Marine Lab Collecting Water Samples from Island Canals

16 May 2023

By Isabella McDonnell, SCCF Research Assistant

In partnership with the City of Sanibel, the SCCF Marine Laboratory collects water samples from island canals. The analysis of the water collected will offer an understanding of the health of Sanibel’s waterways, which can provide early detection of large environmental issues. This year is a canal-testing year, while even-numbered years focus on lakes.

“The data we collect for this project is unique. There is no other water quality data existing for canals around Sanibel,” said Research Associate Mark Thompson. “We send this data to the Florida Department of Environmental Protection and they then evaluate the waterbodies to see if they meet state water quality criteria. Many of these sites do not. This brings the problems to light.”  

Sanibel’s canals are man-made. The slow and low flows of canals can be the start of algae blooms, fish kills, and low oxygen levels. There are many differences between canals, located from the east to the west end of the island, with some lined with seawalls, others with mangroves, and some near reclaimed water. Along with development density near the canals, these factors influence the conditions of the waterways. 

Samples are collected once during the dry season, from February to May, and again during the wet season, from July to September. The wet season testing corresponds with the seasonal fertilizer ban and sampling is performed within two days of significant rainfall. The samples will be analyzed for different forms of nitrogen and phosphorus, common nutrients that contribute to nutrient pollution. 

In addition to the nutrient sampling done by the certified lab, SCCF analyzes each sample for dissolved oxygen, turbidity, CDOM, chlorophyll a, pH, salinity, and temperature. Dissolved oxygen is necessary for the survival of marine creatures like fish and crabs. Turbidity, or how clear the water is, CDOM, the amount of organic matter in the water, and the rest of these parameters can indicate issues in water quality early, including conditions ideal for an algae bloom. 

Sanibel Communities for Clean Water publishes the results of water quality studies on their website. Here you can see how the health of lakes and canals near your home compares to others. 

Sanibel Communities for Clean Water offers suggestions on how to improve the health of your local waterway. These include planting shoreline buffers, runoff control, and water-friendly landscaping.