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 In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>