title: The great 2012 Arctic Ocean summer cyclone enhanced biological productivity on the shelves.
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.
authors.affiliation: Applied Physics Laboratory, University of Washington Seattle, Washington, USA.
authors.forename: Jinlun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Biology, Woods Hole Oceanographic Institution Woods Hole, Massachusetts, USA.
authors.forename: Carin
authors.initials: C
authors.lastname: Ashjian
authors.affiliation: Graduate School of Oceanography, University of Rhode Island Kingston, Rhode Island, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Campbell
authors.affiliation: Department of Ocean Earth and Atmospheric Sciences, Old Dominion University Norfolk, Virginia, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Hill
authors.affiliation: College of Earth Ocean and Atmospheric Sciences, Oregon State University Corvallis, Oregon, USA.
authors.forename: Yvette H
authors.initials: YH
authors.lastname: Spitz
authors.affiliation: Applied Physics Laboratory, University of Washington Seattle, Washington, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Steele
keywords: arctic ocean; cyclone effects on biology; ocean mixing