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Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought.

ABSTRACT: Ecosystem function measurements can enhance our understanding of nitrogen (N) delivery in coastal catchments across river and estuary ecosystems. Here, we contrast patterns of N cycling and export in two rivers, one heavily influenced by wastewater treatment plants (WWTP), in a coastal catchment of south Texas. We measured N export from both rivers to the estuary over 2 yr that encompass a severe drought, along with detailed mechanisms of N cycling in river, tidal river, and two estuary sites during prolonged drought. WWTP nutrient inputs stimulated uptake of N, but denitrification resulting in permanent N removal accounted for only a small proportion of total uptake. During drought periods, WWTP N was the primary source of exported N to the estuary, minimizing the influence of episodic storm-derived nutrients from the WWTP-influenced river to the estuary. In the site without WWTP influence, the river exported very little N during drought, so storm-derived nutrient pulses were important for delivering N loads to the estuary. Overall, N is processed from river to estuary, but sustained WWTP-N loads and periodic floods alter the timing of N delivery and N processing. Research that incorporates empirical measurements of N fluxes from river to estuary can inform management needs in the face of multiple anthropogenic stressors such as demand for freshwater and eutrophication.

SUBMITTER: Bruesewitz DA

PROVIDER: S-EPMC5726386 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought.

Bruesewitz Denise A DA Hoellein Timothy J TJ Mooney Rae F RF Gardner Wayne S WS Buskey Edward J EJ

Limnology and oceanography 20170531 Suppl 1

Ecosystem function measurements can enhance our understanding of nitrogen (N) delivery in coastal catchments across river and estuary ecosystems. Here, we contrast patterns of N cycling and export in two rivers, one heavily influenced by wastewater treatment plants (WWTP), in a coastal catchment of south Texas. We measured N export from both rivers to the estuary over 2 yr that encompass a severe drought, along with detailed mechanisms of N cycling in river, tidal river, and two estuary sites du ...[more]

PMID: 29263559

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Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought.

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Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought.

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