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Full-Text Articles in Physical Sciences and Mathematics
Modeling Distinct Vertical Biogeochemical Structure Of The Black Sea: Dynamical Coupling Of The Oxic, Suboxic, And Anoxic Layers, T Oguz, Hw Ducklow, P Malanotte-Rizzoli
Modeling Distinct Vertical Biogeochemical Structure Of The Black Sea: Dynamical Coupling Of The Oxic, Suboxic, And Anoxic Layers, T Oguz, Hw Ducklow, P Malanotte-Rizzoli
VIMS Articles
A one-dimensional, vertically resolved, physical-biogeochemical model is used to provide a unified representation of the dynamically coupled oxic-suboxic-anoxic system for the interior Black Sea. The model relates the annual cycle of plankton production in the form of a series of successive phytoplankton, mesozooplankton, and higher consumer blooms to organic matter generation and to the remineralization-ammonification-nitrification-dentrification chain of the nitrogen cycle as well as to anaerobic sulfide oxidation in the suboxic-anoxic interface zone. The simulations indicate that oxygen consumption during remineralixation and nitrification, together with a lack of ventilation of subsurface waters due to the presence of strong stratification, are the …
Radiocarbon Distributions In Southern Ocean Dissolved And Particulate Organic Matter, Erm Druffel, Je Bauer
Radiocarbon Distributions In Southern Ocean Dissolved And Particulate Organic Matter, Erm Druffel, Je Bauer
VIMS Articles
Dissolved organic carbon (DOC) is the largest actively exchanging pool of organic carbon in the ocean, yet its sources and sinks are not well constrained. The average C-14 ages of DOC in the deep N. Atlantic and N. Pacific Oceans are 4,000 [Bauer et al., 1992; Druffel et al., 1992] and 6,000 years [Williams and Druffel, 1987], respectively, and represent the beginning and end of the deep ocean conveyor [Broecker, 1991]. Here we report that the deep Southern Ocean DOC has a C-14 age (5,600 y) much closer to that of the deep N. Pacific, but its concentration in seawater …
A Stable Isotopic Study To Determine Carbon And Nitrogen Cycling In A Disturbed Southern Californian Forest Ecosystem, S Korontzi, Sa Macko, Iris C. Anderson
A Stable Isotopic Study To Determine Carbon And Nitrogen Cycling In A Disturbed Southern Californian Forest Ecosystem, S Korontzi, Sa Macko, Iris C. Anderson
VIMS Articles
This study utilized isotope analyses to contrast nitrogen and carbon dynamics at four sites located along an air pollution gradient in the San Bernardino National Forest in southern California. Natural N-15 and C-13 abundances along with nutritional and edaphic properties were determined in soil, litter, and vegetation samples. Mean bulk nitrogen delta(15)N values of soil and vegetation at Camp Paivika (CP), the most polluted site, were at least 1.7 parts per thousand more enriched than the other, less polluted sites. Mean soil delta(15)NH(4)(+) was also significantly enriched in N-15 at CP compared to Barton Flats (BF), the least polluted site, …
Organic Matter Composition Of Sediments And The History Of Eutrophication And Anoxia In The Mesohaline Chesapeake Bay, Andrew R. Zimmerman
Organic Matter Composition Of Sediments And The History Of Eutrophication And Anoxia In The Mesohaline Chesapeake Bay, Andrew R. Zimmerman
Dissertations, Theses, and Masters Projects
To evaluate the effects of anthropogenic alteration of the Chesapeake Bay (CB) watershed since European settlement, the historical progression of eutrophication and anoxia in the mesohaline region of CB was reconstructed. Lipid biomarker and carbon and nitrogen stable isotopic and elemental composition of CB surficial sediments were examined seasonally in order to identify the present sources of organic matter to CB sediments and the processes controlling their distribution. Temporal variability in surficial sediment composition could be linked to seasonal changes in phytoplankton community composition and biomass while spatial variation was dominated by the delivery of alloclithonous versus autochthonous sources of …
Carbon Dynamics In A Tidal Freshwater Marsh, Scott C. Neubauer
Carbon Dynamics In A Tidal Freshwater Marsh, Scott C. Neubauer
Dissertations, Theses, and Masters Projects
The sources and fates of carbon in a tidal freshwater marsh (Sweet Hall marsh; Pamunkey River, Virginia) were determined to understand the role that these marshes play with respect to estuarine carbon cycling. A carbon gas flux model, based on measured carbon dioxide and methane fluxes, was developed to calculate annual rates of macrophyte and microalgal photosynthesis and community and belowground respiration. Because carbon fluxes out of marsh sediments may underestimate true belowground respiration if sediment-produced gases are transported through plant tissues, gross nitrogen mineralization was used as a proxy for belowground carbon respiration. Annual community respiration exceeded gross photosynthesis, …