Microbial Size Spectra from Diverse Marine Ecosystems

摘要

Microbial size spectra serve as synoptic pictures of the organization of thepelagic food web. However, field data sets are limited and the range and variability of size spectra are still relatively unexplored. In this thesis, we examined how the characteristics of microbial size spectra varied with ecosystem productivity, and how size spectra responded to environmental perturbations. Flow cytometry was used to generate size spectra and to study the temporal and spatial dynamics of bacteria and phytoplankton from high nutrient, productive coastal waters in Massachusetts and Cape Cod Bays, and low nutrient, low productivity waters in the oligotrophic Sargasso Sea. Additional data was collected from the equatorial Pacific a high nutrient, low chlorophyll region. In general, a spectrum reflecting the predominance of larger bacteria and phytoplankton cells