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March 2011 Issue

Newly Discovered Algae Live in Both Freshwater and Ocean
A team of biologists recently announced that it has discovered an entirely new group of algae living in a variety of marine and freshwater environments. This algae, which the researchers dubbed “rappemonads,” has DNA that is distinctly different from that of other known algae. In fact, scientists say humans and mushrooms are more closely related than rappemonads are to some other common algae (such as green algae). Based on DNA analysis, the researchers believe that they have discovered not just a new species or genus, but a potentially large and novel group of microorganisms.

The rappemonads were found in a wide range of habitats, in both fresh and salt water, and at temperatures ranging from 52° to 79° F.

Sebastian Sudek, Heather Wilcox and Alexandra Worden of the Monterey Bay Aquarium Research Institute, along with collaborators at Dalhousie University and the Natural History Museum, London, discovered these microscopic algae by following up on an unexpected DNA sequence listed in a research paper from the late 1990s. They named the algae rappemonads after Michael Rappé, a professor at the University of Hawaii, who was first author of that paper.

Following up on their initial lead, the research team developed two different DNA probes that were designed to detect the unusual DNA sequences reported by Rappé. Using these probes, the researchers analyzed samples collected from the Northeast Pacific Ocean, the North Atlantic, the Sargasso Sea and the Florida Straits, as well as samples collected from several freshwater sites. To the team’s surprise, they discovered evidence of organisms containing the unusual DNA sequence at all five locations.

As to why these apparently widespread algae had not been detected sooner, Sudek speculates that it may be partly due to their size. “They are too small to be noticed by people who study bigger algae such as diatoms, yet they may be filtered out by researchers who study the really small algae, known as picoplankton.”


Fluorescent Color of Coral Larvae Predicts if They Will Settle
Young staghorn coral that fluoresce redder are less likely to settle and develop into coral polyps than their greener peers, University of Texas at Austin biologists have discovered.

“By simply looking at the color of a larval population, we may soon be able to say which larvae are going to be long-range dispersers and which will be short-range dispersers,” Mikhail “Misha” Matz, assistant professor of biology, said. “Under global warming, we expect a lot of evolution of this particular life history trait.”

Matz said researchers expect to see long-range dispersers starting to win, because the corals need to shift to cooler latitudes.

Coral response to the settlement cue is under strong genetic control, but it is not clear yet how that is linked with fluorescence. Matz says the correlation could be completely random; the genes that determine color and those that determine settlement might be next to each other in the chromosome and have no functional connection. Alternatively, fluorescence could somehow be related to the capacity of larvae to sense the proximity of a reef.

The research was published in late January in Proceedings of the Royal Society B.


Coral Reef Algae Could Provide Drugs for Bone Diseases
A recent study in the journal ACS Medicinal Chemistry Letters concludes that largazole, a substance obtained from a coral-reef inhabiting cyanobacterium, appears to be an ideal blueprint for developing new drugs for serious fractures, osteoporosis and other bone diseases.

The Duke University researchers indicate that largazole was derived from and named for marine cyanobacteria that grow in Key Largo, Florida. Their research shows that largazole has an unusual dual action on injured or diseased bones. It stimulates a process in the body called osteogenesis, which involves the growth of new bone and the repair of damaged bone. Largazole also blocks the opposite process in which the body naturally breaks down and resorbs bone. The researchers also showed that largazole mixed with collagen and calcium phosphate—the components of bone—helped heal fractured bones in laboratory mice and rabbits.


Hydrophones Help Locate Right Whales in North Atlantic
Scientists using undersea hydrophones have documented the appearance of endangered right whales in a region east of Greenland, where they historically had been hunted but were thought to be extinct.

The scientists recorded more than 2,000 whale vocalizations from 2007 through 2008. They since have identified them as right whales and mapped the geographic origin of those recordings. This mapping shows that the whales are using an area where ships commonly pass while in transit between the United States and Europe.

Results of the research were published in late January in the journal Biology Letters.

Lead author David Mellinger of Oregon State University said hydrophones enable scientists to listen for whales in remote areas where visual observations are difficult. Right whales have unique vocalization patterns.

“In the last 50 years, there have only been two confirmed sightings of right whales in the Cape Farewell Ground, which is about 500 kilometers east of the southern tip of Greenland,” Mellinger said. “The weather there makes it almost impossible to conduct regular surveys.

“But it was an important area historically for the whales, and we needed to determine if they were still using it. The hydrophones showed that not only are they using the Cape Farewell Ground, but that they’ve broadened the range of where we’ve known them to be in the past.”

Despite more than 75 years of international protection, scientists estimate that fewer than 450 North Atlantic right whales remain.


2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2011:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC

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