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

* 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?

ID Spring Name1 De Leon Springs2 Homosassa Springs Group3 Ichetucknee Springs Group4 Jackson Blue Spring5 Madison Blue Spring6 Manatee Spring7 Ponce De Leon Springs8 Rainbow Springs Group9 Silver Glen Springs Group

10 Silver Springs Group11 Wakulla Spring12 Weeki Wachee Spring

Selected Springs

• De Leon• Homosassa• Ichetucknee• Jackson Blue• Madison Blue• Manatee• Ponce De Leon• Rainbow• Silver Glen• Silver• Wakulla• Weeki Wachee

Selection of Study SpringsName County Magnitude Ownership a

Previously

Studied bDischarge

(ft3/s) *pH

SpCond(uS/cm)

DO(mg/L)

NO3-N

(mg/L)TP

(mg/L)NO3/TP

Ratio (wt)

De Leon Springs Volusia 2nd State Park F,O 28 7.53 821 0.46 1.14 0.05 23Homosassa Springs Group Citrus 1st (Group) State Park F, O, S 87* 7.70 4,520 3.97 0.52 0.03 19Ichetucknee Springs Group Columbia 1st State Park F, S 186* 7.73 306 1.95 0.53 0.04 16Jackson Blue Spring Jackson 1st County Park F, S 61* 7.58 243 7.26 3.30 0.02 165Madison Blue Spring Madison 1st State Park F, S 71* 7.75 277 1.76 1.40 0.04 35Manatee Spring Levy 1st State Park F, O, S 154* 7.04 430 1.60 1.80 0.02 90Ponce De Leon Springs Holmes 2nd State Park F, S 20 7.53 180 3.44 0.20 0.10 2Rainbow Springs Group Marion 1st (Group) State Park F, O, S 634* 7.67 274 5.53 1.13 0.03 35Silver Glen Springs Group Marion 1st (Group) Federal F, S 109* 7.42 1,141 3.02 0.05 0.02 3Silver Springs Group Marion 1st State Park a F, O, S, W 556* 7.23 461 3.09 1.30 0.04 33Wakulla Spring Wakulla 1st State Park F, S 129* 7.20 328 2.39 1.00 0.03 33Weeki Wachee Spring Hernando 1st State Park F, O, S 161* 7.68 320 1.29 0.70 0.01 100

b Researchers F = Florida Geological Survey (water quality) O = H.T. Odum (1950s) S = Jan Stevenson (FDEP algae study) W = Wetland Solutions, Inc. (ecosystem metabolism)

* From First magnitude springs of Florida. Florida Geological Survey. Open File Report No. 85.a Silver Springs is managed as a private attraction, Weeki Wachee became a state park Nov. 2008

Springs Selection – Range in Nitrate Concentrations:

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Avera

ge N

Ox-N

(m

g/L

)

Spring ID

Stats NOx-NAverage 0.803

Min 0.004Max 5.10

Spring ID Spring ID Spring ID

Beecher Spring 1 Fenney Spring 45 Cedar Head Spring 89

Copper Spring 2 Hornsby Spring 46 Wakulla Tubing D-Tunnel 90

Green Cove Spring 3 Horn Spring 47 Gum Spring Main 91

Holton Creek Rise 4 Cypress Spring 48 Little River Spring 92

Orange Spring 5 Starbuck Spring 49 Wakulla Tubing C-Tunnel 93

Suwannee Springs 6 Turtle Spring 50 Double Spring 94

Newport Spring 7 Salt Spring (Hernando) 51 Jackson Mill Pond Spring 95

Waldo Spring 8 Hunter Spring 52 Wakulla Tubing B-Tunnel 96

Warm Mineral Spring 9 Ellaville Spring 53 Rainbow Spring #6 97

Santa Fe Spring (Columbia) 10 Falmouth Spring 54 Silver Spring Main 98

Nutall Rise 11 Alapaha River Rise 55 Hart Springs 99

Alexander Springs 12 Wacissa Springs #2 56 Otter Spring 100

Silver Glen Springs 13 Wakulla Tubing A/K-Tunnel 57 Bubbling Spring 101

Washington Blue Spring (Choctawhatchee) 14 Black Spring (Jackson) 58 Wekiwa Springs 102

Steinhatchee River Rise 15 Wakulla Tubing K-Tunnel 59 Rainbow Spring #1 103

Santa Fe River Rise (Alachua) 16 Wakulla Tubing A/D-Tunnel 60 Deleon Spring (Volusia) 104

Welaka Spring 17 Holmes Blue Spring 61 Ginnie Spring 105

Williford Spring 18 Jackson Blue Hole Spring 62 Reception Hall Spring 106

Juniper Springs 19 Homosassa #1 63 Devils Ear Spring (Gilchrist) 107

Columbia Spring 20 Sanlando Springs 64 Blue Grotto Spring 108

Fern Hammock Springs 21 Suwanacoochee Spring 65 Madison Blue Spring 109

Treehouse Spring 22 Gator Spring (Hernando) 66 Rainbow Spring #4 110

Salt Springs (Marion) 23 Homosassa #2 67 Rock Springs 111

Crays Rise 24 Chassahowitzka Spring Main 68 Mearson Spring 112

Washington Blue Spring (Econfina) 25 Citrus Blue Spring 69 Gilchrist Blue Spring 113

Big Spring (Big Blue Spring) (Jefferson) 26 Levy Blue Spring 70 Manatee Spring 114

Morrison Spring 27 Mission Spring 71 Sun Springs 115

Spring Creek Rise #1 28 Allen Mill Pond Spring 72 Telford Spring 116

St. Marks River Rise (Leon) 29 Chassahowitzka Spring #1 73 Owens Spring 117

Gainer Spring #1C 30 Magnolia Spring 74 Troy Spring 118

Spring Creek Rise #2 31 Homosassa #3 75 Buckhorn Spring 119

Tarpon Hole Spring 32 Rock Bluff Springs 76 Crystal Springs 120

Gainer Spring #3 33 Bugg Spring 77 Lafayette Blue Spring 121

Poe Spring 34 Blue Hole Spring (Columbia) 78 Running Springs 122

Shepherd Spring 35 Springboard Spring 79 Unknown 11365 123

Brunson Landing Spring 36 Volusia Blue Spring 80 Lithia Springs Major 124

Gainer Spring #2 37 Branford Spring 81 Hays Spring (Jackson) 125

Ponce De Leon Springs 38 Siphon Creek Rise 82 Jackson Blue Spring 126

Sulphur Spring (Hillsborough) 39 Little Springs (Hernando) 83 Shangri-La Springs 127

Rhodes Spring #1 40 Weeki Wachee Main Spring 84 Lafayette Ruth Spring 128

Rhodes Spring #2 41 Ichetucknee Head Spring (Suwannee) 85 Fanning Springs 129

Rhodes Spring #4 42 Guaranto Spring 86 Apopka Spring 130

Natural Bridge Spring 43 Wakulla Spring 87

Beckton Springs 44 Gadsen Spring 88

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/m2/y)

Primary Producers(Submersed Aquatic Vegetation community)Sagittaria kurziana w/ periphyton (809 g/m2)

HerbivoresTurtles, Snails, Mullet (36.8 g/m2)

1o ConsumersFish and Midges (10.7 g/m2)

Top ConsumersBass, Birds, and Alligators (1.53 g/m2)

EXAMPLE DETERMINATION OF ECOSYSTEM METABOLISM BASED ON UPSTREAM-DOWNSTREAM DISSOLVED OXYGEN DATA

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1

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10

5/15/05 0:00 5/15/05 6:00 5/15/05 12:00 5/15/05 18:00 5/16/05 0:00

Dis

so

lved

Oxyg

en

(m

g/L

)

Upstream

Downstream

-1

-0.5

0

0.5

1

1.5

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DO

Rate

-of-

Ch

an

ge (

g/m

2 /hr)

Corrected

Uncorrected

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

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0.8

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1.2

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Co

rre

cte

d D

O R

ate

-of-

Ch

an

ge

(g

/m2/h

r)

0

500

1000

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2500

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PA

R (

um

ol/

m2 /s

)

Air

Plant Level

Air = 39.30 mol/m2/d

Plant Level = 28.52 mol/m2/d

GPP = 8.45 g/m2/d

CR = 8.40 g/m2/d

NPP = GPP- CR = +0.05 g/m2/dPAR Eff. = GPP / PAR = 0.30 g O2/mol

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…