Monthly Archives: March 2011
The research shows, for the first time, that while hard corals can take up from the environment new stress-tolerant algae that provide critical nutrients, the coral may not be able to sustain the relationship with these algae over a long period, a process known as symbiosis.
The findings may mean that certain types of coral will not be able to adapt rapidly enough to survive global warming, says the study’s lead author, Mary Alice Coffroth, PhD, UB professor of geological sciences in the College of Arts and Sciences.
“Our findings suggest that not all corals can maintain a long-term symbiosis with these stress-tolerant strains of algae,” she says.
“That’s the problem,” Coffroth continues, “if they can’t take up the stress-tolerant symbionts, or if they take them up but can’t maintain the symbiosis with them, as we found, then they likely won’t be able to adapt rapidly enough to survive global warming.”
The demise of coral reefs will deprive fish of food and shelter, severely threatening reef fish populations and marine diversity.
Co-authors on the paper include Eleni L. Petrou, a recent UB Honors College undergraduate who worked in Coffroth’s lab, as well as Daniel M. Poland, a recent PhD graduate, and Jennie C. Holmberg, a former graduate student, both of whom worked in Coffroth’s lab, and Daniel A. Brazeau, research associate professor in UB’s Department of Pharmaceutical Sciences.
During the past two decades, Coffroth explains, coral reefs, known as the rain forests of the sea for their incredible biological diversity, have suffered bleaching events due to high water temperatures and light levels that cause them to literally “spit out” their algal symbionts, which provide their sustenance. Severe bleaching can lead to coral death.
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In recent years, though, it has been reported that some corals appear to respond to rising sea temperatures by acquiring new stress-tolerant symbionts from the environment, which could allow them to survive the warmer oceans caused by climate change.
Coffroth says that the UB research shows that while the corals they studied were able to acquire new stress-tolerant symbiont strains from the water, they were unable to maintain that symbiosis for very long.
After about five weeks, the proportion of new symbionts within the coral had declined dramatically and after 14 weeks was no longer detectable in the corals.
“While it’s true that coral can be flexible in the kinds of symbionts they take up, that will only work within limits,” she says. “It’s possible that the new symbionts were either unable to multiply in the host or to compete with the existing residual populations of symbionts in the coral.
“Our findings suggest that if a coral doesn’t naturally host this kind of stress-tolerant symbiont, it cannot acquire it from the environment.”
She noted that the outlook may be more promising for corals that naturally harbor the stress-resistant symbionts. These symbionts appear to be able to protect corals from sea temperatures that are one-to-two degrees higher than normal; however, Coffroth cautions that most estimates predict that by the year 2100, global warming will cause sea temperatures to rise by as much as two-to six-degrees above current temperatures.
The UB researchers studied Porites divaricata, a common shallow-water scleractinian coral found throughout the Caribbean.
The coral samples were retrieved from a site within the Florida Keys National Marine Sanctuary; in the laboratory, the scientists induced bleaching by exposing the coral to incremental increases in water temperatures until it reached 33 degrees C, about 91 degrees F.
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Lieutenant General Mahmoud Ashkenani, in charge of the environmental projects in the team, told KUNA that some of the bleached coral reefs showed signs of recovery with the re-growth of the algae and re-appearance of swarms of fish swirling around the locations.
The divers, who scoured the sites off the coast, located some locations with full bleaching, many “dead ones,” noting drop of the water temperature by three degress, reaching 32 degree, he said, renewing the call on visitors of these locations to refrain from harmful action to the corals.
Meanwhile, Lieut. Gen. Ashkenani declared the first successful Kuwaiti experience of planting coral settlements at Umm Al-Mardem island , after completing a special session in the Maldives, in coordination with French experts.
The Ningaloo Reef could withstand a massive rise in sea temperature that threatens to wipe out 90 per cent of the world’s coral reefs because of cooling ocean currents that circulate off the WA coast.
New scientific research has pointed to a worst-case scenario 4C rise in ocean temperatures as soon as 2050, with WA waters already heating up faster than the rest of Australia.
But CSIRO science fellow Beth Fulton, in Perth to present her findings from ecosystem modelling to the international Frontiers of Science marine conference, said the currents off Exmouth could act as an air-conditioner for the world-famous reef.
“Temperature-wise it looks like the reef will be buffered because there is a deep cold-water plume that gets sucked up seasonally and protects the reef, a bit like having an air-conditioner that it can throw on to save itself from massive bleaching,” she said.
“But we don’t know for sure because the ocean acidification, which is also rising rapidly, potentially makes the reef a lot more brittle.”
Dr Fulton described the research as a mixed bag for WA once temperatures rose and acidification took hold, with some of the biggest ocean temperature changes in Australia happening off the west coast.
The cooling currents will not save North-West beaches that are predicted to be wiped out by sea-level rises.
“Sea-level rise is very likely to affect the beaches up there – the work suggests we could lose all of the major tourist beaches,” Dr Fulton said.
The make-up of the Indian Ocean off WA would also become unrecognisable with tropical fish species, including emperor and snapper species, potentially found off Perth.
“It’s not necessarily all going to be bad,” she said. “Some species will find benefits, they will expand their range, they’ll be more productive . . . often fast growing species that like warm waters will move further south.
“But some of the more cold water species are finding it hard to find anywhere to live . . . they run out of habitat so they face problems.”
There was even potential for whale sharks to move further south during their annual stay off WA. Dr Fulton stressed the science behind her modelling was ever changing and had to be constantly monitored.
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By Zadie Neufville*
KINGSTON, Oct 12, 2010 (IPS/IFEJ) – Anxious to prevent the collapse of Jamaica’s overexploited marine fisheries, the Ministry of Agriculture and Fisheries is promoting the consumption of lionfish to control its burgeoning population. At risk officials say, are the nation’s marine biodiversity, its food security and economic well- being.
“The situation in Jamaica is urgent,” said Nelsa English, national coordinator for the Jamaican component of a Caribbean-wide Invasive Alien Species Project at the National Environment and Planning Agency (NEPA).
“A lack of sufficient natural predators suggests that it (lionfish) could be a potentially significant threat to Jamaica’s biodiversity and the ecosystem in general,” she noted.
Jamaica’s marine resources are stretched to the breaking point, its reefs overfished and degraded due to environmentally unfriendly fishing practises such as the use of explosives, poisons and fishing nets that are below the legal mesh size.
Scientists agree that many of the reefs have been reduced to coral communities and no longer function as vital ecosystems because their biodiversity is so severely degraded. Some studies suggest that only two percent of some reefs are live coral and the structures themselves are reportedly being eroded faster than they can regenerate.
“Currently our fishing industry survives on the removal of young adults. This practice does not allow for enough fish to mature and reproduce which puts pressure on the fecundity of the ecosystem,” English told IPS.
According to English, the presence of the lionfish – which ranges in colours from orange to maroon – in such a depleted marine environment could wipe out the fishing industry. The Ministry of Agriculture and Fisheries estimates that there are more than 30,000 fishers on the island.
The lionfish (Pterois volitans and Pterois miles) was first seen in Jamaican waters in 2008 but rapidly spread island- wide. Experts say they can reduce survival rates of small reef fish by as much as 80 percent; growing to an average of 15 inches and spawning up to 30,000 eggs at least twice a year. There are few predators of this Pacific native in the region besides groupers – and there are not many in these overfished waters.
The Montego Bay Marine Park, a marine reserve and fish sanctuary on the island’s north coast, is culling the lionfish to reduce their numbers.
“During underwater surveys, it would be normal to encounter at least three lionfish during a daytime dive. During dusk/dawn hours, these numbers could be easily reach three or four times that number,” said Brian Zane, the park’s executive director.
Cullings are carried out in association with the Fisheries Division of the Ministry of Agriculture and NEPA, the agency responsible for managing Jamaica’s natural resources. Officials are examining the feasibility of installing a branching reef structure – said to be inhospitable to lionfish – in what is also a national park. NEPA and its partners have drafted a National Strategy and Action Plan for invasive alien species (IAS).
Agriculture and Fisheries minister Christopher Tufton is already leading an aggressive public education campaign to get Jamaicans eating lionfish. Television programmes, videos of high-profile locals like Prime Minister Bruce Golding enjoying meals of lionfish, and some of the hotel industry’s most decorated chefs preparing what Tufton describes as “good food” are broadcast regularly. Tufton believes that Jamaicans can eat their way out of the lionfish problem.
“I believe the way to control the lionfish is to promote its consumption. We are going to bring in chefs who know how to prepare them and we are going to eat them,” Tufton said at the start of the campaign.
Jamaica has one of the highest rates of endemism – unique local species – in the Caribbean and also has one of the largest numbers of invasive alien species – a total of 102. This puts it third behind Puerto Rico and the Dominican Republic, islands that are also fighting the lionfish invasion.
Like Jamaica, regional governments are pitting the human predator against the lionfish in a race to keep its population in check.
In May, hoteliers in Negril, Jamaica sponsored a three-day competition in which teams of fishermen caught a total of 1,446 lionfish.
Last year in Puerto Rico, the U.S. National Oceanic and Atmospheric Administration (NOAA) sponsored a five-city tour of the island complete with celebrity chefs as part of its efforts to commercialise the lionfish.
Elsewhere, fishermen who are willing to work hard and risk a painful sting will be rewarded. In the Bahamas, lionfish reportedly sells for about $12 per pound – up to three times other varieties. In the Turks and Caicos Islands, government has a $3,000 prize for the first fisherman who catches 3,000 of the candy-striped predator.
The lionfish’s adaptability to the mangrove and seagrass beds that provide sanctuary to juvenile reef fish will, scientists say, make it difficult to eradicate. Already there have been sightings at the Bogue Lagoon, the primary mangrove area within the Montego Bay National Park.
“Sightings have been reported along the residential periphery of the Bogue Lagoon Fish Sanctuary. It would stand to reason that they may be distributed throughout the deeper reaches of the lagoon, however, reports are limited and proper underwater surveys are inhibited by poor visibility,” Zane said.
With several countries affected, governments are working together to find a common solution to the problem.
The United Nations Environment Programme’s Global Environment Facility (UNEP-GEF) is funding the Mitigating the Threat of Invasive Alien Species in the Insular Caribbean Project, which aims to assist regional scientists from Trinidad and Tobago to Bahamas, to come up strategies to manage the threat of Invasive Alien Species (IAS) including the lionfish.
The programme aims to develop a system for early detection, response and control of invasive alien species as well as systems to prevent their introduction.
The four-year project will tackle IAS in five countries including Trinidad and Tobago and St. Lucia, as well as the lionfish infestation in Jamaica, Dominican Republic and the Bahamas. The University of the West Indies Discovery Bay Marine Lab is working with the Montego Bay Marine Park, NEPA and other stakeholders to develop a management strategy, record data on the lionfish and develop passive capture mechanisms.
In the short term, Zane proposed culling as the most viable response. He is also calling for an immediate ban on the capture of predator populations including the Goliath and Nassau Grouper and protection for branching corals.
Worldwide, the impact, prevention and control of invasive species are estimated to cost $100 billion and the damage they cause at $1.4 trillion, or about five percent of global GDP.
*This story is part of a series of features on biodiversity by IPS, CGIAR/Biodiversity International, IFEJ and UNEP/CBD, members of Communicators for Sustainable Development (http://www.complusalliance.org).
In a forthcoming study in the journal Geophysical Research Letters, researchers report Pacific island soft corals reveal the “thermocline”, the point where cold, deep water meets warm surface water has gotten shallower, an indication of decreased ocean circulation predicted by global warming models.
“Climate modelers looking at how the Pacific might respond to global warming have predicted that the atmospheric patterns in the tropical Pacific would weaken, and if that happened, you would expect the thermocline to get shallower in the western tropical Pacific,” says study co-author Branwen Williams of the University of Toronto, in a statement. “Our data are some of the first proxy data to support what the modelers have been predicting.”
In the study, the researchers looked at corals at depths of 16, 280 and 345 feet depth, looking at how they grew in tree-ring-like patterns over time that are revealed in nitrogen and carbon measurements. Cold water brings more nutrients to the corals, leading to more growth, and serving as an indicator of circulation strength in the Pacific Ocean.
By Dan Vergano
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