Cascading ecological effects of low-level phosphorus enrichment in the Florida everglades

J Environ Qual. Mar-Apr 2005;34(2):717-23. doi: 10.2134/jeq2005.0717.


Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 microg L(-1) above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Ecosystem*
  • Florida
  • Food Chain*
  • Phosphorus / analysis*
  • Phosphorus / metabolism*
  • Water / chemistry
  • Water Pollutants / analysis*
  • Water Pollutants / metabolism*
  • Water Supply


  • Water Pollutants
  • Water
  • Phosphorus