Date of Award

Summer 1973

Document Type


Degree Name

Master of Science (MS)


Ocean & Earth Sciences



Committee Director

Jacques S. Zaneveld

Committee Member

Peter Fleischer

Committee Member

Anne Raymond

Committee Member

R. K. Heide

Call Number for Print

Special Collections LD4331.O35W65


Seasonal periodicity of benthic algae of the estuarine eulittoral of Smith Island, Virginia, (37°07’55” N, 75°55’ W), has been investigated on a qualitative and quantitative basis. Forty-three taxa of benthic eucaryiotic algae were found to be present; of these, twenty-one were quantitatively significant at least once during the course of the study. Five species represent additions to the Virginia flora, and, at the same time, also represent southern extensions of the known U.S. east coast range. The range of three other species has been extended, though they are not new to Virginia.

Review of the literature suggests two models of periodicity which may apply to the United States and Canadian Atlantic coasts. One is a “two season model” typified by Hoyt's (1920) interpretation of the Beaufort, North Carolina, flora. The other is a "continual change model” typified by the interpretation of the Digby Neck, Nova Scotia, flora by Edelstein et al., (1970). Analysis of the Smith Island data, and that from published studies of other areas, indicates that a pattern of alternation between a "summer red algal period" and a "winter brown algal period" may be described. However, the published literature provides no objective evidence in support of an alternation between a discrete summer flora and a discrete winter flora, as would be required in a two season model. To provide an objective basis for interpreting seasonal patterns for the benthic algae of the estuarine eulittoral of Smith Island Jaccard and Kulczyński coefficients have been employed. The results of this analysis indicate that the estuarine algal flora of Smith Island conforms to the continual change model. Data from published studies of the seasonal distribution of benthic algae in other localities were treated in the same fashion. While there were some indications that in some instances the flora persisted for two and occasionally three months there was no indication of an alternation between floras. It is concluded that the continual change model is most applicable.


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