Marine Water Quality

Background
Estuaries are semi-enclosed coastal bodies of water that have free connection with the open sea and within which sea water mixes with fresh water. The key feature of an estuary is that it is an interface between sea water and fresh water and there is an influence of the ocean tide creating a dynamic relationship between the two waters. Estuaries contain critical habitat for a variety of fish, and wildlife species. They serve as nursery habitats for fish, crustaceans, and shellfish and foraging habitat for birds and mammals while providing a multitude of recreational opportunities including boating, fishing, and bird watching. These are fragile ecosystems vulnerable to impacts caused by development and use. Severe impacts including alterations to hydrodynamic processes, exposure to levels of chemical contaminants that cause mortality, altered growth, and reduced reproduction and exposure to more frequent and severe hypoxia can be seen in estuarine habitats from urban and industrial development (Lerberg et al. 2000). In addition, macrobenthic communities in impacted areas are characterized by low diversity, low numbers of rare and pollution sensitive species, and low macrobenthic abundances (Lerberg et al. 2000). In areas with increased impervious cover, stormwater runoff is flashy and greater then natural amounts of fresh and polluted waters are released into estuaries (Holland et al. 2004).

The SECN monitoring design will include fixed site and probability-based sampling, described below.

Monitoring Approach - Fixed Sites
This monitoring approach is modeled after the water quality monitoring program established by the National Estuarine Research Reserve Program (NERR) (Wenner and Geist 2001) and will be used to address the monitoring objectives listed below. Overall, this approach is based on fixed monitoring sites that use automatic data loggers to collect semi-continuous data on pH, dissolved oxygen, temperature, salinity/conductivity, depth, and turbidity. Guidance from local, regional and national experts at our water quality monitoring scoping meeting (DiDonato 2005) for estuarine and nearshore marine waters suggested additional samples be taken monthly (standardized at low tide) at each fixed site. Parameters included in this sampling are Total Dissolved Nitrogen (TDN), Total Dissolved Phosphorus (TDP), Chlorophyll a (Chl a) and Secchi depth. Quarterly, dissolved nutrients should be broken down by species. Sampling these additional parameters will help us to address management concerns regarding development, discharges, land use practices and recreational use.

• Determine the trends as well as diel, monthly, and annual variability of salinity, dissolved oxygen, pH, and temperature at select sites in park estuaries
• Determine the trends as well as monthly and annual variability of total dissolved nitrogen, total dissolved phosphorus, secchi depth, and chlorophyll a at select sites in park estuaries

Monitoring Approach - Probabilistic
To meet the objectives listed below, the SECN will adopt a design used by EPA's Environmental Monitoring and Assessment Program (EMAP) - probabilistic site selection using simple, random, stratified or nested designs. An integrated design for assessing water quality will incorporate multiple tools in a tiered approach to address management decisions at multiple scales. These tools include probabilistic designs, landscape and water quality monitoring and targeted site-specific monitoring. This tiered approach will allow NPS to make statistically valid inferences of the extent that waters meet water quality standards, to predict which waters are most likely degraded or at risk for degradation, and to target site-specific monitoring needed to address local water quality concerns and short-term variability. The efficiencies of an integrated design should extend beyond monitoring costs to program costs because it can help States prioritize which waterbodies need more immediate attention.

• Determine the status, trends, and spatial variability of salinity, dissolved oxygen, pH, nutrients, chlorophyll, temperature, and sediment chemistry in park estuaries

Parks Where Protocol Will be Implemented
Cape Hatteras National Seashore (CAHA), Cape Lookout National Seashore (CALO), Cumberland Island National Seashore (CUIS), Canaveral National Seashore (CANA), Timucuan Ecological & Historic Preserve (TIMU), Fort Caroline National Monument (FOCA) and Fort Pulaski National Monument(FOPU)

Data Summary Reports
All available data summary reports are located on the Reports and Publications webpage.

Principal Investigator
Brian Gregory, Water Quality/Aquatic Ecology Specialist