Seasonal and Diel Patterns of Abundance and Productivity of Phototrophic Picoplankton in the Lower Chesapeake Bay

<p>This study was performed to evaluate phototrophic pico-plankton (0.2 to 2.0 μm) dynamics within the lower Chesapeake Bay. A 15 month study of phototrophic picoplankton abundance and productivity was made from June 1988 to October 1989. Annual picoplankton abundance using epifluorescence microscopy ranged from 7.26 x 10⁶ cells/1 in the winter to 9.28 x 10⁸ cells/1 during late summer.</p> <p><em>In situ</em> incubations of natural picoplankton populations over the 15 month study were used to test the applicability of the frequency of dividing cells technique in estimating phototrophic picoplankton growth rates. The regression equation o fμ = 2.37 x 10^-3 (FDC) + 0.024 was developed to estimate phototrophic picoplankton growth rates in the lower Chesapeake Bay where productivity values were estimated using phototrophic picoplankton abundance and carbon content. Limitations and improvements in using the frequency of dividing cells technique were discussed. Productivity estimates using both frequency of dividing cells and sodium ¹⁴C-bicarbonate fractionation techniques identified phototrophic picoplankton contributing over 50% of total primary productivity during the summer season.</p> <p>Two high frequency diel studies measuring phototrophic picoplankton abundance and productivity in summer and winter seasons revealed physical factors in the water column partly determining phototrophic picoplankton distribution. Higher phototrophic picoplankton concentrations were associated with waters seasonally above the pycnocline. In summer, phototrophic picoplankton concentrations were highest during ebb tide when the dominant phototrophic picoplankton was phycocyanin enriched <em>Synechococcus sp</em>. In winter, phototrophic picoplankton concentrations were highest during flood tide when phycoerythrin enriched <em>Synechococcus sp.</em> dominated phototrophic picoplankton composition. Availability of phototrophic picoplankton carbon within the water column is discussed as to its influence to Bay trophodynamics.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

1990

Author dc:creator

• Affronti, Lewis Francis, Jr.

Contributors dc:contributor

• H. G. Marshall
• Kneeland Nesius
• Andrew S. Gordon
• William Dunstan
• James Melchor

• Picoplankton
• Seasonal patterns
• Chesapeake Bay
• Phototrophic
• Ecology and Evolutionary Biology
• Oceanography

Statement dc:rights

• <p>In Copyright. URI: <a href="http://rightsstatements.org/vocab/InC/1.0/">http://rightsstatements.org/vocab/InC/1.0/</a> This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).</p>

Repository record dc:identifier

https://digitalcommons.odu.edu/biology_etds/92

OAI identifier oai:identifier

oai:digitalcommons.odu.edu:biology_etds-1091