Distribution of Diatoms and Development of Diatom-Based Models for Inferring Salinity and Nutrient Concentrations in Florida Bay and Adjacent Coastal Wetlands of South Florida (USA)

Authors

Anna Wachnicka, Department of Earth and Environment and Southeast Environmental Research Center, Florida International UniversityFollow
Evelyn E. Gaiser, Department of Biological Sciences and Southeast Environmental Research Center, Florida International UniversityFollow
Laurel Collins, Department of Earth and Environment and Department of Biological Sciences, Florida International UniversityFollow
Thomas J. Frankovich, Southeast Environmental Research Center, Florida International UniversityFollow
Joseph N. Boyer, Southeast Environmental Research Center, Florida International UniversityFollow

Abstract

The composition and distribution of diatom algae inhabiting estuaries and coasts of the subtropical Americas are poorly documented, especially relative to the central role diatoms play in coastal food webs and to their potential utility as sentinels of environmental change in these threatened ecosystems. Here, we document the distribution of diatoms among the diverse habitat types and long environmental gradients represented by the shallow topographic relief of the South Florida, USA, coastline. A total of 592 species were encountered from 38 freshwater, mangrove, and marine locations in the Everglades wetland and Florida Bay during two seasonal collections, with the highest diversity occurring at sites of high salinity and low water column organic carbon concentration (WTOC). Freshwater, mangrove, and estuarine assemblages were compositionally distinct, but seasonal differences were only detected in mangrove and estuarine sites where solute concentration differed greatly between wet and dry seasons. Epiphytic, planktonic, and sediment assemblages were compositionally similar, implying a high degree of mixing along the shallow, tidal, and storm-prone coast. The relationships between diatom taxa and salinity, water total phosphorus (WTP), water total nitrogen (WTN), and WTOC concentrations were determined and incorporated into weighted averaging partial least squares regression models. Salinity was the most influential variable, resulting in a highly predictive model (r _apparent ²  = 0.97, r _jackknife ²  = 0.95) that can be used in the future to infer changes in coastal freshwater delivery or sea-level rise in South Florida and compositionally similar environments. Models predicting WTN (r _apparent ²  = 0.75, r _jackknife ²  = 0.46), WTP (r _apparent ²  = 0.75, r _jackknife ²  = 0.49), and WTOC (r _apparent ²  = 0.79, r _jackknife ²  = 0.57) were also strong, suggesting that diatoms can provide reliable inferences of changes in solute delivery to the coastal ecosystem.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Wachnicka, A., E.E. Gaiser, L. Collins, T.A. Frankovich, J. Boyer. 2010. Distribution of Diatoms and Development of Diatom-Based Models for Inferring Salinity and Nutrient Concentrations in Florida Bay and Adjacent Coastal Wetlands of South Florida (USA). Estuaries and Coasts 33(5): 1080-1098.