Description
The Jobos Bay National Estuarine Research Reserve (JBNERR) is a coastal plain estuary in southern Puerto Rico that experiences a gradient of human influence, ranging from relatively undisturbed areas to sites affected by urbanization and runoff. The varying levels of anthropogenic pressure can alter benthic community structure and habitat conditions. Reserve managers need sensitive, low-cost biomonitoring tools to assess the health of the coastal ecosystems and improve management efforts. Benthic foraminiferal assemblages and Cassiopea (upside-down jellyfish) offer valuable insight into environmental conditions, making them potential bioindicators for assessing habit quality and anthropogenic stress. In December 2023, surficial sediment samples and Cassiopea coverage data were recorded from a total of 15 sites within JBNERR. This study focused on three sites representing different levels of natural and anthropogenic influence. At the low-impact site (CAR1), Quinqueloculina was the most abundant genus (43%), representing the small heterotrophic morphogroup, likely linked to the presence of seagrass beds. In contrast, the high-impact site (PA) was dominated by the stress-tolerant genus Ammonia (63%), associated with muddier, finer sediments and terrestrial runoff from urbanization. Among the 20 genera identified, the stress-tolerant genus Cibroelphidium (40%) dominated the moderate site (PUR). No Cassiopea was observed at any of the three sites during sampling, suggesting potentially unfavorable conditions for this species across the gradient. These findings suggest that benthic foraminiferal assemblages are influenced by sediment characteristics, sources of organic matter, surrounding habitat, and human activities. The results confirm that foraminiferal assemblages and Cassiopea coverage reflect habitat conditions and levels of anthropogenic impact within JBNERR.