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 Live from the ocean research vessel Atlantis
13.12.2018 | National Science Foundation

nachricht NSF-supported scientists present new research results on Earth's critical zone
13.12.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Data use draining your battery? Tiny device to speed up memory while also saving power

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>