Concerns about the environmental and human health impacts of plastic pollution have grown significantly in recent decades. Each year, an estimated 23 million metric tonnes of plastic waste enter the world’s oceans, yet only about 1% remains afloat. Microplastics (MPs)—particles smaller than 5 mm—constitute approximately 92% of marine plastic pollution. The structural, hydrodynamic, and ecological complexity of coral reefs likely makes them particularly vulnerable to MP trapping and retention. Despite this, the processes governing MP transport, distribution, and accumulation within tropical coral reef systems remain poorly understood.
Although the Great Barrier Reef (GBR) is the largest coral reef system globally, it has been the subject of only eight dedicated MP studies to date. Of these, five focused exclusively on surface waters, and none accounted for temporal variability. Recent research underscores the urgent need for vertically stratified and temporally repeated sampling to better understand MP dynamics in reef environments.
This presentation addresses critical knowledge gaps in sampling and introduces novel approaches to establish a baseline snapshot of MP concentrations and characteristics throughout the water column, with a focus on Davies Reef, GBR. To capture spatial and temporal variability, multiple sampling techniques were employed, including surface tows, underway system pumping, submersible pumping, and a sediment trap array. These methods enable estimation of both surface and downward transport flux rates, serving as proxies for MP settlement potential.