Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Where does the plastic go? Microplastic loading in seagrass. (#305)

Angela Capper 1 , Andrew Irving 2 , Amie Anastasi 2 , Katherine Jones 3
  1. Coastal Marine Ecosystems Research Centre, CQUniversity, Gladstone, Qld, Australia
  2. Coastal Marine Ecosystems Research Centre, CQUniversity, Rockhampton, Qld, Australia
  3. International Centre for Island Technology, Heriot-Watt University, Stromness, Orkney, Scotland

Plastic pollution from anthropogenic activities on land and sea is a ubiquitous global issue. Much less conspicuous is the extent of microplastics (< 5 mm) contamination. Microplastic fibres, fragments and particles, which sorb multiple contaminants, are now found in every aquatic ecosystem, including seagrass habitats. These highly dynamic habitats reduce water velocity, increasing the settling of small particles. In a recent study in Orkney, Scotland we found microplastics adhered to biofilms on Zostera marina blades, with likely trophic transfer to important seagrass grazers. Microplastic loading was also significantly higher in Z. marina sediments than bare adjacent sediments and sediment grain size may be linked to trapping capability. Seagrass may play a beneficial role in trapping microplastics and reducing the flux to offshore habitats. An ideal location to investigate this potential buffering role is Gladstone, Queensland, where seagrass (predominantly Z. muelleri) are often referred to as the ‘kidneys of the Great Barrier Reef’. The results of this research will be discussed: (1) microplastic loading of seagrass beds in relation to urban and industrial proximity; (2) microplastic trapping capabilities as a function of sediment grain size. This research will provide vital information on the impacts of microplastic contamination in seagrass ecosystems.