Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA satellite sees ocean plants increase, coasts greening

04.03.2005


A few years ago, NASA researcher Watson Gregg published a study showing that tiny free-floating ocean plants called phytoplankton had declined in abundance globally by 6 percent between the 1980s and 1990s. A new study by Gregg and his co-authors suggests that trend may not be continuing, and new patterns are taking place.



Why is this important? Well, the tiny ocean plants help regulate our atmosphere and the health of our oceans. Phytoplankton produce half of the oxygen generated by plants on Earth. They also can soften the impacts of climate change by absorbing carbon dioxide, a heat-trapping greenhouse gas. In addition, phytoplankton serve as the base of the ocean food chain, so their abundance determines the overall health of ocean ecosystems. Given their importance, it makes sense that scientists would want to closely track trends in phytoplankton numbers and in how they are distributed around the world.

Gregg and his colleagues published their new study in a recent issue of Geophysical Research Letters. The researchers used NASA satellite data from 1998 to 2003 to show that phytoplankton amounts have increased globally by more than 4 percent. These increases have mainly occurred along the coasts. No significant changes were seen in phytoplankton concentrations within the global open oceans, but phytoplankton levels declined in areas near the center of the oceans, the mid-ocean gyres. Mid-ocean gyres are "ocean deserts", which can only support low amounts of phytoplankton. When viewed by satellite, these phytoplankton-deprived regions look deep-blue, while in aquatic regions where plant life thrives, the water appears greener.


"The ocean deserts are getting bluer and the coasts are getting greener," said Gregg, an oceanographer at NASA’s Goddard Space Flight Center (GSFC), Greenbelt, Md. "The study suggests there may be changes occurring in the biology of the oceans, especially in the coast regions."

Phytoplankton amounts have increased by 10.4 percent along global coast regions, where the ocean floor is less than 200 meters (656 feet) deep. Ocean plant life has greened the most in the Patagonian Shelf and the Bering Sea, and along the coasts of the Eastern Pacific Ocean, Southwest Africa, and near Somalia. Both the Patagonian Shelf and the California/Mexican Shelf showed large increases in phytoplankton concentrations of over 60 percent.

Meanwhile, the researchers observed declines in phytoplankton amounts in five mid-ocean gyres over the six-year study period, including the North and South Atlantic, and North and South Pacific oceans, and a possible new gyre region in the North Central Indian ocean. At the same time, for all but the North Atlantic gyre, sea surface temperatures increased in at least one season. "In the mid-ocean gyres, the downward trends in phytoplankton concentrations do appear related to mid-ocean sea surface temperatures," said Gregg.

Phytoplankton growth is largely dependent on amounts of nutrients and light available to the plants. Warmer water temperatures can create distinct layers in the ocean surface, which allows less of the nutrient-rich, colder deeper water to rise up and mix with sunny surface layers where phytoplankton live. Winds churn and mix the ocean water, carrying nutrient-rich waters to the sunny surface layer, so when winds decline mixing declines, and phytoplankton can suffer.

In a number of open ocean regions, increases in phytoplankton levels countered the declines found in the gyres and other areas. For example, a 72 percent increase in phytoplankton abundance occurred in the Barents Sea. The researchers observed a smaller 17 percent increase in phytoplankton amounts in the Western Central Pacific near Indonesia and the Philippines. The waters cooled in the Western Pacific, while wind stresses increased by 26 percent over the study period. The cooling water and increasing winds are consistent with climate conditions that lead to greater mixing of water.

The six full years of data used in this analysis came from NASA’s Sea-viewing Wide Field-of-view Sensor (SeaWiFS), which detects ocean colors. Chlorophyll is the substance or pigment in plants that appears green and captures energy from sunlight. The sunlight, along with carbon dioxide and water, are processed by the phytoplankton to form carbohydrates for building cells. SeaWiFS measures this greenness. While the study refers to the measurement of chlorophyll a concentrations in the ocean, researchers use the measures of chlorophyll a to estimate amounts of phytoplankton.

While declines in phytoplankton abundance in mid-ocean gyres appear related to warming oceans, a number of factors requiring more study to may be contributing to the coastal increases in plant life. "We don’t know the causes of these coastal increases," said Gregg. "The trends could indicate improved health of the ecosystems as a whole, or they could be a sign of nutrient stress." Causes of nutrient stress include land run-off that deposits agricultural fertilizers and other nutrients in the oceans. The run-off can promote large algal blooms that can deplete the water of oxygen.

Gregg and coauthors caution that the length of time the data cover is too short to answer questions about long term trends, but for the time being the phytoplankton declines in the global oceans observed between the 1980s and 1990s appear to have subsided.

Co-authors on the study include Nancy Casey of Science Systems Applications, Inc., who works at NASA GSFC, and Charles McClain, also a researcher at NASA GSFC.

Rob Gutro | EurekAlert!
Further information:
http://www.gsfc.nasa.gov

More articles from Earth Sciences:

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

nachricht Canadian glaciers now major contributor to sea level change, UCI study shows
15.02.2017 | University of California - Irvine

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>