Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenland ice sheet releasing 'Mississippi River' worth of phosphorus

03.02.2016

Not only is Greenland's melting ice sheet adding huge amounts of water to the oceans, it could also be unleashing 400,000 metric tons of phosphorus every year - as much as the mighty Mississippi River releases into the Gulf of Mexico, according to a new study. Phosphorus is a key nutrient that could, if it reaches the open ocean, enrich waters of the Arctic Ocean, potentially stimulating growth of the marine food chain, the study's authors said.

Phosphorus is an essential nutrient that feeds plankton at the base of the ocean food web. Glacial meltwater has long been known to contain phosphorus, but now new research shows that as the Greenland ice sheet melts it could be releasing far more of the nutrient than previously thought, reports Jon Hawkings, a Cabot Institute researcher at the Bristol Glaciology Centre at the University of Bristol in the United Kingdom.


This is the sediment-rich meltwater river originating from Leverett Glacier in southwest Greenland, pictured in June 2012.

Credit: Jon Hawkings

Hawkings and his collaborators spent three months in 2012 and 2013 gathering water samples and measuring the flow of water from the 600-square-kilometer (230-square-mile) Leverett Glacier and the smaller, 36-square-kilometer (14-square-mile) Kiattuut Sermiat Glacier in Greenland as part of a Natural Environment Research Council-funded project to understand how much phosphorus, in various forms, was escaping from the ice sheet over time and draining into the sea.

They then used that data to extrapolate how much phosphorus was likely being released from the entire Greenland ice sheet.

They found greater amounts of phosphorus in the waters of the Leverett Glacier than had been detected at previous study sites, which have looked mostly at smaller glaciers. The large Leverett Glacier, however, is more representative of the glaciers that contribute the bulk of meltwater coming from the Greenland ice sheet, said Hawkings.

"We find annual phosphorus input (for all of Greenland's outlet glaciers) are at least equal to some of the world's largest rivers, such as the Mississippi and the Amazon," Hawkings and his colleagues report in a new study accepted for publication in Global Biogeochemical Cycles, a journal of the American Geophysical Union. That amount could increase as the climate warms and more ice melts, according to the study's authors.

It is not clear yet how much of the phosphorus being released from the ice sheet is reaching the open ocean, but if a large amount of phosphorus coming off the glacier makes it to the sea, the nutrient could rev up biological activity of Arctic waters, according to the study's authors. The nutrient could stimulate growth of plankton at the base of the ocean food web that could impact birds, fish and marine mammals higher up the food chain. The research also suggests ice sheet-derived phosphorus could eventually reach the northern Pacific and Atlantic oceans, which are connected to the Arctic Ocean.

Unleashing nutrients

Oceanographers have historically thought of glaciers and ice sheets as frozen systems that don't add nutrients or water to the oceans, Hawkings explained. Research over the past couple of decades has shown there is flowing water at the base of glaciers. As climate change warms Greenland and more ice melts and makes its way into the sea, the ice sheet is potentially becoming a more important source of nutrients, he said.

Glacial meltwater gains phosphorus when it travels in moulins, or "pipes" through the ice - through the guts of the glacier and down to the where the ice meets the bedrock. Where the ice meets the bedrock at the very bottom of the glacier, the meltwater is exposed to phosphorus-rich rocks that are pulverized by the moving glacier.

"Glaciers are very, very good at crushing up rock," said Hawkings.

The concentrations of dissolved phosphate the researchers found in the Leverett Glacier meltwater - which is just one form of phosphorus found in the meltwater - were similar to concentrations found in Arctic rivers, and among the highest levels recorded in glacial meltwaters worldwide. The total phosphorus concentrations found in the meltwater of the Leverett Glacier - which includes phosphorus-rich particles - was 10 times greater than concentrations found in Arctic river waters.

If the majority of the phosphorus found in meltwater from all of Greenland's glaciers reaches the sea, it would be equal to about 400,000 metric tons (440,000 U.S. tons) per year of phosphorus, more than Arctic rivers are estimated to contribute to the Arctic Ocean, according to the new study. However, how much phosphorus makes it from the meltwater into the open oceans is not yet known. The largest portion of phosphorus, which is in the form of powdered rock minerals, could be settling out of the meltwater and end up buried in Greenland's fjords before it has time to dissolve, Hawkings said.

"This is an important finding because it highlights the role that the rapidly changing Greenland ice sheet plays in supplying nutrients to the Arctic Ocean," observed Eran Hood of the University of Alaska Southeast in Juneau, who studies the meltwater from coastal glaciers in Alaska, and was not involved in the new study.

"Now we need to understand how much of this phosphorus, especially in the particulate, ends up being utilized in high-latitude marine ecosystems form," said Hood. "I think that's an important open question."

###

The following press release and accompanying images can be found at: http://news.agu.org/press-release/greenland-ice-sheet-releasing-mississippi-river-worth-of-phosphorus/

AGU contact:

Nanci Bompey
+1 (202) 777-7524
nbompey@agu.org

University of Bristol contact:

Simon Davies
+ 44 (0)117 928 8086
simon.l.davies@bristol.ac.uk

http://www.agu.org 

Nanci Bompey | American Geophysical Union

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>