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An Ecosystem-Level Study of Florida’s Major Spring Systems . Jackson Blue Springs Working Group Tuesday, January 13, 2009. Robert L. Knight, Ph.D. An Ecosystem-Level Study of Florida’s Major Spring Systems .
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An Ecosystem-Level Study of Florida’s Major Spring Systems Jackson Blue Springs Working Group Tuesday, January 13, 2009 Robert L. Knight, Ph.D.
An Ecosystem-Level Study of Florida’s Major Spring Systems • A State Wildlife Grant administered through the Florida Fish and Wildlife Conservation Commission * • Funding Partners- • Three Rivers Trust, Inc. • St. Johns River Water Management District • Southwest Florida Water Management District • Florida Springs Initiative & Florida Park Service • Florida Fish and Wildlife Conservation Commission * http://myfwc.com/wildlifelegacy/
OBJECTIVES & BENEFITS • Ecosystem level study of 12 of Florida’s major spring ecosystems, using quantitative and reproducible sampling methods. • Ten of which have historic data (50+ years ago). • Have trends occurred? • Analysis of the environmental factors affecting ecosystem productivity • and therefore the systems’ ability to support fish and wildlife. • We can address the question, “What factors affect a springs ecosystem (and metabolism) the most?” • Physical? Nutrients? • Flow? SAV type (none, vascular, algal)? • Recreation? Other?
Selected Springs • De Leon • Homosassa • Ichetucknee • Jackson Blue • Madison Blue • Manatee • Ponce De Leon • Rainbow • Silver Glen • Silver • Wakulla • Weeki Wachee
PROJECT TIMELINE • July – September 2008 – project planning and mobilization • October 2008 – September 2009 – synoptic sampling of 12 springs • De Leon, Homosassa, and Madison Blue completed • Sampling Jackson Blue this week • October – December 2009 – data analysis and reporting
PARAMETERS • Physical characteristics of the spring run segments (length, width, cross sections, discharge and estimated volume)
PARAMETERS cont. • Incident solar radiation and vertical light attenuation measured continuously in each spring segment
PARAMETERS cont. • Diffusion of oxygen from air to water measured
PARAMETERS cont. • Water temperature, pH, conductivity, dissolved oxygen, chlorophyll a, chloride, color, nutrients - at the upstream and downstream end of each spring run segment
PARAMETERS cont. • SAV characterized in each spring segment - species, percent cover estimates for macroalgae and vascular plants
PARAMETERS cont. • Aquatic insect (adult Diptera, Ephemeroptera, Lepidoptera) emergence rates measured using floating, pyramid traps;
PARAMETERS cont. • Particulate export measured using plankton net;
PARAMETERS cont. • Visual counts of macro fauna (reptiles, fish, birds, mammals)
PARAMETERS cont. • Human use observations such as park attendance numbers, recreation, etc.
PARAMETERS cont. • Ecosystem metabolism • Gross and net primary production [GPP & NPP], • Community respiration [CR], • P:R ratio, • Photosynthetic efficiency) • in a single, representative spring run segment, • using the upstream-downstream dissolved oxygen change method • for a continuous 72-hour period (or more);
Benthic algae oxygen production • Sunfish respiration
Why measure metabolism (via changes in dissolved oxygen)? • Integrated measure of the spring ecosystem (includes biotic and abiotic factors) • Provides an estimate of primary productivity (organic carbon production with the release of oxygen) • Provides a rate (typically in grams of oxygen per square meter per day) that can be extrapolated in time and/or space
Silver Springs Ecosystem Metabolism(6,390 g dw/m2/y) Top Consumers Bass, Birds, and Alligators (1.53 g/m2) 1o Consumers Fish and Midges (10.7 g/m2) Herbivores Turtles, Snails, Mullet (36.8 g/m2) Primary Producers (Submersed Aquatic Vegetation community) Sagittaria kurziana w/ periphyton (809 g/m2)
EXAMPLE DETERMINATION OF ECOSYSTEM METABOLISM BASED ON UPSTREAM-DOWNSTREAM DISSOLVED OXYGEN DATA
Summary • Ecosystem study methods will help to synthesize spring response to a variety of stressors • Last spring-wide baseline conducted in 1950s – this study will update and expand on that work • Jackson Blue field work is being conducted this week. A summary report is due by December 2009.