Wildfire smoke may amplify phytoplankton blooms in the Arctic

Earth and Environment Communications (2022). DOI: 10.1038 / s43247-022-00511-9″ width=”685″ height=”416″/>

Large summer phytoplankton bloom near the North Pole (Eastern Eurasia Basin) in summer 2014. Average satellite-derived chlorophyll concentration within the bloom zone (28–155°E, 80–85°N) during summer 2014 (a). The dot color represents which satellite sensor (MODIS Aqua, Terra, or VIIRS) is used. Point size is relative to the number of observations obtained (that is, pixels). The blue line is the daily climate average of surface chlorophyll concentration during the period 2003-2019 (excluding 2014) with shading envelope corresponding to the interval between the first and third quartiles. Sea ice concentration and sea surface temperature, for the entire period from July 28 to August 31 (b), and for the three time periods July 27-28, August 13-15, and August 29-31 (ce, respectively). Sea ice concentration and chlorophyll concentration, at the same dates as be, are shown in panels fi. For bi: the location of the inflorescence is within the dotted box (28-155°E, 80-85°N) and the continental shelf (bottom depth <50 m) is shown by cross shading. credit: Mathieu Ardyna et al, Earth and Environment Communications (2022). DOI: 10.1038 / s43247-022-00511-9

Smoke from wildfires in Siberia may have moved enough nitrogen into parts of the Arctic Ocean to amplify phytoplankton reproduction, according to new research from North Carolina State University and the Takovic International Research Laboratory (CNRS/Laval University) in Canada. The work that appears in Earth and Environment Communicationssheds light on some of the potential environmental impacts of wildfires in the Northern Hemisphere, particularly as these fires become larger, longer and more intense.

In the summer of 2014, satellite images He detected a larger-than-normal algal bloom in the Laptev Sea, located in the Arctic Ocean about 850 kilometers (528 miles) south of the North Pole.

“In order for a boom of this magnitude to occur, the area would need a large influx of new nitrogen Because the Arctic Ocean is depleted of nitrogen,” says Douglas Hamilton, associate professor of marine, land and atmospheric sciences at NC State and co-first author of a paper describing the work. Hamilton was previously a research associate at Cornell University, where the research was conducted.” So we needed to find out where this nitrogen came from.”

First, the researchers looked at “usual suspects” for nitrogen inputs, such as melting sea ice, river drainage, and ocean flow, but they found nothing that would explain the amount of nitrogen needed for flowering to occur.

But during the same time period, exceptionally big forest fires In Siberia, Russia, located directly upwind, nearly 1.5 million hectares (or about 3.5 million acres) of land have burned.

So the researchers turned their attention to the composition of the atmosphere. They used the Community Earth System Model (CESM), a computer model It can simulate what happens to emissions from natural and anthropogenic sources as they enter and leave the atmosphere. The model was fed with information about wind, temperature, and atmospheric composition – including the formation of Forest fires Smoke – from the respective time period.

Simulations showed that during late July and August of 2014—when blooms were detected and forest fires in Siberia were burning—the deposition of nitrogen from the atmosphere was nearly double what it was in previous and subsequent years.

“The forest fires were in the northern regions that were warming rapidly, and which had a lot of peat in the permafrost thaw, says Hamilton. Peat is very nitrogen-rich, and smoke from burning peat is assumed to be the most likely source of much of the extra nitrogen. “

“We have known that fires can affect Phytoplankton bloom, although it would not be expected to see something like this in the Arctic Ocean,” says Matteo Ardena, co-first author and CNRS researcher at Takwick International Research Laboratory (CNRS/Laval University). Most likely, because fires are place-specific and hard to predict, blooms like this won’t be the norm — but when these wildfires occur, the nutrients they bring can lead to sustainable or multiple blooms.”

Next steps for researchers could include reviewing the historical satellite record and further characterizing the chemical composition of the particles within the smoke to get a clearer picture of how wildfires like these affect different ecosystems.

“A one-off bloom like this isn’t going to change the structure of the ecosystem, but Siberia and the Canadian High Arctic are getting more bushfires,” says Hamilton. “So it may be interesting to explore the potential downstream effects if fire activity and nutrient supply remain high.”

Increased iron from wildfire smoke an additional advantage of the carbon cycle in the Southern Ocean

more information:
Mathieu Ardyna et al, Wildfire aerosol deposition likely amplifies Arctic phytoplankton blooms in summer, Earth and Environment Communications (2022). DOI: 10.1038 / s43247-022-00511-9

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