TRaCK: Tropical Rivers and Coastal Knowledge

Science and knowledge that governments, communities, industries for sustainable use of Australia's tropical rivers and estuaries

How are biogeochemical processes differentially affected by nutrient loading?

TitleHow are biogeochemical processes differentially affected by nutrient loading?
Publication TypeConference Participation
Year of Publication2010
AuthorsBurford, MA, Smith, J, Revill, A, Haese, R
Keywords5: Foodwebs and biodiversity

Many studies examining the effect of nutrient loading rates on biogeochemical processes have typically focussed either on few rate processes in multiple impacted aquatic systems, or multiple processes in one system. Studies of multiple biogeochemical processes across more than one system are less common, but provide a broader perspective of the links between nutrient loads and biogeochemical processes. Our study compared rates of multiple processes across three scales of sewage nutrient loading in tropical tidal creeks to identify which parameters are most sensitive to increased loading. Water column primary productivity, sediment nutrient fluxes and sediment denitrification efficiency were the parameters most affected by increased loading. Nutrient loads directly promoted primary productivity which in turn stimulated increased remineralisation of nutrients. A reduction in denitrification efficiency compounded the effect. Water column and sediment respiration, and sediment primary productivity were less affected by nutrient loads. This study identifies processes most impacted by nutrient loads, and when combined with tidal flushing data, provides key data for developing models of threshold nutrient loads which impact ecosystem functioning.