4. What can we learn about Narragansett bay by measuring chlorophyll a?
Chlorophyll a is used as an indicator of phytoplankton abundance. Phytoplankton abundance is related to natural cycles in nutrient availability and to the input of phosphate and nitrate. Excess phosphate and nitrate can come from groundwater or water treatment plants and sewer overflow (nitrate and phosphate are not removed in most sewage treatment plants). Excess nutrients can cause blooms of phytoplankton, which can contribute to bottom water anoxia under stratified conditions.
Chlorophyll a is used for basic studies of the biota of Narragansett Bay and understanding the natural cycles of the Bay.