Predator Effects on Dense Zooplankton Aggregations in the Coastal Ocean

The distribution of organisms in the ocean is highly heterogeneous, influencing both sampling and ecological structure. The complex spatial and temporal structure of predators and prey affect one another. Numerous studies in pelagic systems have investigated the effects of prey distribution on predator behavior and studies in benthic habitats have revealed the significant impacts predators can have on prey distribution. However, primarily because of sampling difficulties, few studies have investigated the effects of predators on prey distribution in pelagic systems. In the last decade, advances in measurement capabilities have led to the discovery of plankton aggregations over continental shelves with vertical dimensions of tens of centimeters. These ‘thin layers’ can have a horizontal extent of several kilometers and may persist for days. Sharply distinct from the surrounding water column, the density of phytoplankton and zooplankton in these layers can be orders of magnitude higher than at surrounding depths. The discovery of these ubiquitous layers of plankton has opened up new possibilities in studying aggregation in the ocean. The long-term goal of this work is to understand the ecological importance of thin layers of plankton