The outwelling hypothesis and North Inlet, South Carolina

Abstract

Extensive measurements of material concentrahons and water velocities at a transect across North Inlet, South C a r o h a (USA) allowed the estimation of net material and water fluxes. Sampling periods were distnbuted seasonally and according to tidal height. Statistical and hydrodynanlic models were used to develop flux estimates for specific tidal cycles. There was a net discharge of water from the marsh-estuanne system to the Atlantic Ocean which is attributed to rainfall runoff and freshwater input from an adjacent estuary. All constitutents were exported seasonally and annually from the system -except total semments, imported during fall and winter, and chlorophyll a and zooplankton, imported in summer and fall. ATP, bird biomass and macrodetritus were exported throughout the year. Export of carbon, nitrogen and phosphorus from North Inlet is high compared to other systems studied to date. Large net fluxes of DOC during winter imply coupling with the uplands. The high rates of export of ammonium and orthophosphate along with detritus and microorganisms suggest major decomposition processes are taking place within the system. Export of ammonium and orthophosphate to the coastal ocean also suggest a feedback loop with phytoplankton utilizing these materials, then in turn phytoplankton are imported into the estuary where they are consumed and remineralized. Previous explanations of outwehng and tidal transport are examined and found to be individually lacking. It is proposed that any comprehensive explanahon of the magnitude and direction of transport must include a physical explanation of water motion and the biological and physical mechanisms by which materials are added or removed from tidal waters. A comprehensive explanation of outwelling in North Inlet IS proposed which describes this system as an ebb-dominated, bar-built estuary with good flow connection to the sea and with some freshwater input. It is also a fertile system with high productivity providing materials for export to the coastal ocean and utilization of other imported materials.

Carbon Dioxide and Methane Emissions from Estuaries

“…It constitutes a major source of organic matter to the flat and marsh sediments (Goni and Thomas 2000;Delaune and Pezeshki 2003), but also to the adjacent estuarine waters and sediments, tidal flushing resulting in an outwelling process of carbon and nutrients (Dame et al 1986). Consequently, heterotrophic activity in the adjacent estuary is also partly fueled by tidal inputs from flats and marshes.…”

Carbon dynamics of Deep Bay, eastern Pearl River estuary, China. II: Trophic relationship based on carbon- and nitrogen-stable isotopes

“…Resale or republication not permitted without written consent of the publisher water areas (Dame & Lefeuvre 1994), the geomorphology of the wetlands (Odum et al 1979), the tidal regime (Lee 1990(Lee , 1995, the activities of macrofauna such as crabs (Robertson 1986, Lee 1989, 1997, and general hydrodynamics of the system (Dame et al 1986, Wolanski 1995. In general, however, tropical mangrove ecosystems are expected to be net exporters, although the magnitude as well as spatial extent of export appears to be more limited than previously assumed (Lee 1995).…”

Intertidal marsh as a source of dissolved inorganic carbon and a sink of nitrate in the Satilla River‐estuarine complex in the southeastern U.S.

“…There has been a major controversy over Odum's estuarine outwelling hypothesis regarding whether the marsh-surrounded estuary serves as a source of carbon and nutrients to coastal seas (Odum 1968;Chalmers et al 1985;Hopkinson 1985;Hopkinson et al 1989;Dame et al 1986). However, these studies have been confined mostly to the near shore (Sapelo Island) marine system or to the high salinity portions of estuaries.…”