RESUMEN
We assessed microplastics (MPs) contamination in water, sediments, and tissues (gills, digestive tract, and muscle) of two intertidal crab species with different ecological traits and commercial importance (Menippe mercenaria and Callinectes sapidus), from a coastal lagoon in the southeastern Gulf of Mexico. There were significant differences between MP abundances in the abiotic matrices and between crab species. The burrower, sedentary and carnivorous M. mercenaria bioaccumulates 50 % more MPs than the free-swimming, omnivorous C. sapidus. However, no differences were observed between species' tissues. Fragments were the predominant shape in the tissues of both species, with the exception in the digestive tract of M. mercenaria. We identified polyethylene, and polyethylene terephthalate in water samples and Silopren® in sediment. In both crab species, Silopren and polyethylene predominated. Differences in ecological traits resulted in different bioaccumulation patterns in intertidal crabs.
Asunto(s)
Braquiuros , Contaminantes Químicos del Agua , Animales , Bioacumulación , Braquiuros/fisiología , Monitoreo del Ambiente , Golfo de México , Microplásticos , Plásticos , Tereftalatos Polietilenos , Polietilenos , Agua , Contaminantes Químicos del Agua/análisisRESUMEN
To comprehend mangrove crab responses to predicted global climate changes, we assessed submersion and desiccation survival durations and salinity tolerances and upper thermal limits in fiddler crabs from Isla del Carmen, Yucatán Peninsula. Based on their tolerances of extreme ambient conditions, we also calculated safety margins using abiotic monitoring data. The two most terrestrial species, Minuca rapax and Leptuca panacea, exhibited submersion tolerances of from 22 to 40â¯h, and desiccation tolerances of from 30 to 55â¯h; LC50's were ≈45S and UT50's were ≈40⯰C. The two least terrestrial species, M. vocator and L. speciosa, were less tolerant of all experimental challenges, showing submersion and desiccation tolerances of <6â¯h, and LC50's of 36S and UT50's of 38⯰C. While these fiddler crabs inhabit niches closer to their salinity and desiccation/submersion tolerances than to their temperature limits, all are clearly vulnerable to the multiple stressors that accompany anticipated global climate change.
Asunto(s)
Braquiuros , Animales , Braquiuros/fisiología , Cambio Climático , Salinidad , TemperaturaRESUMEN
Globally, nutrient river discharges drive water quality of coastal ecosystems, and excess nutrients can cause eutrophication impacts. The Grijalva-Usumacinta River System (GURS) discharges in the southern Gulf of Mexico (SGoM) and it is the second largest riverine input to the Gulf. To study how contrasting GURS freshwater flow between rainy and dry seasons affects nutrients concentrations in the receiving coastal ecosystem, we evaluated nutrient variability in the water column during both seasons. High inorganic nutrients and total phosphate outline the rivers discharge plumes during rainy season, and were significantly higher than during the dry season throughout the study area, suggesting contrasting seasonal nutrient discharge of the GURS to coastal waters. On average the GURS discharged 141,123 t N yr-1 6893 t P yr-1 and 928,904 t Si yr-1 to SGoM. These results contribute with a nutrient baseline in the SGoM that could be useful for GURS decision-makers.