Benthic nutrient recycling in Port Phillip Bay, Australia

被引:124
作者
Berelson, WM [1 ]
Heggie, D
Longmore, A
Kilgore, T
Nicholson, G
Skyring, G
机构
[1] Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA
[2] Australian Geol Surv Org, Div Environm Geosci & Groundwater, Canberra, ACT 2601, Australia
[3] Victorian Fisheries Res Inst, Dept Conservat & Nat Resources, Queenscliff, Vic 3225, Australia
[4] Skyring Environm Enterprises, Downer, ACT 2602, Australia
基金
美国国家科学基金会;
关键词
benthic recycling; nutrient budgets; bioirrigation; Australian coast;
D O I
10.1006/ecss.1998.0328
中图分类号
Q17 [水生生物学];
学科分类号
071004 ;
摘要
Benthic chamber measurements of the reactants and products involved with biogenic matter remineralization (oxygen, ammonium, nitrate, nitrite, phosphate, silicate, TCO2 and alkalinity) were used to define solute exchange rates between the sediment and overlying water column of Port Phillip Bay, Australia. Measurements at various sites throughout the bay, conducted during the summers of 1994 and 1995, indicate that the variability in flux values within a site is comparable to year-to-year variability (+/-50%). Four regions of the bay were distinguished by sediment properties and the northern region was identified as having 3-30 times greater nutrient regeneration rates than the other regions. Benthic recycling accounted for 63 and 72% of the annualized N and P input, respectively, to the entire bay as determined by summing benthic, dissolved riverine, atmospheric and dissolved effluent sources. However, bay-wide sedimentary denitrification accounted for a loss of 63% of the potentially recyclable N. This fraction is higher than many other coastal regions with comparable carbon loading. Denitrification efficiency is apparently not enhanced by benthic productivity nor by bio-irrigation. The rate of bio-irrigation is negatively correlated with denitrification efficiency. Bio-irrigation was studied using radon-222 and CsCl spike injection chamber measurements. Radon fluxes from sediments in Port Phillip Bay were enhanced over the diffusive flux by 3-16 times. The modelled rate of loss of Cs from chamber water was positively correlated with radon flux enhancement results. Both methods identify regions within Port Phillip Bay that have particularly high rates of non-diffusive pore-water overlying water solute exchange. (C) 1998 Academic Press Limited.
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页码:917 / 934
页数:18
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