Work

Stuck in the mangrove mud: The risk of trace element exposure to shore crabs in restored urban mangroves

Year: 2024

Type: article

Abstract: The restoration of mangroves in urban environments can increase the risk of contaminant exposure and subsequent health effects to resident biota, yet this risk is rarely considered in mangrove restoration programs. Here we assessed the influence of sediment chemistry on contaminant bioaccumulation in shore crabs from restored and natural mangroves in urban environments compared to a reference site. The concentrations of some trace elements were several-fold higher in the sediment and crab tissues of the urban restored site compared to the natural reference site (Cd = 6×, Co = 7×, Cr = 4×, Mn = 30×, and Ni = 18× greater in sediments, while Cd = 4×, Co = 2×, Cr = 2×, Mn = 6×, and Ni = 3× greater in crab tissues). NMR-based metabolomics on crabs revealed higher abundances of proline and glutamate at urban sites, which may be indicative of physiological stress from trace element contamination. Choice experiments were used to test habitat selectivity by crabs from each population, and showed that crabs avoided sediments from the contaminated urban sites. Our results suggest that restoring mangroves in contaminated environments could create ecological sinks, where animals take residence in the new habitat but are exposed to sediment-based contaminants, with potential implications for organism and population health. • Urban contaminants threaten the success of coastal restoration • Sediment and crabs from an urban restored site were the most contaminated • Crabs from urban sites had distinct metabolome profiles • Contaminant burden should be a key metric when monitoring restoration outcomes • Linking metabolome profiles to contaminant levels is challenging in complex ecosystems

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2024.177064