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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan
Editorial: The Marine Iodine Cycle, Past, Present, And Future, Rosie Chance, Gregory A. Cutter, Dalton S. Hardisty, Anoop S. Mahajan
OES Faculty Publications
In this Research Topic, we bring together ten articles from the diverse research communities interested in the marine iodine cycle, including paleoceanographers, atmospheric chemists, and biogeochemists. The physical chemistry underpinning iodine’s chemical speciation and transformations in the ocean is reviewed by Luther; this paper provides a theoretical basis for the field observations presented in this Research Topic.
Re-Evaluating Hydrogen Sulfide As A Sink For Cadmium And Zinc In The Oxic To Suboxic Upper Water Column Of The Pacific Ocean, N. R. Buckley, E. E. Black, J. A. Kenyon, N. T. Lanning, M. Sieber, T. M. Conway, J. N. Fitzsimmons, G. A. Cutter
Re-Evaluating Hydrogen Sulfide As A Sink For Cadmium And Zinc In The Oxic To Suboxic Upper Water Column Of The Pacific Ocean, N. R. Buckley, E. E. Black, J. A. Kenyon, N. T. Lanning, M. Sieber, T. M. Conway, J. N. Fitzsimmons, G. A. Cutter
OES Faculty Publications
Hydrogen sulfide is produced by heterotrophic bacteria in anoxic waters and via carbonyl sulfide hydrolysis and phytoplankton emissions under oxic conditions. Apparent losses of dissolved cadmium (dCd) and zinc (dZn) in oxygen minimum zones (OMZs) of the Atlantic and Pacific Oceans have been attributed to metal-sulfide precipitation formed via dissimilatory sulfate reduction. It has also been argued that such a removal process could be a globally important sink for dCd and dZn. However, our studies from the North Pacific OMZ show that dissolved and particulate sulfide concentrations are insufficient to support the removal of dCd via precipitation. In contrast, apparent …
Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining
Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining
OES Faculty Publications
Particulate phases transport trace metals (TM) and thereby exert a major control on TM distribution in the ocean. Particulate TMs can be classified by their origin as lithogenic (crustal material), biogenic (cellular), or authigenic (formed in situ), but distinguishing these fractions analytically in field samples is a challenge often addressed using operational definitions and assumptions. These different phases require accurate characterization because they have distinct roles in the biogeochemical iron cycle. Particles collected from the upper 2,000 m of the northwest subtropical Atlantic Ocean over four seasonal cruises throughout 2019 were digested with a chemical leach to operationally distinguish labile …
Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao
Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao
OES Faculty Publications
Fully and accurately reconstructing changes in oceanic productivity and carbon export and their controls is critical to determining the efficiency of the biological pump and its role in the global carbon cycle through time, particularly in modern CO2 source regions like the eastern equatorial Pacific (EEP). Here we present new high-resolution records of sedimentary 230Th-normalized opal and nannofossil carbonate fluxes and [231Pa/230Th]xs ratios from site MV1014-02-17JC in the Panama Basin. We find that, across the last deglaciation, phytoplankton community structure is driven by changing patterns of nutrient (nitrate, iron, and silica) availability which, in …
The Impact Of Changing Surface Ocean Conditions On The Dissolution Of Aerosol Iron, Matthew P. Fishwick, Peter N. Sedwick, Maeve C. Lohan, Paul J. Worsfold, Kristen N. Buck, Thomas M. Church, Simon J. Ussher
The Impact Of Changing Surface Ocean Conditions On The Dissolution Of Aerosol Iron, Matthew P. Fishwick, Peter N. Sedwick, Maeve C. Lohan, Paul J. Worsfold, Kristen N. Buck, Thomas M. Church, Simon J. Ussher
OES Faculty Publications
The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols …
Optics And Remote Sensing Of Bahamian Carbonate Sediment Whitings And Potential Relationship To Wind-Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, David J. Burdige
Optics And Remote Sensing Of Bahamian Carbonate Sediment Whitings And Potential Relationship To Wind-Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, David J. Burdige
OES Faculty Publications
Regions of milky white seas or "whitings" periodically occur to the west of Andros Island along the Great Bahama Bank where the bottom sediment consists of fine-grained aragonite mud. We present measurements of inherent optical properties within a sediment whiting patch and discuss the potential for monitoring the frequency, extent, and quantity of suspended matter from ocean colour satellite imagery. Sea spectral reflectance measured in situ and remotely from space revealed highly reflective waters elevated across the visible spectrum (i.e., "whitened") with a peak at 490 nm. Particulate backscattering was an order of magnitude higher than that measured at other …
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma
OES Faculty Publications
Osmium is one of the rarer elements in seawater, with typical concentration of ≈10 x 10-15 g g-1 ( 5.3 x 10-14 mol kg-1. The osmium isotope composition (187Os/188Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (≈ 1.3) and mantle/cosmic dust (≈ 0.13). Here, we show that the 187Os/188Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximate to 0.2) …
Evaluating The Biogeochemical Cycle Of Selenium In San Francisco Bay Through Modeling, Shannon L. Meseck, Gregory A. Cutter
Evaluating The Biogeochemical Cycle Of Selenium In San Francisco Bay Through Modeling, Shannon L. Meseck, Gregory A. Cutter
OES Faculty Publications
A biogeochemical model was developed to simulate salinity, total suspended material, phytoplankton biomass, dissolved selenium concentrations (selenite, selenate, and organic selenide), and particulate selenium concentrations (selenite + selenate, elemental selenium, and organic selenide) in the San Francisco Bay estuary. Model-generated estuarine profiles of total dissolved selenium reproduced observed estuarine profiles at a confidence interval of 91- 99% for 8 different years under various environmental conditions. The model accurately reproduced the observed dissolved speciation at confidence intervals of 81-98% for selenite, 72-91% for selenate, and 60-96% for organic selenide. For particulate selenium, model-simulated estuarine profiles duplicated the observed behavior of total …
Fluxes Of Copper-Complexing Ligands From Estuarine Sediments, Stephen A. Skrabal, John R. Donat, David J. Burdige
Fluxes Of Copper-Complexing Ligands From Estuarine Sediments, Stephen A. Skrabal, John R. Donat, David J. Burdige
OES Faculty Publications
Most studies of the organic complexation of Cu in natural waters have focused on distributions and processes in the water column, where a significant fraction of Cu-complexing ligands may be biologically produced. We present direct evidence for a flux of Cu-complexing ligands from estuarine sediments, demonstrating that sediments are a significant, yet previously unrecognized source of the ligands. Fluxes of Cu-complexing ligands from Chesapeake Bay sediments range from 300 to 1,200 nmol m-2 d-1, exceeding fluxes of total dissolved Cu by 3->40-fold, suggesting that any Cu fluxing from the sediments is likely to be organically complexed. …
The Role Of Benthic Fluxes Of Dissolved Organic Carbon In Oceanic And Sedimentary Carbon Cycling, Davd J. Burdige, Marc J. Alperin, Juliana Homstead, Christopher S. Martens
The Role Of Benthic Fluxes Of Dissolved Organic Carbon In Oceanic And Sedimentary Carbon Cycling, Davd J. Burdige, Marc J. Alperin, Juliana Homstead, Christopher S. Martens
OES Faculty Publications
Benthic fluxes (sediment-water exchange) of dissolved organic carbon (DOC) represent a poorly quantified component of sedimentary and oceanic carbon cycling. In this paper we use pore water DOC data and direct DOC benthic flux measurements to begin to quantitatively examine this problem. These results suggest that marine sediments represent a significant source of DOC to the oceans, as a lower limit of the globally-integrated benthic DOC flux is comparable in magnitude to riverine inputs of organic carbon to the oceans. Benthic fluxes of DOC also appear to be similar in magnitude to other sedimentary processes such as organic carbon oxidation …
Lava-Seawater Interactions At Shallow-Water Submarine Lava Flows, Francis J. Sansone, Joseph A. Resing, Gordon W. Tribble, Peter N. Sedwick, Kevin M. Kelly, Ken Hon
Lava-Seawater Interactions At Shallow-Water Submarine Lava Flows, Francis J. Sansone, Joseph A. Resing, Gordon W. Tribble, Peter N. Sedwick, Kevin M. Kelly, Ken Hon
OES Faculty Publications
Hydrothermal plumes associated with nearshore lava flows from Kilauea Volcano, Hawaii were studied on five occasions during 1989-1990 to address the current lack of data on direct lava-seawater interactions. The following enrichments were found in the sea-surface hydrothermal plumes above the active underwater lava flows: H2, 15,000x ambient seawater concentrations; Mn, 250x; and Si, 20x. Water temperatures reached 46°C. Lower concentrations and temperatures were observed in the plumes with increasing distance from shore, with H2, Si, and Mn concentrations linearly related to seawater temperature. Unlike deep sea spreading center hydrothermal plumes, no CH4 enrichment was …