Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Find Link Between the Input of Iron and Biological Productivity in the Ancient Pacific Ocean

16.03.2012
A team of researchers has just published a new paper, lead authored by Boston University Professor of Earth Sciences Richard W. Murray, that provides compelling evidence from marine sediment that supports the theory that iron in the Earth’s oceans has a direct impact on biological productivity, potentially affecting the amount of carbon dioxide in the atmosphere and, in turn, atmospheric temperature. These findings have been published in the March 11, 2012 online edition of the journal Nature Geoscience (DOI: 10.1038/NGEO1422). (See www.nature.com/naturegeoscience.)

The oceans are the world's largest inventory of reactive carbon. Over time, oceanic carbon exchanges with the atmospheric reservoir of carbon in the form of carbon dioxide (CO2). Much of the carbon present in the surface oceans is taken up by the growth of marine plants (primarily by phytoplankton) through photosynthesis. Consequently, marine biological productivity is recognized as a factor in determining the amount of atmospheric carbon dioxide at various times in the Earth’s history.

The magnitude of ocean biological productivity depends on the availability of key nutrients, including nitrogen, phosphorous and metals such as iron. In fact, previous research has established that biological productivity in the equatorial Pacific and the oceans around Antarctica is limited by the amount of iron, a micro-nutrient, more than by the better-known 'major' nutrients nitrogen and phosphorus.

The link between iron and marine biological productivity first gained attention more than twenty years ago with the publication of a controversial paper by the late John Martin, an oceanographer at the at the Moss Landing Marine Laboratories (California State University). Martin’s “Iron Hypothesis” postulates that biological productivity could be stimulated by increasing the amount of iron in the ocean, which in turn would draw down atmospheric carbon dioxide. He further argued that this process contributed to ancient ice ages: When the earth was drier and therefore dustier, more iron was deposited in the oceans, thus stimulating biological productivity, reducing atmospheric carbon dioxide and cooling the earth (the inverse of global warming). This could result in prolonged glacial periods. By closely examining the sedimentary record, Murray and his colleagues have established a clear relationship between plant plankton (diatoms) and the input of iron, exactly as Martin predicted.

Many researchers since Martin have established that the availability of iron in the modern ocean determines the amount of biological production in high-nutrient, low-chlorophyll regions and may be important in lower-nutrient settings as well. By examining the paleo-oceanographic record of iron input and the deposition of diatoms, Murray and his colleagues found that the ancient system is highly consistent with what occurs in the oceans today.

The new publication provides an important sedimentary record from the high-nutrient, low-chlorophyll region of the equatorial Pacific Ocean, and shows strong links between iron input and the export and burial of biogenic silica (opal produced from diatoms) over the past million years. Although the direct relationship to climate remains unclear, data collected by the team demonstrate that iron accumulation is more closely tied to the accumulation of opal than any other biogenic component, and that high iron input closely correlates with substantially increased opal sedimentation. The strong links between iron and opal accumulation in the past are in agreement with the modern biogeochemical behavior of iron and silica, and the response of the diatom community to their mutual availability, all of which supports Martin’s postulate of a biological response to iron delivery over long timescales.

The co-authors of this study are Margaret Leinen, Executive Director, Harbor Branch Oceanographic Institution and Associate Provost for Marine and Environmental Initiatives, Florida Atlantic University, and Christopher W. Knowlton, Graduate School of Oceanography, University of Rhode Island, Narragansett. Murray first began working on these research ideas while a post-doctoral researcher in Leinen’s laboratory at the University of Rhode Island in the 1990’s, and Knowlton is a former graduate student of Leinen’s who studied the opal distribution in these sediments.

About Boston University—Founded in 1839, Boston University is an internationally recognized private research university with more than 30,000 students participating in undergraduate, graduate, and professional programs. As Boston University’s largest academic division, the College and Graduate School of Arts & Sciences is the heart of the BU experience with a global reach that enhances the University’s reputation for teaching and research.

Richard W. Murray, Professor
Department of Earth Sciences
Boston University
685 Commonwealth Avenue
Boston, MA 02215
Office Phone (617) 353-6532
Email rickm@bu.edu

Richard W. Murray, Professor | Newswise Science News
Further information:
http://www.bu.edu

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>