Effects of aerobic and anaerobic conditions on exchange of nitrogen and phosphorus across sediment-water interface in Lake Kasumigaura

在实验室控制条件下,研究了日本霞浦湖土浦湾和湖心区底泥中形态氮磷,在好氧和厌氧条件下水土界面交换量变化及差异.结果表明:好氧条件下,NO₃^--N、NO₂^--N、NH₄⁺-N、和PO₄^3--P均有释放作用产生,量值多数较小.DTN和DTP则净释放作用接近零;厌氧条件下,NO₃^--N和NO₂^--N呈负释放状态,NH₄⁺-N和PO₄^3--P的释放速率是好氧条件下的2-8倍.比较实验柱样品中营养物含量和释放结果对应关系表明,沉积物中间隙水与湖水中营养物含量在水土界面所形成的浓度差是决定其在好氧或厌氧条件下释放作用大小的主要因素之一.;The variations and difference of the formal nitrogen and phosphorus exchanges across the sediment-water interface in Tsuchiura Bay and the central part of Lake Kasumigaura were studied under a laboratorial control of aerobic and anaerobic conditions, the results show that in aerobic, the released NO₃^--N, NO₂^--N, NH₄⁺-N and PO₄^3--P observed are smaller than in anaerobic. And the exchanged DTN and DTP were in fluctuation states, the net release nearing to zero. In anaerobic. an obvious release occurred for the most of nutrients, the release rates of NH₄⁺-N and PO₄^3--P were 2-8 times as much as in aerobic. By a comparison between the sediment samples in the corresponding nutrient concentrations and their release rates, a conclusion is drawn that the nutrient content ratio, at the vSediment-water interface, namely the differenciation between the intervStitial and the superficial lake water, was a decisive factor of the release rate in quantity.