Boundary effects on benthic microbial phosphorus concentrations and diatom beta diversity in a Hydrologically-modified, Nutrient-limited Wetland

Evelyn E. Gaiser, Pamela Sullivan, Franco A.C. Tobias, Andrew J. Bramburger, Joel C. Trexler

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Water flow and flooding duration in wetlands influence the structure and productivity of microbial communities partly through their influence on nutrient loading. The effect of flow-regulated nutrient loads is especially relevant for microbial communities in nutrient-poor settings, where delivery controls nutrient uptake rates and the intensity of microbial interactions. We examined the effect of hydrologic history and proximity to water sources on nutrient enrichment of benthic microbial assemblages (periphyton) and on their diatom species composition, along the artificial boundaries of Taylor Slough, a historically phosphorusdepleted drainage of the Florida Everglades. Concentrations of phosphorus in periphyton declined from the wetland boundary near inflow structures to 100-m interior, with spatial and temporal variability in rates dependent on proximity to and magnitude of water flow. Phosphorus availability influenced the beta diversity of diatom assemblages, with higher values near inflow structures where resources were greatest, while interior sites and reference transects contained assemblages with constant composition of taxa considered endemic to the Everglades. This research shows how hydrologic restoration may have unintended consequences when incoming water quality is not regulated, including a replacement of distinctive microbial assemblages by ubiquitous, cosmopolitan ones.

Original languageEnglish (US)
Pages (from-to)S55-S64
Issue numberSUPPL. 1
StatePublished - Jun 2014

Bibliographical note

Funding Information:
This project was funded by cooperative agreement Cooperative Agreement H5000060104, Task No. J5284060023 and J5297080001 between Everglades National Park (ENP) and Florida International University. This publication was produced as part of a special issue devoted to investigating the ecological response of over 20 years of hydrologic restoration and active management in the Taylor Slough drainage of Everglades National Park. Support for this special issue was provided by the Everglades National Park, the Southeast Environmental Research Center, the Florida Coastal Everglades Long-Term Ecological Research program (under National Science Foundation Grant Nos. DEB-9910514 and DBI-0620409), the Everglades Foundation and the South Florida Water Management District. This is contribution number 597 of the Southeast Environmental Research Center. We thank Josette La Hée and Jorge Carreno for assistance counting and identifying diatoms for this project, Rafael Travieso, Felipe Zuniga and Catherine Hamilton for help in the field and laboratory, and collaborators Alicia LoGalbo, René Price, Len Scinto, Dilip Shinde, Donatto Surratt, and Mike Zimmerman for helpful discussions about this work.


  • Beta diversity
  • Diatoms
  • Everglades
  • Hydrology
  • Periphyton
  • Wetlands


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