Filella Montserrat, Rellstab Christian, Chanudet Vincent, Spaak Piet
Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, Quai Ernest-Ansermet 30, Geneva 4, Switzerland.
Water Res. 2008 Apr;42(8-9):1919-24. doi: 10.1016/j.watres.2007.11.021. Epub 2007 Nov 24.
To quantify the effect of the filter feeder Daphnia on the aggregation of mineral particles, temporal changes in the particle size distribution of inorganic colloids were experimentally determined both in the presence and in the absence of Daphnia in water samples of Lake Brienz, Switzerland, an oligotrophic lake rich in suspended inorganic colloids. The results obtained show that daphnids favour the aggregation of mineral colloids, but only for particle sizes above the Daphnia filter mesh size. However, the number concentration of particles smaller than the Daphnia filter mesh size simultaneously increases in the presence of the filter feeder, suggesting either the break-down of existing aggregates or the aggregation of particles with initial sizes below the measured size range. The density of daphnids in this lake is currently too low to have any significant effect on the fate of inorganic colloidal particles as compared with aggregation due to physical processes of particle collision. However, in more productive water bodies where Daphnia is more abundant, they may play a significant role.
为了量化滤食性水蚤对矿物颗粒聚集的影响，在瑞士布里恩茨湖（一个富含悬浮无机胶体的贫营养湖）的水样中，分别在有和没有水蚤的情况下，通过实验测定了无机胶体颗粒大小分布的时间变化。所得结果表明，水蚤有利于矿物胶体的聚集，但仅针对大于水蚤滤网尺寸的颗粒大小。然而，在存在滤食性动物的情况下，小于水蚤滤网尺寸的颗粒数量浓度同时增加，这表明要么是现有聚集体的分解，要么是初始尺寸低于测量尺寸范围的颗粒发生了聚集。与颗粒碰撞的物理过程导致的聚集相比，该湖中目前水蚤的密度过低，对无机胶体颗粒的归宿没有任何显著影响。然而，在水蚤数量更多的富营养水体中，它们可能会发挥重要作用。
