Inter-annual variability of wet season freshwater plume extent into the Great Barrier Reef lagoon based on satellite coastal ocean colour observations

• Published in: Marine pollution bulletin 2012-01, Vol.65 (4-9), p.210-223
• Main Authors: Schroeder, Thomas, Devlin, Michelle J., Brando, Vittorio E., Dekker, Arnold G., Brodie, Jon E., Clementson, Lesley A., McKinna, Lachlan
• Format: Article
• Language: English
• Subjects: algorithms; Australia; CDOM; chlorophyll; color; Coral Reefs; dissolved organic matter; environmental health; Environmental Monitoring - methods; Flood plumes; Floods - statistics & numerical data; Fresh Water - analysis; Fresh Water - chemistry; freshwater; Great Barrier Reef; lagoons; Marine; moderate resolution imaging spectroradiometer; MODIS; nutrients; particulates; pollutants; Remote Sensing Technology; risk assessment; Salinity; Satellite remote sensing; Seasons; Seawater - chemistry; sediments; Spacecraft; Water Movements; water pollution; wet season
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2012.02.022

► CDOM is a useful surrogate for salinity in Great Barrier Reef coastal waters. ► Satellite remote sensing is a cost effective method for large scale mapping of CDOM. ► The freshwater extent was successfully estimated for the entire GBR region. ► Remotely sensed freshwater extent is significantly correlated with river discharge. ► Low salinity waters were found to reach a number of inner and mid-shelf reefs. Riverine freshwater plumes are the major transport mechanism for nutrients, sediments and pollutants into the Great Barrier Reef (GBR) lagoon and connect the land with the receiving coastal and marine waters. Knowledge of the variability of the freshwater extent into the GBR lagoon is relevant for marine park management to develop strategies for improving ecosystem health and risk assessments. In this study, freshwater extent has been estimated for the entire GBR lagoon area from daily satellite observations of the Moderate Resolution Imaging Spectroradiometer (MODIS) between 2002 and 2010. To enable a reliable mapping of freshwater plumes we applied a physics-based coastal ocean colour algorithm, that simultaneously retrieves chlorophyll-a, non-algal particulate matter and coloured dissolved organic matter (CDOM), from which we used CDOM as a surrogate for salinity (S) for mapping the freshwater extent.