Phytoplankton and zooplankton of the Darling-Baaka River Australia: Taxa and possible responses to climate change

The lowland Darling-Baaka River is one of the major inland rivers of Australia. The river water is characterized by high turbidity with median levels around 65NTU; however, this can vary greatly with lower turbidity under low flow conditions often associated with algal blooms, especially by the saxitoxin-producing cyanobacteria Dolichospermum circinale during the summer period. The river also supports a diverse array of noncyanobacterial phytoplankton and rotifer-dominated zooplankton including endemic species. Turbidity, thermal stratification, light availability, and river flow are important drivers of the phytoplankton community. Reductions in catchment rainfall and river flows as well as higher air temperatures are predicted to be experienced in the region as a result of climate change and are likely to benefit some cyanobacteria, increasing the potential for more toxic blooms. The predicted reduction in river flows is also expected to have a negative impact on the recruitment patterns and processes of zooplankton (particularly of cladocerans) through reduced flooding and river-floodplain connectivity.