Grazing and Dynamics of Grazer Populations in a Temperate Fjord

在温带峡湾达博湾(华盛顿州)，浮游植物现存量和生产量的年度周期在春季和秋季表现出惊人的增长(浮游植物水华)，表明缺乏食草动物种群的控制。然而，几乎所有浮游植物在水华期间产生的有机物质最终都被食草动物消耗。此外，很大一部分放牧(每年约67%)似乎是由大型浮游动物悬浮觅食者造成的，微型浮游动物是次要捕食者。建立了德博湾放牧的概念模型，假设了大型和微型浮游动物食草动物的身份，并假定浮游植物生长和放牧之间的大致年度平衡的机制。对这一概念模型进行了实地测试，并在1990-91年对达巴湾的三次扩大研究游轮上进行了测试。这个项目将完成对样本和数据的分析，并产生一个综合。通过直接测量，这项研究将对控制浮游植物生产动态及其在高生产力沿海远洋生态系统中的命运的过程的机制和速率提供定量评估。

In Dabob Bay (Washington), a temperate fjord, the annual cycles of phytoplankton standing stock and production rate exhibit spectacular increases (phytoplankton blooms) in spring and autumn, indicating lack of control by grazer populations. Yet virtually all organic matter produced by the phytoplankton during blooms is ultimately consumed by grazers. Moreover, a major fraction of the grazing (about 67% on an annual basis) appears to be due to macrozooplankton suspension-feeders, with microzooplankton being secondary grazers. A conceptual model of grazing in Dabob Bay was developed, hypothesizing the identities of the macro- and microzooplankton grazers and postulating mechanisms for the approximate annual balance between phytoplankton growth and grazing. A field test of the conceptual model was developed and carried out on three extended research cruises to Dabob Bay in 1990-91. This project will complete the analysis of samples and data, and produce a synthesis. By direct measuerements this study will provide quanitative assessment of mechanisms and rates of processes governing the dynamics of phytoplankton production and its fate in a highly productive coastal pelagic ecosystem.