An Ecosystem-Level Study of Florida’s Major Spring Systems Robert L. Knight, Ph.D. Jackson Blue Springs Working Group Tuesday, January 13, 2009

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 *

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

Selection of Study Springs

Springs Selection – Range in Nitrate Concentrations:

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.

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); PARAMETERS cont.

Sunfish respiration Benthic algae oxygen production

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/m 2 /y) Primary Producers (Submersed Aquatic Vegetation community) Sagittaria kurziana w/ periphyton (809 g/m 2 ) Herbivores Turtles, Snails, Mullet (36.8 g/m 2 ) 1 o Consumers Fish and Midges (10.7 g/m 2 ) Top Consumers Bass, Birds, and Alligators (1.53 g/m 2 )

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.

Discussion…