Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Southern Ocean: Iron fertilization might be less efficient for deep-ocean carbon dioxide storage

11.11.2014

A new study performed by a team of international scientists reveals that a complex ecosystem response to iron fertilization in the Southern Ocean might reduce the efficiency of biological carbon pump in transporting carbon dioxide into the deep ocean.

Lead author Dr. Ian Salter from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and a team of international collaborators, discovered that iron fertilization significantly promotes the growth of shelled organisms that feed on phytoplankton.


The Southern Ocean plays an important role in the exchange of carbon dioxide between the atmosphere and the ocean. Photo: Frank Rödel, Alfred Wegener Institute

These organisms produce carbon dioxide when building their calcareous shells. In a naturally iron-fertilized system in the Southern Ocean the growth and sinking of these shelled grazers reduces deep-ocean storage of carbon dioxide by up to 30 per cent.

Ignoring the response of these organisms could result in an overestimate of the marine carbon dioxide storage capacity resulting from ocean iron fertilization, a potential strategy for the mitigation of climate change. The study is published by the scientific journal nature geoscience.

The Southern Ocean plays an important role in the exchange of carbon dioxide between the atmosphere and the ocean. One aspect of this is the growth of phytoplankton, which acts as a natural sponge for carbon dioxide, drawing the troublesome greenhouse gas from the atmosphere into the sea. When these plankton die they can sink to the bottom of the ocean and store some of the carbon dioxide they have absorbed, a process scientists call the “biological carbon pump”.

Although many areas of the Southern Ocean are rich in nutrients, they often lack iron, which limits phytoplankton growth. An important idea in oceanography is that adding iron to the Southern Ocean could stimulate phytoplankton growth and the biological carbon pump. Some scientists believe that this process can partly explain cycles in atmospheric carbon dioxide over Earth’s recent history and it has also been widely debated as a mitigation strategy for climate change.

In two previous studies carried out in the last five years it has been shown that iron fertilization of the Southern Ocean can export carbon dioxide to the deep-sea. “However, to understand the net storage of carbon dioxide in the ocean interior, sinking phytoplankton are only one part of the story”, explains Dr. Ian Salter from the Alfred Wegener Institute. “These phytoplankton can be a food source for certain types of planktonic grazers, foraminifer and pteropods, that make shells from calcium carbonate - a process which produces carbon dioxide”.

The biogeochemist, and an international team of collaborators, were the first to quantify production and sinking of these calcium carbonate shells resulting from a phytoplankton bloom in the Southern Ocean, close to the Crozet Islands, with surprising results. Natural fertilization, caused by iron leached from the basaltic islands, increased the production and sinking of these calcium carbonate shells to a greater extent than sinking phytoplankton. This has important implications for the deep-sea storage of the carbon dioxide resulting from these blooms.

“The production and sinking of these calcium carbonate shells affects the balance of carbon dioxide in the surface ocean over 100 to 1000 year timescales”, explains Dr. Ian Salter. “Our calculations suggest that this process reduces the amount of carbon dioxide transferred to the ocean interior via sinking phytoplankton by up to 30 per cent in this naturally fertilized system. However, it is unclear that purposefully added iron would have the same impact.”

Interestingly the reduction in the efficiency of the biological carbon pump was not just caused by a higher abundance of these organisms, but also by changes in species composition. “In our samples from iron fertilized areas we found more species that produce larger calcium carbonate shells, and in turn produce more carbon dioxide per individual”, explains the biogeochemist. Iron fertilization can therefore affect biodiversity and ecosystem structure with important knock-on effects for climate interactions. “It is important to recognise that our findings are only from a specific area of the Southern Ocean. The ecology of these shelled organisms can be very different depending on the species and exactly where in the ocean they live”, cautions Dr. Ian Salter.

In future research projects Dr. Ian Salter will continue to investigate the sinking of phytoplankton and shelled calcifying organisms in other naturally iron-fertilized areas of the Southern Ocean, in addition to the Arctic Ocean, where melting sea ice conditions may also affect this delicate balance.

Notes for Editors:

The original paper was published in nature geoscience under the following title:

Salter, et al.: Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone. nature geoscience, DOI: 10.1038/ngeo2285

Images for the release can be found here: http://www.awi.de/en/news/press_releases/

Your scientific contact person at the Alfred Wegener Institute is Dr. Ian Salter (tel.: +49 471 4831-2386; e-mail: Ian.Salter(at)awi.de). Your contact person in the Dept. of Communications and Media Relations is Kristina Bär ( tel. +49 471 4831-2139; e-mail: medien@awi.de).


Follow the Alfred Wegener Institute on Twitter and Facebook. In this way you will receive all current news as well as information on brief everyday stories about life at the institute.


The Alfred Wegener Institute conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Ralf Röchert | idw - Informationsdienst Wissenschaft
Further information:
http://www.awi.de

More articles from Earth Sciences:

nachricht Weather extremes: Humans likely influence giant airstreams
27.03.2017 | Potsdam-Institut für Klimafolgenforschung

nachricht Sun's impact on climate change quantified for first time
27.03.2017 | Schweizerischer Nationalfonds SNF

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

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...

Im Focus: Tracing down linear ubiquitination

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...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

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...

Im Focus: Researchers Imitate Molecular Crowding in Cells

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Big data approach to predict protein structure

27.03.2017 | Life Sciences

Parallel computation provides deeper insight into brain function

27.03.2017 | Life Sciences

Weather extremes: Humans likely influence giant airstreams

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>