Water source utilization and nutrient status in tree islands in Shark River Slough,

Everglades National Park

Tree island sites

Profile of a tree island

Vegetation zones on a tree island - Chekika

Emergent Hardwoods

Floodtolerant veg.

Sawgrass/Slough

Wet season: Two POSSIBLE water sources in tree islands

1. Soilwater – rain trapped in leaf litter – NUTRIENT RICH2. Regional surface/groundwater – NUTRIENT POOR

These two sources can be ISOTOPICALLY DISTINCT

Evaporating pool of water = enriched in heavy isotopeAllows for differentiating pools of water

Water(H2O):

Hydrogen has 2 isotopes – 1H (lighter) and 2H (heavier)

Oxygen has two major isotopes -- 16O (lighter) and 18O (heavier)

Stable isotopes of water

10001‰)(tan

xR

R

dards

sample

dD

(o

/oo

) W

AT

ER

d18O (o/oo) WATER

dD=(8*d18 O)+10 M

eteoric W

ater

Soil Water

Wet

Dry

WetDry

Fig 3b. Blue dots indicate sampling stations on tree island.Yellow and orange dots represent actual trees sampledaround station.

ENP Tree Islands - sites and methods

• Nutrient sampling: every 2 months for 1 year

• Foliar N and P

• Water sampling: for 1 year

-Rainwater on Grossman Hammock

-Soil water (organic horizon) ( every 2 months )

-Plant stem water ( every 2 months )

• Cryogenic distillation of soil and stem water

• Isotopic analysis on mass spectrometer

Chekika – airboat/helicopterSatinLeaf – airboat/on footGrossman Hammock – car/foot

Per island:

20 upland plants

30 lowland plants:1. Sawgrass-flooded ecotone

2. Flooded – hammock ecotone

Results so far… Chekika

nov plant stem waters

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

-8.0 -6.0 -4.0 -2.0 0.0 2.0 4.0

O18

2H

SL1 flooded

SL2 f looded

upland hardw oods

rain

met w ater line

acknowledgements

Leo Sternberg - advisorFernando Miralles-Wilhelm (FIU) – PI on NSF Biocomplexity ProjectMike Ross (FIU) – collaboration and logistics on tree islands

Fieldwork and LabworkPablo Ruiz, Mike Klein, Brooke Shamblin, Daniel Gomez, Diane, Jeanette, Astrid, Anita , Daniel Ramirez, John Cozza, Eric, Hao, Patrick Ellsworth, Xin Wang, Patricia, Maria Camila Pinzon, Cassandra

My committee – Don DeAngelis, David Janos, Leo Sternberg, Fernando Miralles-Wilhelm

Funding: NSF Biocomplexity in the Environment project