Fixed-station water-quality monitoring at Canaveral National Seashore: 2012 data summary

Rinehart, Aaron; Gregory, M.; Wright, Wendy

doi:10.36967/2195325

In 2007 the National Park Service (NPS) Southeast Coast Network (SECN) began collecting water-quality data in the estuarine waters of Canaveral National Seashore as part the NPS Vital Signs monitoring program. The scope of the monitoring program includes Mosquito Lagoon and is comprised of continuous water-quality monitoring conducted by the SECN at one site and is augmented with monthly data collected at five stations by St. Johns River Water Management District (SJRWMD). The continuous-monitoring data station is located at the Canaveral National Seashore visitor center dock and collects pH, dissolved oxygen, temperature, salinity, turbidity and water-level data every 30 minutes. The five stations located throughout Mosquito Lagoon are sampled by Volusia County for the SJRWMD as part of the District’s Indian River Lagoon Water-Quality Monitoring Network; data at these five stations include monthly measurements of water-clarity conditions, nutrients, and chlorophyll a levels. Both the SECN and the SJRWMD programs use methods adapted from, or compatible with, the water-quality monitoring program established by the National Estuarine Research Reserve Program. The Canaveral National Seashore fixed-station water-quality monitoring site is part of the SECN estuarine water- and sediment-quality monitoring efforts, which routinely collects data in the vicinity of seven park units along the southeastern U.S. coast. Information collected by this monitoring program will be used to help managers make better-informed decisions by understanding trends and variability related to water-quality conditions in park waters. A summary of 2012 data is presented below. Dissolved inorganic nitrogen (DIN) was mostly good throughout the year, with a few fair readings occurring most commonly in June. Three of the five sites had a fair reading for dissolved inorganic phosphorous (DIP) in November. DIP for the remaining sites, and the rest of the year, was rated as good. There were no poor readings for DIN or DIP at any of the sites throughout the year. Some values for DIN and DIP were below the detection limit of the laboratory instrumentation. Chlorophyll a readings were widely variable throughout the year and throughout Mosquito Lagoon. There were 17 good, 17 fair, and 20 poor readings. A majority of the poor readings occurred in the summer and early autumn months. Water clarity conditions ranged from poor to good across most sites with a majority of the poor observations occurring during late summer and fall. Poor and fair water clarity conditions tended to occur during periods with elevated chlorophyll a levels. Mean daily turbidity readings at the continuous recording station were less than 18 NTUs. Salinity ranged from 31.03 to 45.41 parts per thousand (ppt) with the higher values occurring during the spring months. Monthly averages ranged from 35.1 ppt in September to 41.5 ppt in April. pH values ranged between 7.53 and 8.74 throughout the year with monthly averages ranging from 7.8 in September to 8.2 in January, April and November. Dissolved oxygen concentrations measured during monthly sampling were rated good at all sites throughout the year except at two stations in October. Although continuous data indicated a period between April and October when mean daily values commonly dropped below 5 mg/L (fair), with one daily average below 2 mg/L (poor) in September. Approximately 24% of data collected in 2012 were excluded from reporting because it was considered anomalous. Most anomalous data occurred between June 28 and September 11 due to unknown sonde malfunctions. Short periods of missing data in April and August were due to sonde mount replacement. Data collected at the fixed station as well as discrete nutrient data from SJRWMD are consistent with the ideal growing conditions for brown tide, which was observed between July and September 2012.

Fixed-station water-quality monitoring at Canaveral National Seashore: 2012 data summary

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