Sensitivity of Calcification to Thermal Stress Varies among Genera of Massive Reef-Building Corals

Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously affecting ecosystem function in Atlantic reefs

Avoiding Coral Reef Functional Collapse Requires Local and Global Action

oral reefs face multiple anthropogenic threats, from pollution and overfishing to the dual effects of greenhouse gas emissions: rising sea temperature and ocean acidification [1]. While the abundance of coral has declined in recent decades [2, 3], the implications for humanity are difficult to quantify because they depend on ecosystem function rather than the corals themselves. Most reef functions and ecosystem services are founded on the ability of reefs to maintain their three-dimensional structure through net carbonate accumulation [4]. Coral growth only constitutes part of a reef's carbonate budget; bioerosion processes are influential in determining the balance between net structural growth and disintegration [5, 6]. Here, we combine ecological models with carbonate budgets and drive the dynamics of Caribbean reefs with the latest generation of climate models. Budget reconstructions using documented ecological perturbations drive shallow (6-10 m) Caribbean forereefs toward an increasingly fragile carbonate balance. We then projected carbonate budgets toward 2080 and contrasted the benefits of local conservation and global action on climate change. Local management of fisheries (specifically, no-take marine reserves) and the watershed can delay reef loss by at least a decade under "business-as-usual" rises in greenhouse gas emissions. However, local action must be combined with a low-carbon economy to prevent degradation of reef structures and associated ecosystem services

New and Previous Records of Scleractinian Corals from Clipperton Atoll, Eastern Pacific

Clipperton Atoll was visited from 23 to 25 November 1997. A total of 109 specimens of stony corals belonging to two orders, seven families, and 15 species was collected. Five taxa of Scleractinia represent new records for the atoll: Porites lutea, Porites australiensis, Psammocora superficialis, Astrangia sp., and Balanophylliasp. With these new records and species previously reported in the literature, the total number of scleractinians now known at Clipperton Atoll is 18 species. Observations on the fossil terraces on the island and on the dead coral fauna of the inner lagoon are presented

Simulation and observations of annual density banding in skeletons of \u3ci\u3eMontastraea\u3c/i\u3e (Cnidaria: Scleractinia) growing under thermal stress associated with ocean warming

We present a model of annual density banding in skeletons of Montastraea coral species growing under thermal stress associated with an ocean-warming scenario. The model predicts that at sea-surface temperatures (SSTs) Montastraea species is a clear indication of thermal stress. When all monthly SSTs exceed the optimal calcification temperature, HDBs form during the coldest, not the warmest, months of the year. In addition, a decline in mean-annual calcification rate also occurs during this period of elevated SST. A comparison of our model results with annual density patterns observed in skeletons of M. faveolata and M. franksi, collected from several localities in the Mexican Caribbean, indicates that elevated SSTs are already resulting in the presence of dHDBs as a first sign of thermal stress, which occurs even without coral bleaching

Lista revisada y clave para los corales pétreos zooxantelados (Hydrozoa: Milleporina; Anthozoa: Scleractinia) del Atlántico mexicano

Se presenta una lista anotada y revisada de cincuenta y siete especies de corales pétreos (tres mileporinos y cincuenta y cuatro escleractinios) del litoral oriental mexicano. En este informe se incluyen sinonimias y una clave simplificada para las especies de la lista. En aquellos casos en que los diferentes autores no se ponen de acuerdo en la posición taxonómica y/o la identificación de las especies se hacen observaciones morfológicas y taxonómicas, así como cuando existe información taxonómica pertinente, o cuando los datos de distribución son relevantes para algunas especies en el Atlántico mexicano. También, se presenta un análisis cualitativo sobre la abundancia y distribución geográfica de las especies, y datos sobre su ámbito batimétrico. Existe una reducción en el número de géneros y especies del Caribe mexicano hacia el Golfo de México y, dentro de este, del Banco de Campeche hacia Veracruz. Aún más, el número de especies abundantes es menor en el Golfo de México que en el Caribe mexicano y las especies comunes en todas las zonas arrecifales presentan un ámbito batimétrico más amplio en el Caribe mexicano.<br>A revised and annotated checklist of fifty-seven zooxanthellate stony coral species (three milleporids and fifty-four scleractinian) is presented for the Mexican East Coast. This report includes synonyms and a simplified key to species on the list. Morphological and taxonomic observations are included when authors disagree in the taxonomic position and/or identification of the species, as well as when taxonomic information is pertinent, or when distribution data are relevant for some species in the Mexican Atlantic. A qualitative analysis of species abundance and geographic distribution, and bathymetric range data are presented. There is a reduction in the genera and species numbers from the Mexican Caribbean to the Gulf of Mexico and there, from the Campeche Bank to Veracruz. Furthermore, the number of abundant species is lower in the Gulf of Mexico than in the Mexican Caribbean, and the common species for all reef zones have a wider bathymetric range in the Mexican Caribbean

Tasas retrospectivas de crecimiento del coral hermatípico Montastrea annularis (Scleractinia: Faviidae) en arrecifes al sur del Golfo de México

Coionies of Montastrea annularis were collected from 10 m deptb at Triángulo Oeste; Alacrán, Cayo Arcas, Cayo Arenas, Isla Verde and Anegada de Adentro coral reefs, in tbe soutb of the Gulf of Mexico. Growth rates were determined retrospectively, using tbe conventional radiographic technique (sclerochronology). Contact prints witb good defmition of tbe growth bands were obtained from 53 colonies. The general averages per year showed tbe lowest growth rate for 1972 (0.72 cm/yr) and the highest for 1991 (1.02 cm/yr), witb an average of 0.86 cm/yr for the 53 colonies. Thls·growth rate is similar to those reported for tbe same speeies and depth in otber Atlantic sites.En los arrecifes de Triángulo Oeste, Alacrán, Cayo Arcas, Cayo Arenas, Isla Verde y Anegada de Adentro, localizados al sur del Golfo de México, se recolectaron colonias del coral hermatípico Montastrea annularis a 10 m de profundidad. A cada colonia recolectada se le determinaron las tasas de crecimiento de manera retrospectiva, utilizando la técnica radiográfica convencional (esclerocronología). De 53 colonias se obtuvieron contactos fotográficos que mostraron buena deftnición de las bandas de crecimiento. Los promedios generales por año mostraron la tasa de crecimiento más baja para 1972 (0.72 cm/año) Y la más alta para 1991 (1.02 cm/año), con un promedio de 0.86 cm/año para las 53 colonias. Esta tasa de crecimiento es similar a las registradas en la misma especie a la misma profundidad para otras localidades del Atlántico

Biological responses of the coral Montastraea annularis to the removal of filamentous turf algae.

Coral reef degradation increases coral interactions with filamentous turf algae (FTA) and macroalgae, which may result in chronic stress for the corals. We evaluated the effects of short (2.5 month) and long (10 month) periods of FTA removal on tissue thickness (TT), zooxanthellae density (ZD), mitotic index (MI), and concentration of chlorophyll a (Chl a) in Montastraea annularis at the beginning and end of gametogenesis. Ramets (individual lobes within a colony) consistently surrounded by FTA and ramets surrounded by crustose coralline algae (CCA) were used as controls. FTA removal reduced coral stress, indicated by increased TT and ZD and lower MI. The measured effects were similar in magnitude for the short and long periods of algal removal. Ramets were more stressed at the end of gametogenesis compared with the beginning, with lower ZD and Chl a cm(-2), and higher MI. However, it was not possible to distinguish the stress caused by the presence of FTA from that caused by seasonal changes in seawater temperature. Ramets surrounded by CCA showed less stress in comparison with ramets surrounded by FTA: with higher TT, Chl a cm(-2) and ZD, and lower MI values. Coral responses indicated that ramets with FTA suffered the most deleterious effects and contrasted with those measured in ramets surrounded by CCA. According to published studies and our observations, there could be at least six mechanisms associated to FTA in the stress caused to M. annularis by FTA. Owing to the high cover of FTA (in contrast to macroalgae and CCA) in the Caribbean, the chronic stress, the overgrowth and mortality that this functional algal group can cause on M. annularis species complex, a further decline of this important reef-building coral in the Caribbean is expected

Calcification and growth rate recovery of the reef-building Pocillopora species in the northeast tropical Pacific following an ENSO disturbance

Pocilloporids are one of the major reef-building corals in the eastern tropical Pacific (ETP) and also the most affected by thermal stress events, mainly those associated with El Niño/Southern Oscillation (ENSO) periods. To date, coral growth parameters have been poorly reported in Pocillopora species in the northeastern region of the tropical Pacific. Monthly and annual growth rates of the three most abundant morphospecies (P. cf. verrucosa, P. cf. capitata, and P. cf. damicornis) were evaluated during two annual periods at a site on the Pacific coast of Mexico. The first annual period, 2010–2011 was considered a strong ENSO/La Niña period with cool sea surface temperatures, then followed by a non-ENSO period in 2012–2013. The linear extension rate, skeletal density, and calcification rate averaged (±SD) were 2.31 ± 0.11 cm yr−1, 1.65 ± 0.18 g cm−3, 5.03 ± 0.84 g cm−2 yr-1 respectively, during the strong ENSO event. In contrast, the respective non-ENSO values were 3.50 ± 0.64 cm yr−1, 1.70 ± 0.18 g cm−3, and 6.02 ± 1.36 g cm−2 yr−1. This corresponds to 52% and 20% faster linear extension and calcification rates, respectively, during non-ENSO period. The evidence suggests that Pocillopora branching species responded positively with faster growth rates following thermal anomalies, which allow them to maintain coral communities in the region