RUI: Organic Matter Processing by Filter Feeders in Stream Ecosystems

在大多数河流生态系统中，细颗粒有机物（FPOM）主导着宏观消费者食物网。 然而，溶解有机物（DOM），被认为是只有微型消费者，往往是目前最大的有机物池。 黑蝇的密集聚集，这往往发生在湖泊出口的基岩瀑布，似乎过滤了很大一部分的FPOM进入聚合，但质量的这个池并没有减少，因为它穿过聚合;它增加。 初步数据表明，进入这些聚集体的FPOM通过黑蝇进食和排泄而被DOM增强。 建议的工作的目标是：1）确定DOM和FPOM喂养的重要性，FPOM和DOM池在流中;和2）评估的作用，在黑蝇喂养。 为了实现这些目标，一系列的上游和下游的比较，稳定同位素和染料示踪实验，滤食器去除实验，和实验室饲养实验将被用来测量：1）通过滤食器聚集体的FPOM，包括质量，颗粒的尺寸分布和叶绿素浓度：2）DOM转化为FPOM;和3）DOM池中不同粒径组分（分子量）对黑蝇的可用性。 在这些密集的聚集体中发生的相同过程也可能发生在更多样化的溪流群落中;然而，影响将更难检测。 因此，虽然这些实验侧重于特殊情况下，他们可能有广泛的适用性流有机物动力学。

Hershey Fine particulate organic matter (FPOM) dominates macroconsumer food webs in most stream ecosystems. However, dissolved organic matter (DOM), thought to be available only to microconsumers, is often the largest pool of organic matter present. Dense aggregations of black flies, which often occur at lake outlets an on bedrock cascades, appear to filter a very large portion of the FPOM entering the aggregation, but mass of this pool does not decrease as it passes across the aggregations; it increases. Preliminary data suggest that the FPOM entering these aggregations is augmented by DOM, via black fly feeding and egestion. The objectives of the proposed work are: 1) to determine the importance of DOM and FPOM feeding to FPOM and DOM pools in streams; and 2) to evaluate the role in black fly feeding. To meet these objectives, a series of upstream and downstream comparisons, stable isotope and dye tracer experiments, filter-feeder removal experiments, and laboratory feeding experiments will be used to measure: 1) FPOM passing through a filter-feeder aggregation, including mass, size distribution of particles, and chlorophyll concentration; 2) transformation of DOM to FPOM; and 3) availability of different size fractions (molecular weights) of the DOM pool to black flies. The same processes that occur in these dense aggregations could also occur in more diverse stream communities; however, effects would be harder to detect. Thus, although these experiments focus on special cases, they may have broad applicability to stream organic matter dynamics.