Western Caribbean Research Articles

Nutritional composition of manatee’s diet in the Western Caribbean: from the river to the reef

The endangered Greater Caribbean manatee (Trichechus manatus manatus), one of the largest aquatic herbivores in the Caribbean, plays a crucial role in nutrient recycling within the ecosystem, and the study of its feeding ecology is important for its conservation. Despite several studies determining the items consumed by manatees, there remains limited understanding of their nutritional significance for the species in the Western Caribbean. This study, aimed to analyze the bromatological composition of the food components in the manatee’s diet in the Mexican Caribbean across three distinct environments. We manually collected aquatic and semi-aquatic primary producers potentially part of the manatee diet in marine, brackish and riverine areas of the southern region of Quintana Roo, Mexico. Then, we analyzed them for moisture, crude protein, crude fiber, ash, ether extract, digestible nutrients, and digestible energy. We present the initial data on nutrient values in the manatee diet in the Caribbean, establishing a foundation for exploring the factors that influence spatial, temporal, and species-specific variations in nutrient content at a regional level. Our bromatological analysis demonstrated that the most nutritionally important plants for manatees, based mainly on protein content and freshwater contribution, include the seagrasses Halodule wrightii, Syringodium filiforme, Thalassia testudinum, the water lily Pontederia crassipes, and Vallisneria sp. Effective habitat management for manatees is crucial for their survival, ensuring that feeding resources are maintained in both enough quantity and high quality. Given its nutritional significance for manatees, we recommend that seagrasses in the region should be prioritized as conservation targets.

The Influence of Caribbean Current Eddies on Coastal Circulation in the Southwest Caribbean Sea

Abstract Westward-propagating Caribbean Current eddies modify the volume-integrated potential vorticity (PV) balance in the western Caribbean Sea, influencing the circulation of the Panamá–Colombia Gyre (PCG) and coastal currents hundreds of kilometers to the south of the eddies’ mean trajectory. Using 22 years of output from the Hybrid Coordinate Ocean Model, we apply a volume-integrated eddy phase-averaged 1.5-layer PV balance, showing that PV fluxes into the PCG region are balanced by frictional PV dissipation represented by linear drag along the coastline. Coastal currents in the PCG region vary by a factor of 2 in phase with the passage of a Caribbean Current eddy over the 116-day average eddy period. Flow separation at the Isthmus of Panamá results in a vortex shed from the Darien Gulf, which slows the coastal currents in the gyre region from their maximum during eddy events. An annual ensemble average PV balance in the gyre region shows that the mean PV influx to this region is higher from August to October. Correspondingly, the range of coastal currents in the gyre region over an eddy event is modestly influenced by the PV influx magnitude. Eddy-influenced reversals in the coastal current can occur between November and July at Bocas del Toro and year-round at Colón. Such coastal current reversals are important for the alongshore transport of larvae, freshwater, and chemical tracers.

Biochemistry and associated fauna of holopelagic Sargassum spp. in the Caribbean Sea

Holopelagic Sargassum spp. (sargassum) are the founding species of diverse communities in the Sargasso Sea. Since 2011, a new area of concentration of these algae was formed in the equatorial North Atlantic and Caribbean Sea. We analyzed elemental composition, and the small mobile fauna associated with sargassum collected at 41 stations, during two expeditions in the Caribbean Sea in 2018 and 2019, that covered open-sea stations in two marine ecoregions, and coastal stations (< 20 km from the shore) in one of them. Metal(loid) concentrations generally followed the order As > Zn > Cu > Cd > Se > Pb > Hg, and contents of As (195.5 ± 13.7 µg g−1), Cd (0.59 ± 0.02 µg g−1), and Hg (0.22 ± 0.09 µg g−1) were highest in S. fluitans III in the South-Western-Caribbean ecoregion. Mean [Ctot] per ecoregion varied between 26.1 and 30.1 mg g−1, and variation was mainly accounted for by higher [Cinorg] (likely produced by calcifying epibionts) in the South-Western Caribbean (10.12) compared to the Western Caribbean (8.92 and 7.19); this tendency that was also found for [Ntot] (between 1.06 and 1.27), and these contents were positively correlated with seawater chlorophyll concentrations. Sixty-six taxa of mobile fauna were identified, with the phylum Arthropoda being most abundant and diverse. The faunal community composition was similar in both open-sea regions, but differed in the coastal stations, which was mostly explained by differential relative abundance of Latreutes fucorum, Carpias minutus, Litiopa melanostoma, and some fish species. The Caribbean open-sea rafts harbor a diverse fauna comparable to that found in the Sargasso Sea, and likely provide similar ecosystem services, and thus merit similar protective efforts as those directed towards sargassum in the Sargasso Sea.

Teleseismic measurements of Upper Mantle Shear-Wave Anisotropy in Southern Mexico

The Mexican subduction system is an ideal region to study 3-D mantle deformation patterns in response to changes in slab geometry and the presence of tears. Shear-wave splitting measurements were made using SKS, SKKS, and PKS waves in southern Mexico, where the Cocos slab subducts beneath the North American and western Caribbean plates. For most of southern Mexico, the results are consistent with predominantly trench-normal fast polarization directions that can be interpreted as a consequence of sub-slab entrained flow and 2-D corner flow in the mantle wedge in the presence of A-type olivine fabric (or similar). This pattern of trench-perpendicular fast axes extends northward to the region southeast of the Trans-Mexican Volcanic Belt. Beneath its eastern end, fast axes rotate ∼20° clockwise and are likely controlled by the absolute motion of the North American plate. In southeastern Mexico, along the coast and above the mantle wedge tip, the fast axes are trench-normal and the delay times are the shortest. They were interpreted to result from a possibly serpentinized mantle wedge tip. In the same region above the mantle wedge core, the splitting parameters appear to result from different flow patterns in the mantle wedge and the sub-slab mantle.

Tropical cyclone activity over the past 1200 years at the Pelican Cays, Belize

Tropical cyclone (TC) models indicate that continued planet warming will likely increase the global proportion of powerful TCs (specifically Categories 4 and 5 hurricanes), increasingly jeopardizing low-lying coastal communities and resources such as the Pelican Cays, Belize. The combination of increased coastal development and continued relative sea-level rise puts these communities at even higher risk of damage from TCs. The short TC observational record for the western Caribbean hampers the extensive study of TC activity on centennial timescales, which hinders our ability to fully understand past TC climatology and improve the accuracy of TC models. To better assess TC risk, paleotempestological studies are necessary to put future scenarios in perspective. Here, we present a high-resolution reconstruction of coarser-grained sediment deposits associated with TC (predominately ≥ Category 2 hurricanes) passages over the past 1200 years from Elbow and Lagoon Cays, two coral reef-bounded lagoons at the northern and southern end of the Pelican Cays; the most southern Belizean paleotempestological site to date. Coincident timing of historic storms with statistically significant coarser-grained deposits within cay lagoon sediment cores allows us to determine which historic TCs likely generated event layers (tempestites) archived in the sediment record. Our compilation frequency analysis indicates one active interval (above-normal TC activity) from 1740-1950 CE and one quiet interval (below-normal TC activity) from 850-1018 CE. The active and quiet intervals in the Pelican Cays composite record are anticorrelated with those from nearby and re-analyzed TC records to the north, including the Great Blue Hole (∼100 km north) and the Northeast Yucatan (∼380 km northwest). This site-specific anticorrelation in TC activity along the western Caribbean indicates that we cannot rely on any one single TC record to represent regional TC activity. However, we cannot discount that these anticorrelated periods between the western Caribbean sites are due to randomness. To confirm that the anticorrelation in TC activity among sites from the western Caribbean is indeed a function of climate change and not randomness, an integration of more records and TC model simulations over the past millennium is necessary to assess the significance of centennial-scale variability in TC activity recorded in reconstructions from the western Caribbean.

A baseline of natural radionuclides in water and sediment of a pristine coastal ecosystem: The Xcalak and Mahahual coral reef lagoons in the western Caribbean

In ecosystems, natural radionuclides are present in the environment and living organisms. The 238U natural decay chain produces multiple radioactive elements, such as 234U, 226Ra, 210Pb, and 210Po. These radionuclides can be found in air, water, rocks, soil, and other biotic and abiotic components, mainly derived from minerals, such as zircon and apatite. In this study, we determined the activity concentration of radionuclides from the 238U decay chain in the sediment of a coastal ecosystem on the southern Mexican coast in the western Caribbean, an ecosystem minimally affected by industrial activities. Methods included high-resolution gamma-ray spectrometry and alpha-particle spectrometry. Results showed that the sediment samples had an activity concentration range of 18.2–36.6 Bq/kg for 238U, 25.0–41.4 Bq/kg for 234U, 10.1–37.3 Bq/kg for 210Pb, and 29.9–46.0 Bq/kg for 210Po. Water samples ranged between 17.9 and 36.3 mBq/L and 27.9–66.0 mBq/L for 238U and 234U, respectively. The activity concentration of these radionuclides in the sediment and water of this area is compared with that of other coral reefs worldwide, providing a radiometric baseline for comparison purposes.

First record of the kitefin shark, Dalatias licha (Bonnaterre, 1788) from the Guatemalan Caribbean Sea

Deepwater fishing operations occur close to the shore of the Guatemalan Caribbean. In a study to characterize the deepwater species present in the fishing area, the incidental catch of a kitefin shark, Dalatias licha, was recorded at a depth of ~284-334 m, ca. 11 km northeast of El Quetzalito fishing village. The adult female with a total length of 1420 mm had morphological characteristics consistent with D. licha, which was confirmed by molecular methods. First record of D. licha in the western Caribbean region, a species cataloged at risk by the IUCN red list. With this record, the number of shark species known in the Guatemalan Caribbean increases to 25.

First record of the bluntnose sixgill shark Hexanchus griseus (Bonnaterre, 1788) in the Guatemalan Caribbean Sea

The Guatemalan Caribbean has a deepwater fishing area close to the shore around the Cayman Trench. This study reports the first record of the bluntnose sixgill shark (Hexanchus griseus) from this fishing area. Fishery-independent surveys using longlines at ~430-465 m depth, ~11 km northeast of El Quetzalito fishing village, were conducted in 2022 and 2023. Two bluntnose sixgill sharks were captured during these surveys. The sharks were females with total lengths of 300 and 310 cm, with morphological characteristics consistent with this species. These are the first confirmed records of bluntnose sixgill sharks in the western Caribbean Sea. Expanding coastal fisheries to deeper waters presents an emerging threat to deep-sea chondrichthyans in the region. Therefore, periodic fisheries monitoring is needed to estimate their vulnerability to fishing pressure.

Influence of Tropical Easterly Waves on the ChocoJet during the 2019 OTREC Campaign

Abstract This study investigates how convectively coupled tropical easterly waves (TEWs) affect the Choco low-level jet (ChocoJet) as they move across the western Caribbean. The ChocoJet is a low-level flow over the eastern Pacific (EPAC) that modulates precipitation patterns over the tropical eastern Pacific and northwestern South America. By combining data from the Organization of Tropical East Pacific Convection (OTREC; August–September 2019), ERA5 reanalysis products, and satellite data, we analyze precipitation and circulation patterns during convectively coupled and nonconvectively coupled TEWs, comparing them to non-TEW days. During convectively coupled TEWs days, the ChocoJet strengthens and becomes more southerly, while the ITCZ moves northward, leading to enhanced precipitation over the western Caribbean and drier conditions over the northern part of the Colombian Pacific. In contrast, nonconvectively coupled TEW days exhibit reduced precipitation and precipitable water over the Caribbean and far EPAC, with a layer of northeasterly flow centered at 850 hPa flowing over a shallower, weaker, and more westerly ChocoJet. Additionally, convectively coupled TEWs are associated with a weaker western Caribbean and far eastern Pacific pressure gradient compared to nonconvective TEWs. These observable and predictable synoptic-scale circulation–precipitation relationships contribute to a better understanding of hydrometeorological variability in the region. Significance Statement Tropical easterly waves and related convective organization traversing the Caribbean Sea are important sources of synoptic-scale precipitation–circulation variability in the far eastern Pacific and Colombian Pacific. This eastern tropical Pacific study aims to identify precipitation–circulation relationships that enhance the understanding of synoptic-scale meteorological phenomena.

A Ten-Year Record Shows Warming Inside the Belize Barrier Reef Lagoon

The Belize Barrier Reef system (BBR) in the western Caribbean’s Gulf of Honduras contains a large region of lagoon coral reef, seagrass and mangrove habitat. As the largest lagoon habitat within the Caribbean, this region experiences differing oceanographic and temperature conditions as compared to deeper offshore areas. The occurrence of several endemic species within the Gulf of Honduras area and inside the Belize lagoon supports the hypothesis that this area is a unique biogeographic region. Consequently, the ecological effects of temperature increase due to global climate change may have a long-term adverse impact on this region’s unique marine species. This study reports an in situ temperature record over a ten-year period (2004–2014) collected from a coral reef offshore of Wee Wee Cay within the South Water Cay Marine Reserve of Belize. There was a steady increase in temperature during the decade.

Microbial eukaryotic predation pressure and biomass at deep-sea hydrothermal vents.

Deep-sea hydrothermal vent geochemistry shapes the foundation of the microbial food web by fueling chemolithoautotrophic microbial activity. Microbial eukaryotes (or protists) play a critical role in hydrothermal vent food webs as consumers and hosts of symbiotic bacteria, and as a nutritional source to higher trophic levels. We measured microbial eukaryotic cell abundance and predation pressure in low-temperature diffuse hydrothermal fluids at the Von Damm and Piccard vent fields along the Mid-Cayman Rise in the Western Caribbean Sea. We present findings from experiments performed under in situ pressure that show cell abundances and grazing rates higher than those done at 1 atmosphere (shipboard ambient pressure); this trend was attributed to the impact of depressurization on cell integrity. A relationship between the protistan grazing rate, prey cell abundance, and temperature of end-member hydrothermal vent fluid was observed at both vent fields, regardless of experimental approach. Our results show substantial protistan biomass at hydrothermally fueled microbial food webs, and when coupled with improved grazing estimates, suggest an important contribution of grazers to the local carbon export and supply of nutrient resources to the deep ocean.

Extreme high stress temperatures in Fall 2023 generate mass coral reef bleaching in the western Caribbean, Seaflower Biosphere Reserve

Extreme high temperatures exceeding bleaching thresholds (DHW) occurred at San Andres Island, Seaflower Bosphere Reserve causing massive bleaching on coral reefs and reefs crests—key ecosystems for coastal protection, wellbeing, and economy of the island. We present aerial images comparing the same reef crest during 2022 (no bleaching) and 2023 (bleaching).

Foraminiferal Assemblages As Bioindicators In The Western Caribbean: Albuquerque Cay (Colombia)

Abstract The San Andrés Archipelago (Colombia) constitutes a biological hotspot for the Western Caribbean. However, expanding human populations and unrestrained exploitation of the natural resources jeopardize the sustainability of key ecosystems in most of the islands. We surveyed the benthic foraminiferal assemblages of Albuquerque Cay, a relatively isolated location in the archipelago, during an ecosystem monitoring expedition in 2018. Assemblages recorded from the lagoon and shoreface settings were characteristics of a typical Caribbean reef lagoon. Porcelaneous forms and genera that host algal symbionts, including Archaias, Amphistegina, Heterostegina, Laevipeneroplis, and Sorites, were common, as were smaller taxa, especially Quinqueloculina, Rotorbinella, and Cymbaloporetta were also found in variable proportions, while stress-tolerant and agglutinated taxa were scarce (Elphidium, Clavulina). Results suggest differences in the composition of the assemblages from both sandy cays and the reef lagoon settings, likely conditioned by hydrodynamic fluctuations and nutrient availability. Moreover, a preliminary survey of the FoRAM Index (FI) suggests moderate to good conditions for the environments of Albuquerque Cay, contrasting with estimations of the FI in other insular bodies of the area. Therefore, future studies in the archipelago could reinforce the great potential that foraminiferal assemblages have as bioindicators in this part of the Caribbean.

Marine turtles, umbrella species undergoing recovery

Marine turtles inhabit various coastal and marine ecosystems and play significant ecological roles throughout their life cycles. Because of the significant overlap with other species at risk in their geographic ranges, the successful conservation of marine turtles also protects numerous co-occurring species, a phenomenon known as the “umbrella species effect.” Since several marine turtle populations have shown positive trends, suggesting incipient recovery, it is expected that their umbrella characteristics will coevolve as their populations grow and expand. Recognizing the considerable potential of marine turtles as umbrella species, we advocate for promoting this concept and explicitly integrating it into management and recovery programs. This approach would facilitate concurrent benefits not only for marine turtles but also for other species and their associated habitats. To achieve this goal, we analyzed the conservation status of marine turtles in the Gulf of Mexico and Western Caribbean within the framework of the legal regulations. Additionally, we reviewed the current challenges in marine turtle recovery in the framework of ecological restoration, while also aiming to target and encourage their utilization as umbrella species.

Does depth divide? Variable genetic connectivity patterns among shallow and mesophotic Montastraea cavernosa coral populations across the Gulf of Mexico and western Caribbean.

Despite general declines in coral reef ecosystems in the tropical western Atlantic, some reefs, including mesophotic reefs (30-150 m), are hypothesized to function as coral refugia due to their relative isolation from anthropogenic stressors. Understanding the connectivity dynamics among these putative refugia and more degraded reefs is critical to develop effective management strategies that promote coral metapopulation persistence and recovery. This study presents a geographically broad assessment of shallow (<30 m) and mesophotic (>30 m) connectivity dynamics of the depth-generalist coral species Montastraea cavernosa. Over 750 coral genets were collected across the Northwest and Southern Gulf of Mexico, Florida, Cuba, and Belize, and ~5000 SNP loci were generated to quantify high-resolution genetic structure and connectivity among these populations. Generally, shallow and mesophotic populations demonstrated higher connectivity to distant populations within the same depth zone than to adjacent populations across depth zones. However, exceptions to this pattern include the Northwest Gulf of Mexico and the Florida Keys which exhibited relatively high vertical genetic connectivity. Furthermore, estimates of recent gene flow emphasize that mesophotic M. cavernosa populations are not significant sources for their local shallow counterparts, except for the Northwest Gulf of Mexico populations. Location-based differences in vertical connectivity are likely a result of diverse oceanographic and environmental conditions that may drive variation in gene flow and depth-dependent selection. These results highlight the need to evaluate connectivity dynamics and refugia potential of mesophotic coral species on a population-by-population basis and to identify stepping-stone populations that warrant incorporation in future international management approaches.

Miocene Fossils of Old Providence Island (Western Caribbean, Colombia) and Geological Heritage of the Seaflower Biosphere Reserve

Miocene Fossils of Old Providence Island (Western Caribbean, Colombia) and Geological Heritage of the Seaflower Biosphere Reserve

Diet variability of snappers (Teleostei: Lutjanidae) in a bay-to-reef ecosystem of the Mexican Caribbean

Fishes use environmental resources differently. Snapper ontogenic movements among coastal habitats lead to diverse diets. We investigated the diets of seven snapper species (Lutjanus apodus, L. analis, L. griseus, L. jocu, L. mahogoni, L. synagris, and Ocyurus chrysurus) in three interconnected coastal environments in the western Caribbean: Río Huach channel, Chetumal/Corozal bay, and the adjacent Xcalak reef lagoon. These three encompass all habitats used by the seven species in the study area. Snapper diets were mostly composed of fish and crustaceans, but dominance of either group varied among the studied habitats; for example, fish were the main prey for L. apodus from the reef lagoon zone, but second in the bay. Snappers are piscivorous-invertivorous mesopredators; the species that relied the most on fishes were L. griseus and L. jocu, whereas O. chrysurus preferred crustaceans. Stomach content results revealed a high degree of dietary overlap among species. Our findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas, supporting the hypothesis of niche segregation. Our results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.

Shipwrecks in the Western Caribbean: Archipelago of San Andres, Old Providence, and Santa Catalina: Between Narratives and Hurricanes

Shipwrecks in the Western Caribbean: Archipelago of San Andres, Old Providence, and Santa Catalina: Between Narratives and Hurricanes

Assessing environmental conditions associated with spatially varying rainfall structure of North Atlantic tropical cyclones: An object‐based climatological analysis

AbstractThis study utilizes geographic information system‐based shape analyses with spatial regressions to examine the spatial variations in the relationships between North Atlantic TC rain field patterns and the environmental conditions. We measure the area, solidity, dispersion and closure of rain fields associated with North Atlantic tropical cyclones (TCs) during 1998–2014 from satellite‐based rain rate estimates. The potential contributing factors examined include storm intensity, translational speed, sea surface temperature, total precipitable water, upper‐tropospheric divergence, deep‐layer vertical wind shear and distance to land. Spatial metrics of rainfall, TC attributes and environmental conditions are aggregated onto a hexagon grid, and the average values are used in regression models. Spatial autoregressive regression and geographically weighted regression are applied to investigate the relationships between contributing factors and rainfall patterns. Storm intensity is positively correlated with area, solidity and closure and negatively correlated with dispersion. Higher moisture and larger upper‐level divergence contribute to a larger rainfall field with a more dispersed and less solid pattern, especially over the western Gulf and the western Caribbean. Wind shear and storm motion affect rain field patterns differently depending on the juxtaposition and relative magnitude of storm motion and wind shear vectors and thus exhibit more regional variations. This research further highlights the importance of incorporating a spatial component into the research on TC rainfall climatology. An improved understanding of basin‐wide and sub‐basin‐wide relationships between TC rain fields and contributing factors would benefit rainfall forecasting and hazard mitigation.

Acropora CervicornisData Coordination Hub, an Open Access Database for Evaluating Genet Performance

Once one of the predominant reef-building corals in the region,Acropora cervicornisis now a focal species of coral restoration efforts in Florida and the western Caribbean. Scientists and restoration practitioners have been independently collecting phenotypic data on genets ofA. cervicornisgrown in restoration nurseries. While these data are important for understanding the intraspecific response to varying environmental conditions, and thus the potential genetic contribution to phenotypic variation, in isolation these observations are of limited use for large-scale, multi- institution restoration efforts that are becoming increasingly necessary. Here, we present theAcropora cervicornisData Coordination Hub, a web-accessible relational database to align disparate datasets to compare genet-specific performance. In this data descriptor, we release data for 248 genets evaluated across 38 separate traits. We present a framework to align datasets with the ultimate goal of facilitating informed, data-driven restoration throughout the Caribbean.