Post on 17-Dec-2015
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(1) Assess benthic faunal colonization on banks
(2) Assess trophic status of restored salt marshes
Levin Lab Benthic Studies
Goal: Develop metrics for healthy salt marsh and subtidal habitat
Bank Macrofauna
What are macrofauna?• small worms, clams, crustaceans and other invertebratesSignificance of macrofauna:• major agents of sediment stability/instability• primary food items for bottom feeding fish, shrimpStrategy: • sample macrofauna at time intervals following bank placementSampling and analysis methods
• field - sediment coring, vertical sectioning, preservation• laboratory - sieving, sorting under dissecting microscope,• counting, species identification (~ 1 da/sample)• statistical measures of diversity and community structure
What we learn: • proxy for ecosystem successional state and health
Salt Marsh Trophic FunctionWhat is Trophic Function?
A key ecosystem property,
Food web and energy transfer Goal: Develop a method for assessing recovery of trophic function
in restored Venice Lagoon salt marshes
Rationale: Most measures of recovery examine structural properties rather than function
Approach:Use stable isotopic analyses to examine food web organization
(isotopic signatures differ for different plants/algae and are passed from food to consumer)
Compare food webs in natural and restored salt marshes of different ages
Methods:Sample primary producers and consumers, dry and powderAnalyze isotopic signatures (13C, 15N) on a mass spectrometer.Use mixing models to establish trophic structure
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What we learn
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What forms the base of the food chain in undisturbed marshes?How many trophic levels are present in a healthy marsh?Are these similar in restored marshes? After how many years?Can we develop a functional measure of marsh recovery?
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Salicornia? Spartina? Limonium?
Cyanobacteria?Phytoplankton?
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