|Title||The effects of water quality on back-reef sponge survival and distribution in the Florida Keys, Florida (USA)|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Butler M.J, Weisz E.B, Butler J.|
|Journal||Journal of Experimental Marine Biology and Ecology|
|Type of Article||Article|
|Keywords||algal blooms; bay; benthic suspension feeders; bottom-up; communities; diversity; Environmental Sciences & Ecology; florida; habitat; Marine & Freshwater Biology; marine sponges; populations; salinity; Sponge; Synechococcus; temperature; Water quality|
For decades, water quality in Florida Bay and the shallow, back-reef areas of large portions of the Florida Keys (Florida, USA) have varied dramatically as a consequence of climatic conditions and water management strategies in the adjacent freshwater marshes of the Everglades. The resulting fluctuations in water quality have led to die-offs of seagrass and sponges in hard-bottom habitats, transforming the ecosystem. In this study, we examined the implications of water quality on sponge community structure in two ways. First, in laboratory experiments we tested the tolerance of five prominent sponge species to salinities ranging from 15 psu to 45 psu at typical summer and winter temperatures. We then compared sponge distributions at 32 sites in the Florida Keys with regional patterns in water quality. Our experiments showed that during the summer the loggerhead sponge (Speciospongia vesparium) and glove sponge (Spongia cheiris) were the most tolerant of sustained changes in salinity, but most species died at higher rates at salinities other than 35 psu. Salinity-associated mortality declined in the winter, but was again higher at salinities < 35 psu. A pulsed change in salinity at summer temperatures yielded idiosyncratic results depending on the species. Analysis of the field data showed that some species such as Ircinia variablis and Cinachyrella alloclada grow in most environments, whereas the occurrence of most species declines when salinity is variable and at high nutrient concentrations. These results provide a more detailed picture of the species-specific environmental tolerance of several shallow-water Caribbean sponges, and suggest that changes in environmental conditions are likely to significantly impact their distribution and species composition with potentially drastic impacts on ecosystem function.