RESUMO

The Mexican Caribbean is a vital nesting destination for loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles. Since 2015, massive periodical landings of pelagic Sargassum species (sargasso) have affected coastal ecosystems. Dense accumulations of sargasso on the shoreline may preclude access to sea turtles' preferred nesting areas and compromise hatching. In this study, we assess whether the number of nests and hatches of loggerhead and green sea turtles has been affected by the massive influx of sargasso. We compare data from before (2010-2014) and after (2015-2019) the first sargasso event, obtained from the same 17 marine turtle camps, which collectively account for 72.3 km of sampling distance over a 210 km section of shoreline. No differences in preferences on nesting beaches were recorded between periods for the two species. The mean number of nests per kilometer of coastline remained without statistically significant changes between periods in 16 camps and increased significantly in one camp for each species. Overall, the mean annual number of nests per kilometer of beach was 37% higher in the period after massive landings of sargasso began. The mean number of hatchlings increased significantly in one camp for C. mydas and in three for C. caretta. Periodical massive landings of sargasso from 2015 to 2019 do not appear to have compromised nesting and hatching of loggerhead and green sea turtles along the Mexican Caribbean coast.

Assuntos

RESUMO

Reef corals in the Mexican Reef System have been severely affected by the emergence of a white syndrome that resembles both White Plague II and SCTLD descriptions. Meandroid scleractinian coral species are among the most severely affected. To gain insight into this affliction we conducted a broad study in the brain coral Pseudodiploria strigosa at a rear reef site in the NE Mexican Caribbean. We describe macro and microscopical signals of the disease, characterize the outbreak dynamics, the tissue histopathology, explore immunological responses in the individuals, and compare microbial assemblages associated with the surface mucus layer of healthy and unhealthy colonies. At the study site, the white syndrome outbreak on P. strigosa showed a high incidence rate in summer-fall and a low one in winter, as well as low survival expectation of diseased colonies at the end of the study. After 306 days of observation, out of 96 tracked colonies, eight remained apparently healthy and seven were diseased. No effective resistance to colony disease progression was observed once white syndrome signs developed. Tissue loss rate during the study varied among colonies (mean = 10.8 cm2, s.d. = 7.8 cm2) suggesting a complex relation between causal agents and colony resistance. The deterioration of tissues was evidenced from the basal to the surface body wall of polyps (up to 66% hypertrophy and liquefactive necrosis in unhealthy colonies), implying that microscopic alterations begin before macroscopic signals develop, suggesting this may be a systemic disease. We measured high levels of phenoloxidase (two orders of magnitude higher PO activity than P. strigosa affected by BBD) and antibacterial activity without significant reduction in unhealthy samples from the mucus layer, indicative of an enhanced immunological response. Results showed that opportunistic bacteria dominated damaged colonies, where six genera of the Bacteroidia class were found with significant changes in unhealthy colonies after DeSeq2 analysis. Nevertheless, histological observations did not support infection of the tissues. The opportunistic overload seems to be contained within the mucus layer but may be associated with the mortality of tissues in a yet unclear way. Future research should focus on experimental infections, the tracking of natural infections, and the immunocompetence of corals in the face of environmental pressures due to local, regional, and global impacts. If environmental deterioration is the primary cause of the continuing emergence and re-emergence of lethal coral diseases, as has been proposed by many authors, the only true option to effectively help preserve the coral reef biodiversity and services, is to restore the environmental quality of reef waters at the local scale and reduce greenhouse gases at the global scale.

RESUMO

Ecological processes on coral reefs commonly have limited spatial and temporal scales and may not be recorded in their long-term geological history. The widespread degradation of Caribbean coral reefs over the last 40 years therefore provides an opportunity to assess the impact of more significant ecological changes on the geological and geomorphic structure of reefs. Here, we document the changing ecology of communities in a coral reef seascape within the context of its geomorphic zonation. By comparing basic ecological indices between historical and modern data we show that in 35 years the reef-front zone was transformed from a complex coral assemblage with a three-dimensional structure, to a size-homogenized and flattened one that is quasi indistinguishable from the adjacent non-accretional coral-ground zone. Today coral assemblages at Punta Maroma are characterized by the dominance of opportunistic species which are either tolerant to adverse environmental conditions, including sedimentation, or are known to be the first scleractinian species to recruit on disturbed reefs, implying they reflect a post-hurricane stage of adjustment. Despite an increase in similarity in ecological indices, the reef-front and coral-ground geomorphic zones still retain significant differences in coral assemblages and benthic habitat and are not homogeneous. The partial convergence of coral assemblages certainly has important consequences for the ecology and geological viability of the reef and its role in coastal protection, but environmental physical drivers continue to exert a fundamental role in the character and zonation of benthic communities of this reef seascape.

RESUMO

The CARICOMP site at Puerto Morelos, Mexico was monitored from 1993 to 2005. No significant changes in air temperature, wind patterns, periodicity and quantity of rainfall, sea-surface temperature and water transparency were observed between sampling years. During the study four hurricane impacts were registered. At the coral reef site overall mean cover of fleshy algae (47%) and turf algae (36%) were high, whereas cover of corals (2%) and sponges (3%), and abundance of sea-urchins (0.04 org m-2) were consistently low. Gorgonians were dominant and showed changes in their community structure; the number of species increased from 1993 to 1995, their abundance decreased after Hurricane Roxanne (1995) and recovered by 2001. At four seagrass sites total community biomass remained constant (707.1-929.6 g dry m-2) but the above-ground biomass of the seagrass Syringodium filiforme and fleshy algae increased gradually. Total biomass (531-699 g dry m-2) and leaf productivity (0.89-1.56 g dry m-2 d-1) of the seagrass Thalassia testudinum remained constant, but the species invested proportionally more biomass in above-ground leaf tissues at the end of the study. The minor hurricanes from 1993 until 2005 had no detectable impacts on the seagrass beds, however, the major Hurricane Wilma (October 2005) changed the community composition at three stations and caused complete burial of the vegetation at a coastal station. The gradual changes in the seagrass and reef communities recorded in the 12 years of continuous monitoring of the CARICOMP site may reflect the increased pollution caused by the rapid augment in urban and tourist developments along the coasts and inland from Puerto Morelos, coupled with poor water management practices. Rev. Biol. Trop. 58 (Suppl. 3): 23-43. Epub 2010 October 01.

El sitio CARICOMP en Puerto Morelos, México, se monitoreo de 1993 a 2005. No se registraron cambios significativos en la temperatura del aire, los patrones de viento, la periodicidad y cantidad de lluvia, la temperatura superficial del mar y la transparencia del agua entre los años de muestreo. Durante el estudio se registraron cuatro huracanes menores. En el sitio del arrecife coralino la cobertura global promedio de algas carnosas (47%) y de algas tipo tapete (36%) fue elevada, mientras que la cobertura de corales (2%), esponjas (3%) y la abundancia de erizos (0.04 m-2) fue consistentemente baja. Los gorgonáceos fueron dominantes y mostraron cambios en su estructura comunitaria; el número de especies aumentó de 1993 a 1995, su abundancia disminuyó después del Huracán Roxanne (1995) y se recuperó en el 2001. En cuatro estaciones de pastos marinos la biomasa total de la comunidad permaneció constante (707.1-929.6 gps m-2) pero la biomasa sobre el sustrato del pasto Syringodium filiforme y de algas carnosas aumentó gradualmente. La biomasa total (531-699 gps m-2) y productividad de hojas (0.89-1.56 gps m-2 d-1) del pasto Thalassia testudinum permaneció constante, pero la especie invirtió proporcionalmente más biomasa en el tejido de hojas sobre el sustrato al final del estudio. Los huracanes menores entre 1993 y 2005 no produjeron impactos detectables en las camas de pastos, sin embargo, el huracán mayor Wilma (Octubre 2005) cambió la composición de la comunidad en tres estaciones y causó el enterramiento completo de la vegetación en la estación costera. El cambio gradual en las comunidades de pastos marinos y arrecife registrado en 12 años de monitoreo continuo en el sitio CARICOMP puede reflejar un aumento en la contaminación causada por el rápido incremento en desarrollo urbano y turístico a lo largo de la costa y tierra adentro de Puerto Morelos, acompañado por malas prácticas de manejo del agua.

Assuntos

RESUMO

The CARICOMP site at Puerto Morelos, Mexico was monitored from 1993 to 2005. No significant changes in air temperature, wind patterns, periodicity and quantity of rainfall, sea-surface temperature and water transparency were observed between sampling years. During the study four hurricane impacts were registered. At the coral reef site overall mean cover of fleshy algae (47%) and turf algae (36%) were high, whereas cover of corals (2%) and sponges (3%), and abundance of sea-urchins (0.04 org m(-2)) were consistently low. Gorgonians were dominant and showed changes in their community structure; the number of species increased from 1993 to 1995, their abundance decreased after Hurricane Roxanne (1995) and recovered by 2001. At four seagrass sites total community biomass remained constant (707.1-929.6 g dry m(-2)) but the above-ground biomass of the seagrass Syringodium filiforme and fleshy algae increased gradually. Total biomass (531-699 g dry m(-2)) and leaf productivity (0.89-1.56 g dry m(-2) d(-1)) of the seagrass Thalassia testudinum remained constant, but the species invested proportionally more biomass in above-ground leaf tissues at the end of the study. The minor hurricanes from 1993 until 2005 had no detectable impacts on the seagrass beds, however, the major Hurricane Wilma (October 2005) changed the community composition at three stations and caused complete burial of the vegetation at a coastal station. The gradual changes in the seagrass and reef communities recorded in the 12 years of continuous monitoring of the CARICOMP site may reflect the increased pollution caused by the rapid augment in urban and tourist developments along the coasts and inland from Puerto Morelos, coupled with poor water management practices.

Assuntos

RESUMO

We documented the prevalence of diseases, syndromes and partial mortality in colonies of the Montastraea annularis species complex on 3 reefs, and tested the assumption that a higher prevalence of these parameters occurs when reefs are closer to point-sources of pollution. One reef was isolated from the impact of local factors with the exception of fishing, 1 potentially influenced by local industrial pollutants, and 1 influenced by local urban pollution. Two reefs were surveyed in 1996 and again in 2001 and 1 in 1998 and again in 2001. In 2001, colonies on all reefs had a high prevalence of the yellow-band syndrome and a relatively high degree of recent partial mortality, while the prevalence of black-band and white-plague diseases was low although a new sign, that we named the thin dark line, had relatively high prevalence in all reefs. As no direct relationship was found between disease prevalence and local environmental quality, our results open the possibility that regional and/or global factors may already be playing an important role in the prevalence of coral disease in the Caribbean, and contradict the theory that coral disease prevalence is primarily related to local environmental degradation. Reasons that may partially explain these findings are the high level of potential pathogen connectivity within the Caribbean as a result of its circulation patterns coupled to the large land-derived pollutants and pathogens input into this Mediterranean sea, together with the surface water warming effects which stress corals and enhance pathogen activity.

Assuntos