seagrass and mermaids

Seagrass and Seagrass and MermaidsMermaids

Heidi Dierssen, Univ. CT Heidi Dierssen, Univ. CT

Richard Zimmerman, Old DominionRichard Zimmerman, Old Dominion

Biogeochemical QuestionsBiogeochemical Questions• How much do the shallow carbonate

sediment banks contribute to NPP?

• How do seagrasses on these banks influence the carbon cycle (carbonate dissolution) and heat budgets?

• What are the mechanisms underlying seagrass distributions?

Moving Beyond QualitativeMoving Beyond Qualitative• Qualitative maps

– Presence or absence of benthos– %cover

• Quantitative maps – Leaf area index (LAI) m2 m-2

– LAI or standing crop to NPP– LAI to Carbonate dissolution– Bottom albedo for heat budgets

Comparing two sitesComparing two sites• 1) Bahamas Banks

– Little anthropogenic influence– ~Constant water column IOPs

– Primarily ag, whitings

• 2) Florida Bay– Anthropogenic disturbance– CDOM, sediment, and phytoplankton

Seafloor MeasurementsSeafloor Measurements• Bottom reflectance

– DOBBS

• Seagrass quadrats• Seagrass primary productivity• Digital camera/strobe• Sediment cores

– Reflectance– Particle size spectrum– Chl, PP

• Seagrass blades– Morphometrics– Reflectance

Water columnWater column• ac-9 package, eco-VSF, CTD,

fluorometers (Chl, CDOM, phycoer.)• Hydroscat 6• LISST 100X, particle size analyzer• Irradiance

– Planar, Ed (2 depths), Eu over substrate– Scalar Eod (2 depths), Eou

• Filtered for TSM, Chl, CDOM

Sea surface interfaceSea surface interface• Remote sensing reflectance

– HyperPro– Analytical Spectral Devices (ASD)

• Data available at: http://colors.uconn.edu

Intensive Field workIntensive Field work

Field WorkField Work14

15 1310

982

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36

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11

24 ft. boat24 ft. boat

Jan 2006

10 km

Spatial ScalesSpatial Scales

Florida St. Joseph BayFlorida St. Joseph Bay

5 km 0.5 km

60 m

Spectral InformationSpectral Information• Leaf-level

Spectral InformationSpectral Information• Canopy-level effect

Fate of productionFate of production• Carbonate dissolution

– Assumes seagrass leaves decompose in sediments

– 2% of annual oceanic CO2 uptake

• Export biomass

FL Bay Syringodium Export Carbon out of system

Lesson 5: Avoid hurricane Lesson 5: Avoid hurricane seasonseason

Post-Hurricane Wilma 2005

Jan 2006

Atmospheric CorrectionAtmospheric Correction400 500 600 7000

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Wavelength (nm)

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Atmospheric Correction

Current CollaboratorsCurrent Collaborators• Atmospheric Correction

– TAFKAA model (Bo-Cai Gao)

• Hyperspectral imagery, Paul Bissett FERI

• Total suspended matter, GOBI Model, Mike Twardowski

• Air-Sea CO2 Flux, Wade McGillis• Carbonate dissolution, David Burdige