Gschwend%20thesis.pdf

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Lillick, 1937). Possibly, the benthic algae were responsible for these
autumn nutrient depletions.
Phytoplankton ~
Chlorophyll ~ concentration peaked in late winter in both years
(figure 3-7). Beginning in December, 1977 phaeophytin was determined
and showed increased importance suggesting either the active degradation
of chlorophyll ~ or the return of degradation products to the water
column as winter storms stirred up the sediment.
Phytoplankton counts revealed a tremendous late-winter bloom of
Thalassiosira nordenskioeldii. Several million cells per liter were
found at the peak of this bloom. The appearance of this diatom bloom
coincided with the February, 1978 chlorophyll ~ maximum and the disap-
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pearance of N03, PO 4 ' and Si02. More than 85% of the bloom population
(by cell numbers) consisted of this species.
Other Observations
In the fall (end of September and again at the beginning of November)
large beach washups of the seagrass, Zostera marina, and associated
macroalgae occurred with the incidence of strong storm activity. These
washups may not be solely attributable to stormy weather, but also to a
weakening of the plants by physiological changes generally thought to
occur at this time of year (Sand-Jensen, 1975; Ragen and Jensen, 1978).
These plant materials could be seen to be pulverized in the surf zone
and were responsible for greatly increasing the turbidity of the shallow
water.