Date of Award

Summer 1989

Document Type


Degree Name

Master of Science (MS)


Biological Sciences



Committee Director

Harold G. Marshall

Committee Member

Kneeland Nesius

Committee Member

Andrew Gordon

Call Number for Print

Special Collections LD4331.B46 M53


A 12 month study of cyanobacteria composition and concentrations in the North Landing River and upper Currituck Sound was conducted from March 1986 to February 1987. Epifluorescence microscopy and the fluorochrome proflavin were used to determine cell concentrations and vertical, station to station and seasonal distribution of these cells. Cyanobacterial assemblage patterns were coupled with pH, temperature, salinity and water transparency readings.

Cyanobacteria were found to be a persistent and prolific phytoplankton component of both the river and upper sound. For a comparison of vertical distribution for each station, an analysis of variance for. two groups of equal size was used. An analysis of variance for the means of several groups of equal size, and a T­ method multiple comparison among means were performed on cyanobacterial abundances among stations. No significant differences (P < 0.05) were discovered in the vertical or station to station distribution of these cells.

Results from cluster analysis revealed four main clusters which were identified as seasonal groups. Canonical variate analysis suggested that different species groups and abundance levels of cyanobacteria corresponded to different seasonal and environmental conditions in the river. The greatest species diversity and cell concentrations were during periods of warmer temperatures, higher pH and lower transparency readings. A seasonal community shift occurred from cyanobacterial dominance to chlorophyceae and diatom dominance when pH levels and water temperatures decreased during the winter months.


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