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. / Graduation date: 1975
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28548 |
| Date | 18 September 1974 |
| Creators | Pequegnat, John Eugene |
| Contributors | Small, Lawrence F. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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