Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ocean life depends on single circulation pattern in Southern Hemisphere

31.12.2003


Study raises questions about potential impact of climate change

A study has shown that marine life around the world is surprisingly dependent on a single ocean circulation pattern in the Southern Hemisphere where nutrient-rich water rises from the deep and spreads across the seas.

The results suggest that ocean life may be more sensitive to climate change than previously believed because most global warming predictions indicate that major ocean circulation patterns will change. While oceanographers have identified many ocean circulation patterns, the study found that three-quarters of all biological activity in the oceans relies on this single pattern.



"When we shut off this one pathway in our models, biological productivity in the oceans drops to one-quarter of what it is today," said Jorge Sarmiento, a Princeton oceanographer who led the study published in the Jan. 1, 2004, issue of Nature. Marine organisms account for half all biological productivity on Earth.

The discovery helps oceanographers settle a longstanding question about what keeps the world’s oceans fertile. Most biological activity in the ocean is concentrated near the surface where an abundance of microorganisms perform photosynthesis and support marine food chains. These organisms and their byproducts slowly sink from the surface, decomposing along the way and carrying nutrients to the deep ocean. Until now, it has not been clear how the surface becomes replenished with the nutrients that seemed lost to the deep ocean.

Previous research has shown that ocean water does not mix well across layers of equal density, which are mostly oriented horizontally in the ocean. Once the organic matter sinks to the abyss, it takes a long time for nutrients to cross the layers and return to the surface. Without a mechanism to bring deep water back to the surface, the oceans would lose about one-fiftieth of their nutrients to this sinking process each year, Sarmiento said.

Sarmiento and colleagues identified what amounts to an enormous conveyor belt that carries nutrient-rich seawater southward in the deep ocean, brings it to the surface in the Antarctic Ocean where the density layer barrier is weak and ships it north. The water sinks again in the Northern Hemisphere and starts over. The researchers discovered a chemical signature (the presence of high nitrate and low silicate levels) that is unique to this nutrient carrier, which is called the Subantarctic Mode Water, and used it to trace the influence of this water in surface waters around the world.

"It is really quite amazing," said Sarmiento. "I had no idea of the extent of its influence."

The SAMW is responsible for feeding nearly all the world’s oceans, except for the North Pacific, which is resupplied with nutrients through another circulation pattern, the researchers found.

The finding already has attracted interest among oceanographers. "They have clearly identified the pathway that counteracts the so-called biological pump, which acts to strip the surface layer of its nutrients," said Arnold Gordon of Columbia University. "One now wonders how global change will alter the efficiency of this pathway."

Sarmiento said the research group "is now hard at work investigating the details of this nutrient circulation pattern with an eye to examining how it might respond to global warming in model simulations."


Sarmiento conducted the study in collaboration with Nicholas Gruber of the University of California-Los Angeles, Mark Brzezinski of the University of California-Santa Barbara and John Dunne of the Geophysical Fluid Dynamics Laboratory in Princeton. The research was supported by the National Science Foundation, the National Oceanic and Atmospheric Administration and the Department of Energy.

Patty Allen | EurekAlert!
Further information:
http://www.princeton.edu/

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>