The impact of settleable atmospheric particulate on the energy metabolism, biochemical processes, and behavior of a sentinel mangrove crab.

ABSTRACT

We use the sentinel mangrove crab, Minuca rapax, as a model to investigate the effects of metallic settleable particulate matter (SePM) on wetland. Multiple levels of energetic responses, including (i) metabolic rate and energy budget, (ii) oxidative stress, and (iii) behavioral response by righting time, were assessed as well as the metal and metalloid content in crabs exposed to 0, 0.1 and 1 g.L-1 of SePM, under emerged and submerged conditions over five days, simulating the rigors of the intertidal habitat. Al, Fe, Mn, Cr, and Y exhibited a concentration-dependent increase. Metal concentrations were higher in submerged crabs due to the continuous ingestion of SePM and direct exposure through gills. Exposure concentration up to 1 g.L-1 decreased metabolic rate and enzymatic activities, reduced assimilation efficiency and energy for maintenance, and induces a slower response to righting time, probably by metal effects on nervous system and energy deficits. In conclusion, SePM exposure affects the redox status and physiology of M. rapax depending on he submersion regime and SePM concentration. The disruption to the energy budget and the lethargic behavior in M. rapax exposed to SePM implies potential ecological alterations in the mangrove ecosystem with unknown consequences for the local population.