Date of Award
© 2013 Vanessa O'Donnell
Master of Science in Marine Sciences
The marine sediment-water interface is a dynamic microenvironment containing diatoms, which produce exopolymeric substance (EPS). EPS has various functions for individual cells and for marine ecosystems. EPS substance is a species-specific composition that has strong absorptive qualities and is able to bind metals from even a very dilute aqueous solution. As industrially derived metals tend to accumulate in marine mudflats, where diatoms are the major EPS producing organisms, it is important to determine how marine benthic diatom EPS will bind with metals. To address the metal binding properties of diatom EPS, Cylindrotheca closteriums’ EPS was isolated by tangential flow filtration, exposed to Cu and Cr at a range of pH levels and analyzed using a flame atomic absorption spectrometer. Results indicated that pH was a significant factor in the determination of bound Cu to diatom EPS under all treatments. Maximum bound Cu was 61.7 μg mg-EPS-1 at a pH of 6.0 in a buffered system and 17.1 μg mg- EPS-1 at a pH of 6.0 in an unbuffered system. Cu was preferentially bound over Cr and precipitation of metals occurred above a pH of 6.5. Diatom EPS binding with metals at a near neutral pH is a significant result and has not been shown before in the literature, but metal concentrations used in this study were unnaturally high, reducing practical implications. More research within this area of marine aquatics is needed to understand the greater global ramifications of pH shift effects on estuaries and fate of metals in the marine ecosystem.
O'Donnell, Vanessa, "The Effect Of PH On The Metal Binding Capabilities Of Exopolymeric Substances From A Marine Benthic Diatom" (2013). All Theses And Dissertations. 4.