Long-term changes and impacts of hypoxia in Danish coastal waters

被引:226
作者
Conley, Daniel J.
Carstensen, Jocob
Aertebjerg, Gunni
Christensen, Peter Bondo
Dalsgaard, Tage
Hansen, Jorgen L. S.
Josefson, Alf B.
机构
[1] Natl Environm Res Inst, Dept Marine Ecol, DK-4000 Roskilde, Denmark
[2] Univ Aarhus, Dept Marine Ecol, DK-8200 Aarhus, Denmark
[3] European Commiss, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, Italy
关键词
anoxia; benthic communities; diversity; estuaries; hypoxia; nutrient enrichment; sediment-water fluxes; Skive Fjord; thresholds;
D O I
10.1890/05-0766.1
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
A 38-year record of bottom-water dissolved oxygen concentrations in coastal marine ecosystems around Denmark (1965-2003) and a longer, partially reconstructed record of total nitrogen (TN) inputs (1900-2003) were assembled with the purpose of describing long-term patterns in hypoxia and anoxia. In addition, interannual variations in bottom-water oxygen concentrations were analyzed in relation to various explanatory variables (bottom temperature, wind speed, advective transport, TN loading). Reconstructed TN loads peaked in the 1980s, with a gradual decline to the present, commensurate with a legislated nutrient reduction strategy. Mean bottom-water oxygen concentrations during summer have significantly declined in coastal marine ecosystems, decreasing substantially during the 1980s and were extremely variable thereafter. Despite decreasing TN loads, the worst hypoxic event ever recorded in open waters occurred in 2002. For estuaries and coastal areas, bottom-water oxygen concentrations were best described by TN input from land and wind speed in July-September, explaining 52% of the interannual variation in concentrations. For open sea areas, bottom-water oxygen concentrations were. also modulated by TN input from land; however, additional significant variables included advective transport of water and Skagerrak surface-water temperature and explained 49% of interannual variations in concentrations. Reductions in the number of benthic species and alpha diversity were significantly related to the duration of the 2002 hypoxic event. Gradual decreases in diversity measures (number of species and alpha diversity) over the first 2-4 weeks show that the benthic community undergoes significant changes before the duration of hypoxia is severe enough to cause the community to collapse. Enhanced sediment-water fluxes of NH4+ and PO43- occur with hypoxia, increasing nutrient concentrations in the water column and stimulating additional phytoplankton production. Repeated hypoxic events have changed the character of benthic communities and how organic matter is processed in sediments. Our data suggest that repeated hypoxic events lead to an increase in susceptibility of Danish waters to eutrophication and further hypoxia.
引用
收藏
页码:S165 / S184
页数:20
相关论文
共 67 条
  • [1] TRENDS IN NUTRIENT AND OXYGEN CONDITIONS WITHIN THE KATTEGAT - EFFECTS OF LOCAL NUTRIENT SUPPLY
    ANDERSSON, L
    RYDBERG, L
    [J]. ESTUARINE COASTAL AND SHELF SCIENCE, 1988, 26 (05) : 559 - 579
  • [2] The Phison River plume: coastal eutrophication in response to changes in land use and water management in the watershed
    Billen, G
    Garnier, J
    [J]. AQUATIC MICROBIAL ECOLOGY, 1997, 13 (01) : 3 - 17
  • [3] Box G. E., 1976, TIME SERIES ANAL FOR
  • [4] INPUTS, TRANSFORMATIONS, AND TRANSPORT OF NITROGEN AND PHOSPHORUS IN CHESAPEAKE BAY AND SELECTED TRIBUTARIES
    BOYNTON, WR
    GARBER, JH
    SUMMERS, R
    KEMP, WM
    [J]. ESTUARIES, 1995, 18 (1B): : 285 - 314
  • [5] Coastal eutrophication and trend reversal:: A Danish case study
    Carstensen, Jacob
    Conley, Daniel J.
    Andersen, Jesper H.
    Aertebjerg, Gunni
    [J]. LIMNOLOGY AND OCEANOGRAPHY, 2006, 51 (01) : 398 - 408
  • [6] Sediment denitrification in the Gulf of Mexico zone of hypoxia
    Childs, CR
    Rabalais, NN
    Turner, RE
    Proctor, LM
    [J]. MARINE ECOLOGY PROGRESS SERIES, 2002, 240 : 285 - 290
  • [7] Sediment mineralization, nutrient fluxes, denitrification and dissimilatory nitrate reduction to ammonium in an estuarine fjord with sea cage trout farms
    Christensen, PB
    Rysgaard, S
    Sloth, NP
    Dalsgaard, T
    Schwærter, S
    [J]. AQUATIC MICROBIAL ECOLOGY, 2000, 21 (01) : 73 - 84
  • [8] A 150-year reconstruction of the history of coastal eutrophication in Roskilde Fjord, Denmark
    Clarke, A
    Juggins, S
    Conley, D
    [J]. MARINE POLLUTION BULLETIN, 2003, 46 (12) : 1615 - 1618
  • [9] Long-term trends in eutrophication and nutrients in the coastal zone
    Clarke, A. L.
    Weckstrom, K.
    Conley, D. J.
    Anderson, N. J.
    Adser, F.
    Andren, E.
    de Jonge, V. N.
    Ellegaard, M.
    Juggins, S.
    Kauppila, P.
    Korhola, A.
    Reuss, N.
    Telford, R. J.
    Vaalgamaa, S.
    [J]. LIMNOLOGY AND OCEANOGRAPHY, 2006, 51 (01) : 385 - 397
  • [10] Coastal eutrophication and the Danish National Aquatic Monitoring and Assessment Program
    Conley, DJ
    Markager, S
    Andersen, J
    Ellermann, T
    Svendsen, LM
    [J]. ESTUARIES, 2002, 25 (4B): : 848 - 861