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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 and SENS-simulated vertical profiles of (a) vertical diffusivity, (b) nitrate, (c) PP, (d) phytoplankton, and (e) zooplankton before (4 August 2012), during (7 August), and after (27 August) the cyclone in the upper 50 m averaged over the PSA.
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fig15: CNTL-simulated and SENS-simulated vertical profiles of (a) vertical diffusivity, (b) nitrate, (c) PP, (d) phytoplankton, and (e) zooplankton before (4 August 2012), during (7 August), and after (27 August) the cyclone in the upper 50 m averaged over the PSA.

Mentions: [27] Averaged over the entire PSA (Figure 15) CNTL simulations show, during passage of the storm, enhanced ocean mixing in mainly the upper 10 m of the PSA (Figure 15a). Nitrate concentration is higher in the upper 10 m but generally lower at depth (Figure 15b). The increased nitrate concentration in the surface waters generally leads to higher PP, phytoplankton, and zooplankton (Figures 15c–15e). On average over the entire PSA, however, the increase in PP and plankton in the upper 100 m is only prominent during and immediately after the storm (Figures 16a–16c), even though the model simulates a generally strong and lasting (1 month or slightly longer) biological gain in some areas on the shelves. The gain on the shelves may be partially cancelled by the biomass loss in the central PSA. As a result, the storm increases biological production only for a short period of time on average over the entire PSA (Figures 16a–16c) while drawing down nutrients simultaneously (Figure 16d).


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 and SENS-simulated vertical profiles of (a) vertical diffusivity, (b) nitrate, (c) PP, (d) phytoplankton, and (e) zooplankton before (4 August 2012), during (7 August), and after (27 August) the cyclone in the upper 50 m averaged over the PSA.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig15: CNTL-simulated and SENS-simulated vertical profiles of (a) vertical diffusivity, (b) nitrate, (c) PP, (d) phytoplankton, and (e) zooplankton before (4 August 2012), during (7 August), and after (27 August) the cyclone in the upper 50 m averaged over the PSA.
Mentions: [27] Averaged over the entire PSA (Figure 15) CNTL simulations show, during passage of the storm, enhanced ocean mixing in mainly the upper 10 m of the PSA (Figure 15a). Nitrate concentration is higher in the upper 10 m but generally lower at depth (Figure 15b). The increased nitrate concentration in the surface waters generally leads to higher PP, phytoplankton, and zooplankton (Figures 15c–15e). On average over the entire PSA, however, the increase in PP and plankton in the upper 100 m is only prominent during and immediately after the storm (Figures 16a–16c), even though the model simulates a generally strong and lasting (1 month or slightly longer) biological gain in some areas on the shelves. The gain on the shelves may be partially cancelled by the biomass loss in the central PSA. As a result, the storm increases biological production only for a short period of time on average over the entire PSA (Figures 16a–16c) while drawing down nutrients simultaneously (Figure 16d).

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.