Mapping the pollutants in surface riverine flood plume waters in the Great Barrier Reef, Australia

• Published in: Marine pollution bulletin 2012-01, Vol.65 (4-9), p.224-235
• Main Authors: Devlin, M.J., McKinna, L.W., Álvarez-Romero, J.G., Petus, C., Abott, B., Harkness, P., Brodie, J.
• Format: Article
• Language: English
• Subjects: Australia; chlorophyll; Chlorophyll - analysis; color; Coral Reefs; dissolved inorganic nitrogen; Environmental Monitoring - methods; Floods - statistics & numerical data; Freshwater; herbicides; Herbicides - analysis; Land-based threat; Marine; MODIS images; photosystem II; phytoplankton; Phytoplankton - growth & development; Phytoplankton - physiology; Pollutant exposure; pollutants; remote sensing; Remote Sensing Technology; River plume; Rivers - chemistry; Spacecraft; suspended sediment; Terrestrial runoff; tropics; Water Movements; Water Pollutants, Chemical - analysis; water pollution; Water Pollution, Chemical - statistics & numerical data; watersheds
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2012.03.001

► Mapping and modelling of plume exposure is a key link to identifying the influence of terrestrial inputs. ► This work estimates the number of inshore ecosystems exposed to surface plume pollutants (DIN, TSS, PS-II herbicides). ► Surface exposure is calculated by annual pollutant loads against frequency and extent of the plumes from each main catchment. ► Mapping of water characteristics within plume waterscan provide detailed spatial and temporal water quality information. The extent of flood plume water over a 10year period was mapped using quasi-true colour imagery and used to calculate long-term frequency of occurrence of the plumes. The proportional contribution of riverine loads of dissolved inorganic nitrogen, total suspended sediments and Photosystem-II herbicides from each catchment was used to scale the surface exposure maps for each pollutant. A classification procedure was also applied to satellite imagery (only Wet Tropics region) during 11 flood events (2000–2010) through processing of level-2 ocean colour products to discriminate the changing characteristics across three water types: “primary plume water”, characterised by high TSS values; “secondary plume water”, characterised by high phytoplankton production as measured by elevated chlorophyll-a (chl-a), and “tertiary plume water”, characterised by elevated coloured dissolved and detrital matter (CDOM+D). This classification is a first step to characterise flood plumes.