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- RESEARCHERS REVIEW EVOLUTIONARY HISTORY OF MODERN ALGAE
- SCRIPPS RESEARCHERS DOCUMENT SIGNIFICANT CHANGES IN THE DEEP SEA—CLIMATE AND FOOD SUPPLY FLUCTUATIONS MAY HOLD MAJOR CONSEQUENCES FOR LIFE IN THE ABYSS
ET FIRST CONTACT "WITHIN 20 YEARS" By Marcus Chown From New Scientist
Texas A&M University release 21 July 2004 Trees and grass are usually the only "heroes" that come to mind for consuming carbon dioxide and producing oxygen for planet Earth, but they have allies in the water: phytoplankton, or in another word, algae. Phytoplankton are mostly single-celled photosynthetic organisms that feed fish and marine mammals. They are responsible for nearly 50 percent of the earth’s annual carbon-dioxide consumption and more than 45 percent of the oxygen production. Despite the important roles of modern phytoplankton, their evolutionary origins and rise to prominence in today’s oceans was an unresolved question in marine science. In the first study that looks at phytoplankton from combined perspectives of biology, chemistry and geology, researchers from three countries, including Texas A&M University at Galveston Assistant Professor Antonietta Quigg, who specializes in algae ecology and chemistry, examined modern phytoplankton development and reviewed their evolutionary history. Findings of the project appear in the current issue of Science magazine. Funding for the study is supported by a grant through the National Science Foundation Biocomplexity program, which aims to make new advances by bringing people together from different fields. Despite the early origins of cyanobacteria, an essential component of modern phytoplankton, the ancestors of the majority of phytoplankton that dominate the modern seas did not appear until 250 million years ago, the researchers note. This is fairly recent in geological terms. Cyanobateria appeared 3.8 billion years ago. A cyanobacterium is a single-celled photosynthetic organism, which with the help of sunlight could make carbon dioxide and water into oxygen and energy providing chemicals. The researchers showed that modern phytoplankton began to form at a time when the low oxygen conditions characterized much of the world’s oceans. Since a cyanobacterium was capable of producing oxygen and nutrients, another bacterium, or a one-celled organism, ate the cyanobacterium, kept a part of the cyanobacterium undigested, and let it function as an oxygen and energy generating organelle. This added the photosynthesis function to the eater, and transformed it into the phytoplankton that would later dominate the sea. The researchers found that changes in sea level, water chemistry and the amount of carbon-dioxide in the water, and even the evolution of grass-eating animals on land all contributed to the rise of the three dominant phytoplankton groups. For example, rising sea levels provided more ecospace for the phytoplankton, promoting increased diversity among the phytoplankton. Quigg, coauthor of the Science magazine article said the study could help scientists understand the effects of increased carbon dioxide, or the green house gases on life in the ocean at present and in the future. "One way to do that is to understand what was happening in the past," Quigg says. "If we have a theory or an idea, we could look in the past and check if that idea works." She says since some algae do very well with increase carbon dioxide and some do poorly, the evolutionary history will tell, with increased carbon-dioxide, what changes there may be in the types of algae in the water and how that will affect the fish and marine mammals that eat the algae. "If you have an ocean full of algae that use a lot of carbon-dioxide, then we may be able to resolve the problem of green house effect," Quigg says. "But if you have an ocean full of algae that do not like to use carbon-dioxide, then you are in big trouble. Carbon-dioxide will keep increasing." Quigg started participating in the study as a postdoctoral fellow at Rutgers University and continued the research after she joined Texas A&M at Galveston. Other coauthors of the article are Paul G. Falkowski, professor of biochemistry, biophysics and physiological adaptation, Oscar Schofield, associate professor of marine biology and ocean optics, Miriam E. Katz, assistant research professor at Rutgers University, Andrew H. Knoll, professor of evolutionary biology at Harvard University, John A. Raven, professor of biology at University of Dundee, UK, and F. J. R. Taylor, professor of biology at University of British Columbia, Canada. Read the original news release at http://www.tamu.edu/univrel/aggiedaily/news/stories/04/072104-5.html. An additional article on this subject is available at http://www.spacedaily.com/news/life-04zzu.html. SCRIPPS RESEARCHERS DOCUMENT SIGNIFICANT CHANGES IN THE DEEP SEA—CLIMATE AND FOOD SUPPLY FLUCTUATIONS MAY HOLD MAJOR CONSEQUENCES FOR LIFE IN THE ABYSS Scripps Institution of Oceanography release 22 July 2004 Although it covers more than two-thirds of Earth's surface, much of the deep sea remains unknown and unexplored, and many questions remain about how its environment changes over time. A new study led by scientists at Scripps Institution of Oceanography at the University of California, San Diego, has shed new light on significant changes in the deep sea over a 14-year period. Scripps Institution's Henry Ruhl and Ken Smith show in the new issue of the journal, Science, that changes in climate at the surface of the ocean may be impacting communities of larger animals more than 13,400 feet below the ocean surface. Important climatic changes such as El Niño and La Niña events are well known to affect regional and local areas, but Ruhl and Smith describe how such changes also can extend to the deep ocean, one of Earth's most remote environments. 
Scientists prepare to launch a "sled" used for capturing images of the deep sea environment. The sled takes nearly two-and-a-half hours to reach its destination more than 13,000 feet deep. "Large animals, the kind you would be able to see if you were standing on the bottom of the ocean, may be impacted by climate just the same as animals in shallow water or terrestrial environments," said Ruhl. In 1999, Smith and colleague Ronald Kaufmann showed that seafloor-dwelling animals were experiencing a long-term food shortage. The new study indicates that food supplies have since increased and that climate, food supplies and the abundance of large animals on the seafloor are linked. Since 1989 members of Smith's laboratory team have studied a deep-sea location in the eastern North Pacific Ocean approximately 136 miles west of Point Conception off the central California coast. "Station M," as the location is known, has been the site of one of the longest time-series studies of any abyssal area in the world. "It's important to study these places on a long timescale because you can't predict what is going to happen by just studying it once," said Smith, a research biologist in the Marine Biology Research Division at Scripps. "If you have changes such as these in such a large portion of the globe, you've got to pay attention to it." Ruhl and Smith use time-lapse photography, sediment traps and a host of other equipment to capture basic ecological information related to the seafloor community.  
Left: an image of the animal, Psychropotes longicauda, on the seafloor at Station M. Right: tracks made by the sea urchin, Echinocrepis sp., are clearly visible from the camera sled. The Science paper illustrates a stark contrast in the community structure of the 10 most dominant mobile animals before and after the powerful 1997-1998 El Niño/La Niña event. Animals examined as part of the study include deep-ocean sea cucumbers, urchins and brittle stars. While numbers of some animals decreased when food supplies were low during the 14-year period, certain other species seemed to thrive on such conditions. For a number of possible reasons, some of these animals may have a competitive advantage during food shortages. During their many trips to Station M, the researchers worked aboard the Scripps research vessel New Horizon. Each expedition began with a 30-hour trip out of San Diego heading northwest covering 300 miles. The researchers typically remained at Station M for a week or more to complete the various tasks necessary to retrieve, maintain and deploy instrumentation. One of the key pieces of equipment they used is a camera mounted on a "sled" that moves across the ocean bottom. Once lowered overboard, the device takes nearly two-and-a-half hours to reach its more than 13,000-foot-deep destination. A small animal-collecting net also makes the trip so the scientists can retrieve and inspect the various animals seen in the photography. The camera records about one photograph every five seconds. One hour of images can lead to weeks of analysis for the scientists. Forty-eight such photo transects (one transect can be nearly one mile across) were analyzed as part of the study. "The ocean is a source of food for human populations, but it's also a place of waste disposal," said Smith. "It's important to consider how you impact the deep sea. In that view it's puzzling that we don't study the deep sea in more detail." Funding for the study was provided by the National Science Foundation. Contacts: Mario Aguilera or Cindy Clark Phone: 858-534-3624 E-mail: scrippsnews@ucsd.edu Read the original news release at http://scrippsnews.ucsd.edu/article_detail.cfm?article_num=640. Additional articles on this subject are available at: http://www.astrobio.net/news/article1102.html http://www.spacedaily.com/news/life-04zzv.html Directory: projects -> marsbugs -> 2004 projects -> Rajinder Sachar Committee projects -> Cape Lookout National Seashore Historic Resource Study By projects -> Cape Lookout National Seashore Historic Resource Study By projects -> Revolutionizing Climate Modeling – Project Athena: a multi-Institutional, International Collaboration projects -> What is a Hurricane? projects -> General Information projects -> Press Information projects -> 1 Introduction 3 2 Designing an Embedded System 4 2004 -> Editor/Publisher 2004 -> Editor/Publisher Download 1.87 Mb. Share with your friends:
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