Oral Presentation Australian Society of Fish Biology and Oceania Chondrichthyan Society Conference 2016

Using biogeochemical tracers and sclerochronologies derived from fish otoliths to detect environmental change (#6)

Gretchen Grammer 1
  1. SARDI Aquatic Sciences, West Beach, SA, Australia

Biogeochemical tracers and sclerochronologies are used to answer many ecological questions that require linking organisms with the environment. Calcified hard parts of organisms that remain chemically inert after formation are particularly advantageous for extracting information (e.g. otoliths, shells, coral) on both the organism and the environment. My research has focused on otoliths (fish earstones) as an environmental proxy, since they contain both biogeochemical (i.e. radiocarbon and trace elements) and sclerochronological (i.e. growth) signals that reflect changes in aquatic systems. In my presentation, I will describe using these otolith-based chemical and growth signals to: (1) establish a radiocarbon record for upwelled waters in the southeastern Indian Ocean, and (2) describe physiological and environmental controls on otolith chemistry, using a novel modelling framework paired with a strong, local upwelling signal as an extrinsic cue. Consequently, after considering life history traits and physiological processes of a test species, otoliths carbonate records are an accessible mechanism that gives us the capacity to examine magnitude and direction of environmental change in both a spatial and temporal context.