A Design Procedure for Anchors of Floating Ocean Current Turbines on Weak Rock

In recent years, ocean current turbines have proven to be a reliable device for renewable energy generation. A crucial element of these turbines are the foundations, since they limit the displacement of the turbine, which is key in achieving efficiency in energy conversion, and can account for up to 26% of the total cost of the project. Most design procedures for foundations focus on sandy and clayey soils, but rock soils often predominate in tropical locations where marine currents are suitable for the installation of this type of turbine. This paper presents a design procedure for steel pile anchors (PAs) and concrete dead weight anchors (DWAs) on weak rock soils, using the assumptions of current technical documents and design codes commonly used in the industry for marine structures. Using specific designs for PA and DWA anchors, the procedure was theoretically assessed for a site off Cozumel Island, Mexico. The results show that the dimensions needed for DWAs are substantially larger than those for PAs. Therefore, whenever drilling is economically and operatively possible, piles would be preferable for the foundations of current turbine systems.

Bactrospora cozumelensis sp. nov. from Mexico

Bactrospora cozumelensis is described as a new species associated with mangrove forests in Cozumel Island, Mexico. The specimens were collected on Rhizophora mangle bark in Punta Sur Ecological Park, Cozumel Island Biosphere Reserve, Quintana Roo, Mexico. This species is characterized by an erumpent to sessile apothecium, laterally carbonized excipulum, and 3-septate ascospores that are slightly constricted in the middle.

Assessing Hydrokinetic Energy in the Mexican Caribbean: A Case Study in the Cozumel Channel

This paper presents a techno-economic assessment of hydrokinetic energy of Cozumel Island, where ocean currents have been detected, but tourist activities are paramount. The main objective of this research is to identify devices that have been used to harvest hydrokinetic power elsewhere and perform an economic analysis as to their implementation in the Mexican Caribbean. First, the energy potential of the area was evaluated using simulated data available through the HYCOM consortium. Then, for four pre-commercial and commercial turbines, technical and economic analyses of their deployments were performed. Socio-environmental constraints were reviewed and discussed. Three optimal sites were identified, with an average annual hydrokinetic energy density of 3–6 MWh/m2-year. These sites meet the socio-environmental requirements for marine kinetic energy harvesting. Of the turbines considered in the analysis, the best energy price/cost ratio is that of SeaGen device, with a maximum theoretical energy extraction of 1319 MWh/year with a Capacity Factor of 12.5% and a Levelised Cost of Energy (LCOE) of 1148 USD/MWh. Using this device, but assuming a site-specific design that achieves at least 25% of Capacity Factor, 20-year useful life, and a discount rate of 0.125, the LCOE would be 685.6 USD/MWh. The approach presented here can be applied for techno-economic analyses of marine turbines in other regions.

Changes in Organic Matter Deposition Can Impact Benthic Marine Meiofauna in Karst Subterranean Estuaries

Subsurface mixing of seawater and terrestrial-borne meteoric waters on carbonate landscapes creates karst subterranean estuaries, an area of the coastal aquifer with poorly understood carbon cycling, ecosystem functioning, and impact on submarine groundwater discharge. Caves in karst platforms facilitate water and material exchange between the marine and terrestrial environments, and their internal sedimentation patterns document long-term environmental change. Sediment records from a flooded coastal cave in Cozumel Island (Mexico) document decreasing terrestrial organic matter (OM) deposition within the karst subterranean estuary over the last ∼1,000 years, with older sediment likely exported out of the cave by intense storm events. While stable carbon isotopic values (δ13Corg ranging from −22.5 to −27.1‰) and C:N ratios (ranging from 9.9 to 18.9) indicate that mangrove and other terrestrial detritus surrounding an inland sinkhole are the primarily sedimentary OM supply, an upcore decrease in bulk OM and enrichment of δ13Corg values are observed. These patterns suggest that a reduction in the local mangrove habitat decreased the terrestrial particulate OM input to the cave over time. The benthic foraminiferal community in basal core sediment have higher proportions of infaunal taxa (i.e., Bolivina) and Ammonia, and assemblages shift to increased miliolids and less infaunal taxa at the core-top sediment. The combined results suggest that a decrease in terrestrial OM through time had a concomitant impact on benthic meiofaunal habitats, potentially by impacting dissolved oxygen availability at the microhabitat scale or resource partitioning by foraminifera. The evidence presented here indicates that landscape and watershed level changes can impact ecosystem functioning within adjacent subterranean estuaries.

Birds of the Land of the Swallows: Cozumel Island

For being a relatively small island, of approximately 480 km2, Cozumel receives particular national and international attention for the coral reefs to which it is related, which are part of the Great Mesoamerican Barrier Reef. Due to its ecological importance, in 1996 the Arrecifes de Cozumel National Park was decreed in order to protect these unique and invaluable natural resources. However, tourism takes advantage of its spectacular underwater attractions, being considered one of the most important sites for diving worldwide. The island's urban center, San Miguel de Cozumel, is currently home to more than 70,000 inhabitants and has grown significantly in recent years. Particularly in the case of birds, a great diversity of species can be found on the island, many of which are migratory, that is, they spend only one season of the year (generally winter) on the island. Over the years, more than 230 species have been recorded, which have been compiled at: www.avesdecozumel.org. However, there is a group of species that are very abundant, and sometimes very striking, that can be seen relatively easily on the island if you are in the right season and place, since some species are migratory and others only inhabit certain ecosystems. . Thus, this document provides information on 31 common and remarkable species of Cozumel Island.

A Business Case for Marine Protected Areas: Economic Valuation of the Reef Attributes of Cozumel Island

Tourism to Cozumel Island generates USD 762 million annually in local economic activity, and 111 visitors stay in local hotels for each inhabitant. The island’s coast is its principal attraction, yet water quality and reef health are threatened. This paper studies the link between the local economy and management of Arrecifes de Cozumel National Park, using a choice experiment to assess the economic value visitors assign to underwater visibility, biodiversity, and visitor congestion in reef areas. We found that, on average, tourists are willing to pay USD 190 per visit to avoid a projected decrease in biodiversity, USD 120 per visit to prevent a projected decline in visibility, and USD 98 to avoid high congestion during reef visits. We find high heterogeneity in willingness to pay estimates, which may be useful for targeting both conservation and marketing efforts. On the other hand, increasing the reef access fee from USD 2 to USD 6 could fully fund effective protected area management, with no substantial effect on visitors’ consumer surplus. Results suggest that a conservation surcharge could be added to all tours, with little impact on visitation, and that significantly increasing private sector collaboration and government spending on conservation would be good economic choices.

New species of Microscleroderma and Amphibleptula (Demospongiae, Tetractinellida, Scleritodermidae) from two contrasting marine environments

We record for the first time a nominal species of the genus Microscleroderma in the Western Atlantic, and the first record of the genus Amphibleptula in Mexico. Two new species of ‘lithistid’ Tetractinellida are described: Microscleroderma mexica sp. nov. from crevices of two reefs in Veracruz, Mexico, and Amphibleptula aaktun sp. nov. from the anchialine cave El Aerolito, Cozumel Island, Mexico. Microscleroderma mexica sp. nov. is characterized by its tubular and cup-shaped to wavy laminar habitus, hirsute surface and two size categories of oxea diactines. Amphibleptula aaktun sp. nov. is characterized by its ficiform or lobular habitus with an exhalant area at the flat top of the body, divided into numerous vertical septa-like structures; its desmas have thinner epirhabds, and thinner oxea than those of Amphibleptula madrepora. This is the second species of Amphibleptula that has been described; hence, we propose the redefinition of the genus. Both species described have a shallow distribution (≤21 m depth); they are differentiated from each other by the disjunction between their habitats as well as by their morphology.

Historical analysis of a karst aquifer: recharge, water extraction, and consumption dynamics on a tourist island (Cozumel, Mexico)

On Cozumel Island, access to freshwater depends on the extraction of the resource from the aquifer located north of the island (catchment area). Water resource management on the island must be based on updated knowledge of the indicator dynamics related to the recharge of the aquifer, groundwater extraction and the distribution of the resource. In this study, trends, variations and time series of 30 years of monthly data for precipitation, temperature, evapotranspiration, and estimated aquifer recharge were calculated for the catchment area. Additionally, groundwater extraction, water consumption for the main uses over a 13-year period (monthly data), and the 5-year status of wells were considered. The results show decreasing trends in precipitation and estimated recharge volumes in the catchment area, in addition to increasing trends in mean air temperature, evapotranspiration, water extraction volumes and consumption by the commercial sector for the considered time periods. Additionally, an increase in dejected (77%) and reposed (38%) wells within the catchment area was observed. Evidence from this study suggests a dynamic behaviour of the analysed indicators over time that increases pressure on karstic, Caribbean aquifers for which monthly monitoring and data analysis are encouraged as the basis for adequate management.

Yucatec Land and Labor before and after Spanish Incursions

Yucatec land and labor arrangements before and after Spanish incursions are examined for ruptures and continuities. The Western concept of private property is found to ring hollow in a landscape in which intersecting spheres of authority (including those of supernaturals) guide protocols of access and extraction. Furthermore, no simple dichotomy between pre- and post-colonial can explain the range of land arrangements and networks of labor that existed across Yucatán. Through the input of labor or as a consequence of geomorphology, a patchwork of high-productivity micro-environments can be found across Yucatán and on Cozumel Island. Cultivation and/or extraction at these resource-intensive production zones encompassed a large range of labor arrangements and interdependencies during Pre-Columbian times. In general, land and labor are conceptualized as suspended within relationships of shifting authority. In reference to both land labor, authors break with the construct of “control over” and embrace the phrase “authority to,” which recognizes the role of negotiation and the inclusion of supernatural forces perceived to have played a structuring role in the disposition of land and labor.