Utilization of nitrogen and carbon by phytoplankton in Moreton Bay, Australia

摘要: Water samples were collected within river mouths, at plume sites and well flushed ocean-influenced Moreton Bay, a shallow subtropical embayment in south-eastern Queensland. Rates of inorganic nitrogen (NH4+ NO3-) carbon uptake determined across temporal spatial scales by use N-15 C-14 incorporation. Phytoplankton productivity, measured as CO2 uptake, was highest the mouths. NH4+ exceeded rates NO3- all times. Relative preference indices demonstrated consistent phytoplankton for higher than river-mouth sites. Inorganic nutrient chlorophyll concentrations mouths; however, greatest occurred sites, reflecting greater dependence on 'recycled' N 'new' N. Biomass-independent increased with increasing water temperature; decreasing temperature, lower temperature optimum nitrate reductase. The range ranges reported other coastal waters, strong gradients Bay. This trend C dynamics from oligotrophic to river-influenced waters seasonal flows is likely exist many tropical Australia.