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Physical Sciences and Mathematics

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William & Mary

2004

Physical Sciences Peer-Reviewed Articles

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Temporal Variability Of Delta C-14, Delta C-13, And C/N In Sinking Particulate Organic Matter At A Deep Time Series Station In The Northeast Pacific Ocean, J Hwang, Erm Druffel, S Griffin, Kl Smith, Rj Baldwin, Je Bauer Oct 2004

Temporal Variability Of Delta C-14, Delta C-13, And C/N In Sinking Particulate Organic Matter At A Deep Time Series Station In The Northeast Pacific Ocean, J Hwang, Erm Druffel, S Griffin, Kl Smith, Rj Baldwin, Je Bauer

VIMS Articles

A 6-year time series of Delta(14) C, delta(13) C, and C/N measurements in deep sinking particulate organic matter ( POM) is presented for an abyssal site, Station M in the northeast Pacific Ocean. The Delta(14)C values revealed that sinking POM at 3450 m depth ( 650 m above bottom) contained old carbon despite its presumed short transit time in the water column. The isotopic and chemical properties of the sinking POM varied with time and appear to be controlled by more than one major process. In 1993, 1994, and late 1996, isotopic signatures and C/N molar ratios indicate negligible or …


Bacterial Utilization Of Transient Plankton-Derived Dissolved Organic Carbon And Nitrogen Inputs In Surface Ocean Waters, J Cherrier, Je Bauer May 2004

Bacterial Utilization Of Transient Plankton-Derived Dissolved Organic Carbon And Nitrogen Inputs In Surface Ocean Waters, J Cherrier, Je Bauer

VIMS Articles

The majority of bacterial growth and respiration in the upper ocean is thought to result from coupling between microheterotrophic populations and the reactive soluble components of planktonic primary and secondary production. However, we know little about the potential turnover of these components and the concomitant growth of bacteria under conditions of intermittent or transient inputs of natural dissolved organic matter (DOM) compared to quasi-steady state, low DOM conditions. The present study evaluated the short-term (similar to3 d) rates and net extents of utilization (as measured losses) of selected constituents of plankton-derived DOM (DOMPD) by indigenous bacterioplankton populations in eastern North …


High Rates Of Ammonium Recycling Drive Phytoplankton Productivity In The Offshore Mississippi River Plume, B Wawrik, Jh Paul, Da Bronk, Et Al Apr 2004

High Rates Of Ammonium Recycling Drive Phytoplankton Productivity In The Offshore Mississippi River Plume, B Wawrik, Jh Paul, Da Bronk, Et Al

VIMS Articles

As part of an integrated study of the regulation of carbon fixation in the offshore Mississippi River plume, we measured the rates of N-15-labeled ammonium and nitrate uptake in the surface plume waters from offshore to nearshore along the plume axis towards the Mississippi Delta. Concentrations of nitrate in the plume ranged from 0.19 to 2.5 muM with the highest concentrations primarily in the shoreward stations, while ammonium ranged from 0.17 to 0.44 muM, showing little spatial variability. Rates of ammonium uptake ranged from 16.5 to 260 nM h(-1), and showed a strong trend of increasing values from offshore towards …


Assessing Sources And Ages Of Organic Matter Supporting River And Estuarine Bacterial Production: A Multiple-Isotope (D14c, D13c, And D15n) Approach, S. Leigh Mccallister, James E. Bauer, J Cherrier, Hugh W. Ducklow Jan 2004

Assessing Sources And Ages Of Organic Matter Supporting River And Estuarine Bacterial Production: A Multiple-Isotope (D14c, D13c, And D15n) Approach, S. Leigh Mccallister, James E. Bauer, J Cherrier, Hugh W. Ducklow

VIMS Articles

We used radiocarbon (D14C) and stable isotopic (d13C, d15N) signatures of bacterial nucleic acids to estimate the sources and ages of organic matter (OM) assimilated by bacteria in the Hudson River and York River estuary. Dualisotope plots of D14C and d13C coupled with a three-source mixing model resolved the major OM sources supporting bacterial biomass production (BBP). However, overlap in the stable isotopic (d13C and d15N) values of potential source end members (i.e., terrestrial, freshwater phytoplankton, and marsh-derived) prohibited unequivocal source assignments for certain samples. In freshwater regions of the York, terrigenous material of relatively recent origin (i.e., decadal in …