How can the effects of increased phosphorus loading be determined at the landscape level for Everglades structure and functions?

Poster presented May 1999, at the South Florida Restoration Science Forum

Part 1: Process Based Research Across Multiple Scales in the Everglades Landscape

Phosphorus in Everglades Wetlands

• Unimpacted Everglades wetlands are highly oligotrophic; P is the limiting nutrient.
• water column [TP] rarely exceed 0.3 µM (10 ppb); [SRP] are typically at or below detection limits in unimpacted wetlands.
• soil P levels are generally 200 µg P/g dry wt. soil in unimpacted wetlands.
• nutrient (water quality) impacts are generally associated with point source canal inputs.

Objective: Quantify water quality criteria for Everglades wetlands

Method: Low level P additions cause changes in components

Hypothesis: In situ P enrichment using flow-through flumes 5 TP pools & 6 working groups

Key Element Research Groups

• BIOGEOCHEMICAL - Boyer, Jones, Scinto
• SOILS - Jayachandaran, Meeder, Scinto
• MACROPHYTES - Kuhn, Lee, Ross, Smith
• PERIPHYTON - Gaiser, Richards, Scinto
• CONSUMERS - Pechmann, Trexler
• SPATIAL ANALYSIS & DATA SYNTHESIS - Childers, Kenne
• MODELLING AND DATA INTEGRATION - Buzzelli, Childers

BIOGEOCHEMICAL GROUP

• Nutrient flux and budgets - upstream and downstream water column samples taken twice daily.
• spatially-explicit nutrient flux and budgets - samples taken from any point in any channel at any time.
• water column processes - including primary productivity, net community metabolism, nitrification-denitrification, organic matter transformations.
• rainwater and dry depositional inputs of nutrients.
• mobile hydrolab datasonde collection at any point in any channel at any time.

SOILS GROUP

• soil accretion - feldspar marker horizons at 3 locations per channel.
• soil nutrients - C, N, P content, bulk density, % OM, alkaline phosphatase activity (APA) quantified at 6 locations per channel.
• soil porewater nutrients - dissolved nutrients and organics, APA quantified [at variable depths] at 6 locations per channel.
• soil microbial processes - aerobic respiration, methanogenesis, sulfate reduction, nitrification-denitrification, N-fixation quantified at 6 locations per channel.

MACROPHYTES GROUP

• net community production - nondestructive sampling of aboveground biomass at 4 locations in each channel.
• biomass turnover - plant tagging and tracking at 4 locations in each channel.
• primary productivity - NAPP estimates from biomass measures; whole-system gas flux measurements, quantifying of leaf-specific photosynthesis rates.
• species composition & % cover - stem counts, analysis of digital camera photography.
• belowground biomass - root ingrowth cores and microrhizotrons at 3 locations in each channel.
• tissue nutrients - C:N:P ratios of aboveground tissue.

PERIPHYTON GROUP

• net community production - periphytometers at 3 locations (glass slides) and 10 locations (wood dowel) in each channel.
• biomass and % cover - HPLC pigment analysis, analysis of digital photography + biovolume-dry weight conversions.
• primary productivity - NAPP from biomass estimates, light-dark bottle incubations of small samples at 3 locations in each channel.
• species composition - identifications from periphytometers, HPLC pigment analysis.
• tissue nutrients - C:N:P analysis of periphyton mat samples.
• association of periphyton with aquatic macrophytes.
• microbial processes - N-fixation, respiration.

CONSUMER (FAUNA) GROUP

• species composition and biomass of aquatic invertebrates and fishes - sweepnets and funnel samplers at 4 locations in each channel.
• growth rates of fishes and macroinvertebrates - enclosure cages at 2 locations in each channel.
• tissue nutrients - C:N:P analysis of selected animal tissues.
• food web linkages - stable C and N isotopic analysis.

SPATIAL ANALYSIS, INTEGRATION, AND MODELLING GROUP

• change detection - image analysis and GIS preparation of very low altitude photographs taken of complete flume channels.
• biogeochemical budgets - C, N, and P budgets all channels and for selected segments of channels, calculated twice annually.
• nutrient spiralling models - one-dimensional models of P spiralling lengths in all channels, calculated annually.
• process-based simulation models - based on an initially simple conceptual diagram, calibrated regularly with new data, key tool for data integration and adaptive management of research program.

1 Loxahatchee NWR flume 2 Everglades Nat. Park (Shark River Slough) flumes (Click on the map to the left for a full-sized version.)

Next: Introduction to the Flume Project