Levin Lab Benthic Studies
(1) Assess benthic faunal colonization on banks
(2) Assess trophic status of restored salt marshes
Goal: Develop metrics for healthy salt marsh and subtidal habitat
Bank Macrofauna
What are macrofauna?
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small worms, clams, crustaceans and other invertebrates
Significance of macrofauna:
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major agents of sediment stability/instability
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primary food items for bottom feeding fish, shrimp
Strategy:
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sample macrofauna at time intervals following bank placement
Sampling 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:
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proxy for ecosystem successional state and health
Salt Marsh Trophic Function
What is Trophic Function?
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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 powder
Analyze isotopic signatures (d13C, d15N) on a mass spectrometer.
Use mixing models to establish trophic structure
What we learn
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?
Salicornia?
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Spartina? Limonium?
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Phytoplankton?
Cyanobacteria?
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