Date of Award

1986

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

The objective of this study was to compare benthic microfloral production on the west and gulf coasts of the U.S.A., and to determine what factors govern that production. Intensive, month long field studies were conducted at two sites in a salt marsh lagoon (Mugu Lagoon) in southern California and at two sites in a shallow water estuary (Barataria Estuary) in southwest Louisiana. For both studies, fluctuations in production during a single month approximated those measured previously over an entire year: daily production varied from 0 to 1500 mg C (.) m('-2). A comparison was made between the sources of error likely to be introduced by insufficient sampling in space and time with the error likely to be introduced by the commonly used conversions of hourly productivity to monthly production. The error introduced by inadequate sampling in space and time outweighs the error introduced by converting measured midday productivity to estimated monthly production. For a given number of days per month, sampling at a few stations several times per month is more informative than sampling at many stations once or twice a month. The cumulative error introduced in the annual estimates by insufficient sampling and inappropriate conversion assumptions accounts for the total range of variation in existing annual estimates for different regions of the world. The data sets were not amenable to standard statistical analyses, because correlations between productivity and the individual environmental variables varied through time. Multichannel information analysis indicated that the collective information for all the measured variables produced periodicities of 14 days, 7 days, or less, reflecting the dynamic nature of the benthic microfloral system and the need for frequent sampling. Entropy data analysis indicated that no single variable limits productivity. Instead, the variables integrate into factors and these factors change over time. At all 4 sites, productivity was influenced primarily by several different types of disturbance: tidal currents, meteorological and man-made waves, and direct and indirect disturbance by macrofauna were most important. Solar radiation became important in the absence of disturbance. The concept of an ecosystem "grammar" is developed as a tool for describing the rules that govern the interrelationships amongst variables.

Pages

196

Share

COinS