The contribution of benthic nutrient fluxes to water column primary production in Weeks Bay, Alabama

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dc.contributor Kiene, Ronald P.
dc.contributor Findlay, Robert H.
dc.contributor.advisor Mortazavi, Behzad Riggs, Ashley Arielle 2017-03-01T14:36:32Z 2017-03-01T14:36:32Z 2010
dc.identifier.other u0015_0000001_0000435
dc.identifier.other Riggs_alatus_0004M_10595
dc.description Electronic Thesis or Dissertation
dc.description.abstract In shallow estuaries benthic and pelagic processes are tightly coupled such that the nutrients fueling primary production are regenerated from the sediments by the decomposition of organic matter. Weeks Bay, Alabama, a National Estuarine Research Reserve (NERR) site is characterized by high rates of gross primary production and is one of several shallow sub-estuaries, which has the potential to alter nutrients before exporting them to Mobile Bay. The overarching goal of the study was to determine the role of the sediments in providing nutrients for water column primary production in Weeks Bay. The study was conducted over a one year period (April 2009 - March 2010) at two sites, Magnolia River and Mid Bay. Monthly measurements of water column dissolved oxygen (DO), salinity, temperature, chlorophyll-a (chla), nutrients, and porewater profiles of dissolved inorganic nitrogen (DIN) and phosphate (PO_4 ^3- ) were made from 0-10 cm over 1 cm intervals. In addition, intact sediment cores were used to measure benthic fluxes of DIN (NO_3 ^- , NH_4 ^+ , and PO_4 ^3- ), sediment oxygen consumption (SOC), and di-nitrogen gas (N_2 ). Denitrification potential rates were measured using the acetylene inhibition method to determine if NO_3 ^- was limiting to denitrification. Net Ecosystem Metabolism (NEM), gross primary production, and respiration were calculated using the open water method from continuous dissolved oxygen concentrations measured at two sites. In general, there was an uptake of NO_3 ^- by the sediments. There was a seasonal pattern with NH_4 ^+ fluxes with the greatest effluxes occurring during the warmer months. N_2 fluxes were variable and in general there was an uptake into the sediments. There was no detectable site or seasonal pattern in SOC or PO_4 ^3- . Respiration exhibited a strong seasonal pattern in both sites and increased from spring to summer, peaked in the summer, and decreased in the fall and winter. There was not a strong seasonal pattern for gross primary production. Net ecosystem metabolism revealed net heterotrophy year-round. Phytoplankton nitrogen demand (PND) calculated from gross primary production suggest the sediments provide approximately 9% of PND.
dc.format.extent 97 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Biogeochemistry
dc.title The contribution of benthic nutrient fluxes to water column primary production in Weeks Bay, Alabama
dc.type thesis
dc.type text University of Alabama. Dept. of Biological Sciences Marine Science The University of Alabama master's M.S.

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