Ecoengineering on an artificial causeway: A potential for microplastic hotspots

In response to the effects of growing populations and human-induced climate change such as coastal erosion, diverse forms of coastal structures have been proposed and built. More recently eco-engineered has focused on tackling the loss of biodiversity through creating novel habitats with features such as tide pools, pits, grooves, and towers that promote biodiversity within artificial environments. To study the effectiveness and functionality of eco-engineered rock pools installed in an artificial causeway in Galway, Ireland in 2013 (n=80) the biodiversity of rock pools, were analysed and compared to the established community ten years after their construction in 2023 and for their potential to act as hotspots for microplastics. Destructive sampling was carried out on 28 rockpools for microplastics (18 from the exposed westerly side and 10 from the sheltered easterly side). Results show that the exposed pools were effective at maintaining biodiversity over long periods and functional diversity was retained. MPs were recorded from all artificial pools on both the exposed and sheltered side. There were significantly more microplastics found per litre of water in the pools at the upper shore height than in the lower shore pools. The quantity per rockpool was highly variable, 14.7± 8.35 MPs recorded from the exposed rockpools and 10.7 ± 6.9 MP in the sheltered pools which had become inundated with sediments, thus failing to function as rock pools as intended. Furthermore, the rockpools recorded on average 19.6 ±15.3 MP L-1 are deemed a hotspot for the bay with significantly higher numbers recorded than from the surface water in Galway Bay in previous studies. Results can be used to aid the design of future coastal engineering projects and marine pollution. Also see: https://micro2024.sciencesconf.org/559176/document