Poster Australian Marine Sciences Association 2022

Cumulative effects of microplastics and nitrogen loading on microphytobenthos and sediment-dwelling infauna   (#499)

Saskia Foreman 1 , Candida Savage 1 , Amandine Sabadel 2 , Bridie Allen 1
  1. Marine Science, University of Otago, Dunedin, New Zealand
  2. Zoology, University of Otago, Dunedin, New Zealand

Estuary health is declining globally due to an increase in anthropogenic stressors including microplastics and nutrient loading. Although these stressors are often studied individually, this is the first study to evaluate their interacting effects in intertidal soft sediment communities. In this laboratory experiment, the effects of micro-beads and nitrogen loading on a key surface deposit feeding bivalve (Macomona liliana), microphytobenthos (MPB), and sediment nutrient pools was assessed. Polyethylene microplastic beads and a Nitrogen addition were tested for individual and synergistic effects on the infaunal community and biogeochemical processes. I will present data on the effects of elevated microplastic and nitrogen levels on microphytobenthos quality (indicated by fatty acid biomarkers and percentage N) and M. liliana feeding rates and bioturbation. The study highlights the complex interactions between subtle shifts in food quality and infaunal behaviour that affects productivity and nutrient cycling at the sediment-water interface in coastal ecosystems.