Water Quality and River Plume Monitoring in the Great Barrier Reef: An Overview of Methods Based on Ocean Colour Satellite Data

Abstract

A strong driver of water quality change in the Great Barrier Reef (GBR) is the pulsed or intermittent nature of terrestrial inputs into the GBR lagoon, including delivery of increased loads of sediments, nutrients, and toxicants via flood river plumes (hereafter river plumes) during the wet season. Cumulative pressures from extreme weather with a high frequency of large scale flooding in recent years has been linked to the large scale reported decline in the health of inshore seagrass systems and coral reefs in the central areas of the GBR, with concerns for the recovery potential of these impacted ecosystems. Management authorities currently rely on remotely-sensed (RS) and in situ data for water quality monitoring to guide their assessment of water quality conditions in the GBR. The use of remotely-sensed satellite products provides a quantitative and accessible tool for scientists and managers. These products, coupled with in situ data, and more recently modelled data, are valuable for quantifying the influence of river plumes on seagrass and coral reef habitat in the GBR. This article reviews recent remote sensing techniques developed to monitor river plumes and water quality in the GBR. We also discuss emerging research that integrates hydrodynamic models with remote sensing and in situ OPEN ACCESS Remote Sens. 2015, 7 12910 data, enabling us to explore impacts of different catchment management strategies on GBR water quality.

Estimating the Exposure of Coral Reefs and Seagrass Meadows to Land-Sourced Contaminants in River Flood Plumes of the Great Barrier Reef: Validating a Simple Satellite Risk Framework with Environmental Data

“…Several water quality parameters are monitored, including salinity, temperature, particulate and dissolved nutrients, phytoplankton, total suspended solids (TSS), diffuse attenuation coefficient of photosynthetically active radiation (Kd(PAR)), coloured dissolved organic matters (CDOM), chlorophyll-a (Chl-a) and herbicides [15]. Other remote sensing products (not used in this study) developed to monitor river plumes and water quality in the GBR were outlined in a recent review [15]. November, 1984-June, 2010) and the modelled (mod.)…”

“…The seagrass and coral reef sites monitored though the Great Barrier Reef Marine Monitoring Program are indicated with green asterisks and white dots, respectively. Table 1 gives examples of remote sensing monitoring products developed through the GBR Marine Monitoring Program (MMP) to improve our understanding of the relationships between coastal water quality in river plumes and its effects on marine ecosystems [15]. River plume maps have been developed to document the spatial extent and frequency of occurrence of the GBR plume water types (Table 1A).…”

“…Each plume water type is associated with characteristic optical properties, light levels and colours, as well as different concentrations and proportions of land-sourced contaminants (e.g., [11][12][13][14][15][16]). Table 1 gives examples of remote sensing monitoring products developed through the GBR Marine Monitoring Program (MMP) to improve our understanding of the relationships between coastal water quality in river plumes and its effects on marine ecosystems [15]. River plume maps have been developed to document the spatial extent and frequency of occurrence of the GBR plume water types (Table 1A).…”

“…River plume maps have been developed to document the spatial extent and frequency of occurrence of the GBR plume water types (Table 1A). Coupled with in situ data, river plume maps have been used to document water quality conditions associated with river plumes (Table 1B) (e.g., [12][13][14][15]). The remote sensing outputs are produced as single-week and multi-week (seasonal and multi-annual, see Table 1) composite maps and provide an aggregated approach to reporting contaminant concentrations in the GBR marine environment.…”

“…The remote sensing outputs are produced as single-week and multi-week (seasonal and multi-annual, see Table 1) composite maps and provide an aggregated approach to reporting contaminant concentrations in the GBR marine environment. Several water quality parameters are monitored, including salinity, temperature, particulate and dissolved nutrients, phytoplankton, total suspended solids (TSS), diffuse attenuation coefficient of photosynthetically active radiation (Kd(PAR)), coloured dissolved organic matters (CDOM), chlorophyll-a (Chl-a) and herbicides [15]. Other remote sensing products (not used in this study) developed to monitor river plumes and water quality in the GBR were outlined in a recent review [15].…”