Sources of nutrients fuelling post-flood phytoplankton biomass in a subtropical bay.

Extreme rainfall from an ex-tropical cyclone caused a major flood event in the Logan River system in southeast Queensland, Australia. This resulted in a significant flood plume, containing nutrients and sediment, being discharged into the adjacent estuary/Bay system. The spatial extent of higher phytoplankton biomass (Chl a) matched the distribution of higher nutrient and sediment concentrations post-flood, suggesting nutrients fuelled phytoplankton production.

Effects of terrestrial dissolved organic matter on a bloom of the toxic cyanobacteria, Raphidiopsis raciborskii.

The concentration of coloured terrestrial dissolved organic matter (tDOM) from vegetation appears to be increasing in lakes in some regions of the world, leading to the term brownification. The light attenuating effect of coloured tDOM on phytoplankton growth has been a major focus of attention, but the phytotoxic effects of tDOM, particularly on cyanobacterial blooms, are less well understood. This mesocosm study tested whether coloured tDOM, leached from the leaves of a Eucalyptus tree species, inhibited a naturally occurring bloom of the toxic cyanobacterium, Raphidiopsis raciborskii, in a reservoir over a 10 day period.

Comparing the importance of freshwater flows driving primary production in three tropical estuaries.

Estuaries in the tropical Gulf of Carpentaria (GOC) in Australia are under increasing pressure from catchment water development, potentially affecting productivity. We examined the potential effect of changes in freshwater inputs on the primary productivity of three estuaries (Flinders, Gilbert and Mitchell Rivers). The addition of nutrients stimulated mudflat primary production in all estuaries at multiple sampling times, suggesting chronic nutrient limitation.

Differences in nitrate and phosphorus export between wooded and grassed riparian zones from farmland to receiving waterways under varying rainfall conditions.

Agricultural activities in catchments can cause excessive nutrient loads in waterways. Catchment nitrogen (N) and phosphorus (P) flows may be intercepted and assimilated by riparian vegetation. While prior studies suggest that woody vegetation is preferable for reducing P loads, the question remains: is woody vegetation or grass cover more effective at reducing catchment N and P exports to waterways.

Biotic and abiotic controls on nitrogen leaching losses into waterways during successive bovine urine application to soil.

Cattle waste products high in nitrogen (N) that enter waterways via rainfall runoff can contribute to aquatic ecosystem health deterioration. It is well established that N leaching from this source can be reduced by plant assimilation, e.g.