| Farewell from Ningaloo |
| 3 June 2010 |
| The CReefs Ningaloo 2010 expedition has come to a close. |
The expedition has given Australian and international marine scientists the opportunity to collect samples from a large but mostly understudied reef. It has also provided an important forum for researchers from different areas of specialised expertise within marine science to collaborate with, and learn from each other.
Many researchers will return to their home laboratories to confirm and describe new species discovered in the past three weeks. Others will increase their understanding of existing species.
|The work of the researchers who participated in the CReefs project will 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, as part of the Census of Marine Life. This will be the last field trip to Ningaloo Reef as part of the CReefs project, but CReefs will visit Lizard and Heron Islands later in the year.|
| Into the unknown |
| 3 June 2010 |
| "What's out there?" |
According to Gareth Belton of the University of Adelaide, this is the question that science must answer for conservation efforts to be truly effective.
"You can't do conservation if you don't know what you're trying to save," Gareth says.
"There are only a million or so species described, but there could be anywhere between 10 and 100 million species in existence that we are yet to discover and describe. For example, we have only explored two per cent of the ocean below 200 metres. We really don't know what's out there," he says.
Gareth is working with the University of Adelaide's Dr Fred Gurgel to collect and identify species of macro-algae and seagrass on the CReefs Ningaloo expedition.
"On this trip, we are gathering the most basic of data: how many species are there, and how much genetic diversity is there within species from different regions of Australia," Gareth says.
This information will help set the baseline knowledge about the Ningaloo Reef marine flora, without which we cannot detect significant changes - if and when they occur. Algal species can be monitored against this baseline over time.
| Algae are a diverse group, ranging from microscopic forms, such as phytoplankton, to 30 metre-long seaweeds such as the giant kelps found in southern Australia and Tasmania. |
Algae play various roles in the marine environment. They are major primary producers – producing oxygen, fixing carbon dioxide, and removing nutrients from the oceans. Algae provide refuge and food for fish and invertebrates and on corals reefs they play a vital role in cementing the structures of the reef itself.
However, direct human impacts to coastal environments as well as the increase in atmospheric carbon dioxide concentrations which will result in ocean acidification, can have negative effects on algae, especially the calcareous algae.
"All the elements within an ecosystem are linked. If the algae go, that will eventually affect everything else in the reef," Gareth says.
"So if they go, who knows what will happen?"
Samples of the algae Gareth collects on the CReefs Ningaloo expedition will be pressed for herbarium collections, deposited and curated at the SA State Herbarium, and samples will be taken for DNA analysis to better understand the genetic diversity and evolution of marine macro-algae.
This knowledge will assist other scientists working in marine research and conservation.
| Poison in the blood |
| 2 June 2010 |
| The zoanthids studied by Yuka Irei are small, sturdy and look great in your aquarium at home. They could also contain enough poison to kill you. |
Zoanthids, related to corals and sea anemones, are an order of colonial animals found in deep sea environments and fringe habitats, such as intertidal, back reef and other shallow areas over dead corals.
Described as button-like, individual polyps are usually less than three centimetres in diameter and feature two rows of weak tentacles. Zoanthids do not grow skeletons, but some incorporate small pieces of sediment, sand and rock into their tissue, and colonies can form a mat on the ocean floor or on other reef structures. Zoanthids gain energy through a combination of photosynthesis through creating symbiotic relationships with algae, and feeding on plankton.
Perhaps the most striking characteristic of zoanthids is that some of them produce palytoxin, one of the most toxic organic substances in the world. Palytoxin 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.
For example, it has been reported 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.
| Yuka adds her own story of a researcher who merely swam near a Palythoa species, and was sent to hospital. |
"Some Palythoa species have a very strong toxin," Yuka explains.
"If you were to eat it, you would probably die," she says.
Not all zoanthids create the toxin, however.
"Some colonies have very strong toxicity but other colonies don't. It seems to depend on the environment," Yuka says.
While palytoxin is not yet well understood, chemists are investigating it for medical applications, such as use as an anaesthetic.
Yuka is collecting specimens and establishing the diversity of zoanthids from Ningaloo Reef. When she returns to Japan she will study the phylogeny, assisted by her supervisor, Associate Professor James Reimer, who participated in the CReefs Heron Island expedition in November 2009.
Yuka has collected species of Palythoa and Zoanthus, the genera most commonly found in tropical and sub-tropical waters.
She has also made some exciting discoveries.
"I found this specimen of the genus Acrozoanthus living on a worm tube. They have very long tentacles. I've seen this in Taiwan, but I've never seen it in Okinawa," Yuka says.
"I've also found a specimen of Neozoanthus. We don't have distribution data on this species, but it has been seen before in Australia and Madagascar. It's interesting because we found a very similar specimen in Okinawa, and we want to compare the specimens," Yuka explains.
"I think they are similar, but zoanthids often have a large number of different morphs of the same or similar species, so we are not yet sure," she says.
| Colourful defence |
| 26 May 2010 |
| The nudibranch specimen of the genus Chromodoris collected on the CReefs Ningaloo expedition may not be a new species, but it will help marine scientists better understand these amazing creatures. |
Nudibranchs, sometimes called sea slugs, are soft-bodied mollusks that shed their shells after the larval stage. Nudibranchs of the superfamily Doridoidea breathe through branchial plumes clumped on their backs instead of gills: the word "nudibranch" means naked gills in Latin. The horn-like tentacles, called rhinophores, on their heads are chemical sensors that lead them to food or other members of their species. Many also have protruding structures called cerata that aid in respiration.
Nudibranchs range in size from two to 60 centimetres and can weigh up to 1.5 kilograms. Most are carnivorous, feeding on sponges, bryozoans, anemones, barnacles and even other sea slugs. Some species store algae in their outer tissues to gain energy from the algae's photosynthesis.
The bright colour of many nudibranchs warns would-be predators that they are dangerous: some species produce toxic secretions, while others store the stinging cells from anemones or bluebottles, which they eat, in sacs at the tips of their cerata and use these for defence.
This specimen of Chromodoris will be examined by Dr Arthur Anker and his colleagues at the Florida Museum of Natural History.
| Something from nothing |
| 26 May 2010 |
| Sometimes finding nothing can tell you something, according to Catalina Aguilar, a Masters student at the University of Ryukyus in Okinawa, Japan. |
This is her first CReefs expedition, but she is comparing the specimens she collects in Ningaloo to those found by her supervisor, Associate Professor James Reimer, on the CReefs Heron Island expedition in November 2009. She will also compare specimens from Australia to those collected in Japan.
A coral of the genus Melithaea.
"The specimens I have collected here are not as varied as those Jamie brought back from Heron Island," Catalina says.
"There are many different colours and colony shapes within the Melithaeidae family, but here most of the specimens are red or white. I would say there is less diversity in soft corals on Ningaloo Reef than on the Great Barrier Reef," Catalina says.
"This suggests that the high-energy water of the narrow reef at Ningaloo is a less favourable habitat than the wider reef with different tidal layers on the east coast of Australia," she says.
Catalina aims to construct the Melithaeidae phylogeny, and the specimens she collects here will contribute to her understanding of the family.
"There is some description of Melithaeidae species, but no one has put together a full taxonomy of the family, or what relationships the genera have to each other," she says.
The most significant characteristic of Melithaeidae is that they have conspicuous nodes on their branches.
When Catalina takes her specimens back to her university laboratory, she will conduct DNA analyses on all the samples, and describe the morphology of specimens that are most representative for each genus.
| Of description, drawings and DNA |
| 25 May 2010 |
| Tracking the identity of a species is a tricky business, especially when the populations you need to study are located in all four corners of the globe. |
One of the three presently known species, Philarius gerlachei, was originally described, very briefly, in the early 1900s based on specimens from the Persian Gulf. Dr Anker has specimens of Philarius from a Biotas expedition to Madagascar, a Biocode expedition to Moorea in French Polynesia, and the CReefs expedition to Heron Island on the Great Barrier Reef. These specimens share many characteristics with the Persian Gulf specimens, but are different enough, he and his co-author believe, to be classified as separate species.
"The specimen from Heron Island is much bigger than the others and more red in colour, the specimen from Madagascar has white spots, and the specimen from Moorea is greenish and semi-transparent – but these different types have all been all treated in the past as the same species, Philarius gerlachei," Dr Anker says.
He says it will be necessary to compare these recently collected specimens with the type series from the Persian Gulf – the specimen from which Philarius gerlachei was first described – which is deposited in the National Natural History Museum in Paris. The specimen from French Polynesia may well be the species originally described as Philarius gerlachei.
"Once we fix the original species, then we can describe all the others as new," he explains.
"Some descriptions from the 19th or early 20th centuries were taxonomically not adequate, which means today they match several closely related species and we are left to guess what the author meant," Dr Anker says.
"After we revise old species and describe new species, it will be much easier for other scientists to contrast their specimens with our descriptions, which contain not only morphological descriptions, but also detailed drawings, colour photographs, keys, and sometimes also DNA sequence data," he says.
"Now they will not have to guess: they will know."
| Spot the difference |
| 25 May 2010 |
| Chad Buxton, from the Museum of Tropical Queensland, is almost certain that he has discovered a new species of marine life. |
Chad's focus is on the order of crustaceans called isopods. He specifically studies the Stenetriidae family, which are free-living on coral reefs and are microscopic in size, ranging from two to five millimetres.
"Stenetriidae haven't been particularly well-described on Australian coral reefs, so most of the species that I'm pulling up are likely to be new to science," he says.
Chad has been diving and examining the material from the Autonomous Reef Monitoring Structures (ARMS) to collect isopod specimens. He found the new species in an ARMS sample. Since then, he has also found the same species free-living on the reef.
"The antennae of these particular isopods are banded yellow and clear, and they have a distinct black dot on the posterior region of their dorsal side," he explains.
"They are significantly different from other species I've seen, so I suspect that when I get them back in the lab under a high-powered microscope, I will be able to confirm that they are a new species," he says.
The colouration, banding patterns, dots and speckling is a good indicator of species in some genera of isopod, such as the Joeropsidae studied by Senior Curator at the Museum of Tropical Queensland Dr Niel Bruce, Chad's supervisor and a participant on previous CReefs expeditions.
Although Chad's discovery is based on unique colouration, species in the Stenetriidae family are typically identified by differences in the first pereopod, the first pair of legs or front claws.
"Stemetriium have chelate first legs or claws, and the shape of the claw is a good trait for identifying species: some are narrow, some wide, some have a large hook, and some are very setose, that is, they have a lot of hairs," Chad says.
Chad is endeavouring to establish a more accurate taxonomic categorisation for the Stemetriidae, identifying new species, and tracing the ancestry, evolution, spread and diversification of species. The fossil record of isopods dates back 300 million years.
Chad's participation in this project may also reveal more about the role isopods play in coral reefs. It is thought that they provide a food source for fish, and also help to clean the oceans by feeding on dead fish and other detritus.
"Isopods are widespread and found in large numbers in some parts of the ocean, so they are likely playing an important role in the ecosystem of coral reefs and in the oceans at large," Chad says.
To date, there are more than 10,000 known species of isopod, classified into approximately 100 families. Around half of the known species are found in marine environments.
|Golden petals of the sea|
| 24 May 2010 |
| Polychaetes, or segmented worms, are amongst the most common and widespread invertebrates in the oceans. |
There are species that live in the coldest darkest abyss, such as the three-metre-long cold seep tube worm Lamellibrachia luymesi; species such as the Pompeii worm, Alvinella pompejan, that tolerate extreme high temperatures near hydrothermal vents on the floor of the Pacific Ocean; even one as-yet-unclassified species found by robot probes at 10,902 metres underwater, one of the deepest areas of the oceans explored by humans.
On 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.
Several polychaete families are named after nymphs and goddesses, such as Nereis, commonly known as the clam worm, and Aphrodite, known as the sea mouse. Others are less nobly titled, such as a species of Osedax dubbed the "bone-eating snot flower".
But of all of the approximately 80 families of known polychaetes, polychaete expert Charlotte Watson of the Museum and Art Gallery of the Northern Territory has picked her favourite: the Chrysopetalidae.
"The Chrysopetalidae are pretty small, from two to 10 millimetres in length. Their hairs are expanded structures, like little leaves, that cover their backs and fit together like tiles on a roof. They are coloured gold and silver and bronze. Chrysopetalidae means golden petals in Latin," she explains.
This is Charlotte's fourth CReefs expedition. She estimates there have been 30 new chrysopetalid species found on CReefs expeditions, as well as a new species of Syllidae found from Lizard and Heron Islands.
"It's about five millimetres long, with brightly-coloured yellow and orange lobes on the back, with little white tips on the end of the lobes. The only other species of this genus was collected in New Zealand in the 1950s, so this is a new species and record for the tropics."
Charlotte has named the species Clavisyllis yongei, after Yonge Reef, Great Barrier Reef, were it was first discovered.
A polychaete of the genus Spirobranchus.
| Hitching a ride |
| 24 May 2010 |
| Human interaction with the oceans is changing how marine species evolve and spread, according to Museum Victoria honorary associate and bryozoan expert Phil Bock. |
There are around 6000 known species of bryozoans around the world, but Phil believes that there are hundreds more to be discovered.
"There are at least two families which were previously known from New Zealand, Indonesia, the Philippines or other places which are now known to be in Australia as well due to the collecting made possible by CReefs. Some specimens of these families will be classified as new genera. Another group was already known, but because of new information from CReefs, we're classifying it as a new family. I would say there will be between 100 and 200 new species discovered through this project," Phil says.
The specimens Phil collects on CReefs expeditions will enable scientists to investigate how bryozoans have spread and evolved.
"Bryozoans don't move across the deep ocean very easily," Phil explains.
"Some populations which are thought to be one species at present are found in Hawaii, Indonesia, the Solomon Islands and Australia, and in some cases right across to the Red Sea, so somehow they have spread. But there are others which are isolated on one particular sea mount. There is no simple pattern," he says.
"Some research has focused on a group of bryozoans that foul the hulls of ships, and through the movement of ships have spread around the world. DNA analysis of the genetic differences among populations may tell us more about how human interaction with the oceans has contributed to the distribution and evolution of these species," he says.
| Snap, crackle and pop |
| 24 May 2010 |
| The snapping shrimp studied by Dr Art Anker of the Florida Museum of Natural History are bubbly creatures – they create bubbles for stunning prey, self-defence and communication. |
The typical alpheid shrimp feature is an oversized claw that possesses a snapping mechanism – hence the name – almost like clicking their fingers. The claw can issue a jet of water and make a cavitation bubble, which the shrimps "pop" to create a shockwave strong enough to stun or injure other organisms.
"If they catch a little worm and it wriggles around, they just snap a few times to stun it," Dr Anker explains.
However, the snapping can be used also for self-defence or for defence of the shrimp's territory or domicile.
"When the crown-of-thorns sea star, Acanthaster, tries to crawl over coral where alpheid shrimps live, the shrimps, along with some crabs sharing the coral head, pinch and snap very aggressively until the sea star goes away," Dr Anker says.
Alpheid shrimps are extremely abundant on coral reefs and much of the crackling noise heard underwater is due to their snapping. There is even a theory that the noise of snapping shrimp may assist turtles and large marine mammals such as whales to find their way to coral reefs.
Dr Anker also believes that alpheid shrimps may also snap to communicate with each other.
Some alpheid shrimps play an important role in bioerosion – the term used for reef damage due to biological (mostly animal) activity – and renewal of reefs.
"Many of them are reef destroyers. They bore into both living and dead coral. It degrades reefs, but also clears away dead coral and allows new life to grow, and creates new microhabitats, so it's a very important process," Dr Anker says.
| Softly, softly |
| 24 May 2010 |
| The fossil record of soft corals dates back millions of years, but pollution of the oceans could significantly reduce the number and diversity of these important animals in a much shorter time frame. |
"Some individual reef building soft corals such as Sinularia could be hundreds of years old," he says.
Dr Ekins and his colleague Dr Monika Schlacher-Hoenlinger, also from the Queensland Museum, are focusing on soft corals during the CReefs Ningaloo expedition.
Soft corals are so named because most do not have hard external skeletons; instead many rely on hydrostatic pressure created by actively pumping water into their tissues for structural support. However gorgonians, also known as sea fans, do construct a solid internal axis of gorgonin, a proteinaceous horn-like material. Most soft corals also have hard sclerites, made from calcite, which provide additional structure. These sclerites also provide taxonomists with diagnostic characters that can be studied under a microscope for species identification. The soft corals are also known as octocorals, as they have eight tentacles fringing each polyp, as distinct from the six-tentacle morphology common to hard corals.
While most genera of soft corals are not reef-building, they play other roles, such as filtering water and providing habitat for other creatures.
Drs Ekins and Schlacher-Hoenlinger are collecting specimens of soft corals, looking for new species, and setting a baseline for the abundance and density of species by performing counts on transects: each transect is 5-metres long and the numbers of each species found within half a metre either side of the line are counted. The results allow Drs Ekins and Schlacher-Hoenlinger to determine which species are common or rare, and to compare between reefs.
While they have found less diversity on Ningaloo Reef than on the Great Barrier Reef, there have still been surprises.
"We are excited because we've found a Zignisis," Dr Schlacher-Hoenlinger says.
Drs Monika Schlacher-Hoenlinger and Merrick Ekins prepare for a dive.
"This is not a new species – the genus is known from the west coast of Australia – but we haven't found it on any previous CReefs trips. It seems to be rare," she says.
"We won't know until we have identified the samples in the lab, but definitely there will be lots of new species from the CReefs project," she says.
But will these species of soft corals survive for another million years? Drs Ekins and Schlacher-Hoenlinger say that pollution could have a negative effect.
"Pollution and turbidity can affect the health of soft corals," Dr Ekins says.
"If there's construction on land and you get more run-off and sediment, it's likely to change the species makeup in an area. Some soft corals are partially photosynthetic, so if the water becomes dirtier, those species will be affected," he says.
| The Barnacle Window |
| 23 May 2010 |
| Specimens of barnacles collected during the CReefs Ningaloo expedition by Andrew Hosie of the Western Australian Museum may provide insight into the symbiotic relationship between certain species of barnacles and sponges. |
Andrew is the first researcher ever to visit Ningaloo Reef solely to document the diversity of barnacle fauna. He is particularly interested in sponge barnacles.
"It's unknown whether the barnacle burrows into the sponge, or the sponge grows around the barnacle, but effectively by the barnacle's adult stage, it is buried by the sponge with just a small hole uncovered through which the barnacle can feed on plankton," Andrew says.
Most barnacles grow a shell wall made up of a series of overlapping plates, but the shell of certain sponge barnacles leave a membrane-covered window between the animal and the sponge. Andrew hopes to collect specimens from Ningaloo Reef that will enable him to better understand the relationship between barnacle and sponge, and the purpose of the window in the barnacle shell.
"It could be as simple as conserving energy: the barnacle is protected by the covering of sponge so it may not need to build a strong shell. It could enable chemical communication: perhaps the barnacle is convincing the sponge's immune system not to attack. It is possible that the barnacle is deriving nutrients from the sponge, although in some parasitic barnacles that derive nutrients from the host rather than from plankton, the feeding apparatus atrophies, but is not the case with these species," Andrew explains.
Andrew will examine specimens under scanning and transmission electron microscopes to learn more about the window function.
Andrew says that identifying differences between barnacle species, and expanding the taxonomy of marine life more generally is essential for us to understand, and hopefully to protect, the natural world.
He draws on an analogy made by Dr Ashley Rowden of the New Zealand National Institute of Water and Atmospheric Research.
To paraphrase Dr Rowden: "Think of the world as a car. If you are just driving your car to the market on Sundays, you probably don't need to know exactly what all the parts do. You might understand the steering wheel and the gearbox and the tyres; we can think of these as the species that are common, understood and useful to humans.
"But if you are driving your car in the Paris-to-Dakar Rally, you want to have at least some idea of the function of every piston, nut and valve on that car; and we can think of these parts as the species we do not yet know about.
"Until very recently we have understood our world as if we were Sunday drivers, but driving it as hard as if we were in the Paris-to-Dakar Rally.
"The least we can do is learn how it works," he says.
A coral barnacle of the genus Cantellius. Image: Gary Cranitch.
| Gone fishing - for parasites |
| 23 May 2010 |
| From the beach or a boat, with a snorkel or on scuba, using nets, lines, spear guns or clove oil, Holly Heiniger and Dr Terry Miller of the University of Queensland and the Queensland Museum spend most afternoons on the CReefs Ningaloo expedition going fishing. |
Holly and Terry are documenting and describing the biodiversity of internal parasites in Indo-Pacific coral reef fishes.
Holly is looking for microscopic parasites of the phylum Myxozoa, which can be found in various tissues, including the gall bladder, brain, muscle and heart of fish.
Terry's focus is on trematodes, which are parasitic flatworms of the phylum Platyhelminthes, that can be found in the internal organs of fish, particularly the intestines and stomach. Parasites of these phyla also inhabit the gills, body cavity, liver, spleen, and urinary bladder of certain fish species.
"The diversity and richness of parasitic taxa on coral reefs is fascinating. Every fish species has a parasitic fauna of some kind, whether internal or external – some fish may host up to five or 10 different species," Terry says.
"Based on what we know already about host preferences and distributions of many of the parasite families we have recovered so far, we are certain that we have found new species on this expedition. Although, until we sequence the DNA and analyse the morphometrics of the parasites, we can't definitively say how many species we have found," Holly adds.
The work will contribute to the overall knowledge of parasitic taxa, host-parasite relationships and their ecological interactions in coral reef ecosystems. Another major component of their study is to explore the evolution and biogeography of parasites in marine fishes.
"We have found parasite species that are genetically and morphologically identical between Ningaloo Reef and the Great Barrier Reef and even wider in the Indo-West Pacific, so we're interested in how these parasites have dispersed over large geographic ranges," Terry explains.
"These expeditions have provided us an unprecedented chance to explore the taxonomy and systematics of internal parasites of reef-associated fishes, which together form a major component of the overall biodiversity found in coral reef ecosystems," he says.
| Frenemies of the reef |
| 23 May 2010 |
| The tiny, colored or semitransparent, one-eyed crustaceans that make up the subclass Copepoda may be among the most ecologically important animals in the world – but according to Dr Viatcheslav "Slava" Ivanenko of the Moscow State University, they may also pose a serious danger to coral reefs. |
However, the news on copepods is not all good. Many copepods form parasitic relationships with corals and can damage coral reefs.
These copepods, however, have not been well studied in the world's oceans – Dr Ivanenko is one of very few marine biologists to focus on symbiotic copepod biodiversity. This group of copepods was discovered by coral aquaculturists.
"In French Polynesia and the South-China Sea, I found some taxa of copepods which we think could be quite damaging to corals. The parasitic copepods eat the coral hosts," Dr Ivanenko says.
"People from North America and Europe keeping aquaria had exchanged samples of an endangered species of Acropora – a very diverse genus of stoney corals, but they had problems from some particular species of copepods. Whole coral colonies died; it's like a disease. Interestingly, we know a little about the diversity of these copepods but almost nothing about their relationships with corals in the natural environment," he says.
Dr Ivanenko is studying the diversity and evolution of copepods, describing many new species and preparing specimens for DNA analysis. He hopes his work can inform ecological research.
"I am doing taxonomy but my goal is not only taxonomy. My task is to help people use information about small crustaceans living on the corals and other invertebrates, to identify them and to understand if they pose a danger to the reef. I have to attract the attention of ecologists. To my mind, it's quite important," he says.
Dr Slava Ivanenko examines coral for copepods.
| Colonial forces |
| 23 May 2010 |
| Discovering a colony of social snapping shrimps of the genus Synalpheus has been a highlight of the CReefs Ningaloo expedition for Dr Arthur Anker of the Florida Museum of Natural History. |
"Social colonies have been found in the Caribbean, but the colony we found on Ningaloo Reef is the first clear proof of their existence in the Indo-West Pacific," he says.
Dr Anker found the shrimp colony in a sponge. The colony comprised more than 50 individuals, all descendants of the same female, the "queen".
A shrimp of the genus Synalpheus, found in a colony in a sponge.
| "Only the queen has embryos; it is the only reproducing female in the colony," Dr Anker says. |
"There must be one or several males to fertilise the queen, but we cannot distinguish the king from the other colony members without conducting paternity testing, which is possible but very expensive and time-consuming," he says.
"We also don't know yet how the queen is able to suppress the reproduction of other colony members," he says.
Dr Anker theorises that living in a colony might allow the shrimp to better defend their home.
"Sponges are in high demand as habitat for animals on reefs. Social shrimp, by forming these large groups, can take over the entire sponge. They probably defend the sponge together, so if a worm or another shrimp is trying to get in, the shrimp may combine forces, snap at it aggressively, and chase it out," says Dr Anker.
Dr Anker's main research focus is on the snapping shrimps of the family Alpheidae. One of the most conspicuous feature of snapping shrimps is an oversized claw that the shrimp snap – hence the name – for self-defence, stunning prey, and possibly also for communication.
"Most alpheid shrimps live in pairs, but like this species, rarely in colonies. Normally they are quite aggressive and they would immediately start snapping at each other, but these Synalpheus shrimps are living together in a similar system to termite colonies," Dr Anker explains.
Shrimps are among the most abundant and diverse creatures found on coral reefs. The genus Alpheus, for instance, has approximately 300 known species, but Dr Anker estimates there may be as many as 800-1000 species worldwide.
Dr Anker is the only researcher in the world currently specialising in alpheid shrimps. His participation in the CReefs expedition to Lizard Island in February 2009 resulted in the identification of at least three new species in this family.
| Killer algae |
| 23 May 2010 |
| To the untrained eye, it looks like a bunch of grapes, but the University of Adelaide's Dr Carlos Frederico "Fred" Gurgel knows this alga could be a killer. |
"There are several different varieties of Caulerpa racemosa – the morphology varies widely, and wildly – and one of these varieties has now being introduced in Adelaide, in South Australia, as well, which suggests that this genus, more than others, is prone to producing species with ecologically-negative impacts," he says.
"Caulerpa taxifolia introduced populations grow very fast. They smother temperate reefs and displace the local species, other algae and animals, everything. The end result is a mono-culture: fields of Caulerpa and almost nothing else. "
Dr Gurgel has been awarded a significant Australian Research Council grant to study Caulerpa. He will compile a DNA barcode database of the approximately 30 Caulerpa species found in Australia plus species from other countries so that any new introductions can be identified promptly and before populations become invasive.
The project will also simulate, in the laboratory in aquaria systems, scenarios of climate change in the marine environment in order to test the effects of differing values of temperature, salinity, acidity, light and nutrients on the these algae.
| "We want to pinpoint exactly which physical conditions weaken the plant the most, use models to predict when those environmental conditions will occur, and implement eradication mechanisms to coincide with those conditions. This will provide us with the information to help us eradicate the invasive species more effectively and therefore also more cheaply," he says. |
The project will also track the origin of the invasive populations in Australia using techniques of biogeography and population genetics.
"Australia is probably the richest place for species in this genus," Dr Gurgel explains.
"The species in the tropics are native. It is only when they are introduced into temperate, cold waters in New South Wales and South Australia that they become invasive, but as yet we don't understand how they are spreading to these areas," he says.
From left to right: Caulerpa peltata, Caulerpa racemosa and Hypnea pannosa collected and photographed at Ningaloo Reef by Fred Gurgel. Image: Fred Gurgel.
| * 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.