Phylogenetic relationships of Pseudo-nitzschia subpacifica (Bacillariophyceae) from the Mexican Pacific, and its production of domoic acid in culture.

Pseudo-nitzschia is a cosmopolitan genus, some species of which can produce domoic acid (DA), a neurotoxin responsible for the Amnesic Shellfish Poisoning (ASP). In this study, we identified P. subpacifica for the first time in Todos Santos Bay and Manzanillo Bay, in the Mexican Pacific using SEM and molecular methods. Isolates from Todos Santos Bay were cultivated under conditions of phosphate sufficiency and deficiency at 16°C and 22°C to evaluate the production of DA. This toxin was detected in the particulate (DAp) and dissolved (DAd) fractions of the cultures during the exponential and stationary phases of growth of the cultures. The highest DA concentration was detected during the exponential phase grown in cells maintained in P-deficient medium at 16°C (1.14 ± 0.08 ng mL-1 DAd and 4.71 ± 1.11 × 10-5 ng cell-1 of DAp). In P-sufficient cultures DA was higher in cells maintained at 16°C (0.25 ± 0.05 ng mL-1 DAd and 9.41 ± 1.23 × 10-7 ng cell-1 of DAp) than in cells cultured at 22°C. Therefore, we confirm that P. subpacifica can produce DA, especially under P-limited conditions that could be associated with extraordinary oceanographic events such as the 2013-2016 "Blob" in the northeastern Pacific Ocean. This event altered local oceanographic conditions and possibly generated the presence of potential harmful species in areas with economic importance on the Mexican Pacific coast.

Effect of organophosphorus pesticides in juveniles of Litopenaeus vannamei: alteration of glycogen, triglycerides, and proteins.

The presence of pesticides has recently been reported in shrimp farms adjacent to agricultural areas on the east coast of the Gulf of California. This study assessed the possible effect of organophosphorus pesticides in the coastal environment of Sinaloa, México, using the white shrimp Litopenaeus vannamei as a bioindicator since their presence, abundance or behavior indicate some process or state of the system in which they live. Sublethal bioassays were performed on shrimps in intermolt state using commercial brands of organophosphorus pesticides, chlorpyrifos (0.0015 mg l-1), diazinon (0.0120 mg l-1), methamidophos (1.207 mg l-1), azinphos-methyl (0.0101 mg l-1), and methyl parathion (0.0075 mg l-1) were tested. Results showed reductions in glycogen, triglycerides, and total protein concentrations in shrimp muscle, except for the diazinon treatments, in which an increase in triglyceride level was detected. The observed alterations in the three cellular components were probably due to the metabolic compensation mechanism of the shrimp in reaction to the stress produced by organophosphorus pesticides, which act as endocrine disruptors. The establishment of continuous environmental monitoring programs of the coastal zone of Northwestern Mexico is strongly recommended.

Seasonal variability of copepod community structure and abundance modified by the El Niño-La Niña transition (2010), Pacific, Mexico / Variabilidad estacional de la estructura comunitaria y abundancia de copépodos, modificada por la transición El Niño-La Niña (2010) en el Pacífico, México

Abstract Copepods are an important planktonic group, and account for most of the total biomass and species diversity in pelagic marine ecosystems. Seasonal variability of the community structure of copepods in the Eastern tropical Pacific off central Mexico was studied during three distinct hydrodynamic periods in 2010 using statistical and multivariate analyses. The survey period included the second half of the 2009-2010 El Niño (January), the neutral transition period (May-June), and the first half of the 2010-2011 La Niña (October). Seventy-eight copepod species were identified; richness ranged from 11 to 47 species per station, with seasonal averages from 25 species in May to 35 species in January. Cluster analysis indicated that there were four principal groups present across the surveyed periods, defined by January (El Niño), October (La Niña), May offshore stations, and May upwelling stations (cyclonic eddy and coastal stations). There were no significant differences in abundance, but the January (El Niño) cluster was most diverse with 32 species, May offshore and October (La Niña) clusters each had 25 species, and the May upwelling was the least diverse cluster with 18 species. Mesoscale processes were strongest during May, which was the only period with a significant inshore-offshore gradient of species richness and diversity. Canonical correspondence analysis (CCA) revealed that variability was primarily driven by subsurface (75-200 m) ammonium, and surface (0-50 m) temperature, nitrates+nitrites, salinity and phosphorus. Copepodites and adults of the primarily herbivorous Eucalanidae dominated the stations of the upwelling cluster, while copepodites and adults of the carnivorous Euchaetidae dominated the January (El Niño) station cluster. The higher Chl a levels during the less productive (reduced upwelling) El Niño period were probably due to reduced grazing activities and increased ammonium availability through increased zooplankton metabolism. The horizontal distribution of copepods in the Eastern Tropical Pacific off Mexico appears to be principally defined by mesoscale eddy processes (offshore) and upwelling (coastal). These mesoscale processes were affected by El Niño - La Niña transitions, which subsequently disrupted the inshore-offshore gradient and in the case of El Niño likely caused reductions in copepod abundance across the entire region which persisted for the entire study period, and possibly longer.(AU)

Resumen Los copépodos son un importante grupo planctónico y representan la mayor parte de la biomasa total y la diversidad de especies en los ecosistemas marinos pelágicos. La variabilidad estacional de la estructura de la comunidad de copépodos se analizó en el Pacífico central mexicano durante tres períodos hidrodinámicos durante el 2010, mediante análisis estadísticos y multivariados. El período de estudio incluyó la segunda mitad del Niño 2009-2010 (enero), el período de transicional (mayo) y la primera mitad del La Niña 2010-2011 (octubre). Setenta y ocho especies de copépodos fueron identificadas; la riqueza varió de 11 a 47 especies por estación, con promedios estacionales de 25 especies en mayo a 35 especies en enero. El análisis de clúster indicó la presencia de cuatro grupos principales en los períodos estudiados: enero (El Niño), octubre (La Niña), un grupo de estaciones oceánicas en mayo, y un grupo de estaciones de afloramientos en mayo (remolino ciclónico y estaciones costeras). No hubo diferencias significativas en la abundancia entre grupos, pero el grupo de enero (El Niño) fue más diverso con 32 especies. Los grupos de mayo (oceánico) y octubre (La Niña) tenían 25 especies cada uno, y el grupo de mayo (afloramientos) fue el menos diverso con 18 especies. Los procesos de mesoescala fueron más intensos durante mayo, que fue el único período con un gradiente significativo costeroocéano de riqueza de especies y diversidad. El análisis de correspondencias canónicas explicó que la variabilidad se debe principalmente a la concentración de amonio en la capa profunda (75-200), y la temperatura, nitratos + nitritos, salinidad y fósforo presente en la capa superficial (0-50 m) de la columna de agua. Los copepoditos y adultos herbívoros de la familia Eucalanidae, dominaron las estaciones de surgencia, mientras que los copepoditos y adultos carnívoros de Euchaetidae dominaron las estaciones de enero (El Niño). Las concentraciones más altas de Clorofila a durante El Niño, que fue el periodo menos productivo (surgencia reducida), se deben probablemente a la reducción de actividades de pastoreo. La distribución horizontal de copépodos en el Pacífico central mexicano parece estar definida principalmente por la influencia de remolinos de mesoescala (mar adentro) y surgencias (costera). Estos procesos oceanográficos fueron afectados por la transición de El Niño a La Niña, que posteriormente interrumpieron el gradiente costero-oceánico y en el caso de El Niño probablemente causó una disminución en la abundancia de copépodos en toda la región durante todo el período de estudio, que posiblemente persistió en los meses posteriores.(AU)

Effects of terrestrial runoff on the coral communities in Santiago Bay, Colima, Mexican Pacific Coast

Abstract:Coral reef ecosystems are under stress of different origins, from factors including sedimentation, fragmentation, overfishing, and tourism, depending on their geographical location, depth, and proximity to recreation areas. In this study of Juluapan Lagoon, we examined the relationship between various water-quality attributes and the status indicators of the coral community at La Boquita reef. During 2011 (12 months of sampling), six monitoring stations in the Juluapan lagoon were established in order to observe the gradient of the distribution of the physicochemical parameters: three stations on the upper part, or BI, (S4 to S6) and three more in the lower part, or BII, (S1 to S3). A control station (CS) was located in the coral reef close to the lagoon channel, and where dissolved inorganic nutrients and cellular carbon content were determined. Additionally, we considered the monitoring of three of the eight largest coral structures/headlands of this community: the first was the station closest to the channel communicating with Juluapan lagoon (C1), the second was in the intermediate region with respect to that lagoon (C2), and the third was farthest from the channel (C3). Three line intercept transects (LIT) 30 m in length and perpendicular to the coast provenance were established in each station, and the parameters indicative of the status of corals were evaluated in an area of 60 m2 on each transect (180 m2 by the station). Turbidity, evidence of fishing, signs of settling, algal coverage, abundance of fish, rate of sediment, and coral health records (as for CoralWach chart) were determined in situ and from digital photographs and videos. Considering various community status indicators used in the reef area, we could recognize a state of general deterioration, which was reflected in the loss of 17% of coral coverage. The main anthropogenic disturbances in adjacent areas to La Boquita reef included wastewater discharges into the lagoon, tourist developments in the coastal zone, deforestation and erosion resulting from inappropriate development, and the runoff of nutrients from agricultural lands nearby the lagoon. All these significantly contributed to the nutrient-enriched waters of the lagoon, especially in summer, with negative effects on the coral community. Continued exposure to these factors, coupled with the lack of control over other anthropogenic components, has promoted the maintenance of a chronic stress state in the studied coral community. Our findings highlight the need for the development of appropriate coastal management and conservation policies for the coral reefs of the Mexican Pacific Coast. Rev. Biol. Trop. 64 (3): 1185-1200. Epub 2016 September 01.

ResumenDependiendo de la ubicación geográfica, la profundidad, y la proximidad a zonas de recreo, algunos arrecifes de coral están bajo estrés por factores que incluyen la sedimentación, la fragmentación, la sobrepesca y el turismo. En la presente investigación, se estudian los diferentes atributos de calidad de agua de la Laguna Juluapan e indicadores del estatus de la comunidad coralina La Boquita. Durante 2011 (12 meses de muestreo), seis estaciones de monitoreo fueron establecidas dentro de la laguna de Juluapan, a fin de observar el gradiente de distribución de los parámetros fisicoquímicos: tres estaciones en la parte interna ó B1, (S4 a S6), y tres en la parte más externa, ó B2 (S1 a S3); una estación control (CS) fue ubicada en la zona coralina cercana a la comunicación con la Laguna de Juluapan, fueron determinados nutrientes inorgánicos disueltos y contenido de carbono celular. Adicionalmente se realizó el monitoreo de tres de los ocho cabezales coralinos que conforman esta comunidad. El primero de ellos fue localizado en la cercanía de la intercomunicación con la Laguna Juluapan (C1), el segundo en la región intermedia respecto a la proximidad de dicho cuerpo lagunar (C2), y el tercero totalmente alejado respeto a la intercomunicación (C3). En cada estación fueron colocadas, tres líneas de transectos de intersección (LIT) de 30 m de longitud de forma perpendicular al perfil de la costa, a partir de ello, fueron evaluados diversos parámetros de la condición coralina, cubriendo un área de 60 m2 en cada transecto (180 m2 por estación). En cada área de transecto fue evaluada la turbidez, evidencias de daños por pesca, daños por sedimentación, cobertura de algas, abundancia de peces, tasa de sedimentación, además de obtenerse registros de la salud coralina usando como indicador la tarjeta CoralWatch in situ, a partir de tomas fotográficas y videos. Considerando los diferentes indicadores del estatus de la comunidad coralina estudiada, nosotros pudimos reconocer un estado general de deterioro, reflejado en la pérdida del 17% de la cobertura de coral. Las principales alteraciones antropogénicas en las zonas adyacentes al arrecife La Boquita corresponde a descargas de aguas residuales en la laguna, desarrollos turísticos en la zona costera, la deforestación y efecto erosivo asociado al desarrollo urbano inadecuado, así como el escurrimiento de nutrientes de tierras agrícolas alrededor de la laguna. Estos factores contribuyen de manera significativa al enriquecimiento de nutrientes a la laguna, sobre todo en verano, con efectos negativos sobre la comunidad de coral. La exposición continua a estos factores, junto con la falta de control sobre otros componentes antropogénicos, promueve la existencia de un estado de estrés crónico en la comunidad coralina estudiada. Nuestros resultados destacan la necesidad de implementar políticas apropiadas de conservación para los arrecifes coralinos de la costa del Pacífico mexicano.

The inhibitory effect of a non-yessotoxin-producing dinoflagellate, Lingulodinium polyedrum (Stein) Dodge, towards Vibrio vulnificus and Staphylococcus aureus

ResumenEl aumento de la resistencia bacteriana a los antibióticos ha causado preocupación a nivel mundial, por lo que se ha promovido la búsqueda de nuevos compuestos. Debido a su abundancia y diversidad, el fitoplancton marino constituye una importante fuente potencial de tales compuestos. La investigación sobre dinoflagelados ha llevado al descubrimiento de inhibidores de crecimiento bacteriano. El dinoflagelado marino Lingulodinium polyedrum causa proliferaciones algales en diferentes regiones del mundo, incluyendo México, y también se sabe que regula el crecimiento de otras especies en las aguas costeras. En este trabajo, se investiga la taxonomía de este dinoflagelado y se caracteriza la capacidad de sus extractos para inhibir el crecimiento de dos bacterias de importancia médica (Vibrio vulnificus y Staphylococcus aureus) en placas de cultivo de agar. La caracterización taxonómica se realizó por PCR y amplificación del gen de ITS, y se confirmó que la especie aislada en la costa del Pacífico de México fue L. polyedrum. Para demostrar el efecto inhibidor de los extractos de L. polyedrum, los cultivos se cosecharon por centrifugación. Los pellets de tres abundancias celulares se extrajeron con agua, metanol, hexano y cloroformo. Los experimentos en V. vulnificus mostraron una inhibición alta del crecimiento para los cuatro extractos, variando entre 77 y 98 %. Sorprendentemente, la inhibición del crecimiento fue menor cuando los extractos se originaron a partir de una mayor abundancia de células L. polyedrum, varía de 0 a 34 %. Para S. aureus, la inhibición del crecimiento también fue alta, pero no estadísticamente diferente para todos los extractos y abundancias de células, con un rango de 62 hasta 99 %. Esto resultados son prometedores para futuras aplicaciones farmacológicas. La cepa mexicana de L. polyedrum no produjo yesotoxinas detectables.

AbstractThe increased bacterial resistance to antibiotics has caused global concern, prompting the search for new compounds. Because of their abundance and diversity, marine phytoplankton are an important potential source of such compounds. Research on dinoflagellates has led to the discovery of inhibitors of bacterial growth. The marine dinoflagellate Lingulodinium polyedrum blooms in different regions of the world, including Mexico, and is also known to regulate the growth of other species in coastal waters. Here, we investigated the taxonomy of this dinoflagellate and characterized the ability of its extracts to inhibit the growth of two bacteria of medical importance (Vibrio vulnificus and Staphylococcus aureus). Taxonomic characterization was performed by PCR and gene amplification of ITS, and confirmed that the species isolated off the Pacific coast of Mexico was L. polyedrum. To prove the inhibitory effect of L. polyedrum extracts, cultures were harvested by centrifugation. Pellets from three cellular abundances were extracted with water, methanol, hexane and chloroform. The experiments on V. vulnificus showed a high growth inhibition for the four extracts, ranging from 77 to 98 %. Surprisingly, the growth inhibition was lower when the extracts originated from a higher L. polyedrum cell abundance, ranging from 0 to 34 %. For S. aureus, the growth inhibition was also high, but not statistically different for all extracts and cell abundances, ranging from 62 to 99 %. This study obtained promising results for future pharmacological applications. Our Mexican strain of L. polyedrum did not produce any detectable yessotoxins. Rev. Biol. Trop. 64 (2): 805-816. Epub 2016 June 01.

The inhibitory effect of a non-yessotoxin-producing dinoflagellate, Lingulodinium polyedrum (Stein) Dodge, towards Vibrio vulnificus and Staphylococcus aureus.

The increased bacterial resistance to antibiotics has caused global concern, prompting the search for new compounds. Because of their abundance and diversity, marine phytoplankton are an important potential source of such compounds. Research on dinoflagellates has led to the discovery of inhibitors of bacterial growth. The marine dinoflagellate Lingulodinium polyedrum blooms in different regions of the world, including Mexico, and is also known to regulate the growth of other species in coastal waters. Here, we investigated the taxonomy of this dinoflagellate and characterized the ability of its extracts to inhibit the growth of two bacteria of medical importance (Vibrio vulnificus and Staphylococcus aureus). Taxonomic characterization was performed by PCR and gene amplification of ITS, and confirmed that the species isolated off the Pacific coast of Mexico was L. polyedrum. To prove the inhibitory effect of L. polyedrum extracts, cultures were harvested by centrifugation. Pellets from three cellular abundances were extracted with water, methanol, hexane and chloroform. The experiments on V. vulnificus showed a high growth inhibition for the four extracts, ranging from 77 to 98 %. Surprisingly, the growth inhibition was lower when the extracts originated from a higher L. polyedrum cell abundance, ranging from 0 to 34 %. For S. aureus, the growth inhibition was also high, but not statistically different for all extracts and cell abundances, ranging from 62 to 99 %. This study obtained promising results for future pharmacological applications. Our Mexican strain of L. polyedrum did not produce any detectable yessotoxins.

Effects of terrestrial runoff on the coral communities in Santiago Bay, Colima, Mexican Pacific Coast.

Coral reef ecosystems are under stress of different origins, from factors including sedimentation, fragmentation, overfishing, and tourism, depending on their geographical location, depth, and proximity to recreation areas. In this study of Juluapan Lagoon, we examined the relationship between various water-quality attributes and the status indicators of the coral community at La Boquita reef. During 2011 (12 months of sampling), six monitoring stations in the Juluapan lagoon were established in order to observe the gradient of the distribution of the physicochemical parameters: three stations on the upper part, or BI, (S4 to S6) and three more in the lower part, or BII, (S1 to S3). A control station (CS) was located in the coral reef close to the lagoon channel, and where dissolved inorganic nutrients and cellular carbon content were determined. Additionally, we considered the monitoring of three of the eight largest coral structures/headlands of this community: the first was the station closest to the channel communicating with Juluapan lagoon (C1), the second was in the intermediate region with respect to that lagoon (C2), and the third was farthest from the channel (C3). Three line intercept transects (LIT) 30 m in length and perpendicular to the coast provenance were established in each station, and the parameters indicative of the status of corals were evaluated in an area of 60 m2 on each transect (180 m2 by the station). Turbidity, evidence of fishing, signs of settling, algal coverage, abundance of fish, rate of sediment, and coral health records (as for CoralWach chart) were determined in situ and from digital photographs and videos. Considering various community status indicators used in the reef area, we could recognize a state of general deterioration, which was reflected in the loss of 17 % of coral coverage. The main anthropogenic disturbances in adjacent areas to La Boquita reef included wastewater discharges into the lagoon, tourist developments in the coastal zone, deforestation and erosion resulting from inappropriate development, and the runoff of nutrients from agricultural lands nearby the lagoon. All these significantly contributed to the nutrient-enriched waters of the lagoon, especially in summer, with negative effects on the coral community. Continued exposure to these factors, coupled with the lack of control over other anthropogenic components, has promoted the maintenance of a chronic stress state in the studied coral community. Our findings highlight the need for the development of appropriate coastal management and conservation policies for the coral reefs of the Mexican Pacific Coast.

Lead in shrimp Litopenaeus vannamei Boone in sublethal concentrations.

Determination of the accumulation and elimination of sublethal lead (Pb) in different shrimp tissues may be useful as an indicator of uptake and elimination characteristics of this metal. Aquaculture ponds are particularly influenced by Pb contamination, where aquatic animals may acquire the metal through adsorption to exoskeletons or gills from the surrounding water. Cationic Pb is accumulated preferentially in the nonedible fraction of shrimp, followed by exoskeleton, and to a minor extent in muscle. Lead contents in different tissues were lower than metal levels in exoskeleton. However, the presence of Pb in sediment due to purging may exert adverse consequences on shrimp as bottom feeders.

Bloom of Gymnodinium catenatum in Bahía Santiago and Bahía Manzanillo, Colima, Mexico.

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88 microM DIN, 0.78 microM PO4 and 24.34 microM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x 10(7) cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8 microg STXeq/100g), and in phytoplankton (10.9 pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico.

Bloom of Gymnodinium catenatum in Bahía Santiago and Bahía Manzanillo, Colima, Mexico

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x10(7)cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8μg STXeq/100g), and in phytoplankton (10.9pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico.

La proliferación de Gymnodinium son motivo de preocupación, debido a que en algunas circunstancias producen toxinas, que tienen consecuencias desfavorables para los ecosistemas marinos, la salud humana y la economía. Este trabajo describe las condiciones fisicoquímicas presentes durante una proliferación algal detectado en mayo de 2010 en la Bahía de Santiago y Bahía Manzanillo (Colima, México). La proliferación algal inició poco tiempo después de registrarse las temperaturas oceánicas superficiales más bajas del año, las cuales permitieron un aumento de las concentraciones de nutrientes (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) que favorecieron el desarrollo de G. catenatum (hasta 1.02 x10(7)cel/L). Esta proliferación se detectó en las bahías durante dos semanas y fue relacionada con toxicidad en ostiones de la localidad (1525.8μg STXeq/100g) y en muestras de fitoplancton (10.9pg STXeq/cel). Fuertes variaciones en la toxicidad de G. catenatum (1.4 a 10.9pg STXeq/cel) pudieron reflejar la disponibilidad de nutrientes inorgánicos. El perfil de toxinas de las muestras del fitoplancton consistieron en 11 toxinas semejantes a las de varias cepas de G. catenatum aisladas de otras áreas de las costas de México.

Response to short term ultraviolet stress in the reef-building coral Pocillopora capitata (Anthozoa: Scleractinia).

Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata Verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32 h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required.

Response to short term ultraviolet stress in the reef-building coral Pocillopora capitata (Anthozoa: Scleractinia)

Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata Verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required. Rev. Biol. Trop. 58 (1): 103-118. Epub 2010 March 01.

Los arrecifes de coral se ven afectados por una serie de variables ambientales que afectan su crecimiento y supervivencia, siendo los principales factores la alta irradiación y las fluctuaciones de temperatura. Los especímenes de Pocillopora capitata Verrill 1864 fueron expuestos a radiación activa fotosintéticamente (PAR) y radiación ultravioleta (RUV) por 32h en condiciones de laboratorio. Nosotros determinamos las concentraciones de peroxidación lipídica (MDA), actividades de enzimas antioxidantes (SOD, CAT, GPx y GST), clorofila a (Chl a), pigmentos carotenoides (CPS), aminoácidos tipo micosporina (MAAS), y la expulsión de las zooxantelas. Nuestros resultados muestran que los corales expuestos a los rayos UV presentaban niveles relativamente bajos de carotenoides y actividad de las enzimas antioxidantes en comparación con los expuestos al PAR, así como tasas de CPs/Chl a bajas. Aunque MAAs y CPs se producen rápidamente como antioxidantes no enzimáticos en respuesta a la radiación ultravioleta en los corales, éstos no fueron suficientes, incluso en la fase oscura del experimento, para mitigar los daños causados por la formación de especies reactivas de oxígeno (ROS), lo que provocó una ruptura en la relación simbiótica entre las zooxantelas y el coral con una relación 33 veces mayor que en el tratamiento de PAR. A nivel enzimático, P capitata presentó una serie de ajustes orientados a resistir los efectos derivados de la propagación de ROS y con ello favorecer su adaptación y capacidad reproductiva en ambientes oceánicos caracterizados por altos niveles de UVR.