Phytoplankton is a microscopic ocean plant and an important part of the ocean food chain. By knowing what limits its growth scientists can better understand how ecosystems respond to climate change.
The study focused on phytoplankton in the tropical Pacific Ocean. It is an area of the ocean that plays a particularly important role in regulating atmospheric carbon dioxide and the world's climate. This area of the ocean is the largest natural source of carbon dioxide to the atmosphere.
"We concluded that nitrogen is the primary element missing for algae growth and photosynthesis in the northern portion of the tropical Pacific, while it was iron that was most lacking everywhere else," said Michael J. Behrenfeld, an ocean plant ecologist from Oregon State University, Corvallis, Ore.
Scientists determined when phytoplankton is stressed from lack of iron; it appears greener, or healthier than they really are. Normally, greener plants are growing faster than less green plants. When iron is lacking, enhanced greenness does not mean phytoplankton are growing better. They are actually under stress and unhealthy. These conclusions solved the mystery why healthy looking phytoplankton are actually not so healthy.
"Because we didn't know about this effect of iron stress on the greenness of algae or phytoplankton before, we have always assumed that equally green waters were equally productive," Behrenfeld said. "We now know this is not the case, and that we have to treat areas lacking iron differently."
For the tropical Pacific, correction for this "iron-effect" decreases scientists' estimates of how much carbon ocean plants photosynthesize for the region by roughly two billion tons. This figure represents a tremendous amount of carbon that remains in the atmosphere that scientists previously thought were being removed.
The results about the false health of phytoplankton allow scientists using computer models to re-create the movement of carbon around the world much more accurately. Resource managers will become more knowledgeable about where carbon is going and the impact of recreational, industrial or commercial processes that use or produce carbon. Researchers better understand the Earth as an ecosystem, and can incorporate these findings in future modeling, analysis and predictions.
While satellite data from NASA's Sea-viewing Wide Field-of-view Sensor played an important part in the study, the real cornerstone of the discovery was ship-based measurements of fluorescence.
Fluorescence occurs when plants absorb sunlight and some of that energy is given back off again as red light. Scientists looked at approximately 140,000 measurements of fluorescence made from 1994 to 2006 along 36,040 miles of ship tracks. They found that phytoplankton give off much more fluorescence when the plants do not have sufficient iron. It is this signal they used to fingerprint what parts of the ocean are iron-stressed and what parts are nitrogen-stressed.
It is important that scientists understand how ocean plants behave because all plants play a critical role in maintaining a healthy planet. Plants annually take up billions of tons of carbon dioxide from the atmosphere through photosynthesis and use this carbon to create the food that nearly all other organisms on Earth depend on for life.
Nutrients that make ocean plants thrive, such as nitrogen and phosphate, mostly come from the deep parts of the ocean, when water is mixed by the wind. Iron also can come from dust blowing in the air.
Approximately half of the photosynthesis on Earth occurs in the oceans, and the remainder on land. Ocean and land plants share the same basic requirements for photosynthesis and growth. These requirements include water, light and nutrients. When these three are abundant, plants are abundant. When any one of them is missing, plants suffer.
Rob Gutro | EurekAlert!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
22.03.2017 | Materials Sciences
22.03.2017 | Physics and Astronomy
22.03.2017 | Materials Sciences