Seasonal patterns of food limitation in Daphnia galeata: separating food quantity and food quality effects
Seasonal patterns of food limitation in Daphnia galeata: separating food quantity and food quality effects
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帽状水蚤食物限制的季节性模式：分离食物数量和食物质量的影响
DOI：
10.1093/plankt/18.7.1137
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发表时间：
1996
影响因子：
2.1
通讯作者：
W. Lampert
中科院分区：
文献类型：
--
作者：
D. Müller;W. Lampert
在实验室标准化条件下，用天然湖泊悬浮物培养了一个生长季，测定了枝水蚤Daphnia galeata的食物限制。增长率与食物数量的几个措施有关。颗粒有机碳（POC）<30 μ m是总食物有效性的最佳预测因子。它优于叶绿素a（Chl-a）的相同尺寸的部分，藻类体积计算的细胞计数或总颗粒体积由库尔特计数器测量。在相同的条件下，将水蚤与尖叶栅藻一起生长，并比较它们的生长速度。Sestonic碳浓度与栅藻碳浓度相关，提供了相等的生长速率。两种食物类型的碳浓度的比率（悬浮物。栅藻）代表悬浮物的食物品质。因此，天然湖泊悬浮物的营养质量相对于一个标准的悬浮物，确定了一个生长季节。悬浮物喂养的动物的生长速度表明，它们在一年中的很长一段时间内食物有限。这也通过野外动物的标准窝卵数来确定。然而，在研究期间，食物限制的原因各不相同。而在清水阶段，食物量是有限的（而质量是高的：100%栅藻）。6月10日和6月17日之后不久，由于食物质量差，食物条件接近临界浓度。对于夏季的剩余时间，POC为0.3-0.6 mg C1 '，具有约50%栅藻的质量。导致水蚤的中度食物限制。
Food limitation for the cladoceran Daphnia galeata was measured growing them with natural lake seston for one growing season under standardized conditions in the laboratory. Growth rates were related to several measures of food quantity. Paniculate organic carbon (POC) <30 u.m was the best predictor of total food availability measured. It was better than chlorophyll-a (Chl-a) of the same size fraction, algal volume calculated from cell counts or total particle volume from Coulter Counter measurements. Daphnids were also grown with Scenedesmiis acutus under the same conditions and their growth rates were compared. Sestonic carbon concentrations were related to Scenedesmus carbon concentrations, that provided equal growth rates. The ratio of the carbon concentrations of both food types (seston. Scenedesmus) represented the food quality of seston. Thus, the nutritional quality of natural lake seston relative to a standard alga was determined over one growing season. Growth rates of seston fed animals revealed that they were food limited during long periods of the year. This was also ascertained by standard clutch sizes of field animals. However, the causes of food limitation varied within the duration of the studied period. Whereas during the clear-water phase the food quantity was limiting (while the quality was high: 100% Scenedesmus). shortly after on 10 June and 17 June food conditions were close to threshold concentrations due to low food quality. For the remainder of the summer, a POC of 0.3-0.6 mg C 1' with a quality of —50% Scenedesmus. resulted in moderate food limitation of Daphnia.