Event Title

Managing Eutrophication Along the Freshwater-Marine Continuum: Why the Need for Dual Nutrient (N & P) Input Controls?

Presenter Information

Hans Paerl

Location

Eccles Conference Center Auditorium

Event Website

http://water.usu.edu

Start Date

3-31-2015 9:15 AM

End Date

3-31-2015 9:55 AM

Description

Coastal watersheds support nearly 75% of the world’s human population and are experiencing unprecedented urban, agricultural and industrial expansion. The freshwater-marine continua draining these watersheds are increasingly impacted by nutrient inputs and resulting eutrophication, including harmful algal blooms, hypoxia, finfish and shellfish kills and loss of higher plant and animal habitat. In addressing nutrient input reductions needed to stem and hopefully reverse eutrophication, phosphorus (P) has traditionally received priority in upstream freshwater regions, while controlling nitrogen (N) inputs has been the focus of management strategies in estuarine and coastal waters. However, freshwater, brackish and full-salinity components of the continuum are structurally and functionally connected. Intensification of human activities has caused imbalances in N and P loading, making it difficult to control eutrophication along the continuum by reducing only one nutrient. Furthermore, controlling only one nutrient upstream (e.g., P) can exacerbate N-driven eutrophication downstream. There are an increasing number of examples in these watersheds that point to dual N and P input constraints as the only effective management option for long-term control of eutrophication. Nutrient reduction formulations should take human hydrologic modifications (e.g., construction of upstream reservoirs and diversions, water withdrawal for agricultural and industrial purposes) and climatic changes (warming, changes in rainfall and freshwater discharge) into consideration, because these changes may alter nutrient-eutrophication thresholds. Case studies from the US, Europe and Asia will be examined in order to develop a better understanding of and rationale for dual nutrient input controls.

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Mar 31st, 9:15 AM Mar 31st, 9:55 AM

Managing Eutrophication Along the Freshwater-Marine Continuum: Why the Need for Dual Nutrient (N & P) Input Controls?

Eccles Conference Center Auditorium

Coastal watersheds support nearly 75% of the world’s human population and are experiencing unprecedented urban, agricultural and industrial expansion. The freshwater-marine continua draining these watersheds are increasingly impacted by nutrient inputs and resulting eutrophication, including harmful algal blooms, hypoxia, finfish and shellfish kills and loss of higher plant and animal habitat. In addressing nutrient input reductions needed to stem and hopefully reverse eutrophication, phosphorus (P) has traditionally received priority in upstream freshwater regions, while controlling nitrogen (N) inputs has been the focus of management strategies in estuarine and coastal waters. However, freshwater, brackish and full-salinity components of the continuum are structurally and functionally connected. Intensification of human activities has caused imbalances in N and P loading, making it difficult to control eutrophication along the continuum by reducing only one nutrient. Furthermore, controlling only one nutrient upstream (e.g., P) can exacerbate N-driven eutrophication downstream. There are an increasing number of examples in these watersheds that point to dual N and P input constraints as the only effective management option for long-term control of eutrophication. Nutrient reduction formulations should take human hydrologic modifications (e.g., construction of upstream reservoirs and diversions, water withdrawal for agricultural and industrial purposes) and climatic changes (warming, changes in rainfall and freshwater discharge) into consideration, because these changes may alter nutrient-eutrophication thresholds. Case studies from the US, Europe and Asia will be examined in order to develop a better understanding of and rationale for dual nutrient input controls.

https://digitalcommons.usu.edu/runoff/2015/2015Abstracts/3