Characteristics of autochthonous deposition and resuspension of sediments in the Takahamairi Bay of Lake Kasumigaura
Characteristics of autochthonous deposition and resuspension of sediments in the Takahamairi Bay of Lake Kasumigaura
复制标题
霞浦湖高浜湾沉积物自生沉积与再悬浮特征
DOI：
10.3739/rikusui.48.special_107
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
K. Muraoka
中科院分区：
文献类型：
--
作者：
T. Fukushima;M. Aizaki;K. Muraoka
沉积速率测定的沉积物陷阱在五个站在肥肥的高滨湾霞浦湖1981-1986年选定的时期。沉积通量到本地和沉积物再悬浮成分的分离尝试的基础上的叶绿素浓度的示踪剂。即使在海湾中心站，本地物质的日平均通量也只有4g·m-2·d-1，而再悬浮物的日平均通量为46 g·m-2·d-1。初级生产力的峰值与沉积通量的峰值之间存在1 ~ 2个月的时滞，导致了盛夏湖水叶绿素a浓度的显著增加。计算的碳、氮、磷在回水区和入流河口附近的原地沉积速率远高于近海，这是由于外来物质的污染。再悬浮率随水深的增加呈对数下降趋势，并与气象条件有显著的相关性。通过质量平衡法和沉积物定年法估算的沉积物中的累积速率，其内源和外源沉积通量之和分别超过氮和磷的累积速率8-17倍和2-10倍，均远大于在其他湖泊中观测到的比率。该湖的浅，极大地影响了这些比例，因为大的再悬浮率，然后在湖水中快速分解和底栖生物的高活性。
Deposition rates were measured by means of sediment traps at five stations in hypertrophic Takahamairi Bay of Lake Kasumigaura for the selected periods of 1981-1986. Separation of deposited fluxes into autochthonous and sediment resuspension components was attempted on the basis of chlorophyll a concentration for the tracer. Even at the central station of the bay, the average daily flux of autochthonous matter was 4g·m-2·d-1 compared with 46g·m-2·d-1 of resuspension. There was a time lag of one or two months between the peak of primary production and that of autochthonous deposited flux, which resulted in a surprising increase in chlorophyll a concentration of lake water in mid-summer. Calculated autochthonous deposited rates of carbon, nitrogen, and phosphorus in backwater regions and near the inflow river mouth were much higher than those at offshore due to the contamination of allochthonous matter. In regard to the resuspension rates, a logarithmic decrease against water depth and significant correlations with some meteorological conditions were observed. The sum of autochthonous and allochthonous deposited fluxes exceeded the accumulation rates in sediments estimated both by the mass balance method and the sediment dating method by a factor of 8-17 for nitrogen and 2-10 for phosphorus, both of which were much larger than the ratios observed in other lakes. The shallowness of this lake greatly influenced these ratios because of the large resuspension rate followed by rapid decomposition in lake water and high activity of benthos.