Woods Hole Oceanographic Institution

Kelton McMahon

»Deep-sea coral export production
»Ocean Ecogeochemistry
»Estimating movement of marine animals
»Functional connectivity in a coral reef seascape
»Carbon isotopes identify snapper nursery habitat
»Otolith amino acid carbon isotope method
»Amino acid fractionation in fish tissues
»Stable isotope fractionation in fish muscle and otoliths
»Transequatorial Migrations by Basking Sharks
»Tracking top predator migration with isoscapes
»Bivalves as bioproxies for climate change
»Serries groenlandicus
»Digestibility of Ice algae and Phytoplankton
»Salt marsh fish movement and trophic dynamics

Kelton W. McMahon, Li Ling Hamady, Simon R. Thorrold, A review of ecogeochemistry approaches to estimating movements of marine animals, Limonology and Oceanography, 58:697-714, 2013

Ecogeochemistry—the application of geochemical techniques to fundamental questions in population and community ecology—has been used in animal migration studies in terrestrial environments for several decades; however, the approach has received far less attention in marine systems. This review includes comprehensive meta-analyses of organic zooplankton δ13C and δ15N values at the base of the food web, dissolved inorganic carbon δ13C values, and seawater δ18O values to create, for the first time, robust isoscapes for the Atlantic Ocean. These isoscapes present far greater geographic variability in multiple geochemical tracers than was previously thought, thus forming the foundation for reconstructions of habitat use and migration patterns of marine organisms. We review several additional tracers, including trace-element-to-calcium ratios and heavy element stable isotopes, to examine anadromous migrations. We highlight the value of the ecogeochemistry approach by examining case studies on three components of connectivity: dispersal and natal homing, functional connectivity, and migratory connectivity. We also discuss recent advances in compound-specific stable carbon and nitrogen isotope analyses for tracking animal movement. A better understanding of isotopic routing and fractionation factors, particularly of individual compound classes, is necessary to realize the full potential of ecogeochemistry.

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