Biogeochemistry

, Volume 54, Issue 3, pp 229–250

Decomposition responses to phosphorus enrichment in an Everglades (USA) slough

Authors

    • Everglades DepartmentSouth Florida Water Management District
  • H. Kumpf
    • Everglades DepartmentSouth Florida Water Management District
  • J.A. Laing
    • Everglades DepartmentSouth Florida Water Management District
  • W.C. Kennedy
    • Everglades DepartmentSouth Florida Water Management District
Article

DOI: 10.1023/A:1010659016876

Cite this article as:
Newman, S., Kumpf, H., Laing, J. et al. Biogeochemistry (2001) 54: 229. doi:10.1023/A:1010659016876

Abstract

The effects of phosphorus (P) enrichment ondecomposition rates were measured in a Ploading experiment conducted in an oligotrophicmarsh in the northern Everglades, USA. In thisstudy, eighteen 2.5 m2 enclosures(mesocosms) were placed in a pristineopen-water (slough) wetland and subjectedweekly to 6 inorganic P loads; 0, 0.2, 0.4,0.8, 1.6 and 3.2 g·m−2g·yr−1. Phosphorus accumulated rapidly in the benthicperiphyton and unconsolidated detrital (benthicfloc) layer and significantly higher Pconcentrations were recorded after 1 yr of Paddition. In contrast, a significant increasein surface soil (0–3 cm) TP concentrations wasmeasured in the surface soil layer only after 3yr of loading at the highest dose. Plantlitter and benthic floc/soil decompositionrates were measured using litter bags,containing sawgrass (Cladium jamaicenseCrantz) leaves, and cotton (cellulose) strips,respectively. Litter bag weight losses weresimilar among treatments and averaged 30% atthe end of the 3 yr study period. Litter Nconcentrations increased over time by anaverage of 80% at P loads < 1.6g·m−2·yr−1, and by > 120% at Ploads ≥ 1.6 g·m−2·yr−1.In contrast,litter P concentrations declined up to 50% inthe first 6 months in all P loads and onlysubsequently increased in the two highestP-loaded mesocosms. Cotton strip decaydemonstrated that benthic floc and soilmicrobial activity increased within 5 mo of Paddition with more significant treatmenteffects in the benthic than the soil layer. The influence of soil microbial transformationswas shown in porewater chemistry changes. While porewater P levels remained close tobackground concentrations throughout the study,porewater NH4 + and Ca2+increased in response to P enrichment,suggesting that one significant effect of Penrichment in this oligotrophic peat system isenhanced nutrient regeneration.

cellulose cotton strip decomposition Everglades nutrient regeneration phosphorus enrichment

Copyright information

© Kluwer Academic Publishers 2001