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

No description available.

Thesis (Ph. D.)--University of California, Santa Cruz, 1989. / Typescript. Includes bibliographical references.

Thesis (M.S.)--University of California, Santa Cruz, 1996. / Typescript. Includes bibliographical references.

by Oi-Ming Cheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 104-108). / Chapter 1 --- INTRODUCTION / Chapter A) --- Sources of zinc and its functional role --- p.10 / Chapter B) --- Effects of excessive zinc intake --- p.11 / Chapter (a) --- Human --- p.11 / Chapter (b) --- Animal --- p.11 / Chapter (c) --- Fish --- p.12 / Chapter C) --- Techniques in zinc determination --- p.12 / Chapter 2 --- ANODIC STRIPPING VOLTAMMETRY / Chapter A) --- Basic principles --- p.16 / Chapter (a) --- Cell --- p.16 / Chapter (b) --- Electrodeposition and stripping --- p.20 / Chapter B) --- Major interferences in anodic stripping and the common solutions to these problems --- p.25 / Chapter (a) --- Intermetallic compound formation --- p.25 / Chapter (b) --- Overlapping peaks --- p.26 / Chapter (c) --- Organic compounds adsorbed at the electrode --- p.28 / Chapter 3 --- MUTUAL INTERFERENCE FROM ZINC AND COPPER / Chapter A) --- Introduction --- p.30 / Chapter B) --- Review of reported methods to remove copper interference --- p.31 / Chapter (a) --- Dual-working electrode approach --- p.31 / Chapter (b) --- Adjustment of the deposition potential --- p.31 / Chapter (c) --- Standard addition --- p.33 / Chapter (d) --- Addition of a third element --- p.33 / Chapter C) --- The proposed solution --- p.35 / Chapter 4 --- EXPERIMENTAL / Chapter A) --- Proposed method --- p.37 / Chapter (a) --- Apparatus --- p.37 / Chapter (b) --- Reagents --- p.38 / Chapter (c) --- Procedure --- p.40 / Chapter B) --- Reference method --- p.45 / Chapter (a) --- Apparatus --- p.45 / Chapter (b) --- Reagents --- p.45 / Chapter (c) --- Procedure --- p.47 / Chapter 5 --- RESULTS AND DISCUSSION / Chapter A) --- Optimization of instrumental parameters and working conditions --- p.49 / Chapter (a) --- Effect of plating potential on zinc peak current --- p.49 / Chapter (b) --- Effect of plating time on zinc peak current --- p.53 / Chapter (c) --- Effect of holding time and holding potential on zinc peak current --- p.56 / Chapter (d) --- Effect of sweep rate on zinc peak current --- p.58 / Chapter (e) --- Effect of final potential and strip time on zinc peak current --- p.61 / Chapter (f) --- Effect of pH on the peak current and recovery of zinc in the presence of copper after the sulphide treatment --- p.63 / Chapter (g) --- Effect of the concentration of buffer on the peak current --- p.66 / Chapter (h) --- Effect of the reaction time of sulphide with copper on the zinc recovery --- p.68 / Chapter B) --- "Calibration graph, precision and detection limit" --- p.71 / Chapter C) --- Effect of copper on the zinc determination by the proposed method --- p.78 / Chapter D) --- Interference studies --- p.80 / Chapter E) --- Recovery tests --- p.84 / Chapter F) --- Determination of zinc in real samples using the proposed method --- p.86 / Chapter (a) --- Clean water samples such as sea water and tap water --- p.86 / Chapter (b) --- Contaminated natural water and domestic wastewater samples --- p.91 / Chapter (c) --- Air samples --- p.93 / Chapter (d) --- Oyster tissue samples --- p.96 / Chapter (e) --- Sewage sludge and sediment samples --- p.99 / Chapter 6 --- CONCLUSION --- p.102 / REFERENCES --- p.104

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (p. [200]-229).

Thesis (Ph. D.)--University of Washington, 1997. / Includes bibliographical references (leaves [200]-229).

Thesis (M.S.)--University of California, Santa Cruz, 1994. / Typescript. Includes bibliographical references (leaves 159-166).

The distribution and speciation of trace metals in natural waters is only slightly, at best, understood. Interactions with organic substances can effectively distribute the metals throughout many ill-defined physical and chemical. To better comprehend the complexity of metal-organic interactions this work focused on the delineation of trace iron species present in a natural system. The separation of Fe(II) and Fe(III) was successfully accomplished using a variation of an ion exchange method involving resin-loaded filter paper. The quantitation of the various iron species was determined using linear scan voltammetry and atomic absorption. The total iron concentration, determined as the sum of the various separate species, compares favorably with the total iron concentration as determined directly using atomic absorption methods.

Thesis (M.A.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 146-156).