitch.

"They are very beautiful, diverse and have very interesting biology – and they are tropical, so I get to spend time on coral reefs," Dr Marin says.

Dr Marin is scuba diving and snorkelling to collect pontoniines during the CReefs trip, using several collection techniques. Underwater on the reefs, he shakes the tentacles of soft corals and anemones into sample bags, hoping to dislodge any pontoniines living inside. He also collects rubble and pieces of hard corals that are likely to house pontoniines.

Back in the lab at Lizard Island Research Station, he takes photographs of every specimen he finds. These will allow him to describe colouration. He then fixes the specimens in alcohol.

He examines each specimen using a microscope with camera lucida: a device that superimposes the image of the shrimp onto a piece of drawing paper, so he can see both the shrimp and his drawing simultaneously. This allows him to trace the outlines of the shrimp's body and to more easily make accurate drawings of its morphology – that is, its shape, form and details of its limbs, mouth appendages and other body structures.

Samples of DNA from each specimen will be analysed to assist with identifying species.

When Dr Marin, a scientific researcher at the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, returns to his own institution, he will compare the specimens he has found around Lizard Island to previously described species from other reefs throughout the Indo-Pacific area to see if he has found anything new in Australia.

"Most of the specimens we've found are still undescribed. At this stage, we are studying biodiversity just to add to the general knowledge about coral reefs," Dr Marin explains.

He hopes, however, that eventually this knowledge will contribute to the conservation of coral reefs.

"This is a kind of fundamental research. We are just gathering information, and then, in the future, we will get an ecological result from that," he says.

 

Back to top

 

Past, present and future
25 August 2010

 

CReefs is just one of 17 projects worldwide that tie into the Census of Marine Life, a comprehensive survey of the diversity, distribution and abundance of marine life in the oceans; past, present and future.

While the CReefs Australia research is largely based around field expeditions and laboratory work to collect and describe new and existing species of marine life, other Census projects take quite different approaches.

A project on the history of marine animal populations documented bluefin tuna abundance in the early 1900s by scouring fishery reports, fishing magazines and other records.

Another project, focused on the future of marine animal population, is using predictive models to forecast scenarios of potential change that humanity and nature will cause to the oceans over time. 

Such models can be updated to include the most up-to-date information on current biodiversity, such as the data from the CReefs Australia program.

In this way, research from a project like CReefs Australia can be used to inform sustainable oceans policy, conservation and management.

CReefs Australia team leader and Principal Research Scientist with the Australian Institute of Marine Science Dr Julian Caley explains.

"Management effectiveness will in the end be judged by how well it can sustain biodiversity in the face of competing interests, such as fisheries, other marine-based industries, human coastal development and transport," Dr Caley says.

"Conservation and management in any environment faces similar challenges, but the oceans can present, an even greater challenge. If you are trying to manage a forest, you can your resource – the trees; when you're talking about the oceans, and trying to manage the fish you can't see them and because the oceans seem unbelievably vast and never-ending, it's really easy for people to think, for example, that we can never fish out the oceans – but this is certainly not the case."

"A crucial component of effective management is having an appropriate baseline against which you can measure management success – and that is why CReefs Australia is so significant," he says.

The Census of Coral Reef Ecosystems, of which CReefs is one part, is a key field project of the Census of Marine Life because of the incredible biodiversity of coral reefs worldwide.

The marine environments off the coast of Australia are among the most biodiverse in the world. With 33,000 marine species described from these waters alone, Australia accounts for almost 15 per cent of the named worldwide ocean biodiversity.

There are currently around 230,000 named marine species, but less than five per cent of the underwater world has been explored, and many species that have been discovered await description and naming.

Coral reefs themselves account for only two per cent of the area of the global oceans, but they are home to a high proportion of the diversity of marine plant and animal life. Estimates of the total number of species living in coral reefs are very uncertain ranging from less than one million species, up to perhaps nine million.

 

Back to top

 

Hidden diversity
25 August 2010

 

 

In a pristine coral reef environment, 50 per cent of the biodiversity is parasites, according to Dr Rob Adlard, Head of Marine Zoology and Senior Curator of Parasitology at the Biodiversity Program of the Queensland Museum.

Dr Adlard is one of a team of scientists studying parasites in fish on the CReefs expedition to Lizard Island this month.

The CReefs Australia project has already discovered 1150 species of marine life thought to be new to science, with many more expected to be discovered – so if Dr Adlard's estimate holds true, there is potential for hundreds, if not thousands, of new parasite species to be found.

"If you stick your head underwater here, the first thing you're hit with is the diversity of fishes, corals and invertebrates. What we find fascinating is that within that diversity, there is another, hidden diversity of parasites," Dr Adlard says.

"Much more attention is paid to obvious, large vertebrates. People get excited, for example, about populations of whales, but are much less interested in the worms in their guts – but parasite diversity is as important as any other diversity," he says.

Every fish hosts a parasite of some kind; some have five or 10 different species. Dr Adlard likens an infected fish to a space station, with all manner of internal and external parasites docking, taking off, and releasing satellites in the form of spores.

Dr Rob Adlard and the parasites team scuba diving.

Dr Rob Adlard and the parasites team scuba diving. Image: Gary Cranitch.


In fact, Queensland Museum research suggests that the diversity of myxozoans may exceed the diversity of their fish hosts. The research predicts, for example, that within in one genus, Ceratomyxa, there may be one species of parasite for every species of fish – or more than 1500 species of Ceratomyxa on the Great Barrier Reef alone.

Dr Adlard is focusing on microscopic parasites of the group Myxozoa, which can be found in various tissues, including the gall bladder, brain, muscle and heart of fish. His particular interest is in myxozoans of the genus Kudoa.

"We are finding kudoids in muscle, brain and heart tissues of fish, and we're finding other myxozoans in gall bladders and urinary bladders," Dr Adlard says.

Dr Adlard's work will contribute to the overall knowledge of parasitic taxa, host-parasite relationships and their ecological interactions in coral reef ecosystems, and the evolution and biogeography of parasites in marine fish.

 

Back to top

 

Some worms go faster
25 August 2010

 

Sleek, shiny and fast, the opheliids studied by Lynda Avery are the sports cars of the polychaete world.

Polychaetes, a class of segmented marine worms, are among the most common and widespread invertebrates found in the oceans.

There are approximately 100 families of known polychaetes, and more than 10,000 described species. All species have bristles: the name polychaete means "many hairs". Polychaetes range in size from one millimetre to three metres in length, although most are less than 10 centimetres long. They are often brightly coloured, and may be iridescent or even luminescent.
 

A polychaete of the family Eunicidae.

A polychaete of the family Eunicidae. Image: Gary Cranitch.

Body types vary widely between families. Some species of the Opheliidae family have short, stubby grub-like or cigar-shaped bodies, while others are slender, smooth and torpedo-shaped.

"Some are streamlined and can move very quickly," Lynda explains.

Exactly how they are able to move so quickly is still not quite understood. While opheliid bodies have few, indistinct segments, each segment houses a complicated system of muscles. Study of one species, Ophelia bicornis, found a single segment had 59 muscles, each with a different function.

In coral reefs, different polychaetes species can be found burrowing into dead corals, moving freely around coral rubble and algal holdfasts, in tubes anchored to rubble or algae, or swimming amongst the plankton near the surface of deeper waters out from coral reefs.

"The opheliids are in a group of polychaetes that live in the sand bed between coral outcrops, where they dig fast to get away from their many predators," Lynda explains.

Lynda is a polychaete consultant and is associated with the Museum of Victoria. She is one of a number of scientists collecting and identifying polychaete specimens as part of the CReefs Australia project.

Between them, the scientists are targeting 16 families of polychaetes: Terebellidae, Tricobranchidae, Amphinomidae, Owenidae, Chrysopetalidae, Nereididae, Opheliidae, Pectinariidae, Polygordiidae, Polynoidae, Sabellids, Syllidae, Phyllodocidae, Eunicidae, Serpulidae and Eucidae.

The team hopes to establish a baseline for the diversity of the class and describe new genera and species.

 

Back to top

 

The puzzle of classification  
24 August 2010

 

 
Found in oceans around the world, the colonial anemones called zoanthids are relatively common, yet there are very few biologists studying them, so it would seem likely that there are many more to be described. Well, ‘yes and no', says zoanthid expert Associate Professor James Reimer of Japan's University of Ryukyus.

More than 400 species have been described, but a major overhaul of the taxonomy may see many of these classifications changed.

"Two genera, Palythoa and Zoanthus, are commonly found on coral reefs, and each has between 150 and 200 species described – but colour variation is common, so different examples of the same species can look very different," Professor Reimer says.

"I think there are really only 10 or 15 species in each of those genera.

"On the other hand, genuinely new species will be found. Many of the zoanthids living in deeper waters and those living on sponges have not been well studied yet, so there will be more species in those groups.

"Whether the grand total will be more or less – we don't know yet," he says.

Professor Reimer is collecting specimens and establishing the diversity of zoanthids in the waters around Lizard Island during the CReefs field expedition this month. He will compare these with the existing taxonomy of zoanthids found around Australia, in Japan, Singapore and elsewhere.

Complicating the puzzle of classification is the fact that zoanthids often have a large number of different morphotypes of the same or similar species, so it is difficult to classify accurately based solely on their appearance. Zoanthids incorporate sand into their body tissue, making cross sectional analyses of their morphology extremely difficult. Zoanthid behaviour and environment also don't consistently predict species.

Molecular biology, using DNA analyses and phylogenetics, is the most reliable way Professor Reimer has found to classify these marine creatures.
 

For example, says Professor Reimer, "There are groups of zoanthids that live on sponges, others that live on antipatharians, or black coral, others that live on precious coral, and others that live on hydrozoans. It made sense to group each separately – but DNA analysis has shown that, in fact, there are at least three different groups of zoanthids that live on sponges.

"Zoanthids are simple animals: essentially a bag with a hole at the top, some tentacles and a few muscles. Yet even within the four groups that live on sponges, there is significant variation. That's why we use DNA often to identify species," he says.

Professor Reimer is particularly interested in the variation in zoanthids that have formed symbiotic relationships with algae. These zoanthids allow single-celled algae, called zooxanthellae, to live inside them. The zooxanthellae photosynthesise and provide energy for the zoanthids. These zooxanthellae can further complicate classification.

Professor Reimer explains, "There are cases in Japan where one species of zoanthid will have one type of symbiont in the shallow water, but another type in the deep water. So the host is the same but the algae it is harbouring are slightly different.

"I want to compare the zooxanthellate zoanthids I find in Australia to those found elsewhere around the world," he says.

"These are all pieces of the puzzle."

 



A zoanthids of the genus Acrozoanthus.
A zoanthids of the genus Acrozoanthus.  Image: Gary Cranitch.

Back to top

 

Vintage reds  
24 August 2010

 

 
The red algae, or Rhodophyta, is one of the oldest, largest and most diverse group of algae in the world, with around 10,000 species described – but, according to the University of Adelaide's Maria Marklund and Gareth Belton, DNA analyses may uncover many thousands more.

The fossil record of red algae dates back 1200 million years. A fossil of the red alga Bangiomorpha pubescens, from Mesoproterozoic-era arctic Canada, strongly resembles the modern red alga genus Bangia.

But, while red algae have been well-studied and their distribution and evolution are reasonably well understood, advances in DNA sequencing technology have enabled relatively fast and inexpensive analyses of the algae's genetic material.

 



A specimen of alga.

A specimen of red alga. Image: Gary Cranitch.

"A lot of work has been done on the morphology of red algae species, but less work has been devoted to conducting DNA analyses," Maria explains.

"Better understanding of the genetics will be very important because there are a lot of hidden species in the red algae, called cryptic species: they look very similar but might be genetically distinct species," she says.

Algae are diverse groups of plant-like organisms, ranging from microscopic forms, such as phytoplankton, to 30 metre-long seaweeds such as the giant kelps found in southern Australia and Tasmania.

They play various roles in the marine environment, producing oxygen for the environment, fixing carbon dioxide and filtering the oceans, as well as providing habitat and food for fish and invertebrates.

Red algae, in particular, help to build coral reefs. Some red algae, the corraline algae, are like some corals in that they can include calcium carbonate in their cell walls. This makes the algae hard and tough. Other red algae grow in a thin mat over rocks and other hard structures. These forms of red algae bind coral skeletons to strengthen reefs against wave-action and erosion. Fleshy red algae are also common on coral reefs.

Red algae are red because they contain the pigment phycoerythrin, which reflects red light and absorbs blue light. Because blue light penetrates water to a greater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize at greater depths than many other algae.

Maria is using morphology (the study of the shapes, structure and anatomy) and molecular biology (DNA analyses) to ensure the taxonomy of the established species of red algae is accurate and comprehensive, and to describe new species as they are found.

Maria's work will assist the University of Adelaide's Dr Carlos Frederico "Fred" Gurgel, who in collaboration with Murdoch University's Dr John Huisman and Melbourne University's Gerry Kraft, is working on a book of the red algal flora of the Great Barrier Reef that will be published by the Commonwealth Scientific and Industrial Research Organisation and the Australian Biological Resources Study as part of the Algae of Australia series.

 

Back to top

 

Bugging out
24 August 2010

 

If you go snorkelling around Lizard Island, you're not likely to even notice the tiny crustaceans, called copepods, of the family Tegastidae – but they may be posing a danger to the coral reefs.

These tiny, one-eyed crustaceans, about half a millimetre wide, are difficult to see with the naked eye. First described on hard corals in the 1980s, these copepods were "rediscovered" about 10 years ago by coral aquaculturists. Different species of these bugs have very different coloration – white, black or yellow, spotted, striped or transparent – but the species found most commonly in aquaculture is yellow in colour but with a reflective red sheen. Accordingly, coral aquaculturists dubbed them "red bugs" or "red acro bugs", because the family is usually found on corals of the genus Acropora.

In home aquariums, the red bugs form a parasitic relationship with the coral, living on it, feeding on it and causing it harm. Aquaculturists have noted loss of pigment in corals, so colourful corals become bleached or brown; reduced polyp extension; tissue loss; slowed growth rates; and, in extreme cases, death of the host coral.

A copepod of the family Tegastidae.
A copepod of the family Tegastidae. Image: Slava Ivanenko.

 


While the effects of the red bugs on corals in the oceans has not yet been well-documented, Dr Viatcheslav "Slava" Ivanenko, of the Moscow State University, has found several specimens of this family on samples of coral collected from the reefs around Lizard Island during the CReefs field expedition.

"In aquaculture, the crustacean copepods known as "red bugs" are using corals as a food source and as a habitat. If they cause stress to the coral, it becomes weak, its immune system stops working well, it cannot defend itself from the parasites, and as a result they can kill the coral. But we don't know if this is happening in the natural environment," Dr Ivanenko explains.

"The corals have stinging cells to protect them from enemies, but the red bugs have – very unusually for copepods – laterally flat bodies and a hard cuticle, like a layer of armour, to help them survive in extreme environments. They are very adaptive, and can be destructive, so they could potentially cause harm to coral reefs.

"It is not typical behaviour for a parasite to hill its host; it's not in the interest of the parasite. Only very few species of parasites are known to do this," he says.

Dr Ivanenko has found high numbers of different species of "red bugs" on hard corals in French Polynesia and the South-Chinese Sea, but only a few corals hosting copepods of the family Tegastidae have been recorded in Australian waters so far. He plans to study the morphology and DNA of the copepods and their hosts to better understand the relationships between the red bugs and the host corals. He says that the life cycle, taxonomic identity and origin of the red bugs damaging hard corals in home aquariums and aquaculture should also be more carefully observed.

 

Back to top

 

Lizard Island - 2010

International and Australian marine scientists are visiting Lizard Island on the Great Barrier Reef for the final far north Queensland field expedition of the CReefs Australia program.

The island is located on the northern Great Barrier Reef, 270 km north of Cairns, Queensland.

 View across coral reefs from Lizard Island.

View across coral reefs from Lizard Island. Image: Gary Cranitch.
This expedition, running from 24 August to 14 September, is the third and final trip to Lizard Island as part of the four-year CReefs Australia project. Previous expeditions took place in April 2008 and February 2009.

The project has recently been recognised for its contribution to marine science by several of the premier science prize programs in Australia.

CReefs Australia joined an impressive shortlist of finalists in the 2010 Australian Museum Eureka Prizes, which reward originality and excellence in scientific research and innovation. CReefs Australia was recognised in the environmental research category.

The project was also lauded by the United Nations Association of Australia's 2010 World Environment Day Awards, which acknowledge innovation and dedication in research to protect, manage or restore the environment. CReefs Australia was named as a finalist for the Department of Sustainability and Environment's Biodiversity Award.

CReefs Australia team leader and Principal Research Scientist with the Australian Institute of Marine Science Dr Julian Caley said that being selected as a finalist in the awards was national recognition of the work being carried out by the team, which contributes to the coral reef component of the Census of Marine Life, a 10-year program involving researchers in more than 80 countries.This trip's participants include more than 30 people on site at different times during the three weeks, including researchers from Australia, Japan, Russia and the United States, support staff, BHP Billiton employees, and a photographer.

The researchers are sampling animal and plant species associated with coral reefs that have not previously been studied in depth, including species of invertebrate marine animals, shrimps, worms, parasites, algae, soft corals and zoanthids.

The expedition is based at the Lizard Island Research Station.

The Research Station is owned and operated by the Australian Museum and is supported by the Lizard Island Reef Research Foundation and the Coral Reef and Marine Science Foundation.

CReefs is the coral reef component of the Census of Marine Life, a 10-year program involving researchers in more than 80 countries. The Census is the first comprehensive survey of the diversity, distribution and abundance of marine life in the oceans in the past, present and future.

The Australian node of the CReefs program is a partnership between BHP Billiton, the Great Barrier Reef Foundation, the Census of Marine Life, and the Australian Institute of Marine Science.

The Australian Institute of Marine Science is leading a consortium of scientists that will sample and analyse coral reef biodiversity over a series of nine expeditions: three trips each to Ningaloo Reef in Western Australia and Lizard and Heron Islands on the Great Barrier Reef.

 

Back to top

 

* Gary Cranitch is a photographer with the Queensland Museum. His 26 year career has seen his images published in Australian Geographic and New Scientist. His work on the CReefs Australia project has been featured in more than 50 print and online publications worldwide. In 2008 Gary was awarded the Canon Australian Institute of Professional Photography Science, Nature and Environment Photographer of the Year.

 

 

Gary Cranitch.

Gary Cranitch. Image: Merrick Ekins.

   

* Melbourne-based Rebecca Leech is an award-winning journalist. She has a BA with honours from Deakin University, and has worked as a writer, editor and public relations professional.

She currently edits the quarterly education magazine Professional Educator for the Australian College of Educators and the Australian Council for Educational Research.

Rebecca has authored a book on scholarship testing for ACER Press, and has won the 2009 Australian College of Educators Victoria Media Award, the

2007 Writer of the Year in the Australian Business and Specialist Publishers' Bell Awards, and the 2006 Best print-media feature in the Australian Council of Deans of Education's journalism awards.


CReefs Australia: A partnership between BHP Billiton, the Great Barrier Reef Foundation,
the Census of Marine Life and the Australian Institute of Marine Science (AIMS).
CReefs Australia is a node of the Census of Coral Reef Ecosystems (CReefs),
a project of the Census of Marine Life.

Web contact: web@aims.gov.au

Copyright (c)2008-2010 Australian Institute of Marine Science
URL http://www.aims.gov.au/creefs