茄子直播

茄子直播 research finds ponds in High Arctic could be significant source of carbon emissions

Photo of Arctic pond
A researcher collects data from a pond in the High Arctic near the Cape Bounty Arctic Watershed Observatory (photo courtesy of Melissa Lafreni猫re)

A new Canadian study involving researchers from the University of Toronto has found that carbon released by some ponds in the High Arctic could potentially be a hidden source of greenhouse gas emissions.

The study looked at how dissolved organic carbon (DOC) stored in Arctic permafrost 鈥 which is thawing at an accelerated rate due to climate change 鈥 is being released into Arctic watersheds as a result of physical disturbances that relocate nutrients across the landscape. For the first time, researchers were able to determine that the chemical composition of carbon in these ponds is vastly different than in rivers in the High Arctic.

鈥淭hese ponds in the High Arctic seem to be hotspots for DOC degradation,鈥 says Myrna Simpson, professor of environmental science at 茄子直播 Scarborough and co-author of the research.

鈥淰ery little consideration has been given to what鈥檚 happening with DOC in these ponds that are all over the Arctic, and it could potentially be a source of CO2 emissions released into the atmosphere with these disturbances.鈥 

DOC is everywhere 鈥 it can be found in lakes, oceans and in soil. It鈥檚 essentially decomposed plant or animal material that dissolves by coming into contact with water. In the High Arctic, DOC becomes mobile by entering watersheds, which is happening at an accelerated rate due to rapid permafrost thaw and the resulting change to the physical landscape.

鈥淭he rapid thawing results in what鈥檚 called active layer detachments,鈥 explains Simpson. 鈥淭hink of these disturbances as landslides where soil and water gets all mixed up.鈥

When the DOC settles into ponds, it can be biodegraded by microbes more easily than in rivers, which means more carbon can get released into the atmosphere. While past studies have explored how active layer detachments have stimulated microbial activity in Arctic soil, this is the first to look mostly at water sources, including ponds.

鈥淲e didn鈥檛 measure how much carbon was being released because we didn鈥檛 expect to find this,鈥 says Simpson. 鈥淭his is one of the novel findings of the study 鈥 that these ponds could play an important role in the global carbon cycle.鈥  

What鈥檚 more, Simpson notes, the Arctic permafrost stores a lot of carbon because it generally remains frozen, locked into place for a long time. With rapid thawing of the permafrost, that鈥檚 changing. In fact, using radiocarbon dating, the researchers found DOC more than 5,000 years old that was being degraded.

Sampling of the water sources for the study was done by Queen鈥檚 University researchers Melissa Lafreni猫re and Scott Lamoureux out of the near Melville Island in Nunavut.  

An important next step for the research will be to see how widespread the phenomenon is 鈥 for example, if it happens in all Arctic ponds. But as Lafreni猫re points out, it鈥檚 also important to understand the underlying mechanisms driving the difference between DOC in ponds versus rivers.

鈥淲e need to do some mass balance studies to figure out the mass of carbon in these bodies of water. This includes how much carbon is present, and what are the main inputs and outputs controlling how much carbon is in the water,鈥 she says.

In order to do that, they will need to measure not only the amount of carbon in the water but also the different forms of carbon including DOC, dissolved inorganic carbon, particulate organic carbon, gaseous CO2 and methane. 

Future lab and field experiments will be designed to figure out the processes responsible for gains or losses of carbon from these ponds, and also the process behind transforming carbon from one form to another, adds Lafreni猫re.

Analysis of the DOC for the study was carried out in three different labs across Canada in order for researchers to use a host of sophisticated measurements. Professor Yves G茅linas from Concordia University and Professor Andr茅 Simpson from 茄子直播 Scarborough lent their expertise to the study. Data was also collected and compiled by Dr. Jun-Jian Wang, a former postdoctoral researcher in Simpson鈥檚 lab, now an assistant professor at the Southern University of Science and Technology in China.

The research, which is published in the journal , received funding from ArcticNet and the Natural Sciences and Engineering Research Council of Canada (NSERC).

 

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