Biological Oceanography of the Gulf of Carpentaria, Australia: A Review

The Gulf of Carpentariais a pristine, shallow, epicontinental sea in tropical Australia. The Gulf is highly seasonal with shifts in monsoonal winds and rainfall patterns which affect: current and mixing regimes; phytoplankton productivity; and reproductive seasonality and recruitment of coastal marine species (e.g. penaeid prawns). Phytoplankton productivity is high and dominated by nanoplankton. Trichodesmiumand diatoms with nitrogen-fixing symbionts dominate the net phytoplankton. Nitrogen inputs from nitrogen fixers are an important nutrient input to deeper waters whilst the shallow waters are seasonally influenced by nutrients from freshwater runoff. The Gulf’s zooplankton community is biodiverse with relatively high biomasses and inferred productivity. With only limited water exchange, it shares species with adjacent seas to both the east and west. Recruitment of penaeid prawnpostlarvae to nearshoreand estuarine nursery grounds is controlled by the interaction between ontogenetic changes in larval and postlarval behaviour and both alongshore and tidal currents. This mechanism is controlled by a conservative environmental cue (i.e. pressure), and thereby provides a mechanism across a wide range of coastal habitats and current regimes. These pioneering studies have laid the foundation for future studies including the impact of climate changes, and coastal and catchment development pressures.