Short-term impact of Hurricane Dean on the morphology of the beach at Cancun, Mexico

Over the last 30 years, the Mexican Caribbean beach at Cancun, Quintana Roo has experienced such severe erosion that two artificial sand replenishment programs have been needed. The aim of this study is to determine the short-term impact of Hurricane Dean on the morphology of the already modified beach system of Cancun, after the first replenishment in 2006. The combined analysis of the evolution of the coastline, by comparing beach profiles, and the characteristics of the local maritime climate generated by the hurricane allowed for the evaluation of the hurricane´s impact on the study area. As a result of this analysis it was found that Hurricane Dean caused large losses of sand in the northern and central sectors of the beachfront during 2006-2007. It was also shown that during that period the Cancun beaches lost 31 m in width, overall. This significant retreat of the beach is attributed to the combined effects of the hurricane and the anthropogenic modifications of the coastal ecosystem

Retrograde Accretion of a Caribbean Fringing Reef Controlled by Hurricanes and Sea-level Rise

Predicting the impact of sea-level (SL) rise on coral reefs requires reliable models of reef accretion. Most assume that accretion results from vertical growth of coralgal framework, but recent studies show that reefs exposed to hurricanes consist of layers of coral gravel rather than in-place corals. New models are therefore needed to account for hurricane impact on reef accretion over geological timescales. To investigate this geological impact, we report the configuration and development of a 4-km-long fringing reef at Punta Maroma along the northeast Yucatan Peninsula. Satellite-derived bathymetry (SDB) shows the crest is set-back a uniform distance of 315 ±15 m from a mid-shelf slope break, and the reef-front decreases 50% in width and depth along its length. A 12-core drill transect constrained by multiple 230Th ages shows the reef is composed of an ~2-m thick layer of coral clasts that has retrograded 100 m over its back-reef during the last 5.5 ka. These findings are consistent with a hurricane-control model of reef development where large waves trip and break over the mid-shelf slope break, triggering rapid energy dissipation and thus limiting how far upslope individual waves can fragment corals and transport clasts. As SL rises and water depth increases, energy dissipation during wave-breaking is reduced, extending the clast-transport limit, thus leading to reef retrogradation. This hurricane model may be applicable to a large sub-set of fringing reefs in the tropical Western-Atlantic necessitating a reappraisal of their accretion rates and response to future SL rise

A New Long-Term Marine Biodiversity Monitoring Program for the Knowledge and Management in Marine Protected Areas of the Mexican Caribbean

In the Mexican Caribbean, 15 marine protected areas (MPAs) have been established for managing and protecting marine ecosystems. These MPAs receive high anthropogenic pressure from coastal development, tourism, and fishing, all in synergy with climate change. To contribute to the MPAs’ effectiveness, it is necessary to provide a long-term observation system of the condition of marine ecosystems and species. Our study proposes the establishment of a new marine biodiversity monitoring program (MBMP) focusing on three MPAs of the Mexican Caribbean. Five conservation objects (COs) were defined (coral reefs, seagrass beds, mangroves, marine turtles, and sharks-rays) for their ecological relevance and the pressures they are facing. Coral reef, seagrass and mangroves have multiple biological, biogeochemical and physical interactions. Marine turtles are listed as endangered species, and the status of their populations is unknown in the marine area of the MPAs. Elasmobranchs play a key role as top and medium predators, and their populations have been poorly studied. Indicators were proposed for monitoring each CO. As a technological innovation, all information obtained from the MBMP will be uploaded to the Coastal Marine Information and Analysis System (SIMAR), a public, user-friendly and interactive web platform that allows for automatic data management and processing

Puerto Morelos Coral Reefs, Their Current State and Classification by a Scoring System

Marine protected areas have been established as essential components for managing and protecting coral reefs to mitigate natural and anthropogenic stressors. One noteworthy example within the Mexican Caribbean is the Arrecife de Puerto Morelos National Park (APMNP), where several studies on the coral communities have been carried out since 2006. In June 2019, we conducted a study in eight sites of the APMNP applying a coral reef assessment method based on biological indicators of both the benthos and the fish communities. In this paper, we present the quantitative results of our study and provide a qualitative criterion assessing seven condition indexes through a scoring system. We also present a statistical comparison with a previous study carried out in 2016. The general status of coral reefs was classified as regular due to the low values of coral recruitment rate and biomass of key commercial fish species. However, living coral cover average was above 20%, with a slight dominance of framework building coral species and the presence of low values of fleshy algae cover, these being positive indicators. Our study found a higher proportion of reef promoter elements and a lower proportion of detractors, compared to a previous study carried out in 2016