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In a NASA study, scientists have concluded that when Earth's climate warms, there is a reduction in the ocean's primary food supply. This poses a potential threat to fisheries and ecosystems.

By comparing nearly a decade of global ocean satellite data with several records of Earth's changing climate, scientists found that whenever climate temperatures warmed, marine plant life in the form of microscopic phytoplankton declined. Whenever climate temperatures cooled, marine plant life became more vigorous or productive. The findings will appear in the journal Nature on Dec. 7.

The results provide a preview of what could happen to ocean biology in the future if Earth's climate warms as the result of increasing levels of greenhouse gases in the atmosphere.

"The evidence is pretty clear that the Earth's climate is changing dramatically, and in this NASA research we see a specific consequence of that change," said oceanographer and study co-author Gene Carl Feldman of NASA's Goddard Space Flight Center, Greenbelt. Md. "It is only by understanding how climate and life on Earth are linked that we can realistically hope to predict how the Earth will be able to support life in the future."

Phytoplankton are microscopic plants living in the upper sunlit layer of the ocean. They are responsible for approximately the same amount of photosynthesis each year as all land plants combined. Changes in phytoplankton growth and photosynthesis influence fishery yields, marine bird populations and the amount of carbon dioxide the oceans remove from the atmosphere.

"Rising levels of carbon dioxide in the atmosphere play a big part in global warming," said lead author Michael Behrenfeld of Oregon State University, Corvallis. "This study shows that as the climate warms, phytoplankton growth rates go down and along with them the amount of carbon dioxide these ocean plants consume. That allows carbon dioxide to accumulate more rapidly in the atmosphere, which would produce more warming."

The findings are from a NASA-funded analysis of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument on the OrbView-2 spacecraft, launched in 1997. SeaWiFS is jointly operated by GeoEYE, Dulles, Va. and NASA.

The uninterrupted nine-year record shows in great detail the ups and downs of marine biological activity or productivity from month to month and year to year. Captured at the start of this data record was a major, rapid rebound in ocean biological activity after a major El Nino event. El Nino and La Nina are major warming or cooling events, respectively, that occur approximately every 3-7 years in the eastern Pacific Ocean and are known to change weather patterns around the world.

Scientists made their discovery by comparing the SeaWiFS record of the rise and fall of global ocean plant life to different measures of recent global climate change. The climate records included several factors that directly effect ocean conditions, such as changes in sea surface temperature and surface winds. The results support computer model predictions of what could happen to the world's oceans as the result of prolonged future climate warming.

"When we compared changes in phytoplankton activity with simultaneous changes in climate conditions, the agreement between the two records was simply astonishing," Behrenfeld said.

Ocean plant growth increased from 1997 to 1999 as the climate cooled during one of the strongest El Niño to La Niña transitions on record. Since 1999, the climate has been in a period of warming that has seen the health of ocean plants diminish.

The new study also explains why a change in climate produces this effect on ocean plant life. When the climate warms, the temperature of the upper ocean also increases, making it "lighter" than the denser cold water beneath it. This results in a layering or "stratification" of ocean waters that creates an effective barrier between the surface layer and the nutrients below, cutting off phytoplankton's food supply. The scientists confirmed this effect by comparing records of ocean surface water density with the SeaWiFS biological data.

The six-wheel robot spent its first week at Victoria Crater acting like a tourist, snapping pictures of the half-mile-wide jagged crevasse filled with dramatic cliffs of thickly layered rocks, which hold clues about the Martian past.

New aerial images snapped by the Mars Reconnaissance Orbiter, which slipped into orbit last year, gave scientists a bird's-eye view of the crater and evidence of erosion around the rim. In one image, the rover appeared as a speck with its wheel tracks visible in the soil.

Mars' Victoria Crater at Meridiani Planum is seen in this image taken by NASA's High Resolution Imaging Science Experiment (HiRISE) camera in this picture released October 6, 2006. The crater has been a long-term destination for the Mars Rover mission for the past 21 months, and is now being explored by Mars Rover Opportunity.

After embracing a chance to meet with their families, the STS-115 astronauts finished up their landing day answering questions from the media during a televised news conference. Mission Commander Brent Jett reflected on the success of the flight, which delivered a new solar array truss to the International Space Station. "The mission from our standpoint went off very well," summarized Jett.

The commander continued by offering congratulatory thoughts on each of his crew members. Of Pilot Chris Ferguson, Jett said: "He backed me up, kept me out of trouble. It was a real privilege to fly with him." Jett also greatly praised first time astronaut and spacewalker Heidemarie Stefanyshyn-Piper. "Heidi is a natural… she is a very clever person and came up with a lot of ideas that you don't usually get from a first time flier," said Jett.

After a good night's sleep in the crew quarters at Kennedy Space Center, Fla., the astronauts will return home to Johnson Space Center in Houston on Friday. There, the crew will enjoy a happy homecoming as thanks for the successful completion of what is quickly being regarded as one of the most complex and productive space missions in history.

Atlantis glided to a predawn landing at 6:21 a.m. EDT, concluding a successful mission to resume construction of the International Space Station. Launched Sept. 9, the orbiter arrived at the station on the 11th to delivered and install the P3/P4 integrated truss segment duirng three successful spacewalks.

For the latest information on space station activities, please visit: http://www.nasa.gov/mission_pages/station/main/index.html

Scientists have received and are analysing the final data gathered by SMART-1 on 2 September, prior to today's Moon impact. This update presents several of the images received, as well as additional images and information from the worldwide ground observation campaign.

The seven AMIE images included in this update article were taken on 2 September by the AMIE camera on board SMART-1 during the last few orbits prior to Moon impact. They were taken between 15:19 - 17:34 CEST (17:19 - 19:34 UT) and were analysed by camera scientists during the night of 2-3 September.
The images include both oblique and nadir (vertical) views, with the camera pointing mode having been selected to best exploit the illumination conditions during the final orbits over the Moon's night side.

In several of the images, the Moon's horizon can clearly been seen; excellent details of the surface are also visible.

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This a storm shoted by NASA satellite