Impact of Tourist Behavior on the Discharge of Sunscreen Contamination in Aquatic Parks, Sinkholes, and Beaches of the Mexican Caribbean

The Mexican Caribbean is part of the Mesoamerican Barrier Reef System, considered the second largest reef system globally. This system, as well as inland aquatic ecosystems, are at risk of contamination due to the intensive use of sunscreen by the tourists who visit the Riviera Maya each year. At present, the regulation and management of sunscreens are inconsistent, with most policies and legislation focused on the protected marine areas with little current focus on inland aquatic ecosystems. An estimated 229.76 tons of sunscreen are used annually, with residues putting the health of the marine and freshwater aquatic ecosystems and residents at risk. Groundwater is used recreationally (e.g., tourists swimming in sinkholes or cenotes) and as household drinking water. To understand the environmental impacts of sunscreen use and the management implications, a mixed-methods study was carried out, combining survey and interview data on how tourists use sunscreen and their perceptions of discharge of sunscreens into the water, with analysis of regional, national and international policies and legislation. Our findings of touristic behaviors, gaps in current legislation, and the pollution implications of different sunscreen types provide useful information for future decision-making and the creation of stronger environmental regulations.

High resolution spatiotemporal patterns of seawater temperatures across the Belize Mesoamerican Barrier Reef

Coral reefs are under increasingly severe threat from climate change and other anthropogenic stressors. Anomalously high seawater temperatures in particular are known to cause coral bleaching (loss of algal symbionts in the family Symbiodiniaceae), which frequently leads to coral mortality. Remote sensing of sea surface temperature (SST) has served as an invaluable tool for monitoring physical conditions that can lead to bleaching events over relatively large scales (e.g. few kms to 100 s of kms). But, it is also well known that seawater temperatures within a site can vary significantly across depths due to the combined influence of solar heating of surface waters, water column thermal stratification, and cooling from internal waves and upwelling. We deployed small autonomous benthic temperature sensors at depths ranging from 0–40 m in fore reef, back reef, and lagoonal reef habitats on the Belize Mesoamerican Barrier Reef System from 2000–2019. These data can be used to calculate depth-specific climatologies across reef depths and sites, and emphasize the dynamic and spatially-variable nature of coral reef physical environments.

Horizontal and vertical distribution of cephalopod paralarvae in the Mesoamerican Barrier Reef System

Horizontal and vertical distribution of cephalopod paralarvae (PL) from the Mesoamerican Barrier Reef System (MBRS) in the Western Caribbean was studied during two oceanographic cruises in 2006 and 2007. A total of 1034 PL belonging to 12 families, 22 genera, 24 species, 5 morphotypes and a species complex were identified. Abralia redfieldi, Onychoteuthis banksii and Ornithoteuthis antillarum were the most abundant taxa. The taxonomic identification from these three species was corroborated with DNA barcoding (99.8–100% of similarity). Paralarvae of Octopus insularis were reported for the first time in the wild. Most PL occupied the Caribbean Surface Water mass in the 0–25 m depth stratum. Largest paralarval abundances were related to local oceanographic features favouring retention such as the Honduras Gyre and Cozumel eddy. No day-night differences were found in PL abundance, although Abralia redfieldi showed evidence of diel vertical migration. Distribution of PL in epipelagic waters of the MBRS was probably related to ontogenetic migration, hydrographic features of meso and subscale, and to the circulation regimes dominated by the Yucatan Current. The MBRS represents an important dispersion area for PL, potentially connecting a species-rich Caribbean community with the Gulf of Mexico and Florida waters.

Common Caribbean corals exhibit highly variable responses to future acidification and warming

We conducted a 93-day experiment investigating the independent and combined effects of acidification (280−3300 µatm p CO 2 ) and warming (28°C and 31°C) on calcification and linear extension rates of four key Caribbean coral species ( Siderastrea siderea , Pseudodiploria strigosa , Porites astreoides , Undaria tenuifolia ) from inshore and offshore reefs on the Belize Mesoamerican Barrier Reef System. All species exhibited nonlinear declines in calcification rate with increasing p CO 2 . Warming only reduced calcification in Ps. strigosa . Of the species tested, only S. siderea maintained positive calcification in the aragonite-undersaturated treatment . Temperature and p CO 2 had no effect on the linear extension of S. siderea and Po. astreoides, and natal reef environment did not impact any parameter examined. Results suggest that S. siderea is the most resilient of these corals to warming and acidification owing to its ability to maintain positive calcification in all treatments, Ps. strigosa and U. tenuifolia are the least resilient, and Po. astreoides falls in the middle. These results highlight the diversity of calcification responses of Caribbean corals to projected global change.