Methods
Data was collected in 2018, 2019, and 2020 seasons. Each season consists of 6 sampling events from June to September. Sampling events occurred about every 2 weeks, starting in late June, weather depending. The goal was to see how conditions changed throughout the season in a methodical manner. 2018 data was slightly biased since our two August events happened within a few days of each other rather than 2 weeks. Our sampling dates were as follows:
2018 Season: 6/20, 7/3, 7/18, 8/26*, 8/29, 9/19
2019 Season: 6/19, 7/3, 7/17, 8/14, 8/28, 9/18
2020 Season: 6/18, 7/1, 7/16, 8/6, 8/19, 9/16
*sampling date later than expected due to unforeseen circumstances
2019 Season: 6/19, 7/3, 7/17, 8/14, 8/28, 9/18
2020 Season: 6/18, 7/1, 7/16, 8/6, 8/19, 9/16
*sampling date later than expected due to unforeseen circumstances
At each station total depth was recorded as well as T, DO, Turb, Sal, and Chl-a at both the surface (0.5 m below surface) and bottom layers (0.5 m above bottom). If it was a shallow location (depth less than 0.5 m), one measurement was taken at mid-depth. The sonde was lowered to the desired depth and allowed to stabilize for a period of time. Measurements were taken within 3 hours of sunrise during each event to measure the minimum oxygen levels of the day and to ensure uniform sampling event to event. Tides were also recorded for each day. Water samples were collected at one site per sampling event to validate the Chl-a readings from the sonde. Before and after each trip, the sonde was calibrated to ensure accurate measurements were taken.
Fecal coliform samples were collected at each station through grab sampling technique. Grab sampling is a way to collect a water quality sample that will represent a snapshot in time. Samples were processed for fecal coliform enumeration through use of nutrient indicators that detect coliforms and E. coli (intestinal bacteria). Coliforms use an enzyme to metabolize the nutrient indicator which changes the sample from colorless to yellow. Fecal coliform is quantified using the most probably number (MPN) method.
Fecal coliform samples were collected at each station through grab sampling technique. Grab sampling is a way to collect a water quality sample that will represent a snapshot in time. Samples were processed for fecal coliform enumeration through use of nutrient indicators that detect coliforms and E. coli (intestinal bacteria). Coliforms use an enzyme to metabolize the nutrient indicator which changes the sample from colorless to yellow. Fecal coliform is quantified using the most probably number (MPN) method.