Record Details
Trace metals in phytoplankton from an area of coastal upwelling
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Trace metals in phytoplankton from an area of coastal upwelling |
| Names |
Pequegnat, John Eugene
(creator) Small, Lawrence F. (advisor) |
| Date Issued | 1974-09-18 (iso8601) |
| Note | Graduation date: 1975 |
| Abstract | Short-term changes in the distribution, surface to 10 meters, of phytoplankton-associated trace metals (Fe, Mn, Cr, Zn, Co, Ni, and Cu) were studied in the near-shore waters off Humboldt Bay, California, through the summer of 1971. The depth distribution of phytoplankton-associated trace metals was related to local hydrography. During periods of upwelling higher concentrations of phytoplankton-associated Fe, Mn, Cr, and Zn were found at depth (10 meters) than at the surface. During periods of non-upwelling there was less stratification in their distribution. Phytoplankton-associated Cu, Go, and Ni showed no significant increase with depth during either period. The rate of change in trace metal distribution patterns of Fe, Mn, Cr, and Zn were regulated by surface wind patterns and hydrographic regimes. Again, Cu, Co, and Ni did not fluctuate in a significant fashion. The elements studied tended to fall into three ordered groups based on their behavior with respect to 1) depth distribution, 2) correlation with other metals studied, and 3) correlation with biomass indicators. The groupings were Fe, Mn, and Cr; Zn, Co, and Ni; and finally Cu. This ordering is similar to the Irving- Williams series and to the elements relative 'hardness" as a Lewis acid where Fe(III), Cr(III), and Mn(II) are considered hard Lewis acids while Zn(II), Co(II), Ni(II) and finally Cu(II) are considered borderline hard to soft Lewis acids. These properties are related to the relative affinities and selectivities of the elements for organic ligands. There also appears to be some relation between the physical (dissolved versus particulate form) and the chemical (oxidation state and ionic potential) behavior of the elements in sea water and their behavior in the phytoplankton. There was a negative correlation between most phytoplankton-associated trace metal concentrations (Fe, Mn, Cr, Zn, Co, and Ni) and biomass during non-upwelling periods and a positive correlation during upwelling periods. Copper, on the other hand, showed a positive correlation during both periods. This aberrant behavior of copper may be related to its high affinity for organic ligands and its relative softness as a Lewis acid. Since no simple negative correlation was found between phytoplankton biomass and phytoplankton-associated trace metal concentrations, biological dilution does not appear to be as important as the hydrographic regime and the chemical activities of the element in determining the concentrations of trace metals in near shore phytoplankton populations. |
| Genre | Thesis/Dissertation |
| Topic | Trace elements in water |
| Identifier | http://hdl.handle.net/1957/28548 |
