Earth Sciences Commons^™

Sources And Cycling Of Carbonyl Sulfide In The Sargasso Sea, Gregory A. Cutter, Lynda S. Cutter, Katherine C. Filippino

OES Faculty Publications

The cycling of the radiatively important gas carbonyl sulfide (OCS) was studied in surface waters of the Sargasso Sea. In August 1999, surface OCS concentrations averaged 8.6 pmol L^-1, showed minor diel variations, and varied little with depth. An OCS precursor, total dissolved organic sulfur (DOS), was lowest at the surface (40 nmol L^-1) and increased with depth. The photoproduction rate of OCS from in situ incubations averaged 9.6 pmol L^-1 h^-1, whereas dark production was 7.0 pmol L^-1 h^-1. Apparent quantum yields were 10^-5-10^-7 from 313-436 …

Analytical Intercomparison Between Flow Injection-Chemiluminescence And Flow Injection-Spectrophotometry For The Determination Of Picomolar Concentrations Of Iron In Seawater, Andrew R. Bowie, Peter N. Sedwick, Paul J. Worsfold

OES Faculty Publications

A lab- and ship-based analytical intercomparison of two flow injection methods for the determination of iron in seawater was conducted, using three different sets of seawater samples collected from the Southern Ocean and South Atlantic. In one exercise, iron was determined in three different size-fractions (< 0.03 &μm, < 0.4 μm, and unfiltered) in an effort to better characterize the operational nature of each analytical technique with respect to filter size. Measured Fe concentrations were in the range 0.19 to 1.19 nM using flow injection with luminol chemiluminescence detection (FI-CL), and 0.07 to 1.54 nM using flow injection with catalytic spectrophotometric detection with N, N-dimethyl-p-phenylenediamine dihydrochloride (FI-DPD). The arithmetic mean for the FI-CL method was higher (by 0.09 nM) than the FI-DPD method for dissolved (< 0.4 μm) Fe, a difference that is comparable to the analytical blanks, which were as high as 0.13 nM ( CL) and 0.09 nM (DPD). There was generally good agreement between the FI-CL determinations for the < 0.03 μm size fraction and the FI-DPD determinations for the < 0.4 μm size fraction in freshly collected samples. Differences in total-dissolvable ( unfiltered) Fe concentrations determined by the two FI methods were more variable, reflecting the added complexity associated with the analysis of partially digested particulate material in these samples. Overall, however, the FI-CL determinations were significantly (P = 0.05) lower than the FI-DPD determinations for the unfiltered samples. Our results suggest that the observed, systematic inter-method differences reflect measurement of different physicochemical fractions of Fe present in seawater, such that colloidal and/or organic iron species are better determined by the FI-CL method than the FI-DPD method. This idea is supported by our observation that inter-method differences were largest for freshly collected acidified seawater, which suggests extended storage (>6 months) of acidified samples as a possible protocol for the determination of dissolved iron in seawater.

A Holocene Record Of Changing Arctic Ocean Ice Drift Analogous To The Effects Of The Arctic Oscillation, Dennis A. Darby, Jens F. Bischof

OES Faculty Publications

The Arctic Oscillation (AO) controls the configuration of the Transpolar Drift (TPD). If thicker ice from the Beaufort Gyre were exported, the volume of fresh water/sea ice in the Nordic seas would significantly increase, decreasing the formation of North Atlantic deep water. This would cool large parts of the Northern Hemisphere and affect global climate. Therefore, in order to understand how the global climate system functions, it is imperative to know how the TPD changed over the last millennium or more. The provenance of grains in a sediment core located near the confluence of the TPD and the Beaufort Gyre …

Black Carbon In Estuarine And Coastal Ocean Dissolved Organic Matter, Antonio Mannino, H. Rodger Harvey

OES Faculty Publications

We measured black carbon (BC) in ultrafiltered, high-molecular weight dissolved organic matter (UDOM) in surface waters of Delaware Bay, Chesapeake Bay, and the adjacent Atlantic Ocean (U.S.A.) to investigate the importance of riverine and estuarine dissolved organic matter (DOM) as a source of BC to the ocean. BC was 5-72% of UDOM-C (27 ± 17%), which corresponds to 8.9 ± 6.5% of dissolved organic carbon (DOC), with higher values in the heavily urbanized midbay region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of …

Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres

OES Theses and Dissertations

The hydrology of wetlands, particularly how wetland soils collect, store, and redistribute water strongly affects how wetland systems function. In created wetlands, construction processes and materials influence the hydrology and consequently, the potential for successful reestablishment of target vegetation communities. During 2002–2004, the Virginia Department of Transportation constructed large mitigation wetlands on two different Quaternary aged surfaces with very similar hydrogeomorphic conditions. The Sandy Bottom Nature Park site (SBNP) located in Hampton, VA and rests on the sandy loam Tabb Formation while the Charles City Wetland site (CCW) lies on the older and clay-rich Shirley Formation. This study documents and …

An Investigation Of Dissolved Organic Matter In A Shallow Coastal Bay Subject To Aureococcus Anophagefferens Blooms, Jean-Paul Simjouw

OES Theses and Dissertations

Aureococcus anophagefferens, the pelagophyte responsible for brown tide blooms, was identified in Chincoteague Bay in 1997 and has “bloomed” there since at least 1998. Aureococcus anophagefferens is capable of using dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) substrates to support growth, and this utilization is hypothesized to give the organism a competitive advantage relative to other phytoplankton when inorganic nutrient concentrations are low or depleted. Because previous studies suggest dissolved organic matter (DOM) is important in initiating and sustaining brown tide blooms, a field study of the variations in DOC concentration and DOM composition was performed at …

Dissolved Humic Substances: Characterization Of Their Sorption Onto Iron Hydroxide Aluminum Hydroxide Kaolinite And Smectite, Sarah E. Diebel

OES Theses and Dissertations

Humic (HA) and fulvic (FA) acids participate in many geochemical processes and the mechanisms of their sorption to colloidal surfaces are numerous, indicating these substances are complex and heterogeneous. The current study focuses on the interactions of the Fe hydroxide (FE), Al hydroxide, Kaolinite (KA) and Smectite (SM) and these naturally occurring organic acids using Fourier Transform Infrared Spectroscopy (FTIR) and DOC analysis at pH 4. FTIR was used for the initial functional group characterization, as well as the comparison of before and after adsorption spectra of the HA and FA. DOC examined the amounts of HA and FA adsorbed …

Anisotropy And Its Relation To Liquefaction Resistance Of Granular Material, Isao Ishibashi, Omer F. Capar

Civil & Environmental Engineering Faculty Publications

This research establishes quantitative relationships between soil's anisotropy and liquefaction resistance for granular materials. Uniform medium density (D_r = 50%) sand specimens were prepared using three different sample preparation techniques (air pluviated (AP), moist tamped (NIT), and moist vibrated (MV)) to create different initial soil fabrics. Undrained cyclic triaxial tests were then performed to determine the liquefaction resistance of each soil specimen. On the same specimens in the triaxial cell, vertical and horizontal compression wave velocities and vertical shear wave velocity (V_s) were measured using piezoelectric bender elements. Anisotropic (transversely isotropic) elastic constants of the soil specimens were …

New Evidence For Enhanced Ocean Primary Production Triggered By Tropical Cyclone, I. Lin, W. Timothy Liu, Chun-Chieh Wu, George T. F. Wong, Chuanmin Hu, Zhiqiang Chen, Wen-Der Liang, Yih Yang, Kon-Kee Liu

OES Faculty Publications

[1] New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long-speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai-Tak passed over the South China Sea (SCS). During its short 3-day stay, Kai-Tak triggered an average 30-fold increase in surface chlorophyll-a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2-4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long-neglected contribution of tropical cyclones to SCS's annual new production may …

The Role Of Physical, Chemical, And Microbial Heterogeneity On The Field-Scale Transport And Attachment Of Bacteria, Brian J. Mailloux, Mark E. Fuller, Tullis C. Onstott, James Hall, Hailiang Dong, Mary F. Deflaun, Sheryl H. Streger, Randi K. Rothmel, Maria Green, Donald J. P. Swift, Jon Radke

OES Faculty Publications

A field-scale bacterial transport experiment was conducted at the Narrow Channel Focus Area of the South Oyster field site located in Oyster, Virginia. The goal of the field experiment was to determine the relative influence of subsurface heterogeneity and microbial population parameters on flow direction, velocity, and attachment of bacteria at the field scale. The field results were compared with results from laboratory-scale column experiments to develop a method for predicting field-scale bacterial transport. The field site is a shallow, sandy, unconfined, aerobic aquifer that has been characterized by geophysical, sedimentological, and hydrogeological methods. Comamonas sp. strain DA001 and a …

Nitrate Anomaly In The Upper Nutricline In The Northern South China Sea - Evidence For Nitrogen Fixation, George T. F. Wong, Shi-Wei Chung, Fuh-Kwo Shiah, Chung-Chi Chen, Liang-Saw Wen, Kon-Kee Liu

OES Faculty Publications

[1] Up to 2 μM of nitrate anomaly, N*, were found in the upper nutricline at the South East Asia Time-series Study (SEATS) site in the northern South China Sea (SCS). These concentrations were among the higher values reported in the Pacific and indicate the significant contribution of the remineralization of nitrogen-rich organic matter formed by nitrogen fixation to the nutrient dynamics of the area. The concentrations were systematically higher, by up to 2.5 μM, in the Fall through the early Spring, during the northeast monsoon, than in the Summer, suggesting that the impact of nitrogen fixation was higher during …

Intra-Annual Variation In The Stable Oxygen And Carbon And Trace Element Composition Of Sclerosponges, P. K. Swart, S. Thorrold, B. Rosenheim, A. Eisenhauer, C. G. A. Harriason, M. Grammer, C. Latkoczy

Biological Sciences Faculty Publications

This paper presents data to support the presence of (1) intra-annual signals in the chemical composition (δ¹⁸O and Sr/Ca) of the skeletons ofsclerosponges from the Bahamas and (2) variable rates of skeletal accretion. These conclusions are based on data obtained by using a microsampling method for the stable oxygen and carbon isotopes in which material was extracted at a resolution of one sample every 34 μm and a laser microprobe which obtained trace element data every 20 μm (Sr, Mg, and Pb). An age model was established using a combination of changes in the concentration of Pb, the …

Arctic Ice Export Events And Their Potential Impact On Global Climate During The Late Pleistocene, Dennis A. Darby, Jens F. Bischof, Robert F. Spielhagen, Steven A. Marshall, Stephen W. Herman

OES Faculty Publications

Ice sheets in the North American Arctic and, to a lesser extent, those in northern Eurasia calved large quantities of icebergs that drifted through Fram Strait into the Greenland Sea several times during the late Pleistocene. These icebergs deposited Fe oxide grains (45-250 mum) and coarse lithic clasts >250 mum matched to specific circum-Arctic sources. Four massive Arctic iceberg export events are identified from the Laurentide and the Innuitian ice sheets, between 14 and 34 ka (calendar years) in a sediment core from Fram Strait. These relatively short duration (<1-4 kyr) events contain 3-5 times the background levels of Fe oxide grains. They began suddenly, as indicated by a steep rise in the number of grains matched to an ice sheet source, suggesting rapid purges of ice through Fram Strait, due perhaps to collapse of ice sheets. The larger events from the northwestern Laurentide ice sheet are preceded by events from the Innuitian ice sheet. Despite the chronological uncertainties, the Arctic export events appear to occur prior to Heinrich events.

Modeling The Biogeochemical Cycle Of Selenium In The San Francisco Bay, Shannon L. Meseck

OES Theses and Dissertations

Due to recent concerns about selenium toxicity in the San Francisco Bay and the roles of refinery and San Joaquin River inputs on the selenium cycle, the model ECoS 3 (distributed from Plymouth Marine Laboratory, United Kingdom) was modified to simulate the biogeochemical cycle of selenium in the Northern Reach. The model is designed to simulate salinity, total suspended material, phytoplankton concentrations, dissolved selenium and its speciation (selenite, selenate, and organic selenide), and particulate selenium and its speciation (selenite + selenate, elemental selenium, and organic selenide). Actual data from 1999 were used to calibrate the model, while data from other …

Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae

OES Faculty Publications

Carbonyl sulfide (COS) in air and dissolved in seawater was determined during a cruise in August 1999 in the Sargasso Sea in the northwest Atlantic Ocean. Dissolved concentrations at the sea surface displayed only a weak diel cycle with a mean of 8.6 ± 2.8 pmol dm⁻³ owing to low abundance of photochemical precursors and high temperatures causing rapid hydrolysis. Depth profiles measured over the oceanic mixed layer revealed significant vertical gradients of COS concentration with higher values at the surface, suggesting that the rate of photochemical production at the surface exceeds the rate of vertical mixing. The mean …

The Distribution Of Airborne Coal Dust In Soil Profiles Of Norfolk, Va And Its Implication For Arsenic Loading To These Soils, William Joseph Bounds

OES Theses and Dissertations

Norfolk, Virginia is home to the Northern Hemisphere's largest coal terminal the Lamberts Point Docks. The coal loading process of this terminal creates large amounts of coal dust, which subsequently is distributed throughout the local region by atmospheric transport and deposition. While the coal dust itself poses only minor health hazards, certain trace elements within the coal, particularly arsenic, may pose environmental as well as significant health hazards. Within coal, arsenic occurs primarily in the mineral pyrite. As pyrite in the coal dust is subsequently oxidized via exposure to the atmosphere and/or meteoric water, arsenic may be released to the …

Dynamical Sedimentary Models Of Shallow Marine Environments, Yong Zhang

OES Theses and Dissertations

This treatise represents a contribution of quantitative, dynamical sedimentary modeling to the analytical understanding of sedimentary processes in shallow marine environments. The dynamical sedimentary models in this treatise numerically simulate the sedimentary processes from an event time scale, based on the fundamental physics of sediment dynamics in coastal and shelf depositional environments, to a longer, facies time scale. The simulated geologic processes serve to the illustrate shoreface equilibrium profile, shelf storm bed generation, and the shelf sedimentary facies system.

This treatise presents a nearshore profile evolution model for the abandoned Huanghe Delta, a two-dimensional storm deposition model, and a sedimentary …

Uptake Of Dissolved Organic Selenides By Marine Phytoplankton, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter

OES Faculty Publications

Se is present in multiple oxidation states in nature, each of which has unique chemical and biological reactivities. As a consequence, the rate of Se incorporation into food webs or its role as either a limiting nutrient or a toxic substance is a function of complex biogeochemistry. In particular, little is understood about the accumulation of dissolved organic selenides by phyto- or bacterioplankton. We assessed the bioavailability of dissolved organic selenides to marine and estuarine phytoplankton by presenting various algal species with filtered lysates of the diatom, Thalassiosira pseudonana, grown on media amended with radiolabeled selenite (⁷⁵Se[IV]). …

Control Of Phytoplankton Growth By Iron Supply And Irradiance In The Subantarctic Southern Ocean: Experimental Results From The Saz Project, P. W. Boyd, A. C. Crossley, G. R. Ditullio, F. B. Griffiths, D. A. Hutchins, B. Queguiner, Peter N. Sedwick, T. W. Trull

OES Faculty Publications

The influence of irradiance and Fe supply on phytoplankton processes was studied, north (47°S, 142°E) and south (54°S, 142°E) of the Subantarctic Front in austral autumn (March 1998). At both sites, resident cells exhibited nutrient stress (F_v/F_m 0 at 47°S and 9% I₀ at 54°S because of MLDs of 40 (47°S) and 90 m (54°S), when these stations were occupied. The greater MLD at 54°S is reflected by tenfold higher cellular chlorophyll a levels in the resident phytoplankton. In the 47°S experiment, chlorophyll a levels increased to >1 μg/L^-1 only in the high-Fe treatments, regardless …

Control Of Phytoplankton Growth By Iron And Silicic Acid Availability In The Subantarctic Ocean: Experimental Results From The Saz Project, D. A. Hutchins, Peter N. Sedwick, G. R. Ditullio, P. W. Boyd, B. Queguiner, F. B. Griffiths, C. Crossley

OES Faculty Publications

Subantarctic Southern Ocean surface waters in the austral summer and autumn are characterized by high concentrations of nitrate and phosphate but low concentrations of dissolved iron (Fe, similar to0.05 nM) and silicic acid (Si, <1 muM). During the Subantarctic Zone AU9706 cruise in March 1998 we investigated the relative importance of Fe and Si in controlling phytoplankton growth and species composition at a station within the subantarctic water mass (46.8degreesS, 142degreesE) using shipboard bottle incubation experiments. Treatments included unamended controls; 1.9 nM added iron (+Fe); 9 muM added silicic acid (+Si); and 1.9 nM addediron plus 9 muM added silicic acid (+Fe+Si). We followed a detailed set of biological and biogeochemical parameters over 8 days. Fe added alone clearly increased community growth rates and nitrate drawdown and altered algal community composition relative to control treatments. Surprisingly, small, lightly silicified pennate diatoms grew when Fe was added either with or without Si, despite the extremely low ambient silicic acid concentrations. Pigment analyses suggest that lightly silicified chrysophytes (type 4 haptophytes) may have preferentially responded to Si added either with or without Fe. However, for many of the parameters measured the +Fe+Si treatments showed large increases relative to both the +Fe and +Si treatments. Our results suggest that iron is the proximate limiting nutrient for chlorophyll production, photosynthetic efficiency, nitrate drawdown, and diatom growth, but that Si also exerts considerable control over algal growth and species composition. Both nutrients together are needed to elicit a maximum growth response, suggesting that both Fe and Si play important roles in structuring the subantarctic phytoplankton community.

Iron In East Antarctic Snow: Implications For Atmospheric Iron Deposition And Algal Production In Antarctic Waters, Ross Edwards, Peter N. Sedwick

OES Faculty Publications

To evaluate the deposition and solubility of aerosol iron in the Antarctic seasonal sea ice zone (SSIZ), iron was measured in snow samples collected from three areas in the SSIZ (Prydz Bay, Dumont d'Urville Sea and Ross Sea) and one continental area (Princess Elizabeth Land) of East Antarctica. Concentrations of total-dissolvable iron (that soluble at pH ~2) ranged from 20-2950 pg g^-1, with the lowest concentrations measured in snow from the Dumont d'Urville Sea. Using estimates of snow accumulation rates, we calculate atmospheric iron deposition fluxes of 0.017-0.11 mg m^-2 yr^-1(0.30-2.0 μmol m^-2 yr …

Effects Of Iron, Silicate, And Light On Dimethylsulfoniopropionate Production In The Australian Subantarctic Zone, G. R. Ditullio, P. N. Sedwick, D. R. Jones, P. W. Boyd, A. C. Crossley, D. A. Hutchins

OES Faculty Publications

Shipboard bottle incubation experiments were performed to investigate the effects of iron, light, and silicate on algal production of particulate dimethylsulfoniopropionate (DMSP_p) in the Subantarctic Zone (SAZ) south of Tasmania during March 1998. Iron enrichment resulted in threefold to ninefold increases in DMSP_p concentrations relative to control treatments, following 7 and 8-day incubation experiments. Additions of Fe and Si preferentially stimulated the growth of lightly-silicified pennate diatoms and siliceous haptophytes, respectively, to which we attribute the increased DMSP_p production in the incubation bottles. Both of these algal groups were previously believed to be low DMSP_{p …}

Introduction To Special Section: Saz Project, T. W. Trull, Peter N. Sedwick, F. B. Griffiths, S. R. Rintoul

OES Faculty Publications

Oceanographic processes in the subantarctic region contribute crucially to the phys. and biogeochemical aspects of the global climate system. To explore and quantify these contributions, the Antarctic Cooperative Research Center organized the SAZ Project, a multidisciplinary, multiship study carried out south of Australia in the austral summer of 1997-1998. We present an overview of the SAZ Project and some of its major results.

Holocene Sediment Records From The Continental Shelf Of Mac. Robertson Land, East Antarctica, Peter N. Sedwick, Peter T. Harris, Lisette G. Robertson, Gary M. Mcmurtry, Maximilian D. Cremer, Philip Robinson

OES Faculty Publications

Geochemical records are presented for five sediment cores from basins on the continental shelf of Mac. Robertson Land, East Antarctica. The cores contain 2-4 m thick sequences of hemipelagic, siliceous mud and ooze (SMO) deposited under seasonally open marine conditions. The inner and middle shelf SMO sequences are massive dark olive green material, whereas the outer shelf SMO sequences are dark olive material interspersed with light olive green layers similar to1-10 cm thick. The biogenic material is dominated by marine diatoms including Fragilariopsis curta, Fragilariopsis cylindrus, and Chaetoceros spp. in the dark-colored SMO and Corethron criophilum in the …

Modifications Of The C37 Alkenone And Alkenoate Composition In The Water Column And Sediment: Possible Implications For Sea Surface Temperature Estimates In Paleoceanography, Joan O. Grimalt, Jürgen Rullkötter, Marie-Alexandrine Sicre, Roger Summons, John Farrington, H. Rodger Harvey, Miguel Goñi, Ken Sawada

OES Faculty Publications

The literature pertaining to C37 alkenone and C37 and C38 alkenoate production and diagenesis has been reviewed and evaluated for issues that might jeopardize their usefulness in paleotemperature estimation. We also examined the use of the C37 alkenones as paleoproductivity indicators, the stability of their δ13C isotopic compositions, and their incorporation into the nonsolvent extractable organic matter fraction. Biological transformation of organic matter by bacteria and zooplankton does not appear to cause significant changes to the ratio of C37:2 and C37:3 alkenones, but there are major alterations in the relative composition of alkenoates. Studies of water column processes and postdepositional …

Alteration Processes Of Alkenones And Related Lipids In Water Columns And Sediments, H. Rodger Harvey

OES Faculty Publications

Alkenones produced by the haptophyte algae are currently being used as indices of sea surface temperature in recent and past ocean environments, but limited information is available concerning the impact of biotic and abiotic processes on the integrity of these long chain lipids. This synthesis provides selected background information on major alteration processes that must be considered before such indices can be used with confidence. A number of processes in the water column and surface sediments have the potential to impact the structural integrity of alkenones and compromise their ability as temperature markers. Processes discussed include the alteration of alkenone …

Identity, Conflict And Cooperation In International River Basins, Jack V. Kalpakian

Graduate Program in International Studies Theses & Dissertations

This dissertation tests the hypothesis that water disputes cause serious conflict within and between states. It uses a structured case study approach to see whether there is a link between the independent and dependent variables. It also considers the effect of other variables on serious conflict. Specifically it addresses the effects of national identity and the othering process on conflict. The three case studies are built around rivers in the drier parts of the world. This biases the dissertation towards affirming the established mainstream hypothesis which states that water disputes cause serious conflict. In all three cases, historical animosities and …

Jeffress Research Grant Awards

Virginia Journal of Science

Announcements of the Jeffress Research Grants that have been awarded in 1999.

Iron And Manganese In The Ross Sea, Antarctica: Seasonal Iron Limitation In Antarctic Shelf Waters, Peter N. Sedwick, Giacomo R. Ditullio, Denis J. Mackey

OES Faculty Publications

Dissolved iron and manganese and total dissolvable iron were measured in water column samples from the Polynya Region of the southern Ross Sea in cruises in Nov.-Dec. 1994 (spring 1994) and Dec. 1995 to Jan. 1996 (summer 1995). Iron and manganese addition bottle incubation experiments were also performed on these cruises to assess the nutritional sufficiency of ambient iron and manganese concentrations for phytoplankton growth. Generally high dissolved iron concentrations (>0.5 nM) and relatively complex iron and manganese vertical profiles were obtained in spring 1994 vs. summer 1995. Dissolved iron concentrations in the upper water column averaged 1.0 nM …

Zinc Speculation And Ligand Fluxes In Chesapeake Bay And Elizabeth River Pore Waters, Duncan Glover Byers

Chemistry & Biochemistry Theses & Dissertations

Presented here are the first data on the vertical concentrations, complexation, speciation, and fluxes of total dissolved zinc and zinc complexing ligands, and zinc speciation in sediment pore waters in the Chesapeake Bay and Elizabeth River, Virginia.

Sediment pore waters were collected in mid and southern Chesapeake Bay in November 1997 and in the Elizabeth River (Pinner's Point) in March, April, and July 1998. Flux experiments were conducted in Elizabeth River sediment cores in April and July 1998. [TDZn] and zinc complexation were determined using differential pulse anodic stripping voltammetry at a hanging mercury drop electrode (DPASV-HMDE).

[TDZn] in the …