Microbial Size Spectra from Diverse Marine Ecosystems.
Abstract
Microbial size spectra serve as synoptic pictures of the organization of the pelagic 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 was observed in winter and early spring, where low temperatures resulted in well- mixed waters and high nutrient concentrations. Seasonal succession was accompanied by a distinct shift in the size spectrum to smaller cells, coinciding with rising temperatures, stratification of the water column and diminishing nutrient concentrations. In stratified waters, larger mean bacteria and phytoplankton sizes were observed in surface and very deep waters, whereas the smallest sizes were typically seen around the chlorophyll maximum.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1996
- Accession Number
- ADA323873
Entities
People
- Karina Y. Gin
Organizations
- Massachusetts Institute of Technology