Dr Rita Franco-Santos1, Dr Karen Filbee-Dexter2,3, Dr Albert Pessarrodona2, Dr Thomas Wernberg2,3, Dr Mat Vanderklift1
1CSIRO Oceans and Atmosphere, Indian Ocean Marine Research Centre, Crawley, Australia, 2UWA Oceans Institute and School of Biological Sciences, Crawley, Australia, 3Floedevigen Research Station, Institute of Marine Research, Bergen, Norway
Blue carbon (BC) ecosystems are vegetated marine habitats which store locally fixed carbon (C) in below- and above-ground biomass for time periods relevant to climate mitigation. Kelp forests, although highly productive, usually grow on rocky substrate; without sediment to trap the fixed C, the latter is mostly exported elsewhere and potentially sequestered via pathways which have yet to be well-defined. The existing greenhouse gas abatement frameworks for BC do not allocate offset-credits to C which is stored allochthonously. This conservative strategy to minimise the duplication of sequestration gains could, however, lead to underestimated sequestration rates for BC ecosystems and kelp forests, as C sequestered in sediments in the continental shelf or deep sea isn’t accounted for. Scientists can address this challenge to BC policy by accurately tracing the organic C in the sediment of a receiver site to the C fixed in any one of potential donor sites. Stable isotopes (SI) and fatty acids (FA) are commonly used to identify C sources, but these biomarkers are spatially and temporally variable, and don’t always clearly distinguish between primary producers. Their resolution might be improved if these variations are accounted for when assessing C provenance, and/or via compound-specific stable isotope analysis (CSIA). We will verify this assumption for Western Australian ecosystems by analysing legacy SI/FA data for the state’s most abundant macrophytes and by initiating a CSIA-FA data set in the region. Our results will serve as baseline information for identifying WA ecosystems with potential for offshore and continental shelf C sequestration.
Biography:
Rita is a zooplankton ecologist turned blue carbon scientist, currently undertaking a postdoctoral fellowship at CSIRO investigating the fate and magnitude of kelp-derived carbon. She has lived and worked in South, Central, and North America, as well as Europe, studying various aspects of the ecology of cephalopods, crustaceans, echinoderms, and meroplankton, but now calls Perth home.
