Physical Sciences and Mathematics Commons^™

Sources And Cycling Of Dissolved And Particulate Organic Radiocarbon In The Northwest Atlantic Continental Margin, Je Bauer, Erm Druffel, Dm Wolgast, S Griffin

VIMS Articles

Continental shelves and slopes are productive and dynamic ocean margin systems that also regulate the fluxes of terrestrial, riverine, and estuarine materials between the continents and oceans. In order to evaluate the ages, potential sources, and transformations of organic matter in an ocean margin system, we measured the radiocarbon (Delta (14)C and delta (13)C distributions of total dissolved organic carbon (DOC), suspended particulate organic carbon (POC), and dissolved inorganic carbon (DIC) in waters of the Middle Atlantic Bight (MAB) continental shelf and slope in April-May 1994. The Delta (14)C of DOC was greatest (as high as -39 parts per thousand) …

Dynamic Bacterial And Viral Response To An Algal Bloom At Subzero Temperatures, Patricia L. Yager, Tara L. Connelly, Behzad Mortazavi, K. Eric Wommack, Nasreen Bano, James E. Bauer, Stephen Opsahl, James T. Hollibaugh

VIMS Articles

New evidence suggests that cold‐loving (psychrophilic) bacteria may be a dynamic component of the episodic bloom events of high‐latitude ecosystems. Here we report the results of an unusually early springtime study of pelagic microbial activity in the coastal Alaskan Arctic. Heterotrophic bacterioplankton clearly responded to an algal bloom by doubling cell size, increasing the fraction of actively respiring cells (up to an unprecedented 84% metabolically active using redox dye CTC), shifting substrate‐uptake capabilities from kinetic parameters better adapted to lower substrate concentrations to those more suited for higher concentrations, and more than doubling cell abundance. Community composition (determined by polymerase …

Hydrography, Nutrients, And Carbon Pools In The Pacific Sector Of The Southern Ocean: Implications For Carbon Flux, Kendra L. Daly, Walker O. Smith Jr., Gregory C. Johnson, Et Al

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Abstract

We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low f CO₂ values along two transects indicated that much of the study area was a sink for atmospheric CO₂. The f CO₂ values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, …

Doc Cycling In A Temperate Estuary: A Mass Balance Approach Using Natural 14c And 13c Isotopes, Peter Raymond, James E. Bauer

VIMS Articles

We measured dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and their corresponding D14C and d13C values in order to study the sources and fates of DOC in the York River Estuary (Virginia, U.S.A.). The D14C and d13C values of DOC and DIC at the freshwater end-member indicate that during periods of moderate to high flow, riverine DOC entering the York was composed of decadal-aged terrestrially organic matter. In nearly all cases, DOC concentrations exceeded conservative mixing lines and were therefore indicative of a net DOC input flux from within the estuary that averaged 1.2 mM L21 d21 . The …