Biogeochemistry Commons^™

A Comparison Of Metals In Several Ahermatypic Corals And Surficial Sediments: Mobile Pinnacles And Hoffa Reef, Northcentral Gulf Of Mexico, Kathryn M. Conko

OES Theses and Dissertations

Metal concentrations in marine sediment and carbonate secreting invertebrates are representative of surrounding environmental chemistry. Aluminum, Ba Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, and Zn were measured in carbonate and terrigenous phases of the $<$63 um fraction of sediment samples from two locations in the northcentral Gulf of Mexico. Enrichment factors indicate that Al, Ba, Cu, Cr, Mg, Mn, and Ni are all slightly depleted in these sediments relative to crustal abundances. Discriminant function analyses shows that the concentrations of five elements differ between locations.

Ahermatypic coral (106 specimens) from five genera collected from the study sites were analyzed for Cd, Cu, Cr, Pb, Zn, Mn, Sr, Ba, Fe, Ca and Mg. Eight elements vary between some genera, Al and Ba also vary in concentration in corals between either location. All elements except Sr are significantly depleted in the coral with respect to Ca in the …

Nutrient Cycling In Bordenstake Bay Sediments: A Backbarrier Lagoon, Mark J. Herrenkohl

OES Theses and Dissertations

Six sets of sediment cores were collected over a one year period (June 1986 to July 1987) to examine nutrient cycling in Bordenstake Bay, a back barrier lagoon on Virginia's Eastern Shore Peninsula. The sampling times were chosen to examine any seasonal effects (e.g., temperature changes) which may affect the rates of metabolism in these sediments.

The sedimentation rate in Bordenstake Bay is 0.76 ± 0.21 cm/yr, leading to the annual deposition of 7. 05 moles of carbon, 0.46 moles of nitrogen, and 0.15 moles of phosphorus, per square meter of the sediment surface. The remineralization of organic matter in …

The Geochemistry Of Selenium And Sulfur In A Coastal Salt Marsh, David Jay Velinsky

OES Theses and Dissertations

Investigation of the various chemical forms of selenium and sulfur in sediments and pore waters can provide information about various oxidation/reduction processes. Five cores were obtained from the Great Marsh, from April 1985 to June 1986. Sampling times coincided with the seasonal redox cycle known to occur within the marsh system. Sediments were analyzed for various selenium and sulfur phases.

Iron monosulfides and elemental sulfur both display large seasonal changes in concentration and distribution with depth, indicating a coupling with redox conditions. In contrast, the depth distribution of greigite did not show appreciable changes with season. Pyrite underwent large concentration …

Microbial Manganese Reduction By Enrichment Cultures From Coastal Marine Sediments, David J. Burdige, Kenneth H. Nealson

OES Faculty Publications

Manganese reduction was catalyzed by enrichment cultures of anaerobic bacteria obtained from coastal marine sediments. In the absence of oxygen, these enrichment cultures reduced manganates when grown on either lactate, succinate, or acetate in both sulfate-free and sulfate-containing artificial seawaters. Sodium azide as well as oxygen completely inhibited microbial manganese reduction by these enrichment cultures, whereas molybdate had no effect on them. The addition of nitrate to the medium slightly decreased the rate of Mn²⁺ production by these enrichment cultures. These findings are consistent with the hypothesis that the manganese-reducing organisms in these enrichment cultures use manganates as terminal …

The Marine Biogeochemistry Of Selenium: A Re-Evaluation, Gregory A. Cutter, Kenneth W. Bruland

OES Faculty Publications

Vertical and horizontal profiles from the North and South Pacific Oceans demonstrate the existence of three species of dissolved selenium: selenite, selenate, and organic selenide (operationally defined). In surface waters, organic selenide makes up about 80% of the total dissolved selenium, selenite concentrations are uniformly low, and selenate concentrations rise with increased vertical mixing. The organic selenide maximum (thought to consist of seleno-amino acids in peptides) coincides with the maxima of primary productivity, pigments, bioluminescence, and dissolved free amino acids. Deep ocean waters are enriched in selenite and selenate, while organic selenide is nondetectable. In suboxic waters of the tropical …

A Pore Water/Solid Phase Diagenetic Model For Manganese In Marine Sediments, David J. Burdige, Joris M. Gieskes

OES Faculty Publications

A steady state diagenetic model is developed which accounts for changes in both the pore water and solid phase manganese profiles in marine sediments as a result of advection, diffusion, and redox reactions. The model is applied to observations on two cores in the E equatorial Atlantic in which pore water and solid phase manganese data are available. In situ reaction rates for manganese oxidation and reduction are estimated. The oxidation rates calculated here are in good agreement with rates measured in laboratory studies. In addition, the calculated manganese oxidation and reduction rates are compared with other estimated rates for …

The Effects Of Elevated Calcium Chloride And Magnesium Chloride Levels On Larval Growth And Survival Of Macrobrachium Rosenbergii (De Man) (Decapoda Palaemonidae) Reared In The Laboratory, James Thomas Michaels Ii

OES Theses and Dissertations

The effects of elevated CaCl₂ , MgCl₂ , combination CaCl₂ and MgCl₂ concentrations and their associated ionic strengths on larval growth and survival of the freshwater prawn, Macrobrachium rosenbergii were investigated in the laboratory. Larvae were reared in diluted seawater of 15 parts per thousand salinity with elevated calcium concentrations of 330 parts per million and elevated magnesium concentrations of 1275 parts per million. Control larvae were also reared with elevated NaCl concentrations to duplicate the ionic strength increases of the combination CaCl₂ - MgCl₂ test solution which had the highest ionic strength. A …

Suspended Matter And Light Attenuation In A Turbid Estuary, Daniel E. Campbell

OES Theses and Dissertations

A study was made in Hampton Roads, Virginia, to characterize the suspended matter and to investigate its relationship to the light attenuation coefficient. The study gives a detailed description of the seston and its variations with time and space. An evaluation of the light attenuation coefficient as an indicator of seston distributional parameters was made.

The distribution of the suspended matter is obtained through gravimetric, Coulter counter and microscopic analyses. Microscopic analysis is employed to determine the composition of the seston and ATP determinations give the amount of living biomass. The suspended matter is characterized in terms of weight, numbers, …

Methane Distribution And Production In The Georgia Salt Marsh, Larry P. Atkinson, John R. Hall

CCPO Publications

Bacterial action in the anaerobic sediments of Spartina salt marsh produce large quantities of methane. Water in contact with the marsh has methane concentrations 200-300 times normal oceanic concentrations. The methane content of the water varies from maximum of 1.2 mu l CH sub(4)/ super(l) super(-1) in the summer to a minimum of 0.005 mu l CHl1

Water Chemistry Survey Of Boulder Basin, Lake Mead, P. R. Tramutt, Bureau Of Reclamation

Publications (WR)

The survey results indicate that the impoundment of water behind Hoover Dam has not adversely affected the dissolved oxygen (DO) content and that water quality and DO content were uniform regardless of depth. The study made in April-May 1964 will provide water quality data of Lake Mead prior to releases from Lake Powell as a basis for evaluating Lake Powell's effect on water quality and limnology of Lake Mead. The performance of a DO analyzer was tested and found unsatisfactory at depths below 150 ft. Parameters tested by standard chemical analyses of water samples in the Denver Laboratory and by …