Northeast Coastal and Barrier Network Estuarine Nutrient Enrichment Monitoring Program

Plaisted, Holly; Feher, Laura

Water quality and sea grass long-term monitoring program. Approximately one quarter of the NPS land area within the NPS Northeast Coastal and Barrier Network is submerged. These estuaries, bays, and lagoons serve as islands of relatively pristine aquatic habitat within the Northeastern urban corridor. The North Atlantic coastal parks are dependent on high-quality aquatic resources to sustain the complex estuarine and nearshore ecosystems they represent. Diverse threats to NPS estuaries exist, including natural disturbances (e.g. storms, sea-level rise), direct impacts of human activities (e.g. fishing, boating, dock construction), indirect effects of watershed development, and disasters. Of these, park managers throughout the network have repeatedly identified threats to coastal water quality as one of their highest priority management issues. Much of the watershed area of NPS coastal ecosystems lies outside protective park boundaries and is subject to intense developmental pressures. Therefore, there is great potential for human disturbances to coastal watersheds to result in increased nutrient loading to park estuaries. Estuaries can generally assimilate some degree of enrichment without major ecological ramifications, but excessive nutrient inputs typically lead to dense blooms of phytoplankton and fast-growing macroalgae, loss of seagrasses, and decreased oxygen availability in sediments and bottom waters. Ultimately, cascading effects include changes in the species composition and abundance of invertebrates, decline in fish and wildlife habitat value, and the collapse of fin- and shellfish stocks. Protecting the ecological integrity of park estuaries depends on implementing a scientifically-based monitoring program that is capable of diagnosing local causes of nutrient enrichment, detecting changes in nutrient loads, and determining if nutrient inputs are near to exceeding thresholds that would result in shifts in ecosystem structure and function.The goals of estuarine monitoring within coastal parks of the NPS Northeast Region are: 1) to determine whether nutrient loads to park estuaries are increasing over time, and 2) to assess how estuarine natural resources are affected by changing nutrient inputs. Two distinct monitoring protocols have been developed to achieve these goals, and the utility of the protocols and interpretability of the monitoring data from each are tightly linked. Goal (1) is addressed by a separate protocol that prescribes direct monitoring and modeling of nutrient loading to NER coastal parks. Goal (2) is addressed by this protocol, which describes methods for tracking estuarine response to nutrient enrichment. This document describes the development of the monitoring protocol, justification for selection of monitoring variables, approaches and standard operating procedures for implementation throughout NER coastal parks, and guidance for interpreting data.

Northeast Coastal and Barrier Network Estuarine Nutrient Enrichment Monitoring Program

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