Ambergris Caye Research Articles

Trace element concentrations in caudal scutes from Crocodylus moreletii and Crocodylus acutus in Belize in relation to biological variables and land use

Crocodylus moreletii (Morelet’s crocodile) and Crocodylus acutus (American crocodile) are generalist, apex predators of subtropical aquatic habitats in Central America. As top predators, crocodiles may be exposed to high levels of micro pollutants, such as trace elements via bioaccumulation that enter the food web as a consequence of human activities. As such, the status of their population can be considered indicative of that of the entire ecosystem – i.e., crocodiles constitute as genuine indicator species. In this study, we report on the concentrations of trace elements found in the caudal scutes of 178 specimens of C. acutus and C. moreletii from Belize. Our objectives were three-fold: (1) to assess variation in trace element concentration between species, sexes, age classes and body index; (2) to identify areas with elevated exposure to trace elements by comparing concentrations in the scutes of crocodiles at various sites in Belize; and (3) to explore links between crocodile trace element load and local land use. All elements tested (Hg, Pb, Cd, As, Cu, Zn, Co) could be detected in at least some scutes. Many of the readings of As and Co were under or close to the detection limit and were not further analyzed. Relatively high Hg concentrations were observed in adults from Chiquibul Forest (median 3.170 µg/g) and Ambergris Caye (0.834 µg/g). Concentrations of Hg and Pb tended to be higher in adult animals than in juveniles, especially in C. acutus. On the other hand, concentrations of Cd, Cu and Zn were higher in juveniles than in subadult adult animals. Concentrations of Cu were higher in C. acutus than in C. moreletii, but otherwise no species-effects were found for the other trace elements. We found a negative correlation between Hg and Zn concentrations; correlations among Cd, Pb, Cu and Zn concentrations tended to be positive. In both juveniles and adults, animals with high concentrations of Zn had lower body-indices (a proxy for physiological condition). None of the other element concentrations correlated with the body-index. Specimens of C. acutus were more often sampled at coastal sites, while C. moreletii sampling points were typically closer to agricultural or forested areas. A canonical correlation analysis revealed a significant association between trace element load and habitat characteristics. Animals sampled inland, near submontane forests, contained higher levels of Hg, while animals sampled near agricultural, urban or lowland habitats tended to have higher concentrations of Cd, Pb, Cu and Zn. This study identifies the most prevalent trace element concentrations impacting Belizean watersheds while highlighting the exposure risk to non-essential trace elements in less-urbanised areas or protected areas.

Island resource exploitation by the ancient Maya during periods of climate stress, Ambergris Caye, Belize

Ancient Maya societies experienced a period of reorganisation and change in settlement patterns associated with social and climate instability at the end of the Classic period (750-1000 CE) and the subsequent Postclassic period (1200-1500 CE). Although it has been proposed that severe droughts and the breakdown of Classic political systems caused a migration of populations towards the coast, we have little evidence of the nature of land-use at coastal sites. Our understanding of subsistence on islands has been shaped by archaeological research indicating marine-based diets, with maize imported from the mainland. Here we provide, for the first time, palaeoecological proxy data that inform on ancient Maya land-use on an island site, located on Ambergris Caye, Belize. Using pollen and charcoal proxies, we present over 6000 years of environmental change and land-use history. Our reconstruction reveals evidence of cultivation, beginning at 2900 BCE and culminating during the Postclassic Period. We demonstrate that periods of higher land-use intensity correlate with climate instability, which corroborates archaeological evidence of migration to coastal locations. We hypothesize that the diverse marine and terrestrial environments of the island provided sustainable resources for the mainland Maya to use during times of both political and climatic stress.

Land Cover Changes on Ambergris Caye, Belize: A Case Study of Unregulated Tourism Development

Measuring land-use, land-cover change in biodiverse, tropical countries is critical for conservation management and sustainable planning because it provides quantifiable data regarding broad environmental changes. This project uses Landsat satellite imagery to document vegetation cover change on Ambergris Caye, Belize, from 2000 to 2017. The close proximity of the Belize Barrier Reef Reserve System has made Ambergris Caye the most popular tourist destination and economic hub in Belize. As a result, the region has undergone intense commercial and residential development coupled with rapid population growth over the past two decades. Understanding general trends in landscape dynamics is critical for the natural resource–based tourism industry of Belize to continue to thrive. Unsupervised classification methods and a per pixel postclassification comparison were used with Landsat imagery to estimate loss in vegetation cover and increases in urban and barren land. The results indicate a 10.85 percent decrease in vegetation and a 39 percent increase in urban and barren land during the seventeen-year study period with an annual forest loss rate of 0.67 percent per year using a compound interest rate formula. The results of this analysis represent a baseline study of vegetation change on Ambergris Caye to inform management and conservation efforts.

Age and intraspecific diversity of resilient Acropora communities in Belize

The corals Acropora palmata and A. cervicornis are important Caribbean reef-builders that have faced significant mortality in recent decades. While many studies have focused on the recent demise of these species, data from areas where Acropora spp. have continued to thrive are limited. Understanding the genetic diversity, recruitment, and temporal continuity of healthy populations of these threatened Acropora spp. and the hybrid they form (“Acropora prolifera”) may provide insights into the demographic processes governing them. We studied three reef sites with abundant A. cervicornis, A. palmata, and hybrid Acropora populations offshore of Ambergris Caye, Belize at Coral Gardens, Manatee Channel, and Rocky Point. Samples were collected from all three Acropora taxa. We used microsatellite markers to determine: (1) genotypic diversity; (2) dominant reproductive mode supporting local recruitment; (3) minimum and maximum genet age estimates for all three acroporids; and (4) the history of hybrid colonization at these sites. We found that Acropora populations were highly clonal with local recruitment primarily occurring through asexual fragmentation. We also estimated the ages of 10 Acropora genets using recent methodology based on somatic mutation rates from genetic data. Results indicate minimum ages of 62–409 yr for A. cervicornis, 187–561 yr for A. palmata, and 156–281 yr for the Acropora hybrids at these sites. Our data indicate that existing A. cervicornis, A. palmata, and Acropora hybrid genets persisted during the 1980s Caribbean-wide Acropora spp. collapse, suggesting that these sites have been a refuge for Caribbean Acropora corals. Additionally, our data suggest that formation of extant hybrid Acropora genets pre-dates the widespread collapse of the parent taxa.

Marco Gonzalez, Ambergris Caye, Belize: A geoarchaeological record of ground raising associated with surface soil formation and the presence of a Dark Earth

Marco Gonzalez, on the south-west end of the island of Ambergris Caye, Belize, has well-preserved Maya archaeological stratigraphy dating from Preclassic times (ca. 300 B.C.) to the Late Classic period (ca. A.D. 550/600 to 700/760). Although later occupations are recorded by house platforms and inhumations (Terminal Classic to Early Postclassic), and use of the site continued until the 16th century A.D., intact stratigraphy is rare in these cases owing to a greater degree of disturbance. Nonetheless, understanding site formation entails accounting for all processes, including disturbance. The site’s depositional sequence—as revealed through soil micromorphology and chemistry and detailed here—has yielded critical information in two spheres of research. As regards archaeology and the elucidation of Maya activities on the caye over time, soil micromorphology has contributed beyond measure to what we have been able to distinguish as material remains of cultural activity. Detailed descriptions of the nature of the material remains has in turn helped us to clarify or alter interpretations based on artefacts that have been identified or sediments characterised according to traditional recovery techniques. The other major sphere in which soil micromorphology and chemistry play a critical role is in assessment of the environmental impact of human activity, which enables us to construct and test hypotheses concerning how the site formed over time; what materials and elements contributed to the character of the sediments, especially in the formation of a specific Maya Dark Earth type that is developed from carbonate rich deposits; and how the modern surface soils acquired the appearance of a Dark Earth, but essentially differ from them. In terms of agricultural soil sustainability, the Marco Gonzalez surface soil is neo-formed by a woodland vegetation drawing upon the nutrients and constituents present in both the Dark Earth and underlying better preserved stratified deposits.

Quantifying exceptionally large populations of <I>Acropora</I> spp. corals off Belize using sub-meter satellite imagery classification

Caribbean coral reefs have experienced dramatic declines in live coral cover in recent decades. Primary branching framework Caribbean corals, Acropora cervicornis (Lamarck, 1816) and Acropora palmata (Lamarck, 1816), have suffered the greatest collapse. Coral Gardens, Belize, is one of few remaining, and perhaps the largest, refugia for abundant, healthy, but undocumented populations of both Acropora species in the Caribbean Sea. In the present study, GeoEye-1 multispectral satellite imagery of a 25 km2 reefal area near Ambergris Caye, Belize, was analyzed to identify live Acropora spp. cover. We used a supervised classification to predict occurrence of areas with live Acropora spp. and to separate them from other benthic cover types, such as sandy bottom, seagrass, and mixed massive coral species. We tested classification accuracy in the field, and new Acropora spp. patches were mapped using differential GPS. Of 11 predicted new areas of Acropora spp., eight were composed of healthy Acropora spp. An unsupervised classification of a red (Band 3):blue (Band 1) ratio calculation of the image successfully separated Acropora corals from other benthic cover, with an overall accuracy of 90%. Our study identified 7.58 ha of reef dominated by Acropora spp. at Coral Gardens, which is one of the largest populations in the Caribbean Sea. We suggest that Coral Gardens may be an important site for the study of modern Acropora spp. resilience. Our technique can be used as an efficient tool for genera-specific identification, monitoring, and conservation of populations of endangered Acropora spp.

Coastal Maya Obsidian Tool Use and Socio-Economy in the Late Postclassic-Early Spanish Colonial Period at San Pedro, Ambergris Caye, Belize

Microscopic use-wear analysis of the obsidian artifacts recovered from Late Postclassic-Early Spanish Colonial occupations at the site of San Pedro yields useful information for interpreting Maya socio-economic activities. Obsidian traded into the community was used for a variety of tasks with emphasis placed on subsistence and domestic manufacture associated with marine resources, including intermittent and contingent crafting. Trade in obsidian and marine resources likely provided San Pedro community members access to inland economic networks and enabled the acquisition of resources not found on the caye. Microwear on chert and obsidian tools indicates relative stability in the traditional lives of the San Pedro Maya in the 15th–17th centuries a.d. Although the San Pedranos likely suffered to some degree from coastal raiding and the introduction of epidemic diseases by the Spaniards, their off-shore location provided them some protection from the upheaval experienced by the Maya in mainland communities.

The Marco Gonzalez Maya site, Ambergris Caye, Belize: Assessing the impact of human activities by examining diachronic processes at the local scale

Abstract Research at the Maya archaeological site of Marco Gonzalez on Ambergris Caye in Belize is socio-ecological because human activities have been a factor in the formation and fluctuation of the local marine and terrestrial environments over time. The site is one of many on Belize's coast and cayes that exhibit anomalous vegetation and dark-coloured soils. These soils, although sought for cultivation, are not typical ‘Amazonian Dark Earths’ but instead are distinctive to the weathering of carbonate-rich anthropogenic deposits. We tentatively term these location-specific soils as Maya Dark Earths. Our research seeks to quantify the role of human activities in long-term environmental change and to develop strategies, specifically Life Cycle Assessment (LCA), that can be applied to environmental impact modelling today.

Diversity of Lifestyle: A View from Belize

Research on lifestyle migration continues to evolve as these movements become more geographically diverse. This form of movement has emerged as an important aspect of social and economic development in many so-called “less-developed countries.” As an increasing number of individuals from more-developed countries seek less-expensive and more-exotic locales to relocate, challenges are sure to follow. This research explores this growing phenomenon in three locations in Belize, a country that has been touted as one of the most desirable for these lifestyle migrants. The paper argues that these three destinations—Ambergris Caye, Caye Caulker, and Corozal—are attractive for different reasons and are at different phases of their evolution, and that the reaction of locals also varies by destination.

Coastal Maya Obsidian Trade in the Late Postclassic to Early Colonial Period: The View From San Pedro, Ambergris Caye, Belize

ABSTRACT Although substantial work has been done to reconstruct ancient Maya coastal trade from the Late Preclassic through the Early Postclassic periods (400 BC–AD 1200), relatively little is known about trade activity along the Caribbean Coast in Late Postclassic and Early Colonial times (ca. AD 1400 to 1700). By focusing on obsidian artifacts from the site of San Pedro on Ambergris Caye, Belize, one of the few coastal sites for which data are available for the Postclassic to Colonial transition, we attempt to understand how Maya procurement, production, and use of obsidian were organized, and the effect the arrival of the Spaniards had on access to obsidian. The Spanish presence in the Yucatan Peninsula clearly changed Maya life in numerous ways; however, the evidence from San Pedro suggests strongly—although it is not yet unequivocal—that Maya communities along the coast were still able to access obsidian, primarily from the Guatemalan highlands. With comparatively good access to obsidian for blade production, the site appears to have served as an important link in both long-distance and intraregional socioeconomic systems as a way station for moving goods up and down the Caribbean Coast and by funneling resources via a coastal-inland trade network.

An interdisciplinary approach to HIV/AIDS stigma and discrimination in Belize: the roles of geography and ethnicity

Belize experiences the highest rates of HIV/AIDS in Central America, ranging between 2.1 and 3.2% (World Health Organization 2008). To add to the limited literature on HIV/AIDS Stigma and Discrimination (HASD) in Belize, the authors conducted a study to assess whether stigma and discrimination is related to geography and ethnicity. One-hundred forty participants were interviewed using a structured survey instrument at three different parts of the country, and the results were analyzed quantitatively. These places were Cayo District on the western border with Guatemala, Belize City, and two cayes (Caye Caulker and Ambergris Caye). Respondents in Belize City generally held the lowest rates of stigmatizing and discriminatory attitudes towards individuals living with HIV/AIDS, highlighting a possible relationship between geography and ethnicity. Concurrently, self-identifying Afro-Belizeans and Creoles reported lower rates of HASD attitudes in some contexts than other ethnic groups. The results show that there may a relation between geography, ethnicity, and HASD, and that a randomized, controlled study is an important next step in determining the strength of that relation.

Late Pliocene to Holocene platform evolution in northern Belize, and comparison with coeval deposits in southern Belize and the Bahamas

AbstractLithostratigraphy, depositional facies architecture, and diagenesis of upper Pliocene to Holocene carbonates in northern Belize are evaluated based on a ca 290 m, continuous section of samples from a well drilled on Ambergris Caye that can be linked directly to outcrops of Pleistocene limestone, and of overlying Holocene sediments. Upper Pliocene outer‐ramp deposits are overlain unconformably by Pleistocene and Holocene reef‐rimmed platforms devoid of lowstand siliciclastics. Tectonism controlled the location of the oldest Pleistocene platform margin and coralgal barrier reef, and periodically affected deposition in the Holocene. A shallow, flat‐topped, mostly aggradational platform was maintained in the Holocene by alternating periods of highstand barrier‐reef growth and lowstand karstification, differential subsidence, and the low magnitude of accommodation space increases during highstands. Facies in Pleistocene rocks to the lee of the barrier reef include: (i) outer‐shelf coralgal sands with scattered coral patch reefs; (ii) a shoal–water transition zone comprising nearshore skeletal and oolitic sands amidst scattered islands and tidal flats; and (iii) micritic inner‐shelf deposits. Four glacio‐eustatically forced sequences are recognized in the Pleistocene section, and component subtidal cycles probably include forced cycles and autocycles. Excluding oolites, Holocene facies are similar to those in the Pleistocene and include mud‐mounds, foraminiferal sand shoals in the inner shelf, and within the interiors of Ambergris and surrounding cayes, mangrove swamps, shallow lagoons, and tidal and sea‐marginal flats. Meteoric diagenesis of Pliocene and Pleistocene rocks is indicated by variable degrees of mineralogic stabilization, generally depleted whole‐rock δ18O and δ13C values, and meniscus and whisker‐crystal cements. Differences in the mineralogy and geochemistry of the Pliocene and Pleistocene rocks are attributed to variable extent of meteoric alteration. Dolomitization in the Pliocene carbonates may have begun syndepositionally and continued into the marine shallow‐burial environment. Positive dolomite δ18O and δ13C values suggest precipitation from circulating, near‐normal marine fluids that probably were modified somewhat by methanogenesis. Sedimentologic and diagenetic attributes of the Pliocene–Pleistocene rocks in the study area are similar to those in the Bahamas with which they share a common history of sea‐level fluctuations and climate change.

Ancient Maya Procurement and Use of Chipped Chert and Chalcedony Tools at Marco Gonzalez, Ambergris Caye, Belize

Archaeological investigations at the site of Marco Gonzalez on Ambergris Caye, Belize have revealed a long continuous occupation sequence extendingfrom at least the Late Preclassic into the Late Postclassic periods. This location, so rich in many marine-based resources and well placed to serve as a trading seaport, was completely lacking in suitable lithic raw material for chipped stone tool manufacture. Consequently, the Marco Gonzalez Maya developed complex strategies for the curation ofthe limited chert and chalcedony tools importedfrom the mainland. The inhabitants ofthis site focused on maintaining reusing and recycling the formal stone tools to reduce the rate oflithic raw material consumption and extend tool use-lives. They relied on the informal component ofthe assemblage for the further completion oftasks on the caye. To reconstruct the specific patterns of stone tool procurement and use at Marco Gonzalez, the lithic assemblage was examined in terms of tool typology, raw material types, reduction strategies, and tool functions based on microwear analysis.

Coral mortality, recovery and reef degradation at Mexico Rocks Patch Reef Complex, Northern Belize, Central America: 1995–1997

The 1995 coral bleaching event in the western Caribbean was the first reported episode that significantly affected the Belize barrier and lagoonal patch reefs. Bleaching was attributed to a 2 mo period of warm water temperatures above 30°C. Near Ambergris Caye, barrier and patch reefs experienced up to 50% bleaching. At Mexico Rocks patch reef complex, the bleaching resulted in changes in reef health, community, and physical structure. Prior to the hyperthermal episode, patch reef surface area consisted of 47% healthy framework coral coverage, 12% secondarily colonized biotic coverage, 35% dead coral surfaces that were degraded by biological activity and physical erosion, and 6%cavities. six months after bleaching, most corals had regained their color, but, owing to coral mortality, areas of surface degradation had increased to an average 49% (p=0.029 based on Kruskal–Wallis analyses). Eighteen months after bleaching, degraded surface areas expanded to 53% (p=0.0366). Although re-coloring indicates rapid recovery for surviving corals, the persistence in dead coral surfaces suggests that reef skeletal structure recovery lags behind that of individual corals. Initial results of framework measurements indicate that bleaching events may result in an ‘imbalance’ in the carbonate production rate of coral reefs and produce mass wasting of the skeletal structure. Remapping of reef skeletal structure should establish quantitative measures for the long-term effects of bleaching on patch reef frameworks.

Maya Coastal Subsistence and Craft—Production at San Pedro, Ambergris Caye, Belize: The Lithic Use-Wear Evidence

Use-wear analysis of the chipped chert and chalcedony tools excavated from San Pedro, Ambergris Caye, Belize, has provided substantial insight into the activities performed by the Maya living at the site from the Classic through Historic periods. The determination of tool action and the materials that were worked by the ancient inhabitants reveals that most activities concentrated on basic subsistence in a coastal environment, with the possibility of small-scale craft-production for local consumption and some regional trade. There is only minor variation in activities undertaken by the San Pedro Maya throughout the lengthy occupation of this site based on the distribution of stone tools with use-related wear.

Seasonal occurrence of male Antillean manatees (<I>Trichechus manatus manatus</I>) on the Belize Barrier Reef

A fragment of manatee habitat that crosses the border of Belize and Mexico includes both activity centres and travel routes linking rivers, lagoons, seagrass beds and mangrove islands near Chetumal Bay. Little is known about how geophysical features like coral reefs may ine uence manatee movements within and between habitat fragments like this. In this inductive study (1995‐ 2001), we documented the seasonal occurrence of Antillean manatees at breaks in the northern Belize Barrier Reef. Survey locations were at: (1) Bacalar Chico National Park and Marine Reserve on Ambergris Caye (Basil Jones Cut) and (2) breaks in the reef 70 km south near the Drowned Cayes (Gallows Reef). The probability of sighting at least one manatee on a 20-min point scan survey was 40% (n=382). Sighting probability was signie cantly higher during the summer season (May‐ August) compared to winter months (December‐ March). Group size ranged from one to e ve manatees, peaking earlier (May) at the northern than southern site (August). Seventeen identie able individuals accounted for 87% of the sightings at Basil Jones Cut, with re-sightings within and between years. One individual from Basil Jones Cut was re-sighted at Gallows Reef. Of the manatees for which sex was determined, 100% were males. No calves were sighted. To better understand manatee activity centres and travel routes, we identie ed potential hypotheses relating seasonal ine uences, stopover sites for travelling males, and habitat connectivity. To protect this highly vulnerable species, we recommend inclusion of the Belize Barrier Reef as an important component of manatee habitat within the coastal zone of Belize.

ABSTRACT: Platform-Wide Dolomitization in Northern Belize: Modern Analog of Widespread, Early Platform Dolomitization

Holocene dolomite is ubiquitous in northern Belize, apparently more so than in any other area of the world. Average amount in peritidal and shallow-marine deposits is 70% (range 35- 100%) and 12% (range 1-65%), respectively, and it is present throughout such sediment sections. Dolomites are poorly ordered and calcic (39.5-47 mole% MgCO3). Peritidal dolomites occur in both cement and replacive modes; average crystal size is 1.5 microns. Marine dolomites occur dominantly as cement; average crystal size is 7 microns. Despite pronounced differences in pore- water salinities of dolomitic peritidal and marine sediments, mean dolomite del 18O values are identical -- 2.1 o/oo PDB with low standard deviation. These data are enigmatic in that they may suggest a limited salinity range of dolomite formation, or post-formative alteration in normal- salinity pore fluids. Depleted del 13C values of peritidal dolomites (-0.6 to -5.2 o/oo PDB) suggest precipitation facilitated only by sulfate reduction, whereas the range of values of marine dolomites (-5 to +12 o/oo PDB) suggest precipitation facilitated by both sulfate reduction and methanogenesis. Reasons for these differences remain unclear. Dolomite is found on most of the peritidal flats along the length (35 km) of Ambergris Caye, where it is present in Holocene sediments as much as 1 m thick. It is also present within individually extensive areas (20-50 km2) of organic-rich, shallow-marine mud bank and associated sediments (3-8.5 m thick) both on the outer and inner shelves. Accordingly, the Belize dolomite factory is a viable modern analog of widespread early dolomitization in some ancient platforms.

Limits to grazing by herbivorous fishes and the impact of low coral cover on macroalgal abundance on a coral reef in Belize

Widespread rises in the abundance of fleshy macroalgae on Caribbean reefs within the last 20 yr have variously been attributed to eutrophication, overfishing, or the 1983-4 mass mortality of the grazing sea urchin Diadema antillarum. However, none of those factors can satisfactorily explain why macroalgae are abundant today even on lightly fished mid-depth reefs in sparsely pop- ulated areas. Here we explore another explanation for rises in macroalgal cover on such reefs, namely that they are a side effect of declines in coral cover. We suggest that grazing by herbivorous fishes can exclude macroalgae from mid-depth reefs with high cover of hard corals, but that on low- cover reefs, the amount of space occupied by algae overwhelms the ability of grazing fishes to crop it down. We simulated the effect of 10% and 25% rises in coral cover by attaching 'pseudo-corals' (PVC tiles covered in a non-toxic anti-fouling coating) to reef substratum in 5 × 5 m plots (3 groups: control, 10%T and 25%T) on a 12 m deep forereef site in front of Ambergris Caye, Belize. Within 3 mo of attaching tiles, macroalgae had declined by approximately 10% in 10%T plots and 25% in 25%T plots compared with control plots, and these new states persisted for the duration of the experiment (macro-algae averaging 38.0% in control plots, 28.7% in 10%T plots, and 13.6% in 25%T plots). Dra- matic reductions in macroalgae may have made the 25%T plots more attractive to herbivorous fishes, as, in the later stages of the experiment, herbivorous fish biomass and acanthurid feeding rate were higher in those plots than in 10%T and control plots.

Abstract: Sedimentary Architecture and Diagenesis of Modern Carbonate Sands in a Low-Energy Shelf Lagoon, Northern Belize: Modern Analog to Some Ancient Hydrocarbon Reservoirs

A widespread sheet of modem carbonate sands and muddy sands, deposited unconformably on buried soil and karsted Pleistocene limestone, is present in the shallow, low-energy lagoon (Chetumal Bay) behind Ambergris Caye in northern Belize. Sediinent transport and deposition, and overall spatial distribution, are controlled mainly by windinduced currents in this protected environment. As such, these sediments are a modern analog of some ancient innershelf carbonate sands that compose hydrocarbon reservoirs in the Midcontinent. As indicated by 14C dates of buried mangrove peats, deposition was coincident with Holocene transgression in the study area, which began about 6,000 years ago. Surface and inferred buried bedforms include dunes and stacked ripple-fonns, ovenvash lobes, and spits generated as the sands migrate in a southwesterly direction in response to dominant easterly trade winds. Maximum thickness of the sand sheet is 4 inches, and there is control of antecedent bedrock topography and cryptic faulting on facies distribution and thickness variations. Internal facies architecture shallows and coarsens upward in response to decrease in rate of sea-level rise, and has resulted in vertical and lateral heterogeneity in sediment texture and porosity. interparticle pores in sands and muds; effective porosity increases upward in the section. Dolomite cement is present over a wide area in these wholly subtidal deposits, and has precipitated in pore fluids as a likely consequence of bacterial-sulfate reduction or methanogenesis. Partial dolomitization, and secondary pores, similarly are typical in analogous deposits in some upper Paleozoic hydrocarbon reservoirs. Primary porosity in these transgressive-systems-tract deposits includes intraparticle pores within skeletal grains and

Tourist typology observations from Belize

This examination of tourism on the island of Ambergris Caye, Belize, utilizes site investigations, questionnaires and in depth interviews in order to ascertain the various impacts on a rapidly growing Third World destination. It highlights the pitfall of treating tourists as a homogenous group in terms of their behaviour and consequent impact, and points to the utility of a disaggregated approach. The threefold typology arrived at in this paper has two major advantages. It enables a more detailed appreciation of the relationships between tourist consumption and the sociocultural, economic and physical fabric of the destination area, and thus should facilitate the formulation and implementation of more focused policies which consequently target specific issues.