Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Arctic river deltas may hold clues to future global climate

19.05.2009
Scientists struggling to understand how Earth's climate will change in the next few decades have neglected a potential treasure trove of information—sediments deposited in the ocean by major Arctic rivers such as the Colville and Mackenzie rivers—according to geoscientists at The University of Texas at Austin and Texas A&M University.

The researchers' study was published in the May 19 edition of Proceedings of the National Academy of Sciences.

Sediments deposited in large river deltas around the world record information about past sea level, productivity and storminess on the ocean margin, climate on the adjacent continents (including temperatures and precipitation) and human factors that affect sediment delivery to the margin (such as dams and levees), among other things. In addition to these climate factors, Arctic sediments, in particular, could contain records of changes on land due to warming, including permafrost temperature and melting of upland glaciers.

Mead Allison, senior research scientist at The University of Texas at Austin's Jackson School of Geosciences and co-author of the study, said Arctic river deltas have been neglected as records of past climate because the far north is a challenging and expensive environment to work in and it only came to be seen as a bellwether for climate change in the last decade or so.

Arctic river deltas are critical to explore, the researchers reason, because the largest changes in climate are projected for the Arctic. Large amounts of carbon are stored in Arctic permafrost. As those soils thaw, rivers will transport much of their organic carbon to the oceans. As global warming speeds up the melting of shorefast ice (ice attached to the shore), it will likely accelerate coastal erosion from storms, providing a further supply of organic carbon to the coastal zone.

Allison described several ways these sediments could advance scientists' understanding of the global climate system.

They could help answer a hotly debated question about the role of river deltas in the global carbon cycle. Scientists don't know whether large river deltas are a net source or a net sink of carbon. Do they store more carbon than they produce? That's a critical question because carbon dioxide is a major greenhouse gas. Large river deltas are the interface between the land and the oceans and they deliver large amounts of carbon carried along in sediments. As humans alter river systems by adding nutrients from fertilizers, damming water for power and diverting water for drinking and farming, they may be shifting the ability of those systems to fix, burn and store carbon.

"It's a glaring gap in our understanding of the global carbon cycle," Allison said. "It's a potential gotcha in the global climate models. Each river system is different, but we have to get a handle on the net effects."

Arctic river deposits could also confirm the existence of natural climate cycles that climate models need to take into account. For example, there is evidence supporting the existence of a climate cycle called the Arctic Oscillation that affects temperatures, precipitation and storminess at high latitudes. This cycle oscillates over several decades. But because there are only about 50 years of high quality climate data from the Arctic, it's hard to determine to what extent changes now being observed are natural or due to human influence. River delta sediments might allow scientists to reconstruct Arctic climate for thousands of years into the past, and possibly confirm this natural baseline.

Finally, these sediments would establish past climate proxies for specific locations that could be monitored in the future to track the changing climate of the Arctic. If it is a region that will experience the biggest climate changes in this century, it will be important to establish how climate is recorded in sediments.

One advantage of studying margin sediments adjacent to large rivers in the Arctic and elsewhere is that they are deposited at a very high rate. This makes it possible to extract information on a year-to-year basis with high resolution.

The paper "Large-river delta-front estuaries as natural "recorders"of global environmental change" appears in the May 19 Proceedings of the National Academy of Sciences. The lead author is Thomas Bianchi, a professor in Texas A&M University's Department of Oceanography who specializes in estuarine and marine systems. The research was funded by NASA, the Department of Energy, the Office of Naval Research and the National Science Foundation.

Mead Allison | EurekAlert!
Further information:
http://www.utexas.edu

More articles from Earth Sciences:

nachricht A 3-D look at the 2015 El Niño
29.05.2017 | NASA/Goddard Space Flight Center

nachricht 'Tiny clocks' crystallize understanding of meteorite crashes
29.05.2017 | University of Western Ontario

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Camera on NASA's Lunar Orbiter survived 2014 meteoroid hit

29.05.2017 | Physics and Astronomy

Strathclyde-led research develops world's highest gain high-power laser amplifier

29.05.2017 | Physics and Astronomy

A 3-D look at the 2015 El Niño

29.05.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>