ABR: Food Limitation of Deposit Feeding Populations - Field Experiments

这项研究的目的是在沉积物营养质量在空间和时间尺度上的变化的背景下，评估野外环境中摄食沉积物的种群受到食物限制的程度。过去的研究表明，新沉积的海藻碎屑对沉积物捕食者的种群增长有很大贡献，但沉积物中的颗粒状有机质也非常重要。过去两年的季节性研究表明，沉积物促进了从春季到秋季不断下降的种群增长，当沉积物喂食者摄入春季与秋季沉积物时，碳保留量也会下降。这些发现将扩展到现场添加碎屑的实验研究，因为碎屑横向运输的诊断标记是可用的。试验性添加研究将与标记法和笼养捕食对照相结合，以研究沉积物中碎屑添加和季节性有机质变化对优势少毛类蠕虫Paranais litoralis种群增长的影响，以及对泥螺、Ilyanassa obsoleta和水生动物Truncata行为的影响。此外，还将研究摄食行为、泥沙淤积和水流之间的相互作用。这项研究将首次利用空间和时间相结合的方法来考察地表摄食底栖生物种群的碎屑限制。

The objective of this research is to assess the degree to which deposit feeding populations in field circumstances are limited by food, in the context of changes in nutritional quality of the sediment over spatial and temporal scales. Past research has demonstrated that newly deposited seaweed based detritus contributes substantially to population growth of deposit feeders, but that the particulate organic matter in the sediment also is of great importance. Seasonal studies over the last two years demonstrate that the sediment promotes declining population growth from spring to fall and carbon retention also declines when a deposit feeder ingests spring versus fall sediment. These findings will be extended to experimental studies on the addition of detritus in the field, since a diagnostic marker of lateral transport of detritus is available. The experimental addition studies will be combined with the marker approach as well as with caged controls for predation, to examine the impact of detrital addition and seasonal organic matter change in the sediment on the population growth of the dominant oligochaete worm, Paranais litoralis, and on the behavior of the mud snails, Ilyanassa obsoleta and Hydrobia truncata. Interactions between feeding behavior, sediment deposition and flow will also be examined. This study will be the first to utilize the combined spatial and temporal approach to examine detrital limitation of surface feeding benthic field populations.