Monitoring Estuarine Condition at Gateway National Recreation Area (GATE) Mod 003

Stevens, Sara

This proposal is submitted to conduct the spatial water quality monitoring for Gateway NP and to deploy, maintain and retrieve the continuous water quality sonde at the Gateway NP for the 2014 summer sampling season. Monitoring responses to estuarine nutrient enrichment incorporates several spatial sampling designs to address questions at a hierarchy of scales. Vital signs related to estuarine water quality and sediments are sampled using a probability design throughout the boundaries of the Gateway NP submerged resources. For water quality vital signs, spatial sampling is coupled with continuous monitoring at a representative site. We will conduct all field sampling and processing of water samples according to the standard operating procedures outlined in “Monitoring protocols for the National Park Service North Atlantic Coastal Parks: Estuarine Nutrient Enrichment.” Spatial sampling of estuarine water chemistry, water quality and water clarity will use a probability-based systematic survey design. The sampling framework for Gateway NP is a grid of tessellated hexagons that encompasses the entire submerged boundary of the park. This boundary contains 30 hexagons, and vital sign sampling will occur at a random location within each hexagon. The number of hexagons was determined based on the known spatial variability of vital sign measurements and the desired degree of change detection. The systematic survey of water column measurements will occur weekly during a four-week summer index period (July 2014). Because the survey is probability based, it allows inferences to be drawn regarding the status of entire park submerged resources. In addition to this spatial survey, one station will be established for continuous monitoring of water chemistry, water quality, and water clarity measures throughout the index period. This station will not be part of the probability design. The continuous monitoring station will be selected to be representative of the overall estuary. Continuous monitoring data will not used to make inferences to other locations beyond the sampling stations. However, estuarine vital signs are known to exhibit a high degree of temporal variability, with important events occurring more frequently than weekly sampling may detect. Thus the continuous data are valuable in interpreting the patterns observed through systematic sampling.Estuarine water chemistry, estuarine water quality, and estuarine water clarity measurements will be made using the YSI 6600 multi-parameter water quality monitor (sonde) for spatial surveys and the complementary YSI 6600 EDS (extended deployment system) for continuous monitoring of dissolved oxygen, turbidity, chlorophyll a, salinity, and temperature. Attenuation of Photosynthetically Available Radiation (PAR) will similarly be monitored discretely and continuously using LiCor PAR sensors. Continuous monitoring of chlorophyll will be achieved using the YSI optical chlorophyll sensor. Data from this continuous record will be post calibrated against discrete water samples that are collected periodically throughout the monitoring period adjacent to the YSI sonde. These discrete samples will be filtered through glass fiber filters and analyzed for chlorophyll a by extractive methods. For spatial surveys, chlorophyll a is determined directly from near-surface water samples that are filtered and analyzed by extractive methods.

Monitoring Estuarine Condition at Gateway National Recreation Area (GATE) Mod 003

Products