Hirons, Amy C.; Cameron Baxley
Impacts of land-based sources of pollution on two Caribbean coral species
NOAA, NOS, Office of Coastal Management; Nova Southeastern University
"Elevated levels of two common land-based pollutants, phosphate found in fertilizer and endosulfan found in pesticide, have been detected in canals, inlets, and oceanic waters of South Florida. Although both have been shown to have biologically deleterious effects, few studies have tested environmentally realistic levels on Caribbean corals and none have examined the threshold of effects. The levels of orthophosphate and endosulfan were measure in the nearshore water column and sediments, and in the tissues of two Caribbean coral species, Montastraea cavernosa and Porites astreoides. Laboratory dosing experiments using a range of concentrations of the two pollutants were performed to determine the effects on coral health and function. No detectable levels of orthophosphate were found in any coral dosing tanks for the five treatment concentrations. At the same time, an unprecedented algae bloom occurred that obscured the sides of the tanks and covered both coral species, likely utilizing the available limiting nutrient. Endosulfan (I, II, and sulfate) was not detected in ocean water or sediment. Endosulfan II was not detected in the tank water or either coral species at any of the treatment levels and endosulfan sulfate was only discernible at extremely low levels, if at all, in all treatments. Endosulfan I was continuously removed from each treatment tanks' water from the beginning to end of the five day exposure, reducing the amount ultimately found in the water by 41-88%. Tissue incorportation of endosulfan concentrations was on the order of one-one thousandth. P. asteroides struggled to survive throughout the entire experiment. No noticeable trends were observed in zooxanthellae condition or density for either experiment. Increases in endosulfan concentration resulted in increases in number and size of the mucous secretory cells. Phosphate appeared to be a greater stressor as compared to endosulfan. Increased swelling of mucous secretory cells and widespread atrophy in epithelia cells coincided with the highest exposure of phosphate."
FY11; CRCP Project ID: 20412; Project Title: FY11 State and Territory Coral Reef Management Grants; Principal Investigator: Jenny Waddell; Grant Number: NA11NOS4820017