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Marine Resources


June 2011 Issue

Scientists Find Medical Potential in Marine Organism's Genome
An international team of researchers has deciphered the genome of a tropical marine organism known to produce substances potentially useful against human diseases, according to a study published in Proceedings of the National Academy of Sciences in April.

Despite the recognized capability of marine strains of the cyanobacterial genus Lyngbya, specifically the species L. majuscula, to create hundreds of natural products with biomedical promise, little is known about the genetics underlying their production.

But that may change soon, as a research team led by scientists at the Scripps Institution of Oceanogra?phy at the University of California, San Diego, have provided the first insights of the genome of Lyngbya majuscula 3L, a Caribbean organism that generates compounds in development as potential treatments against cancer and neurodegenerative diseases.

The team overcame several obstacles due to the organism's complex, intermeshed growth in the wild with a range of other bacteria, muddying a clear picture of the genome. The results revealed a complex gene network suggesting an enhanced ability of the organism to adapt to shifting conditions in the marine environment.

"These compounds have gained considerable attention due to their pharmaceutical and biotechnology potential, but they are also notorious for their environmental toxicity and threats to humans, wildlife and livestock," the authors noted.

The researchers also studied the limitations and shortcomings of Lyngbya majuscula 3L. For example, it's been assumed that the species and its cousins in the Lyngbya genus convert, or "fix," nitrogen from the atmosphere into organic molecules, but Lyngbya majuscula 3L lacks the genes necessary for nitrogen fixation, the researchers said.

"It's possible that strains of L. majuscula reported to fix nitrogen may have been misidentified because it is visually very similar to other filamentous cyanobacteria species and we found that this marine strain doesn't seem capable of fixing nitrogen on its own," study author Emily Monroe said.

While marine Lyngbya strains are proven prolific generators of natural products with biomedical and pharmaceutical potential, scientists said, the new study shows more work is needed to pinpoint which species generates which natural products. For more information, visit http://ucsdnews.ucsd.edu.

Restricted Fishing Area Shows Recovery, Study Reports
Seafloor communities in a restricted fishing area in NOAA's Stellwagen Bank National Marine Sanctuary showed signs of recovery from chronic fishing gear impacts but are not fully stable, University of Connecticut and Cal?ifornia State University researchers found in April.

The finding is significant, the scientists said, because bottom trawlers, dredges and gillnets, for example, can alter the ocean floor and benthic ecosystems that provide food and shelter for fish and other marine species.

The habitat closure area, located in the western corner of the Gulf of Maine, overlaps 22 percent of the sanctuary and was implemented in 1998 by NOAA to aid in the recovery of groundfish stocks. The area has also provided an opportunity to assess how restricting an area's use can be a tool for conserving biological diversity. Most commercial fishing was prohibited in the closure area, but lobster traps, recreational hook–and–line and mid–water trawls were allowed.

The authors caution that their observations "neither support nor reject" the assumption that cessation or reduction of fishing will allow populations and communities to fully recover. They recommend continued monitoring over a larger number of sites within the sanctuary to determine how seafloor communities in the Gulf of Maine respond to various human uses. For more information, visit www.sciencedaily.com.

Radio Transmitters Used to Find Sea Trout's Migratory Route

Researchers from the University of Gothenburg said they hope to reveal the migratory route the sea trout take to sea by surgically inserting radio transmitters into 100 sea trout from the Halland River in Himleån, Sweden.

"The environmental requirements of trout and their behavior in the rivers where they are born have been studied for several decades, but we know very little about their adult lives at sea. With the aid of radio transmitters, we hope to be able to analyze how sea trout migrate and in what environments they move," said Johan Höjesjö of the University of Gothenburg.

Knowledge of how local populations of sea trout mix in the sea is also lacking. It is important to be able to locate different populations and their spread from the point of view of fisheries conservation. The researchers will therefore also be studying the genetic kinship of trout along the coast.

To obtain as broad a sample as possible, researchers are asking anglers along the Swedish west coast to collect fin samples so they can analyze the kinship of trout from different waters. For more information, visit www.sciencedaily.com.

Scotland's First Marine Reserve Producing Benefits, Study Finds
Scotland's first fully protected marine reserve is already showing positive signs for fishermen and conservationists after only two years of operation, according to a study by the University of York and the Community of Arran Seabed Trust.

The research, published in Marine Biology in April, shows commercially valuable scallops and several species of algae known to promote biodiversity are much more abundant in the marine reserve, where fishing is banned, than in surrounding waters.

One of the most significant findings was the abundance of juvenile scallops was much higher in the reserve than outside. This was linked to the high levels of kelp and maerl, an algae that forms coral–like beds, inside the reserve where adult scallops were also larger and older. As stocks of scallops build up in marine reserves, they can start to breed at high levels, helping to seed surrounding fishing grounds.

While scallops are not widely consumed in the U.K., they are currently the region's third most valuable seafood species, worth almost £50 million in 2009. Dredging for them can severely damage sensitive seabed habitats. For more information, visit www.york.ac.uk.


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