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BBC News: Satellites track turtle ‘lost years’

03/05/2014 admin Leave a comment

http://www.bbc.com/news/science-environment-26435342

5 March 2014 Last updated at 02:43 ET

By Jonathan Amos Science correspondent, BBC News

Very young turtle. Getting tags to stay on fast-growing young turtles has been a challenge

New insights have been gained into the “lost years” of loggerhead turtles.

Tiny satellite tags have tracked months-old animals in the uncertain period when they leave US coastal waters and head out into the wider Atlantic Ocean. The data suggests the loggerheads can spend quite some time in the Sargasso Sea, possibly living in amongst floating mats of sargassum seaweed. The observations are reported in a journal of the Royal Society.

“This has been a fun study because the data suggest the turtles are doing something a little bit unexpected to what everyone had assumed over the past few decades, and it boils down to having the right technology to be able to follow the animals,” said lead author Dr Kate Mansfield from University of Central Florida, Orlando.

Scientists have long struggled to track the earliest years of Atlantic loggerheads (Caretta caretta).

Loggerhead Sea Turtle

Scientific name: Caretta caretta
Loggerheads in the North Atlantic cover thousands of km
Loggerheads are found in the Atlantic, Pacific and Indian oceans.
Considered “endangered” by the International Union for the Conservation of Nature (IUCN).

After emerging from their nests on Florida’s beaches, the infant turtles, or neonates, make a dash for the water and head out on a great adventure.

Precisely where they go and what they do with their time before returning as large juveniles to the US seaboard has been something of a mystery.

Genetics studies, bycatch, strandings and opportunistic sightings offshore had given broad hints – that they travel in a huge circle within the currents associated with the North Atlantic subtropical gyre, reaching the Azores and Cape Verde before heading back to the Gulf of Mexico and Florida. Tracking by satellite would give more definitive answers, but attaching data tags to turtles that are just a few months old, and growing rapidly, has been a struggle.

But by using flexible mounts and preparation techniques usually found in a manicurist’s salon, Dr Mansfield’s team got the tags to stay on the animals’ shells for up to 220 days. And it is with this new data that the scientists can see the young turtles dropping out of the gyre’s predominant currents into the middle of the Atlantic – into what is often referred to as the Sargasso Sea. The way the tags worked indicated also that the loggerheads mostly stayed at the sea surface. This could be seen in the temperature recordings as well, although these readings were quite a bit higher than expected.

Turtles for release. The turtles in this study were released off the US East Coast

Sargassum: The young turtles probably get a warming benefit from associating with sargassum. This has led the team to hypothesise that the turtles are living in and around the great mats of sargassum found in the central Atlantic. The activity is well known and assumed in young turtles to have something to do with the protection from predation and foraging opportunities that the seaweed offers. But Dr Mansfield believes there may be thermal benefits for these cold-blooded creatures, too.

“Their survival, their metabolism, their feeding behaviour – everything is enhanced by optimal temperatures. And the sargassum is almost like a warm, floating micro-habitat. The mats trap water where you can get localised warming,” she told BBC News.

“We actually did a down-and-dirty experiment with sargassum in a bucket of water alongside a water bucket without sargassum, and, sure enough, you get a temperature difference that could explain what we saw from the tags.”

Atlantic loggerheads are classified as endangered, and that concern is heightened because they take so long to reach sexual maturity. It can be 25 years or more before they get reproduce and put back into the population. Knowing what they get up to during their juvenile phases is therefore very useful conservation information.

The new study appears in the journal Proceedings of the Royal Society B. Prof Brendan Godley is a co-ordinator of the Marine Turtle Research Group, which is based at Exeter University, UK. He commented: “This paper marks a major step forward in the development of satellite tracking.

“So far, tracking has focussed on adults, particularly females with few tags on juveniles and a handful on open oceanic life stages. This is the first that has tracked turtles so small. Tracking turtles this way is continually offering new insights into the life history patterns of these elusive species, greatly enhancing our ability to improve the conservation of this important animal group,” he told BBC News.

Hear more from Kate Mansfield on BBC Radio 4’s Inside Science programme with Lucie Green this Thursday at 1630 GMT.

Turtle in hand. Tracking studies inform conservation efforts

Near surface The data indicates the young turtles stayed close to the surface
All images by Jim Abernethy (NMFS permit 1551).

coral

NSF: Press Release 14-025 Overfishing of Caribbean coral reefs favors coral-killing sponges

02/25/2014 admin Leave a comment

http://www.nsf.gov/news/news_summ.jsp?cntn_id=130507

Caribbean-wide study shows protected coral reefs dominated by sponges with chemical defenses
Image of a sponge smothering a living coral head on a reef

A sponge smothers a living coral head on a reef that lacks predatory angelfish.

February 24, 2014

Scientists had already demonstrated that overfishing removes angelfish and parrotfish that feed on sponges growing on coral reefs–sponges that sometimes smother the reefs. That research was conducted off Key Largo, Fla.

Now, new research by the same team of ecologists suggests that removing these predators by overfishing alters sponge communities across the Caribbean.

Results of the research, by Joseph Pawlik and Tse-Lynn Loh of the University of North Carolina Wilmington, are published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

“In fact,” says Pawlik, “healthy coral reefs need predatory fish–they keep sponge growth down.”

The biologists studied 109 species of sponges at 69 Caribbean sites; the 10 most common species made up 51 percent of the sponge cover on the reefs.

“Sponges are now the main habitat-forming organisms on Caribbean coral reefs,” says Pawlik.

Reefs in the Cayman Islands and Bonaire–designated as off-limits to fishing–mostly have slow-growing sponges that manufacture chemicals that taste bad to predatory fish.

Fish numbers are higher near these reefs. Predatory fish there feast on fast-growing, “chemically undefended” sponges. What’s left? Only bad-tasting, but slow-growing, sponges.

Overfished reefs, such as those off Jamaica and Martinique, are dominated by fast-growing, better-tasting sponges. “The problem,” says Pawlik, “is that there are too few fish around to eat them.” So the sponges quickly take over the reefs.

“It’s been a challenge for marine ecologists to show how chemical defenses influence the structure of ocean communities,” says David Garrison, a program director in the National Science Foundation’s (NSF) Division of Ocean Sciences, which funded the research.

“With this clever study, Pawlik and Loh demonstrate that having–or not having–chemical defenses structures sponge communities on Caribbean coral reefs.”

The results support the need for marine protected areas to aid in coral reef recovery, believes Pawlik.

“Overfishing of Caribbean coral reefs, particularly by fish trapping, removes sponge predators,” write Loh and Pawlik in their paper. “It’s likely to result in greater competition for space between faster-growing palatable sponges and endangered reef-building corals.”

The researchers also identified “the bad-tasting molecule used by the most common chemically-defended sponge species,” says Pawlik. “It’s a compound named fistularin 3.”

Similar chemical compounds defend some plants from insects or grazers (deer, for example) in onshore ecosystems, “but the complexity of those ecosystems makes it difficult to detect the advantage of chemical defenses across large areas,” says Pawlik.

When it comes to sponges, the view of what’s happening is more direct, he says. “The possibility of being eaten by a fish may be the only thing a reef sponge has to worry about.”

And what happens to reef sponges may be critical to the future of the Caribbean’s corals.

-NSF-

Media Contacts
Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov

Related Websites
NSF grant: Chemical ecology of sponges on Caribbean coral reefs: http://www.nsf.gov/awardsearch/showAward?AWD_ID=1029515&HistoricalAwards=false

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2014, its budget is $7.2 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

Useful NSF Web Sites:
NSF Home Page: http://www.nsf.gov
NSF News: http://www.nsf.gov/news/
For the News Media: http://www.nsf.gov/news/newsroom.jsp
Science and Engineering Statistics: http://www.nsf.gov/statistics/
Awards Searches: http://www.nsf.gov/awardsearch/

Special thanks to Richard Charter

coral disease

Molecular Ecology: Bacterial profiling of White Plague Disease across corals and oceans indicates a conserved and distinct disease microbiome by C. Roder, C. Arif, C. Daniels, E.Weil, C. Voolstral

02/17/2014 admin Leave a comment

Bacterial profiling of White Plague Disease across corals and oceans indicates a conserved and distinct disease microbiome – Roder – 2014 – Molecular Ecology – Wiley Online Library

Article first published online: 29 JAN 2014

DOI: 10.1111/mec.12638

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Molecular Ecology: Volume 23, Issue 4, pages 965–974, February 2014

16S rRNA gene microarray;
coral disease;
microbial community;
Orbicella faveolata ;
Orbicella franksi ;
Pavona duerdeni ;
Porites lutea ;
White Plague Disease (WPD);
White Plague-like Disease;
White Syndrome (WS)

Abstract

Coral diseases are characterized by microbial community shifts in coral mucus and tissue, but causes and consequences of these changes are vaguely understood due to the complexity and dynamics of coral-associated bacteria. We used 16S rRNA gene microarrays to assay differences in bacterial assemblages of healthy and diseased colonies displaying White Plague Disease (WPD) signs from two closely related Caribbean coral species, Orbicella faveolata and Orbicella franksi. Analysis of differentially abundant operational taxonomic units (OTUs) revealed strong differences between healthy and diseased specimens, but not between coral species. A subsequent comparison to data from two Indo-Pacific coral species (Pavona duerdeni and Porites lutea) revealed distinct microbial community patterns associated with ocean basin, coral species and health state. Coral species were clearly separated by site, but also, the relatedness of the underlying bacterial community structures resembled the phylogenetic relationship of the coral hosts. In diseased samples, bacterial richness increased and putatively opportunistic bacteria were consistently more abundant highlighting the role of opportunistic conditions in structuring microbial community patterns during disease. Our comparative analysis shows that it is possible to derive conserved bacterial footprints of diseased coral holobionts that might help in identifying key bacterial species related to the underlying etiopathology. Furthermore, our data demonstrate that similar-appearing disease phenotypes produce microbial community patterns that are consistent over coral species and oceans, irrespective of the putative underlying pathogen. Consequently, profiling coral diseases by microbial community structure over multiple coral species might allow the development of a comparative disease framework that can inform on cause and relatedness of coral diseases.