Echinoderms contribute to global carbon sink

The impact on levels of carbon dioxide in the Earth's atmosphere by the decaying remains of a group of marine creatures that includes starfish and sea urchin has been significantly underestimated.

"Climate models must take this carbon sink into account," says Mario Lebrato, lead author of the study. The work was done when he was at the National Oceanography Centre, Southampton (NOCS) and affiliated with the University of Southampton's School of Ocean and Earth Science (SOES); he is now at the Leibniz Institute of Marine Science in Germany.

Globally, the seabed habitats occupy more than 300 million million square metres, from the intertidal flats and pools to the mightiest deep-sea trenches at 11,000 meters. The benthos – the animals living on and in the sediments – populate this vast ecosystem.

Calcifying organisms incorporate carbon directly from the seawater into their skeletons in the form of inorganic minerals such as calcium carbonate. This means that their bodies contain a substantial amount of inorganic carbon. When they die and sink, some of the inorganic carbon is remineralised, and much of it becomes buried in sediments, where it remains locked up indefinitely.

Lebrato and his colleagues provide the first estimation of the contributions of starfish, sea urchins, brittle stars, sea cucumbers and sea lilies – all kinds of echinoderm – to the calcium carbonate budget at the seabed. They estimate that the global production from all echinoderms is over a tenth (0.1) of a gigatonne of carbon per year – that is, more than a hundred thousand million kilograms.

This is less than the total biological production in the main water column, or pelagic zone, which scientists believe to be between around 0.6 and 1.8 gigatonnes of carbon per year. But echinoderms apparently deliver more carbon to the sediments than do forams, for example. These microscopic animals live in vast numbers in the oceans and are traditionally regarded along with coccolithophores (single-celled marine plants surrounded by calcium carbonate plates) as one of the biggest contributors to the flux of calcium carbonate from the sunlit surface waters to the ocean's interior – the so-called 'biological carbon pump'.

"Our research highlights the poor understanding of large-scale carbon processes associated with calcifying animals such as echinoderms and tackles some of the uncertainties in the oceanic calcium carbonate budget," says Lebrato: "The realisation that these creatures represent such a significant part of the ocean carbon sink needs to be taken into account in computer models of the biological pump and its effect on global climate."

There is a worry that ocean acidification due to increased carbon dioxide emissions from the burning of fossil fuels could reduce the amount of calcium carbonate incorporated into the skeletons of echinoderms and other calcifying organisms.

However, different echinoderm species respond to ocean acidification in different ways, and the effects of rising temperatures can be as significant as those of rising carbon dioxide. How this will affect the global carbon sink remains to be established.

Lebrato concludes: "The scientific community needs to reconsider the role of benthic processes in the marine calcium carbonate cycle. This is a crucial but understudied compartment of the global marine carbon cycle, which has been of key importance throughout Earth history and it is still at present."

The seven-armed sea star along with another sea star at the Marine Biology Regional Centre’s aquarium in Chennai

The two specimen collected by the officials from the sea near Nochikkuppam area have been exhibited in the Marine Biology Regional Centre (MBRC) aquarium at Foreshore Estate.

K. Venkataraman, Officer-in-Charge, MBRC, Chennai, said the marine aquarium on their office premises was inaugurated four years ago.

"We used to collect specimen for the aquarium from the Rameswaram coast and exhibit them. A couple of days ago when a team of officials went to Nochikuppam area, they found two seven-armed sea stars, which have not been recorded in the entire coastline of the subcontinent so far," he said.

During 1930s researchers from the Madras University identified the presence of coral reef bed along the Chennai coastline. The reef bed was found running along the stretch from the present harbour area up to Mahabalipuram. After 1940s no studies or research work had been taken up. Again last year the Geological Survey of India authorities identified the presence of coral reefs near Mahabalipuram, Dr.Venkataraman said.

Explaining the speciality of the seven-armed sea stars, he said like the house gecko, the seven-armed sea stars shed their arms when threatened by the predators, which would later grow automatically. The seven-armed sea stars do not have blood and eyes. Another speciality of the sea stars was that unlike the other marine organisms, they bring their stomach out and digest the feed externally. A total of 2,000 species of sea stars are found world over, of which 765 were found in the coral reef areas, which included all different varieties of echinoderms, Dr.Venkataraman said.

Available records showed that the seven-armed sea stars were found in Mauritius, Philippines and Hawaii Islands.

Coral reefs and associated organisms were found along the Chennai coastline at a depth of about 30 ft, Dr.Venkataraman said, adding that the presence of reef bed provides livelihood for the fishermen, ensures protection of the coastline and helps researchers to take up study on them.

Monster worm and sea star frenzy

Deep under the Antarctic ice, a rare, colourful burst of starfish and 3m-long monster worms has been filmed by a BBC camera crew.Filmed in time-lapse, the extraordinary swarm of deep-sea creatures gathers to feed in a frenzy on the body of a seal, which had sunk to the ocean floor. Such a bounty of food may only occur once every ten years in the ice-cold waters of McMurdo Sound, Antarctica. The images were taken by divers filming for the natural history series Life. Descending through a hole cut in the ice, cameramen Doug Allan and Hugh Miller set up a time-lapse camera on the ocean floor. The time-lapse sequence revealed the feeding frenzy of hundreds of huge worms, starfish, brittle stars and sea-urchins.Long way down Nemertine worms, also known as boot-lace or ribbon worms, belong in their own phylum, the Nemertea. Some species are scavengers or herbivores, but most are voracious predators, catching prey using a proboscis that shoots out from their mouth. The proboscis may be poisonous or even tipped with a sticky secretion, depending on the type of worm. In Antarctica, such worms often feed on clams and shellfish. However, they also congregate with starfish, which are also called sea stars, to feed on seal droppings. In the sequence filmed for the Life series, the invertebrates gather in a frenzy to feast on a seal carcass that has sunk to the ocean floor. So much food may only arrive in one place once in a decade. The nemertine worms (Parbolasia corrugatus) are able to puncture the seal's skin with their proboscis, opening up the carcass, so that worms and marine isopods such as woodlice can enter to feed. The starfish feed more slowly - by pushing out their stomachs through their mouths. As a sea star pushes its stomach against the seal's skin, it secretes digestive juices that dissolve the seal's tissue.A burst of sea starsSea urchins, such as Sterechinus neumayeri, also get in on the act. Like the giant worms, this species comes in a variety of colours. Not only does it sometimes camouflage itself with bits of shell, but it can live for up to 40 years. Because of the cold temperatures, many creatures under the ice grow extremely slowly. But by doing so, they can reach a great age and a great size. Touching moment In temperate and tropical seas, other more common predators dominate, such as crabs. However, the fossil record shows these animals vanished from the waters of Antarctica about 35 million years ago, when the continent cooled. Today, Antarctica has no lobsters or crabs. There are also few fish, such as sharks and rays. Instead strange animals lurk there, including sea urchins, sea stars, giant worms and large underwater sea spiders, which can grow up to 30cm across and live for several decades. However, last year researchers warned that if global warming continues, it will put this unique marine life at risk.A nemertine worm's deadly proboscis In the last 50 years, sea surface temperatures around Antarctica have risen by 1-2C, which is more than twice the global average. That could encourage crabs to colonise the region, followed by fish such as sharks, which are capable of decimating the local wildlife. If that does happen, the Antarctic seafloor would no longer be dominated by soft-bodied, slow-moving invertebrates, which are believed to be similar to those found in ancient oceans prior to the evolution of shell-crushing predators. 'The Deep' episode of the BBC natural history series Life will be broadcast at 2100GMT on BBC One on Monday 30 November. BBC

Sea Stars Bulk Up to Beat the Heat

A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging temperatures brought about by direct sunlight at low tide.

"Sea stars were assumed to be at the mercy of the sun during low tide," said the study's lead author, Sylvain Pincebourde of François Rabelais University in Tours, France. "This work shows that some sea stars have an unexpected back-up strategy."

The researcher is published in the December issue of The American Naturalist.

Sea stars need to endure rapid changes in temperature. During high tide, they are fully submerged in cool sea water. But when tides receded, the stars are often left on rocky shorelines, baking in the sun.

Clearly the stars had some way of beating the heat, but scientists were unsure how they did it. Pincebourde and his team thought it might have something to do with fluid-filled cavities found in the arms of sea stars. So he set up an experiment to test it.

The researchers placed sea stars in aquariums and varied the water level to simulate tidal patterns. Heat lamps were used to control temperature, with some stars experiencing hotter temperatures than others. The researchers found that stars exposed to higher temperatures at low tide had higher body mass after the high tide that followed. Since the stars were not allowed to eat, the increased mass must be from soaking up water.

"This reservoir of cool water keeps the sea star from overheating when the tide recedes again the next day, a process called 'thermal inertia,'" Pincebourde said.

What appears to be happening, the researchers say, is that a hot low tide serves as a cue telling the star to soak up more water during the next high tide. And the amount of water the stars can hold is remarkable.

"It would be as if humans were able to look at a weather forecast, decide it was going to be hot tomorrow, and then in preparation suck up 15 or more pounds of water into our bodies," said co-author Brian Helmuth of the University of South Carolina in Columbia.

The researchers are concerned, however, that climate change may put this novel cooling strategy in peril.

"This strategy only works when the sea water is colder than the air," said co-author Eric Sanford of the University if California, Davis. "Ocean warming might therefore break down this buffering mechanism, making this sea star susceptible to global warming. There are likely limits to how much this mechanism can buffer this animal against global change." Adapted from materials provided by University of Chicago Press Journals, via EurekAlert!, a service of AAAS.

Sea Star Swells With Tides

A species of sea star has figured out a novel way of keeping cool on rocky shorelines. The animal literally soaks up chilly water during high tides to protect itself from the blazing temperatures that persist when the tide goes out, scientists announce today. Sea stars live at the ocean edge on rocky shorelines, and so they endure rapid changes in temperature as the tide comes in, covering them with chilly water, and then recedes to leave them bare to the sun's rays. "Sea stars were assumed to be at the mercy of the sun during low tide," said the lead study researcher Sylvain Pincebourde of François Rabelais University in Tours, France. "This work shows that some sea stars have an unexpected back-up strategy." Until now, scientists were not sure how the stars beat the heat. But Pincebourde suspected that perhaps fluid-filled cavities in the star's arms might play a role. So they placed so-called ocher sea stars, or Pisaster ochraceus, into aquariums kept at different temperatures and changed the water level to mimic tides. The animals exposed to higher temperatures were essentially bigger, or had a larger body mass, after the following high tide. The researchers figured that since the stars hadn't eaten, the mass must have been from the water. "This reservoir of cool water keeps the sea star from overheating when the tide recedes again the next day," Pincebourde said. The sea stars are likely cued during low tide that it's a hot day, the researchers say, and that signals them to soak up more water during the next high tide. "It would be as if humans were able to look at a weather forecast, decide it was going to be hot tomorrow, and then in preparation suck up 15 or more pounds of water into our bodies," said study researcher Brian Helmuth of the University of South Carolina in Columbia. That's fine and dandy for now, but the researchers say they worry that this cooling process may not hold up in a warming world. "This strategy only works when the sea water is colder than the air," said study researcher Eric Sanford of the University if California, Davis. "Ocean warming might therefore break down this buffering mechanism, making this sea star susceptible to global warming. There are likely limits to how much this mechanism can buffer this animal against global change." Another recent study, however, found that P. ochraceus might grow faster as the water warms. The new research is published in the December issue of The American Naturalist.

Elevated Water Temperature And Acidity Boost Growth Of Key Sea Star Species

New research by UBC zoologists indicates that elevated water temperatures and heightened concentrations of carbon dioxide can dramatically increase the growth rate of a keystone species of sea star.The study is one of the first to look at the impact of ocean acidification on marine invertebrates that don't have a large calcified skeleton or external shell, and challenges current assumptions about the potential impact of climate change on marine species.The findings were published online this week in the Proceedings of the National Academy of Sciences.In the lab, UBC researchers led by Rebecca Gooding manipulated water temperatures and CO2 levels in sea water tanks containing juvenile Purple Ochre Sea Stars (Pisaster ochraceus), a species found along much of North America's Pacific Coast.An increase in temperature of just three degrees and doubling of CO2 concentrations enabled the sea stars to grow almost twice as fast as they normally would over a period of ten weeks."This means the sea stars could potentially reach adulthood in about half the time it would typically take–and consume more mussels, their main diet, at much higher rates," says Gooding, a PhD student in the Department of Zoology working under the supervision of UBC Assistant Professor Christopher Harley.At the end of the period, sea stars reared in warmer, more acidic waters weighed 17 grams, compared to control sea stars that weighed an average of only 11 grams. In contrast, existing studies suggest that an increase in temperature and CO2 levels hinder growth in most species studied so far—usually more calcified species."This complicates current assumptions. It looks like increased CO2 may not have negative effects on all marine invertebrates, suggesting that predicting the impact of climate change should consider how different organisms respond to changing climatic variables."The Purple Ochre Sea Star is a cold-water species of sea star that can be found anywhere from Alaska to Baja California. It is most commonly found in the North Eastern Pacific. They can actually range in color from purple to orange to brown and have five rays that can range in length from 10 to 25cm.They are considered a keystone species—a species that exerts a disproportionate effect on their ecosystem by preying on other animals.University of British Columbia

Coral-killing starfish turns out to be four species, not one

The crown-of-thorns starfish, a notorious threat to coral in the Indian and Pacific Oceans, comprises four species, not one, biologists reported on Tuesday. The spiny predator, known by its Latin name of Acanthaster planci, has been a worsening peril to reefs for at least three decades, latching onto coral polyps and digesting them.A paper published in the British journal Biology Letters said that most research on A. planci has been carried out on in the Pacific, triggered by devastating outbreaks of the pest on Australia's Great Barrier Reef.But DNA analysis of specimens recovered elsewhere shows the creature comprises four distinct species, it says.They are found in the Red Sea, the Northern Indian Ocean and the Southern Indian Ocean as well as in the Pacific.The surprise finding could have important consequences for reef conservation, say the authors.Different species could favour different habitats and have different reproductive and nutritional behaviours, and this in turn could dictate when and where starfish outbreaks occur. But further investigation is needed to see if this is the case.The paper is lead-authored by Gert Woerheide of the Georg-August University in Goettingen, western Germany.

Millions of tiny Seastars inhabit undersea volcano

Marine scientists surveying a large undersea mountain chain were amazed to find millions of tiny Seastars swirling their arms to capture food in the undersea current.An expedition by 19 scientists, including five from Australia, studied the geology and biology of eight Macquarie Ridge sea mounts. They are part of a string of underwater volcanoes — dormant for millions of years — that stretches 875 miles from south of New Zealand toward Antarctica.The scientists also investigated the world's biggest ocean current — the Antarctic Circumpolar Current — amid expectations they would find evidence of climate change in the Southern Ocean.While the expedition's cameras found a wide range of Corals, a high density of Cardinal fish and the huge coral, the vast collection of brittle stars was the highlight of the voyage."I've personally never seen anything like this — all these animals, the sheer volume — all waiting for food from the current," expedition member and marine biologist Dr. Mireille Consalvey said Monday. "It challenged what we as scientists thought we knew."Expedition leader and marine biologist Ashley Rowden said Seastars usually cover only slopes away from the top of the undersea mountains."It got us excited as soon as we saw it," Rowden said of the site, dubbed "Brittle Star City."The Seastars are about 0.4 inch across, with arms about 2 inches long.The expedition began March 26 and returned to port in New Zealand's capital Wellington on April 26.Melbourne-based marine biologist Tim O'Hara, a Brittle star specialist, said the vast collection of brittle stars, or ophiuroid ophiacantha, is "like a relic of ancient times.""Normally fish would prey on them and eat them ... so for whatever reason there's a lack of fish predation there and it's seen this particular animal flourish," he said.O'Hara, who was not part of the voyage, said the speed of the sea current in the area may partly explain why fish were not feeding on the tiny animals.The Circumpolar Current merges the waters of the Atlantic, Indian and Pacific oceans and carries up to 150 times the volume of water flowing in all the world's rivers, oceanographer Mike Williams said.Australian oceanographer Steve Rintoul, who was not involved in the expedition, said there have been few measurements of the Antarctic Circumpolar Current, which "strongly influences regional and global climate" by carrying vast amounts of water and heat across oceans.Fewer than 200 of the world's estimated 100,000 sea mounts that rise more than a half a mile above the sea floor have been studied in any detail.

Thousands of dead starfish found on beach

Thousands of starfish have been found washed up dead on a beach in Kent. A carpet of the dead creatures covered hundreds of yards of the beach at Pegwell Bay near Sandwich. Tony Flashman, from Kingsdown near Deal, who took a photograph [visible on the website] said: "The dead starfish stretched as far as you could see in both directions."Fishermen and bird watchers were among the 1st to stumble on the bizarre sight, and it was quickly picked up by specialist websites. The Environment Agency is investigating the incident but said it was not connected with the recent storms, pollution or climate change.Spokesman Ian Humphries said it was not uncommon for starfish to be washed up on the shore and it was likely they had entered shallow waters in search of mussels to feed on. "As they get hungry they get more desperate... they take risks and come into shallow water where they're more vulnerable." he said.There was speculation on some of the websites that the starfish, which congregate in vast numbers, may have fallen victim to trawlers dredging the sea bottom. The Environment Agency said it was likely the starfish corpses would provide a feast for scavenging gulls.

Scientists sound alarm over starfish threat in Indonesia

The predatory crown of thorns starfish is threatening Indonesia's portion of the "coral triangle," the richest area of coral reef biodiversity on the planet, scientists warned Tuesday. The starfish have been discovered in large numbers by researchers from the Wildlife Conservation Society and the Australian-based ARC Centre of Excellence for Coral Reef Studies, who surveyed reefs around Halmahera in Indonesia's Maluku Islands, a press release said.The triangle lies between Indonesia, Malaysia, the Philippines, Papua New Guinea and the Solomon Islands and contains more than half the world's reefs, considered building blocks for marine life.More than 600 species of coral -- 76 percent of those known -- and more than 3,000 plant and fish species live in the triangle's waters.Scientists said they feared the growth in numbers of the starfish was caused by poor water quality and could be an early warning of widespread reef decline."We witnessed a number of active outbreaks of this coral predator. There was little to suggest that the reefs have been much affected by climate change as yet. The threats appear far more localised," said Andrew Baird from the Centre of Excellence in the statement.The starfish feeds on coral by spreading its stomach over them and using digestive enzymes to liquify tissue.Researchers also saw evidence of blast-fishing which had occurred following communal violence in recent years."The good news is that the reef fish assemblages are still in very good shape," said the Wildlife Conservation Society's Tasrif Kartawijaya. "So these reefs have the capacity to recover if we can address the current threats."The Coral Triangle Initiative announced by six regional governments at last year's climate change conference in Bali "offers hope for the reefs in the region," the researchers said.They said however that the role of research under the initiative, which they see as crucial in working out how to respond to threats on the reef, should be made clearer.The initiative aims to establish a network of protected marine zones, to decrease wear and tear on the reefs caused by the fishing industry and to promote eco-tourism.Marine resources in the coral triangle provide a living for 120 million people and one-third of the world's tuna catches come from the area.

Starfish outbreak threatens corals

Outbreaks of the notorious crown of thorns starfish now threaten the "coral triangle," the richest center of coral reef biodiversity on Earth, according to recent surveys by the Bronx Zoo-based Wildlife Conservation Society and ARC Centre of Excellence for Coral Reef Studies.The starfish - a predator that feeds on corals by spreading its stomach over them and using digestive enzymes to liquefy tissue - were discovered in large numbers by the researchers in reefs in Halmahera, Indonesia, at the heart of the Coral Triangle, which lies between Indonesia, Malaysia, the Philippines, Papua New Guinea and the Solomon Islands. It is considered the genetic fountainhead for coral diversity found on Australia's Great Barrier Reef, Ningaloo and other reefs in the region.Scientists fear the outbreak is caused by poor water quality and could be an early warning of widespread reef decline.Recent surveys of Halmahera by the Wildlife Conservation Society and ARC Centre of Excellence for Coral Reef Studies confirmed that while Halmahera's reefs are still 30-50 percent richer than nearby reefs, some areas were almost completely destroyed."The main cause of damage to the corals was the Crown of Thorns Starfish," Dr. Andrew Baird of the ARC Centre of Excellence for Coral Reef Studies and James Cook University. "We witnessed a number of active outbreaks of this coral predator. There was little to suggest that the reefs have been much affected by climate change as yet: the threats appear far more localized."The team also saw first-hand evidence of recent blast-fishing, an extremely destructive fishing practice that uses explosives. According to locals this accompanied a break down of law and order following communal violence in 2000-2003. During the same time many reef lagoons were mined of their corals for use in construction, an activity encouraged by the Indonesian military."This is clearly a complex human environment and effective management of the marine resources must address the needs of communities. It will also be vitally important to understand the causes of conflict among communities and address them," says Dr Stuart Campbell, Program Leader for the Wildlife Conservation Society's' Marine Program in Indonesia.The researchers pointed out that there were still healthy populations of certain species - and still time to reverse the damage."The good news is that the reef fish assemblages are still in very good shape" said Tasrif Kartawijaya from WCS-IP. "We saw Napoleon wrasse and bumphead parrot fish at almost every site. So these reefs have the capacity to recover if we can address the current threats."The Coral Triangle Initiative (CTI) announced by six regional governments at the Bali Climate Change Conference recently offers hope for the reefs in the region, the researchers say. However, there are few details of how it will work and no mention of the fundamental role of research in the conservation program."We are disappointed research is yet to be fully considered in the CTI. The success of large marine parks, like the Great Barrier Reef Marine Park, is largely due to the primary role of science plays in understanding what's going on, so managers can make good decisions," said Dr Baird."It isn't enough just to document the diversity of the region. Large scale research is required to understand the Coral Triangle ecosystems and work out how best to respond to threats such as poor water quality and overexploitation," Dr Campbell added.Wildlife Conservation Society

Predator Starfish Threaten Coral Reefs In The Philippines

An infestation of predator starfish is decimating large tracts of coral reef throughout the Philippines.

The spiny and toxic crown-of-thorns starfish are voracious predators that can wipe out large areas of coral; an individual can consume up to 6 square metres of living reef per year. Outbreaks of the species often occur when ocean temperatures and nutrient levels increase. Crown-of-thorns starfish have long spines and are capable of severe stings. Contact will almost surely inflict severe swelling, pain and nausea that can last for hours or days.
Unfortunately, some of the starfish’s major predators, such as humphead wrasse and giant triton, which usually keep the species in check have declined in recent years as a result of overfishing.
“We are experiencing a return of the starfish in greater numbers,” said WWF-Philippines CEO Lory Tan. “The situation facing our reefs is far from normal.”
The Philippines once boasted 25,000km2 of coral reef. However, a recent World Bank study shows that barely 1 per cent of this area remains pristine, and more than 50 per cent are reported to be in decline or unhealthy.
To combat the outbreak, WWF-Philippines is enlisting the help of beachgoers to reduce the number of starfish in an infested area. The most recent action netted hundreds from the world-class diving site of Apo Reef off the west coast of the island of Mindoro, about 100km south of the capital, Manila.
“In the long term, the best response to the situation is by putting a stop to overfishing and agricultural runoff, and to better manage sewage,” Tan adds. “It’s important to keep our oceans clean and our reefs well balanced.”
According to a WWF survey, outbreaks of crown-of-thorns starfish have been reported at Apo Reef and Puerto Galera in Mindoro, as well as at Mabini in Batangas, Roxas in Palawan, Bolinao in Lingayen Gulf, and Kiamba and Glan in Sarangani Bay. It is possible that many other coastal areas have been affected as well.
Note: This story has been adapted from a news release issued by World Wildlife Fund