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The great 2012 Arctic Ocean summer cyclone enhanced biological productivity on the shelves.

Zhang J, Ashjian C, Campbell R, Hill V, Spitz YH, Steele M - J Geophys Res Oceans (2014)

Bottom Line: In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass.The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone.The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink.

View Article: PubMed Central - PubMed

Affiliation: Applied Physics Laboratory, University of Washington Seattle, Washington, USA.

ABSTRACT

[1] A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and phytoplankton biomass by up to 40% in the wake of the cyclone. The increase in zooplankton biomass is up to 18% on 31 August and remains 10% on 15 September, more than 1 month after the storm. In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass. The biological gain on the shelves and loss in the central PSA are linked to two factors. (1) The cyclone enhances mixing in the upper ocean, which increases nutrient availability in the surface waters of the shelves; enhanced mixing in the central PSA does not increase productivity because nutrients there are mostly depleted through summer draw down by the time of the cyclone's passage. (2) The cyclone also induces divergence, resulting from the cyclone's low-pressure system that drives cyclonic sea ice and upper ocean circulation, which transports more plankton biomass onto the shelves from the central PSA. The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone. Because the gain on the shelves is offset by the loss in the central PSA, the average increase over the entire PSA is moderate and lasts only about 10 days. The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink.

No MeSH data available.


CNTL-simulated nitrate in the upper (a) 10 m and (b) 100 m of the Arctic Ocean, and (c) primary productivity (PP), (d) phytoplankton, and (e) zooplankton in the upper 100 m on 4 August 2012 just before the storm. Four locations for detailed analysis (section) are marked in each map.
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fig05: CNTL-simulated nitrate in the upper (a) 10 m and (b) 100 m of the Arctic Ocean, and (c) primary productivity (PP), (d) phytoplankton, and (e) zooplankton in the upper 100 m on 4 August 2012 just before the storm. Four locations for detailed analysis (section) are marked in each map.

Mentions: [13] By 4 August 2012, just before the cyclone entered the PSA, the simulated nutrients in much of the surface waters in the Arctic Ocean were already depleted because of summer nutrient drawdown [e.g., Gosselin et al., 1997; Lee and Whitledge, 2005; Tremblay et al., 2008; Codispoti et al., ,]. Surface nitrate concentration at this time is nearly zero in most of the Arctic except in some areas on the shelves of the East Siberian and Laptev seas, in the Eurasian Basin, and near the Canadian Archipelago (Figure 5a). The relatively high surface nitrate concentration in part of the East Siberian and Laptev seas may explain why model results and observations show higher surface chl a there (Figures 4e–4f). Simulated surface nitrate concentration on the East Siberian shelf, however, would continue to decrease (not shown here) throughout the summer to approach the low levels observed by Anderson et al. [2011]. Consistent with the summer observations reported by Codispoti et al. [2013], nitrate also persists in some areas in the Eurasian Basin and near the Canadian Archipelago, where the simulated under-ice chl a concentration is up to 3 mg m−3 in August 2012 (Figure 4e).


The great 2012 Arctic Ocean summer cyclone enhanced biological productivity on the shelves.

Zhang J, Ashjian C, Campbell R, Hill V, Spitz YH, Steele M - J Geophys Res Oceans (2014)

CNTL-simulated nitrate in the upper (a) 10 m and (b) 100 m of the Arctic Ocean, and (c) primary productivity (PP), (d) phytoplankton, and (e) zooplankton in the upper 100 m on 4 August 2012 just before the storm. Four locations for detailed analysis (section) are marked in each map.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508965&req=5

fig05: CNTL-simulated nitrate in the upper (a) 10 m and (b) 100 m of the Arctic Ocean, and (c) primary productivity (PP), (d) phytoplankton, and (e) zooplankton in the upper 100 m on 4 August 2012 just before the storm. Four locations for detailed analysis (section) are marked in each map.
Mentions: [13] By 4 August 2012, just before the cyclone entered the PSA, the simulated nutrients in much of the surface waters in the Arctic Ocean were already depleted because of summer nutrient drawdown [e.g., Gosselin et al., 1997; Lee and Whitledge, 2005; Tremblay et al., 2008; Codispoti et al., ,]. Surface nitrate concentration at this time is nearly zero in most of the Arctic except in some areas on the shelves of the East Siberian and Laptev seas, in the Eurasian Basin, and near the Canadian Archipelago (Figure 5a). The relatively high surface nitrate concentration in part of the East Siberian and Laptev seas may explain why model results and observations show higher surface chl a there (Figures 4e–4f). Simulated surface nitrate concentration on the East Siberian shelf, however, would continue to decrease (not shown here) throughout the summer to approach the low levels observed by Anderson et al. [2011]. Consistent with the summer observations reported by Codispoti et al. [2013], nitrate also persists in some areas in the Eurasian Basin and near the Canadian Archipelago, where the simulated under-ice chl a concentration is up to 3 mg m−3 in August 2012 (Figure 4e).

Bottom Line: In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass.The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone.The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink.

View Article: PubMed Central - PubMed

Affiliation: Applied Physics Laboratory, University of Washington Seattle, Washington, USA.

ABSTRACT

[1] A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and phytoplankton biomass by up to 40% in the wake of the cyclone. The increase in zooplankton biomass is up to 18% on 31 August and remains 10% on 15 September, more than 1 month after the storm. In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass. The biological gain on the shelves and loss in the central PSA are linked to two factors. (1) The cyclone enhances mixing in the upper ocean, which increases nutrient availability in the surface waters of the shelves; enhanced mixing in the central PSA does not increase productivity because nutrients there are mostly depleted through summer draw down by the time of the cyclone's passage. (2) The cyclone also induces divergence, resulting from the cyclone's low-pressure system that drives cyclonic sea ice and upper ocean circulation, which transports more plankton biomass onto the shelves from the central PSA. The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone. Because the gain on the shelves is offset by the loss in the central PSA, the average increase over the entire PSA is moderate and lasts only about 10 days. The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink.

No MeSH data available.