Marine Connectivity in a Large Inverse Estuary

Abstract

KAMPF, J.; PAYNE, N., and MALTHOUSE, P., 2010. Marine connectivity in a large inverse estuary. Journal of Coastal Research, 26(6), 1047-1056. West Palm Beach (Florida), ISSN 0749-0208. With the addition of several thousand passive virtual particles, a well calibrated hydrodynamic model is employed to explore marine connectivity in Spencer Gulf, South Australia, which is a large inverse estuary, on time scales of months to years. Based on a new method of ''cumulative flushing time,'' findings reveal that Spencer Gulf consists of two distinct regimes. Lower Spencer Gulf is advectively flushed every winter on a seasonal basis. In contrast to this, Upper Spencer Gulf is dominated by diffusive rather than advective processes and experiences flushing over much longer time scales (200-400 days). The physical uniqueness of Upper Spencer Gulf might explain why this region accommodates the largest known giant cuttlefish spawning aggregation in the world. Using a simple approach to mimic the bottom-dwelling behaviour of this species, we were able to reproduce some observed migratory features, but the model fails to predict the return of cuttlefish to their spawning grounds, which remains a puzzle for future studies.