Date of Award

Spring 2014

Document Type


Degree Name

Doctor of Philosophy (PhD)


Biological Sciences


Ecological Sciences

Committee Director

Harold G. Marshall

Committee Member

Kneeland Nesius

Committee Member

John R. McConaugha


Microalgal populations are trophically important to a variety of micro- and macroheterotrophs in marine and estuarine systems. In Chesapeake Bay, microalgae facilitate the survival and development of ecologically and economically relevant fauna, including shellfish and finfish populations. While regarded as significant components of coastal environments, microphytobenthic communities are historically understudied. In Chesapeake Bay, the importance of phytoplankton to the ecosystem is understood, but the contribution of microphytobenthos remains unclear. This project surveys intertidal microphytobenthic communities, in relation to phytoplankton communities, around lower Chesapeake Bay describing the taxonomic makeup of these populations, coupled with quantification of cell abundance, biomass, and primary production. Whole water samples and sediment cores were collected at eight sites throughout lower Chesapeake Bay for phytoplankton and microphytobenthic community analysis over a two-year period. Over the span of the study, a total of 142 taxa were identified (124 phytoplankton; 95 benthos). Microphytobenthic community composition, abundance and biomass were dominated by diatoms in spring, autumn and winter, while cyanobacteria were dominant during summer. Similarly, within the water column, diatoms were the most diverse group with greatest cell abundance and biomass throughout the sampling period. Algal abundance, biomass, species richness, and productivity rates all differed between the phytoplankton and benthos. Abundance and biomass values were significantly higher in the benthos than in the phytoplankton throughout the study. Conversely, species richness and productivity rates were significantly higher in the phytoplankton. These results provide evidence that the microphytobenthos are an important, diverse community similar to, but significantly different than neighboring planktonic populations.


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