The dynamics of nutrients, phytoplankton, zooplankton and water clarity of the iconic Great Barrier Reef World Heritage Area (GBRWHA) are influenced by seasonal variation in coastal and oceanic conditions, and anthropogenic inputs.
The greatest impacts to the GBR region over the past 30 years have been damage from cyclones, reductions in water clarity and, for coral reefs, crown of thorns starfish outbreaks and marine heat waves causing mass coral bleaching.
Recent events have emphasised the vulnerability of the GBRWHA with two consecutive years of severe coral bleaching caused by anomalously warm water temperatures, and, the emerging risk of ocean acidification.
In this newly published study the authors present a comparison of the eReefs model conducted against a range of in situ observations that included 24 water quality moorings, two nutrient sampling programs (with a total of 18 stations) and time-series of taxon-specific plankton abundance. The model encompasses the 2300 km long Great Barrier Reef from coast to Coral Sea.
The study used observations from the IMOS National Reference Station moorings at North Stradbroke Island and Yongala to validate the eReefs model. These two sites have high frequency measurements of chlorophyll fluorescence and turbidity form in situ sensors, as well as monthly water sampling for phytopigments, nutrients, phyloplankton and zooplankton species counts.
In addition, the study used data from six other IMOS moorings (Lizard Island, Myrmidon Reef, One Tree East, Palm Passage, Capricorn Channel, Heron South) and Continuous Plankton Recorder surveys.
The comparison of the spatially-resolved statistical model of zooplankton based on >900 observations in the region showed similarities in the relationship and spatial distribution of simulated and observed biomass. Both show zooplankton biomass is greatest inshore, biomass is highest around shallow reef areas and in the southern and central GBRWHA, and greater in summer than winter.
The eReefs simulation contributes to the understanding at a high spatial and temporal resolution of where and how nutrients and plankton originate and interact within the Great Barrier Reef.
eReefs is producing powerful visualisation, communication and reporting tools, and the model simulations, such as those presented in this study, will benefit government agencies, Reef managers, policy makers, researchers, industry and local communities.
To read the full paper: https://www.sciencedirect.com/science/article/pii/S0924796317304529#s0185
eReefs simulations were developed as part of the eReefs project, a public-private collaboration between Australia's leading operational and scientific research agencies, government, and corporate Australia.