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CReefs - The Australian Node

 Heron Island 2010
 

by Rebecca Leech
Photographer: Gary Cranitch*

 
Vox populi
November 22 2010

 

The CReefs Australia program has been not just been about making new scientific discoveries, but also about building capacity and professional networks.

The program has been committed to promoting collaboration internationally and across taxonomic groups, and to building capacity in marine taxonomy.

As the final field trip comes to a close, several of the scientists who have been involved long-term in the program share their thoughts on its benefits.

"There are very few people working on bryozoans around the world, and I have collected so many samples through the CReefs field trips that there is a need for another person to work on them: and CReefs has helped that to happen." – Phil Bock

The team on the CReefs Heron Island expedition 2010.

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

"Without participating in a program like CReefs, it would have been almost impossible for us to go to Ningaloo Reef, which is remote and doesn't have an established research station. Also, we received an Australian Biological Resources Study/CReefs grant, which allows us to employ scientists and research assistants to sort specimens into families, prepare specimens for microscope analysis, study certain families, and to organise our findings into a database." Dr Pat Hutchings

"Having large and diverse groups of taxonomists, specialising in a variety of animals and algae, working at different sites and collecting over some years gives us the chance to make important comparisons across several geographical areas and over time. There has been a fluent collaboration among experts, both in the field and after surveys, which greatly increases the value of collections and future outcomes." – Dr Maria Capa

"Most of the material in our collections has been preserved for study in the lab; but the CReefs field program allows us to see the animals alive, to see their colours and their habitats, and this tells us a lot about the animals." Professor Magdalena Blazewicz

"CReefs is a great chance for me not only to collect unique material but also to work in what are, for marine biologists, the most interesting sites in Australia. The management and atmosphere of all three expeditions in which I took part were perfect. I am excited to return to the lab to work with the samples I have collected here." – Dr Viatcheslav "Slava" Ivanenko

"CReefs is the template for how sampling should be done. With other fieldwork, if I need to pull up a big rock to get one little sample, the rest becomes bycatch. But here, you have people working on many different animals that are all inside the rock, so anything that you get is valuable to other people, and nothing is wasted." Associate Professor James Reimer

"CReefs is, essentially, allowing me to do my job. The specimens that we've collected on these trips will keep me busy for years. Also, as a junior scientist, I have learnt a lot from observing the more experienced scientists in the field, and I know that the connections I have made through this program will have ongoing benefits throughout my career." – Chad Buxton

"After I finish my PhD, I would like to continue working in parasitology or aquatic diseases. Taxonomy will be a part of any field I go on to specialise in – so in terms of capacity building, CReefs has played a role in helping me to develop skills I will continue to use for the rest of my career." – Holly Heiniger

"Without the CReefs program, we wouldn't have had the capacity to come here and sample as long term as we have. There is still a lot of work to do: many, many lifetimes' worth." – Dr Terrence Miller

"It's a very good thing that CReefs has attracted the money to fund research like this – but there is still more work to be done. The mistake would be to think that having had the CReefs program has in any way meant this research is finished." – Associate Professor Thomas Cribb

 


 
CReefs Australia leaves an important legacy
22 November 2010

 

The CReefs Heron Island 2010 expedition has come to a close, and with it, the field program of the CReefs Australia project.

The project has seen the Australian Institute of Marine Science (AIMS) lead a consortium of scientists to study coral reef biodiversity over a series of nine expeditions in three years: three trips each to Ningaloo Reef in Western Australia and Lizard and Heron Islands on the Great Barrier Reef in Queensland.

CReefs Australia 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.

Although the fieldwork is over, research using the samples collected during the project will continue in museums and universities for many years to come.

AIMS Principal Research Scientist and CReefs Principal Investigator Dr Julian Caley estimates that researchers have discovered more than 1200 new species during the CReefs Australia expeditions. He expects that many more will be described as researchers continue to analyse the material they have collected.

It is likely to take many decades to describe all the new species discovered through the project, Dr Caley says, in part due to the shortage of researchers working in taxonomy – but CReefs Australia, which is generously supported by BHP-Billiton, has leveraged some of its funding through the Australian government and natural history museums in Australia in order to fund career- and capacity-building grants in taxonomy.

Australian Institute of Marine Science employee Greg Coleman retrieving ARMS from Ningaloo Reef in May.

Australian Institute of Marine Science employee Greg Coleman retrieving ARMS from Ningaloo Reef in May. Image: Gary Cranitch.

 

Dr Caley hopes this will go some way towards addressing the backlog of samples that need to be processed, and towards ensuring the future of ongoing taxonomic research.

The ongoing laboratory research will contribute to the legacy 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.

CReefs research will also assist with genetic identification of marine species.

A scientist from the Ocean Genome Legacy has participated in several CReefs field expeditions to take tissue samples of much of what is collected. DNA is extracted from each of these samples. 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.

Eventually, scientists will be able to barcode every sample they collect, giving the international scientific community a much better understanding of marine biodiversity.

Once species are identified, they are catalogued on the Ocean Biogeographic Information System, an online database of marine species.

"This is the first globally-distributed, publicly-available facility that allows members of the scientific community to access data about species locations across the oceans at all depths. Anyone can download that data and use it for their own work. We're pleased that the CReefs project will feed into that," Dr Caley says.

AIMS will also continue to manage a database of all the specimens that have been collected through the CReefs Australia project, regardless of whether the specimens have been classified.

"We have compiled a very rich data source, which will assist scientists to conduct analyses and syntheses across taxonomic groups. We hope to further explore the patterns of biogeography, diversity, abundance, distribution and behaviour of marine organisms," Dr Caley says.

 


 

ARMS to live on after CReefs
22 November 2010

 

While the field program of the CReefs Australia program will finish this month, several important developments to come out of the project are only just beginning.

One legacy of the project will be the Automated Reef Monitoring Structures (ARMS).

Collaboratively designed by the Australian, Pacific and Atlantic nodes of the CReefs project, each of the ARMS is a set of stacked PVC plates that provide habitat for marine life.

The ARMS are designed to mimic the complexity of coral reefs to attract coral reef animals, particularly small invertebrates.

Series of ARMS were installed on the ocean floor at all three of the CReefs Australia sites, left for between one and three years, and then retrieved during field expeditions. Samples from the ARMS were then processed to discover all manner of creatures that had set up home in the structures during that time.

There are three sets of ARMS left at Lizard Island, which will be retrieved in early 2011. There are also approximately 500 ARMS deployed all over the world as part of the CReefs program.

The ARMS are designed to provide a standard method for taxonomic and molecular analysis to measure the biodiversity of organisms that could be applied globally and over time. They should also allow scientists to monitor and predict ecological impacts of global climate change, particularly ocean warming and acidification.

AIMS Principal Research Scientist and CReefs Principal Investigator Dr Julian Caley says that some very interesting discoveries have been made using the ARMS. He hopes that the structures will be increasingly used for marine research. The National Oceanographic and Atmospheric Administration in the United States, for example, has been involved in further developing the ARMS and in deploying the structures at several sites.

While the CReefs Australia project itself is winding down, Dr Caley says that there is still a strong need for extensive research into coral reef biodiversity.

CReefs Australia has been a partnership between BHP Billiton, the Great Barrier Reef Foundation, the Census of Marine Life, and the Australian Institute of Marine Science.

 


 

Frying pans, mullets and squelchers
22 November 2010

 

One of the goals of the CReefs Australia project is to build capacity in the field of taxonomy in Australia – and the next generation of parasitologists are benefitting from this commitment first hand.

Three University of Queensland honours students – Vivian Geow, Nancy Trieu and Jon McDougall – are participating in the CReefs field expedition to Heron Island under the watchful eye of their supervisor, Associate Professor Tom Cribb. They are each aiming to measure the biodiversity of certain groups of parasitic worms in host fishes found on reefs in the area.

Vivian is targeting parasites of the genus Xystretrum of the family Gorgoderidae, found in the urinary bladders of ray-finned fishes of the order Tetraodontiformes, which includes triggerfishes, file fishes and puffer fishes.

Very little work has been done on these parasites: the existing taxonomy has just 11 species described, most recently from the 1970s, so no DNA analysis has ever been done," Vivian explains.

The parasitology team: (L-R) Tom Cribb, Nancy Trieu, Vivian Geow, Holly Heiniger, Jon McDougall, Terrence Miller (in boat).

The parasitology team: (L-R) Tom Cribb, Nancy Trieu, Vivian Geow, Holly Heiniger, Jon McDougall, Terrence Miller (in boat). Image: Gary Cranitch.


 

"So far on this field trip, I have found several fish infected with this parasite. I can identify the parasite to family – the Xystretrum have a distinct, frying pan shape, with a round body and an elongated front end – and when I conduct more sophisticated analyses back in the lab, I hope to be able to tell what species they are and how different they are from each other," she says.

Nancy, meanwhile, is interested in exploring host-specificity and potential species complexes of parasites of the family Bivesiculidae found in the intestines of a range of fishes.

"Parasitic worms are increasingly found to be strictly host-specific: each species of parasite is found only in one species, or in a few closely-related species, of fish. One species of the parasites I'm targeting, however, have been found in mullets and blennies, which do not even belong to the same order of fishes," Nancy explains.

"This leads us to suspect that some of these parasites may in fact be, not one species, but a species complex: a group of very closely-related species in which the differences between species are not yet understood," she says.

She will study the morphology (the study of the shapes, structure and anatomy) and molecular biology (DNA analyses) of the specimens she collects here with the intention of resolving the relationships among the parasites and between the parasites and their hosts.

Jon's area of focus is intestinal flukes from the genus Hexangium in the family Microscaphidiidae, found in the fish families Siganidae and Acanthuridae, commonly known as rabbitfish and surgeonfish.

He will use morphological and molecular analysis to determine whether there is a species complex (multiple species within a host) present in each of the two host families. He is also interested in the parasites' morphological and behavioural characteristics, and how unique characteristics can be used to delineate species.

"Most trematodes have an oral sucker and a ventral sucker, which they use to attach to the host – but the parasites I am targeting have neither. We believe they may be able to use part of their body to create a concave surface that acts as a pseudo-sucker, and attach to the host's intestinal wall that way," Jon explains.

"As well, many of these parasites move in unusual ways: some of them squelch along by some form of peristaltic movement; others will sit and wiggle, but do not move much from one spot, generally due to their ventral sucker anchoring them in place.

"I think the method of movement is quite important in distinguishing between the species, as well as colour, size, shape and the internal structures," he says.

Based on the specimens the students collect this month, they expect to be able to confirm which known species are present at Heron, to discover new species, and to refine the existing taxonomies. They hope to contribute to better understanding of the biogeography, host-parasite relationships and life cycles of the parasites they are studying.

 


 

Curvy in all the right places
22 November 2010

 

Up to 40 new bryozoan species may be recorded just from this one CReefs field trip to Heron Island, according to the Museum of Tropical Queensland Curatorial Fellow Kevin Tilbrook; half of these will probably be described as new to science, while others are new records for Australian waters.

Dr Tilbrook is a taxonomist specialising in bryozoans – tiny invertebrate organisms that create often quite substantial colonies on rocks or dead coral in coral reefs.

"Bryozoans are phenomenally diverse in all marine habitats; they seem to be particularly diverse on coral reefs," Dr Tilbrook says. "And they play a major role."

 

Phil Bock and Kevin Tilbrook search for bryozoans.

Phil Bock and Kevin Tilbrook search for bryozoans. Image: Gary Cranitch.

"Most of them produce calcareous skeletons, which form part of the coral reef framework; some act like nets to trap sediment, accumulate it and become an integral part of the reef matrix. Ecologically, bryozoans are food and hosts for other animals, and they are a substantial part of the biodiversity of the reefs," he explains.

"But historically, because they're small and they sit on the undersides of coral, they've been relatively overlooked. Approximately 125 species of bryozoans have previously been described from Heron Island – but those specimens were collected only from snorkelling and intertidal reef walks. We know that the diversity of bryozoans appears to increase substantially below ocean depths of 10 metres, so my interest on this trip is to SCUBA dive in order to access a whole different suite of the fauna that is potentially in this area," he says.

Dr Tilbrook says that while he does not expect to collect every species of bryozoan living on the reefs, the fieldwork will allow him to make an informed estimate of the total number of species in the area.

The likely total number of species can be calculated using a scientific model known as the collectors' curve. This approach weighs the effort involved, such as the number of specimens picked up or the search time while diving, against the number of new species or records identified from each dive.

"You might go for one dive and find 10 species. On the second dive and you might find 20 species, but 10 of those you had found already, a net gain of 10; and on the third dive you might find 25 species, but 20 of those you found already, a net gain of five. There comes a point where there are diminishing returns from the collecting effort; so for X amount more dives, you would only potentially get two or three more species recorded," Dr Tilbrook explains.

At this point, scientists assume that their collection of species recorded is approaching the true total diversity.

"We plot our collection data to see how it peters out, and extrapolate that to get a good estimate of the total fauna. After this field trip, having sampled for two weeks at depths that have not been studied here for bryozoans previously, we might have reached the plateau of our collectors' curve – and with some confidence estimate that there are in the region of 200 species of bryozoans just for this island," Dr Tilbrook explains.

"And this island isn't necessarily representative of the Great Barrier Reef as a whole, because diversity appears to change latitudinally across its length. So while we've found a substantial number of species here, I don't think it is even close to the total bryozoan fauna off the tropical Queensland coast. The total bryozoan fauna from the Great Barrier Reef is probably in the order of 700 species," he says.

Dr Tilbrook has very recently transferred from the Natural History Museum, London to take up a three-year Curatorial Fellowship at the Museum of Tropical Queensland, in Townsville. The position has been created and funded equally through CReefs Australia and the Queensland Museum Foundation as part of CReefs' commitment to capacity building in the field of taxonomy in Australia.

 


 
Fight club
21 November 2010

 

Competition is fierce on coral reefs, and it's often a fight to survive, according to Museum Victoria honorary associate and bryozoan expert Phil Bock.

Phil is collecting bryozoans – tiny invertebrate animals that grow in colonies on dead corals or the underside of rocks – on the CReefs field trip to Heron Island this month.

"The key resource for any of the animals and the plants which encrust on rocks and coral is space," Phil explains.

"They start in one small spot and then spread. Plants grow; bryozoans spread by budding, a process of cloning in which an individual animal repeats itself over and over, expanding exponentially into a larger colony. Usually, the plant or the bryozoan colony will come up against a neighbour which is also trying to spread," he says.

A bryozoan colony.

A bryozoan colony. Image: Gary Cranitch.


The first rule governing this competition in ecology: the law of competitive exclusion, which states that two species competing for the same resources cannot live together if other factors are constant. Even the slightest advantage of one species will force the other species to adapt or die.

Naturally, then, organisms cultivate various forms of advantage in order to win out over competitors.

"The competitions don't all work the same way. Sometimes if you have three competing organisms, you can have A overgrowing B, and then B overgrows C, and then C overgrows A. The actual reasons why some are more successful than others are often hard to work out," Phil explains.

"Different organisms have different strategies by which they deter or kill off the competing neighbour. Some plants and animals, such as sponges, produce rather nasty chemicals to deter other things from overgrowing.

"Bryozoans gain some advantage because they can grow faster than many plants and other colonial animals. They can also dodge competitors: if they come up against a barrier in one direction, they can produce buds to grow in another part of the colony," he says.

Several groups have evolved a strategy of growing upwards like a bush or a tree into the water. These have to compromise between increasing area for filtering food particles, and reducing the possibility of damage by strong waves or currents.

The specimens Phil collects on CReefs expeditions may enable scientists to further investigate bryozoans' competitive strategies.

 


 

Conservation issues
21 November 2010

 

The work Dr Patricia Hutchings is doing today will contribute to the conservation and protection of marine environments for years to come.

Dr Hutchings, a Senior Principal Research Scientist at the Australian Museum in Sydney, is one of a team of researchers focusing on the segmented, invertebrate marine worms known as polychaetes. Members of the team have collected and analysed polychaetes on each of the CReefs nine expeditions over the past three years.

"One focus of our research is to assess whether there are species that are present at all three of the CReefs sites, or whether some of them have very restricted distributions, and to compare this information to other records we've got for polychaetes in areas between Ningaloo Reef and Heron Island, around the north coast," Dr Hutchings explains.

On this trip, Dr Hutchings and her colleague Dr Maria Capa are particularly interested in collecting from habitat types at Heron Island that they were unable to sample on previous trips; looking at the differences in habitats between the three CReefs sites; and building on the existing collection of specimens suitable for DNA analysis.

Dr Hutchings says the work of the polychaete research team will be used in the management and conservation of marine areas.

Coastal waters, she explains, fall into broad ecoregions: large areas each containing a geographically distinct assemblage of species, natural communities and environmental conditions.

Each ecoregion, however, can be further divided into a series of bioregions, which reflect an understanding of which areas are richest in biodiversity and need to be conserved.

The Great Barrier Reef comprises approximately 70 bioregions.

"Australian waters, from the tropics down to the sub-Antarctic, span a vast range of unique habitats. We need to protect a component of each of these of habitats," Dr Hutchings explains.

"Various proxies are used to map the bioregions, such as sediment, depth, presence of seagrass beds or mangroves, and the abundance of fish – but it's also very important to consider the data on polychaetes as a surrogate for the biodiversity of other invertebrate animals," she says.

"This will allow us to make much more robust models of bioregions, and ultimately better decisions about environmental management and conservation," she says.

Dr Hutchings' work on the CReefs expedition to Heron Island is funded by an Australian Biological Resources Study/CReefs grant.

 

Polychaete of the family Sabellidae.

Polychaete of the family Sabellidae. Image: Gary Cranitch.


 

It's time to learn more about tanaids
20 November 2010

 

Tanaids, very small crustaceans of the order Tanaidacea – are found all over the world, from the tropics to the polar regions.

But the close to 1200 species already described are just the tip of the iceberg, according to tanaid expert Professor Magdalena Blazewicz, of the University of Lodz, Poland.

"Before the Census of Marine Life started, we knew something like 800 species," Magda explains.

"Now, more than 1100 species have been classified, and we have another 700 species that are recognised but not yet described.

"In the last 10 years, during the Census of Marine Life, we have almost doubled the number of species that are known in the world," Magda says.

Magda's work on the CReefs trip to Heron Island is part of the first extensive study of tanaids in coral reef habitats.

"Very little research has been dedicated to Tanaidacea so far," she says.

"The high level of taxonomical novelty makes identification of tanaids to species difficult; a problem aggravated by their small size, sibling species, sexual dimorphism or polymorphism, and few and often reduced species-specific morphological taxonomic characters. Thus, Tanaidacea are one of the most reluctantly studied groups and have often been neglected in ecological studies," she explains.

Of the described species, only 40 or so are from coral reefs, because tanaids have been poorly studied on reefs until now. Magda estimates, however, that a further 50 new species will be described from recent samples collected on the Great Barrier Reef.

Based on these samples, Magda aims to establish a baseline for the diversity of the group, describe new genera and species, and investigate the distribution and habitat specificity of tanaids.

"Tanaids appear almost everywhere: in shallow water and in the deep sea; in marine water and estuarine; near hydrothermal vents and cold seeps; in the Antarctic, in tropical waters and also in corals," Magda explains.

"One genus has been described from cold seeps in the Gulf of Mexico and off the coast of Portugal – and recently the same genus has been found in Angola Bay. This suggests that Angola Bay may serve as the same type of habitat; and from the presence of this genus of tanaid, we can predict that cold seeps are there," she says.

That the same genus was found on different sides of the Atlantic Ocean also tells science about the evolution of tanaids.

"These animals cannot swim and they don't have planktonic larvae, so they cannot be distributed by currents; so it means that they had to have already evolved when the Atlantic started to spread out, more than 100 million years ago," she says.

Magda's study of tanaids collected from Heron Island will contribute to better understanding of coral reef habitats and biogeography.

"Australia has high diversity and has had a long isolation since the break-up of the Gondwana landmass, although elements of Indo-West Pacific fauna do occur. For these reasons, global surveys of biodiversity cannot be completed without examination of the Australian fauna," she says.

 


 

New branches on the zoanthid family tree
19 November 2010

 

New specimens discovered on the CReefs expedition to Heron Island may a result in a major overhaul of the taxonomy of several groups of marine animals, according to Associate Professor James Reimer, of Japan's University of the Ryukyus.

Professor Reimer is studying zoanthids, an order of colonial animals that are found in oceans around the world. He and several of his graduate students have discovered a tiny, undescribed species of zoanthid in the waters around Okinawa in Japan, and have found several specimens of the same species both at Ningaloo Reef in Western Australia and here at Heron Island.

The discovery of this and several other unusual groups of zoanthids may see the classification of the order revised dramatically.

"The existing family tree assumes zoanthids are a neat group, clearly divided from related orders such as anemones – but a few groups of zoanthids have been found recently that are really very different from what we already knew. They are part of the tree, but they fit on branches quite far out either side of the main group," Professor Reimer explains.
 

"DNA sequencing of these specimens suggests that the order is much more genetically diverse than we thought. The general idea of zoanthids is correct, but our understanding of the scope that they encompass is definitely going to change," he says.

"At the same time, scientists are also finding anemones that have somewhat similar behaviour to zoanthids, so we may also find that these two groups are much closer than we imagined," he says.

Professor Reimer is collecting specimens and establishing the diversity of zoanthids in the waters around Heron 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.

He is also collecting specimens of small crustaceans of the order Amphipoda for study by one of the post-doctoral researchers in his laboratory in Japan.

Associate Professor James Reimer looking for zoanthids.

Associate Professor James Reimer looking for zoanthids.
Image: Gary Cranitch.


 

Learning in the Field
19 November 2010

 

A key purpose of the CReefs field program is to contribute to the taxonomic classification of coral reef species for the international Census of Marine Life. This classification process occurs not just in the three weeks on Heron Island, but through a combination of field work and then further analysis at the scientists' home research labs over the life of the four-year project.

Such was the case for isopod taxonomist Chad Buxton when describing one of the new species he has discovered during the CReefs program.

Chad is researching the order of crustaceans called Isopoda, with a focus on genera and species of the Stenetriidae family. To accurately describe a new species, he ideally needs to capture and examine mature adult male specimens, as these have diagnostic characteristics that are unique between species.

"We need a good collection of specimens from the field and thorough research in the lab to describe new species," Chad explains. "For example, the material collected from Heron Island last year contained some unusual specimens. They were quite large and had various characteristics of two known genera. I thought these specimens might even belong to a new genus," he says.

"This year, I found some specimens that were even bigger, and only now has the picture become clear.
Due to the size of the 2009 specimens, I had believed that they were adult males, when in fact they were not. This is just a particularly large species compared to what I had previously seen."
 

"I have now collected four adult males, which have unique characteristics that will allow me describe the new species and place it into the appropriate genus," Chad explains.

"This new species will be an exciting addition to the taxonomy of isopods – but just as importantly, the process of discovering it highlights the value both of exploratory field work and laboratory research, and of learning from initial mistakes to build our knowledge and depth of understanding," he says.

"It also demonstrates the value of programs such as CReefs that provide the opportunity to resample the same site repeatedly over time."

Chad says that because he now has a series of specimens, including females, juveniles and fully-grown adult males, he is confident he can now make an accurate description of this new species.

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

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

 

Chad Buxton and Magda Blazewicz SCUBA diving to collect samples.

Chad Buxton and Magda Blazewicz SCUBA diving to collect samples.
Image: Gary Cranitch.


 

Zombie snails on Australian beaches
18 November 2010
 

The parasites studied by Tom Cribb can turn snails into zombies – and that may be the key to their abundance on coral reefs.

Tom, from the University of Queensland, is studying parasitic flatworms of the class Trematoda on the CReefs field expedition to Heron Island.

There are two subclasses of Trematoda: the Aspidogastrea, of which there are perhaps 100 species; and the Digenea, which may number up to 24,000 species.

"The digeneans are probably much more common than the aspidogastreans because of their complicated life cycles," Tom explains.

Digenean parasites have multi-host cycles. Most use a mollusc, usually a snail, as the first intermediate host. A larva will burrow into a snail, or a snail will eat a parasite egg.

"One tiny parasite will reproduce asexually until the snail is filled, completely overwhelmed with parasites. The snail becomes a zombie. It will never reproduce again; it's just being used to produce parasites," Tom says.

Larval parasites will then emerge from the snail to swim in the ocean until each penetrates another animal, which can be anything from a shrimp to a jellyfish or a fish. That animal is then eaten by a fish. The parasite will produce eggs inside the stomach or intestines of its final host, and the eggs will be expelled back into the ocean, eventually to infect a snail – and the cycle begins again.

This is bad for the snail, but good for the parasites!

"That extra round of prolific reproduction inside the mollusc seems to be related to the success of the digeneans," Tom says.

"The aspidogastreans don't have anything like that in their life cycle, which may be why they are far less common," he says.

 

Tom has also found that snails found on beach rock are often heavily infected with digenean larvae, while snails among coral have very low infection levels.

"The asexual reproduction seems to mean that the parasites don't need many infected snails to make the life cycle work," he says.

The mollusc-host stage of the digenean life cycle may also explain some of the distribution of the parasites on coral reefs.

Diversity of marine life tends to be richer in the northern waters, and yet some species of digeneans found here, on coral reefs around Heron Island on the southern Great Barrier Reef, are not found around Lizard Island, north of Cairns.

Tom speculates that this may be due to different species of snails between the two sites.



Associate Professor Tom Cribb with two of his honours students.
Image: Gary Cranitch.

 

 

 

Size does matter
 
18 November 2010

 

Size does matter to Dr Anastassya Maiorova, a post-doctoral researcher with the Russian Academy of Sciences, who is studying sipunculids, a group of unsegmented marine worms, on the CReefs expedition.

While some sipunculid species are only two-millimetres long, and most are less than 10 centimetres, some species, such as the Sipunculus nudus, eaten as a delicacy in China, have been known to grow to 60 centimetres.

But, Dr Maiorova, explains, scientists only measure the worms from the posterior terminal point of the body to the prominent anal opening – which, in sipunculids, is just below the introvert.

"Sipunculids have what is called an introvert, which is like a neck, with tentacles and a mouth at the tip. When they are hiding, in shells or coral or sand, they can extend their introvert for feeding. When they are threatened, they can withdraw it," Dr Maiorova explains.

"So we don't include the introvert when we measure the sipunculid, because it can be stretched out to up to 10 times the length of the body," she says.

Dr Maiorova is exploring the relationships between genera and species within the sipunculid phylum by comparing specimens' DNA with their morphology.

The morphology includes the shapes and features of the body surface, including the papillae (spikes which allow some of the sipunculids to attach to the inside of shells or coral); the internal anatomy; and the hooks and tentacular crown.

"I am most interested in the organisation of the tentacular apparatus, which is very important to the taxonomy of the species. So I am looking for the species in which tentacles are arranged in different ways" she says.

Fossil records suggest that the morphology of sipunculids has changed relatively little since the Cambrian period. Debate among taxonomists about the evolutionary classification of sipunculids, however, has only recently been resolved. Scientific papers published in the past year show that sipunculids are much more closely related to annelids, which are segmented worms, than to other phyla.

Dr Maiorova's work may contribute to better understanding of these evolutionary relationships.

 


 

BHP Billiton enviros wade into field work on Heron Island
17 November 2010

 

BHP Billiton employees Anthony McMullen and Adam West rate the hands-on field work as one of the highlights of their participation this week in the CReefs expedition to Heron Island.

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

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

Anthony is a Senior Environmental Scientist with BHP Billiton Petroleum, the company's oil and gas group, in Perth in Western Australia. Adam is an Environmental Community Coordinator in the Sustainable Development Department of Illawarra Coal, in Wollongong in New South Wales.

Anthony and Adam have snorkelled with the scientists at several reef sites around Heron Island. They have assisted researchers to collect samples of bryozoans – tiny invertebrate organisms that create colonies on dead coral or the underside of rocks in coral reefs. They have also helped to search for sipunculids – marine worms that live in burrows or bore into corals.

Back in the lab, Anthony and Adam have worked with researchers to dissect sponges and tunicates and to sift through coral rubble that has been collected to search for tiny crustaceans such as isopods and amphipods.

They have both spent time over the microscope, classifying species for several of the researchers.

Anthony has worked with the parasitology team, dissecting fish to search for internal parasites. In one afternoon's work, he counted more than 1000 flatworms found in the guts of siganid, or rabbitfish.

Adam, meanwhile, has done technical work with the CReefs field trip data manager, learning more about the systems used to organise information about dive sites and specimens collected during the expeditions.

Anthony and Adam agree their participation in the CReefs expedition is proving an interesting experience.

"I have really enjoyed the chance to be involved, hands-on, in the field work," Anthony says.

"My role at BHP Billiton involves commissioning studies of habitats to ensure oil and gas development projects are undertaken in an environmentally sensitive manner. It's refreshing to be reminded, by seeing it first hand on this field trip, just how much biodiversity can exist in a certain habitat type," he says.

Anthony has also been impressed by the collaborative nature of the expedition.

"Most research projects aren't as cooperative as the CReefs program. It's usually an isolated group of researchers working on just one species or one type of fauna; whereas here, the same samples are shared and re-used to identify all sorts of fauna living in the same habitat," Anthony says.

Adam says he has found the trip valuable for learning about how field research is run.

"In my role at BHP Billiton, I conduct a lot of environmental assessments – not necessarily in marine environments, but some in aquatic habitats – so some of the processes I've observed here will be applicable to my work," Adam says.

"It is interesting to draw comparisons between the CReefs project and how our field teams and laboratories operate. I've picked up a few ideas that I will take back to discuss with my colleagues," he says.

"I'm also keen to communicate to our workforce that our company is involved with this important research, which is contributing to the understanding and preservation of biodiversity on coral reefs," he says.

Anthony and Adam are visiting the Heron Island Research Station from 14 to 20 November.



Anthony McMullen and Adam West collecting coral rubble samples on snorkel. Image: Gary Cranitch.


 

Tattoo on the heart
17 November 2010

 

Parasites can sign their name across the hearts of their fish hosts, leaving clues for scientists about patterns of infection, according to University of Queensland Associate Professor Thomas Cribb.

Tom is working with a team of scientists studying parasitic flatworms, commonly known as flukes, in fish on the CReefs expedition to Heron Island.

Most flukes live in the intestines and stomach of their fish host but one group, the blood flukes, lives right in the circulatory system, usually inside the heart. They lay their eggs there, and these eggs are usually carried to the gills, where they hatch and escape from the fish. Tom has recently discovered, however, that some of the eggs can get lost and end up trapped in the heart of the fish instead.

"We keep finding encapsulated blood fluke eggs in the heart tissues of butterfly fishes that do not have any adult worms living in other organs," he says.

"The adult worms are rare, but these old, dead eggs are common – which tells us that almost all the butterfly fish species have a history of infection with the blood flukes.

"It could have been a year or more since the fish was infected, and the adult worms lived out their lives and died – but the eggs are still there, like a tattoo. The eggs may very slowly degenerate, but the fish may never entirely get rid of them," he says.

Tom says this gives researchers clues to the distribution of the flukes.

"We're starting to use this method on other species of fishes when we're not sure if they have been host to parasites.

"We haven't found an adult blood fluke in the emperor fish from around Heron Island, for example – but we will keep looking, because we're finding old eggs in the heart, which suggests the emperor is a host for an unknown blood fluke," he explains.

"It's an interesting way of finding evidence of where infections have been in the past," he says.

 


 

Parallel evolution
16 November 2010

 

Studying fish and fish parasites simultaneously will allow science to better understand the co-evolution of species, says Charlotte Schoelinck, a PhD student at the Natural History Museum of Paris.

Charlotte is studying groupers – fish of the genera Epinephelus, Cephalopholis, Variola, Plectropomus and Mycteroperca – along with two families of parasites that infect groupers' gills.

The parasites Charlotte is studying are flatworms of the class Monogenea. There are about 50 known families, and thousands of described species of monogeneans. Charlotte is focusing on the Diplectanidae and Ancyrocephalidae families: small worms, half a millimetre long, found in the gills of groupers.

She is using morphology (the study of the shapes, structure and anatomy) and molecular biology (DNA analyses) to understand the evolution, distribution and biodiversity both of the fish and the parasites. She plans to construct a phylogeny for this group of parasite species: essentially a family tree showing the shared evolutionary history of these species, and their patterns of speciation.

"By comparing the grouper phylogeny and the parasite phylogeny, we can study co-evolution: how fish evolution and parasite evolution affect each other," Charlotte says.

"I am interested in both types of animals; not each in isolation, but how they interact," she says.

Charlotte has spent nine months over the past two years collecting samples from New Caledonia, where her PhD supervisor is conducting research. Charlotte has also been in contact with other researchers in South Africa. She expects to further expand her understanding of species diversity by collecting specimens from Heron Island.

"It's very interesting to study the parasitic fauna in one spot, but it's more interesting if we have some comparison," she says.

She estimates she has found 400 specimens of monogeans in groupers so far during this field trip.

Charlotte says there is great cryptic diversity among these parasites: this means there are many closely-related species that look almost identical but which are genetically different.

"Sometimes, we can't distinguish the species by the morphological characteristics, so I have to wait for the DNA analysis to be completed before I can classify the specimens and describe new species.

"I have found at least one new species from Heron Island," she says, "but I think I will find a lot of cryptic species as well."

Charlotte's model of the relationships between host and parasites may help scientists to understand the parasite transmission between groupers. It may also have applications for aquaculture, by assisting to locate sources of infection or to reduce the prevalence of infection in commercial sea-pens.

Charlotte's work will contribute to scientific understanding of the biodiversity of parasites in marine fish, and the understanding of host-parasite relationships.

 


 

 
World travellers
16 November 2010

 

The worms studied by Dr Anastassya Maiorova are often on the move. The larvae can travel in currents crossing an ocean, and as adults, some species regularly change homes throughout their lives.



Dr Maiorova, a post-doctoral researcher with the Russian Academy of Sciences, is collecting sipunculids, or unsegmented marine worms, on the CReefs expedition.

Many sipunculid species live in the discarded shells of other animals, and move on to larger shells as they grow. Others burrow into sand or bore into rock. Some will even take over coral habitat, tunnelling into the hard structures created by the coral.

One species, Phascolosoma saprophagicum, has only been found living on the flesh of a decomposing whale skull at an ocean depth of about 900 metres.

Dr Maiorova has collected samples of sipunculids from waters around Russia and Vietnam. She also collected sipunculids from depths of 1700 metres in the Sea of Japan during a SoJaBio expedition for the MAR-ECO project of the Census of Marine Life, of which CReefs is also a part.

Dr Maiorova does not expect to discover new species during this field trip on Heron Island.

There are only 160 species of sipunculids all over the world. Mostly they are common and widespread, and few of them are cosmopolitan: the same species will be found in different oceans around the world," Dr Maiorova explains.

"They are constant; their features have not changed in hundreds of millions of years. There have only been two new species discovered in the past 10 years," she says.

Instead, she is interested in the biodiversity of the known sipunculid phylum.

"I am looking for any species which are living here. There are 38 species of sipunculids known from around Australia, and I have found eight species of those here at Heron Island so far," she says.

Dr Maiorova is snorkelling in shallow waters and examining coral rubble from depths of up to 30 metres to collect specimens of sipunculids.


 



Dr Anastassya Maiorova searching for sipunculids. Image: Gary Cranitch.

She is also conducting plankton tows: dragging a long, fine-mesh net behind a boat travelling at slow speed to capture plankton from the water column, which Dr Maiorova then examines for larvae.

While some species of sipunculid are able to reproduce asexually, most species produce larvae. Some of the larvae can travel in ocean currents for up to a year. Dr Maiorova says this may be why some species of sipunculids are found throughout the world.


 

Plenty of fish in the sea
16 November 2010

 

For University of Queensland Associate Professor Thomas Cribb, one of the attractions of studying parasites in marine fishes is that there are so many to find.

There are more than 27,000 fish species identified worldwide, and almost every fish carries several types of parasite. For Tom, who is collecting parasitic flatworms of the class Trematoda during the CReefs field expedition to Heron Island, this means there is a great diversity to be studied.

"There are thousands of species of parasites in coral reef fishes. The diversity of parasites is certainly richer than that of their fish hosts," he says.

Tom is working with a team of parasitologists,on the CReefs trip to Heron Island, including a PhD and several honours students whom he is supervising.. In addition to trematodes, other members of the team are focusing on external parasitic flatworms of the class Monogenea and microscopic parasites of the class Myxosporea. The group is interested in a wide variety of host fishes including rabbit fish, tangs, triggerfish, cods, blennies and mullet.

The team's research on this trip will contribute to science's understanding of the diversity, abundance and distribution of parasites on coral reefs in Australia.

The findings will add to and refine parasite taxonomy: that is, the researchers will describe and name new species and place them within existing hierarchies, taking into account the evolutionary relationships between species.

 

Tom estimates his work has contributed to the identification of 300 trematode species on the Great Barrier Reef so far.

His research highlights the diversity of parasite species within the Great Barrier Reef. Although many of the same fish species are found around Heron Island, at the southern end of the Great Barrier Reef, and around Lizard Island, at the northern end, some of the parasites found in the same species of fish,are different.

"This means you can't understand coral reef fish parasites by just looking at them in one place. It's important to study them in different locations," Tom explains.

The team is also interested in increased understanding of parasite life cycles. Most trematodes have complex, multi-host life cycles, with larvae passing through several hosts, including molluscs and other invertebrates, before the adult develops, usually in the intestines and stomach of their final fish host.

 



Coral reef off Heron Island. Image: Gary Cranitch.

"Parasites are an important part of the system that we think is worth understanding," Tom explains.

"Sometimes the parasites can cause disease that can a have a significant effect on other animals – but that's not my starting point. I'm not trying to save the fish from these ‘hideous' parasites; I'm interested in parasites for their own sake," he says.


 

Taxonomists' tools of the trade
15 November 2010

 

Classifying species can be a tricky business – so it's just as well scientists have a trick or two up their sleeves.

A key purpose of the CReefs Australian expeditions is to contribute to the discovery and taxonomic classification of coral reef species. Taxonomy is a discipline in which scientists describe and name species.Systematics is one whereby species are placed within existing hierarchies of species relationships.

Many of the researchers working on the CReefs Australia project attempt to construct a phylogeny for the species they are studying. A phylogeny is a family tree, a representation of the hierarchical structure of the evolutionary relationships among species – and ultimately, a depiction of the ancestry of species, the way in which every living species is connected to all others.

Scientists use a range of tools and techniques to complete their taxonomic work.

They examine organisms under compound and scanning electron microscopes, and make notes and sketches of the organisms' morphology: the physical characteristics, such as shapes, structure and anatomy.

They study their biogeography, which includes patterns of species distributions over geographical areas and through time.

They also extract and analyse genetic material from organisms. The advent of DNA sequencing over the past 20 years has revolutionised molecular biology and is now a reliable and widely-used technique to investigate relationships between species.

DNA sequencing is particularly useful for identifying cryptic species: closely-related species that look almost identical but which are genetically different.

All this work results in a classification of species with increasing specificity, from kingdom, through to phylum, class, order, family, genus and species.

Humans for instance belong to the kingdom Animalia; to the phylum Chordata, which is largely made up of vertebrates (animals with backbones); and to the class Mammalia, which includes air-breathing vertebrates that have hair and or fur, and whose females have the mammary glands from which the name derives.

More specifically, humans fall into the order Primates, which also includes lemurs, monkeys and apes; to the family Hominidae, which comprises humans, chimpanzees, gorillas and orangutans; and to the genus Homo, which includes all species of humans, current and extinct. Finally, you belong to the species sapiens, or modern man, the only living species in the Homo genus.

Now, if this brief glossary seems a little overwhelming to you, you're not alone.

Take a page from the book of undergraduate science students, who are often taught mnemonics so they can remember this vocabulary.

Need help recalling kingdom, phylum, class, order, family, genus, species? Try "King Philip Cuts Open Five Green Snakes" or perhaps "Kids Prefer Cheese Over Fried Green Spinach".

For extra points, learn the order of geological time periods – Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene and Recent - using this doozy: "Cows Often Sit Down Carefully. Perhaps Their Joints Creak? Persistent Early Oiling Might Prevent Painful Rheumatism".

 


 


 

Heron Island 2010
15 November 2010

 

Experts in marine science from around the world are visiting Heron Island on the Great Barrier Reef for the final field expedition of the Australian Census of Coral Reefs (CReefs Australia) program.

This is the third expedition to Heron Island as part of the CReefs Australia project, but the researchers expect many new discoveries to still be made here.

The reefs around Heron Island, on the southern Great Barrier Reef, 530 kilometres north of Brisbane, are home to around 60 per cent of the 1500 species of fish and around 70 per cent of the coral species found in the Great Barrier Reef.

But scientists on the CReefs expedition are looking, not at fishes and corals, but at animals not previously studied in depth, including species of invertebrate marine animals: shrimps, worms, parasites and zoanthids.

The biodiversity of these creatures at this location has not been well documented previously during the CReefs project so this work will make an important contribution to our understanding of the marine life on coral reefs.

CReefs Australia research also contributes to the Census of Marine Life, a 10-year survey of the diversity, distribution and abundance of marine life in the oceans, conducted by 2,700 scientists from 80 nations.

Scientists from Australia, France, Japan, Poland and Russia are participating in the trip, which runs from 12 November to 2 December. It is the ninth and final field expedition as part of the four-year CReefs Australia project.

 

The CReefs Australia project has recently been recognised for its contribution to marine science by several of the premier science prize programs in Australia. It was shortlisted in the environmental research category in the 2010 Australian Museum Eureka Prizes; named as a finalist for the Department of Sustainability and Environment's Biodiversity Award as part of the United Nations Association of Australia's 2010 World Environment Day Awards.

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.

 

 

Heron Island

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.
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* 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. 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.

 

Rebecca Leech


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