Physical controls on hypoxia in Chesapeake Bay: A numerical modeling study

Journal of Geophysical Research: Oceans - Tập 118 Số 3 - Trang 1239-1256 - 2013
Malcolm E. Scully1
1Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, USA

Tóm tắt

ABSTRACTA three‐dimensional circulation model with a relatively simple dissolved oxygen model is used to examine the role that physical forcing has on controlling hypoxia and anoxia in Chesapeake Bay. The model assumes that the biological utilization of dissolved oxygen is constant in both time and space, isolating the role that physical forces play in modulating oxygen dynamics. Despite the simplicity of the model, it demonstrates skill in reproducing the observed variability of dissolved oxygen in the bay, highlighting the important role that variations in physical forcing have on the seasonal cycle of hypoxia. Model runs demonstrate significant changes in the annual integrated hypoxic volume as a function of river discharge, water temperature, and wind speed and direction. Variations in wind speed and direction had the greatest impact on the observed seasonal cycle of hypoxia and large impacts on the annually integrated hypoxic volume. The seasonal cycle of hypoxia was relatively insensitive to synoptic variability in river discharge, but integrated hypoxic volumes were sensitive to the overall magnitude of river discharge at annual time scales. Increases in river discharge were shown to increase hypoxic volumes, independent from the associated biological response to higher nutrient delivery. However, increases in hypoxic volume were limited at very high river discharge because increased advective fluxes limited the overall length of the hypoxic region. Changes in water temperature and its control on dissolved oxygen saturation were important to both the seasonal cycle of hypoxia and the overall magnitude of hypoxia in a given year.

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Tài liệu tham khảo

10.1175/1520-0485(1993)023<1736:NSOFAA>2.0.CO;2

10.2307/1351914

10.1080/089207500263585

10.1175/2009JPO4016.1

10.1017/CBO9780511676567.003

10.1175/1520-0485(1987)017<2232:WIDICB>2.0.CO;2

10.1007/BF02907650

10.1029/94JC02257

10.3354/meps303001

10.1175/1520-0485(1981)011<0324:OOMFMI>2.0.CO;2

10.1029/2004JC002585

10.1029/2010JC006893

10.1029/2011JC007829

10.1175/JPO3082.1

10.3354/meps032149

10.2307/1352591

10.1007/s12237-011-9413-7

10.1016/j.ecss.2009.09.026

10.1126/science.88.2273.80

10.1007/BF02803567

10.1029/2007JC004716

10.1126/science.223.4631.22

10.1357/002224090784984713

10.1007/BF02693915

10.1175/2010JPO4321.1

10.1007/s12237-010-9319-9

10.1006/jcph.1998.5901

10.3354/meps116217

10.3354/ame030251

10.2307/1352079

10.1357/002224001762842253

10.1175/1520-0485(1979)009<0564:WDCITC>2.0.CO;2

10.1080/02723646.1981.10642213

10.1029/2007JC004693

10.1007/s12237‐011‐9423‐5

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Thông tin xuất bản

Journal of Geophysical Research: Oceans

Tập 118 Số 3

1239-1256

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