Date of Award

Fall 2007

Project Type

Dissertation

Program or Major

Plant Biology

Degree Name

Doctor of Philosophy

First Advisor

Arthur C Mathieson

Abstract

Both inanimate and animate intertidal surfaces including Fucus and Ascophyllum develop a biofilm that can bind metals contributed by non-point and point sources of pollution. The biofilm also functions as a habitat for the many organisms, i.e. bacteria, diatoms and other algal cells that are part of the biofilm and contribute to the polysaccharide matrix. Examinations of the biofilm were quantified by polysaccharide analysis using a spectrophotometer. Biofilm samples were recovered from both intertidal rock surfaces and the surface of the surrounding fucoid algae to determine if they bind Cu and Zn. Locations in Kittery, Maine differed by the amount of polysaccharides produced. The widespread cover of polysaccharides indicates that Cu and Zn may have a diffuse impact and accumulation in the intertidal zone.

A laboratory study was conducted using adult Fucus fronds to determine if Cu and Zn were accumulated in the biofilm as well as in tissue. Fucus was collected from a coastal site in Kittery, Maine and brought to the Jackson Estuarine Laboratory (JEL) where it was added to tanks of seawater containing Cu or Zn at 5 mg 1-1. After three weeks the Fucus was used for Energy Dispersive Spectroscopy (EDS) as well as chemical analysis of the metals. The results from that indicated significant amounts of Cu and Zn were recovered from the biofilm and the Fucus tissue.

Because not just adult fucoid algae are exposed to Cu and Zn present in tidal waters, zygotes were exposed to combinations of copper and zinc that ranged from 0.02 mg 1-1 to 2 mg 1-1. Environmental parameters were also altered including salinity, particulate or dissolved organic matter, presence or absence of a biofilm and pH. Germination and growth of the germlings was determined using a light microscope equipped with an ocular micrometer following 2 to 4 day exposure to treatments. Germlings of Fucus, following Cu and Zn exposure, do best when grown in 32 ppt seawater containing dissolved and particulate organic matter. In this static study, the presence of a biofilm on the glass slides did not improve germination or growth.

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