Quantifying Trophic and Demographic Rates of Plankton-Rich Layers in East Sound, Orcas Island, Washington

摘要

Localized concentrations of plankton (i.e. patches) alter the optical and acoustical properties of the water column and can have significant ramifications for the ecological dynamics of marine communities. The goal of this research is to develop a mechanistic understanding and predictive capability of the biological drivers of plankton patch formation, persistence and decline. This goal will be addressed by concurrent characterization of the physical, chemical and biological parameters associated with patch occurrence and dissipation with biologically meaningful resolution (meters and days). The objective of the funded work is to quantify the contribution of ecological processes to plankton patch formation in the coastal ocean. These objectives will be addressed by simultaneously quantify (1) spatial and temporal characteristics of large plankton patches, (2) the physical and chemical conditions these patches occur in and (3) the plankton population dynamics of the dominant layer forming species through simultaneous measurements of their growth and mortality rates. The methodological approach of this research is to concurrently quantify the population dynamics of whole plankton communities and the environmental conditions they occur in. Frequent, small boat surveys allow us to characterize physical water column structure and capture discrete samples to measure nutrient, plankton biomass and Chlorophyll-a concentrations as well as laboratory measurements of plankton growth and grazing rates. This research utilizes methods widely used in biological oceanography as well as more recent approaches established and tested during my work in East Sound.