Date of Award

Summer 1978

Document Type


Degree Name

Master of Science (MS)


Ocean & Earth Sciences



Committee Director

Harold G. Marshall

Committee Member

Ronald E. Johnson

Committee Member

Kneeland Nesius

Call Number for Print

Special Collections LD4331.O35N33


This investigation was directed toward satisfying a recognized lack of informat on regarding phytoplankton composition and density in shelf waters between Nova Scotia and the Chesapeake Bay. A sedimentation technique was used in determining the phytoplankton composition of 99 samples collected between 2 March and 3 April 1971. Chlorophyll-a samples collected concurrently were analyzed fluorometrically. Simple correlation analyses were utilized in describing distributional patterns of phytoplankton density and chlorophyll-a concentration with respect to water temperature, salinity, density, depth, distance from shore and latitude. Analysis of variance was employed in assessing regional differences in phytoplankton density and chlorophyll-a.

The phytoplankton flora consisted of 281 species which were typically a mixture of cold-water and cosmopolitan forms exhibiting both neritic and oceanic distributions. Phytoplankton densities were highest over the continental shelf south of Cape Cod. Spring flowering was noted at six stations which were typically adjacent the coast. Diatoms and pyrrhophyceans were the principle phytoplankton groups. The most important general were Eiddulphia, Chaetoceros, Coscinodiscus, Nitzschia, Thalassisara Ceratium, Gymnodinium,oxytoxum and Peridinium. Silocoflagellates were represented largely by Distephanus speculum V. regulars. while Acanthoica ornata and coccolithus pelagicus were the most frequently observed coccolithophores. The major euglensis species were Eutreptia marina and E. viridis. Diatoms and silocoflagellates were more abundant inshore, while pyrrhophyceans and coccolithophores exhibited an offshore distribution. Chlorophylle exhibited an inverse relation­ ship with latitude and distance from snore and was significantly correlated with diatom, pyrrhophycea, silicoflagellate, and total phytoplankton densities.


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Oceanography Commons