Chemical Indicators of Anthropogenic Nitrogen-Loading in Four Pacific Estuaries

Anthropogenic Impacts on Estuaries

Nitrogen Loading from Coastal Watersheds to Receiving Estuaries: New Method and Application

In this paper we develop a model to estimate nitrogen loading to watersheds and receiving waters, and then apply the model to gain insight about sources, losses, and transport of nitrogen in groundwater moving through a coastal watershed. The model is developed from data of the Waquoit Bay Land Margin Ecosystems Research project (WBLMER), and from syntheses of published information. The WBLMER ...

Anthropogenic Pu distribution in Tropical East Pacific.

The geographical distribution of the anthropogenic radionuclides (238)Pu and (239+240)Pu in the Tropical East Pacific in 2003 was studied from the viewpoint of material migration. We measured the contents of Pu isotopes in seawater and in sediment from the sea bottom. The distributions of Pu isotopes, together with those of coexisting nitrate and phosphate species and dissolved oxygen, are disc...

Effects of Nonpoint Source Marsh Loading on Complex Estuaries

A foundational element in determining Total Maximum Daily Loads (TMDLs) is the determination of the relative impacts of point and nonpoint source impacts on the dissolved oxygen concentration (DO) of an impaired stream. It is not uncommon that the ultimate oxygen demand during a rain event can be greater than the effects of the fully permitted point source loading to the stream. Traditionally, ...

Ecology: Impact of Nutrient Loading on Estuaries and Marshes

Childs River and Quashnet River, combined with the absence of such spikes at Sage Lot and Flat Ponds, suggests input by plumes from septic tanks. Mean NI&+ concentration in groundwater varied over a relatively small range across the three sites (Fig. 1, middle panels). NH4+ contributed less than 5% of the mean dissolved inorganic nitrogen (DIN) at Childs and Quashnet Rivers. Most of the inorgan...