210Pb-derived sediment accumulation rates across the Wider Caribbean Region.

The Wider Caribbean Region is an important tourist destination where agricultural, industrial and shipping activities are also carried on. Coastal zones are heavily populated and receive a high human pressure; however, few monitoring programmes allow assessing long-term anthropogenic impact trends in these areas, which are especially useful for integrated management programs. Through the support of the International Atomic Energy Agency (project RLA/7/012), sediment core activities of 210Pb and 137Cs were used to evaluate changes in sedimentation rates in 11 relevant coastal areas of the region, where environmental information is scarce, but needed to support national environmental policies. Most 210Pb activity profiles were atypical, attributed to non-steady sedimentation conditions; whereas 137Cs activity profiles, showing very low values, were of little help for 210Pb-dating corroboration. Results evidenced conspicuous changes in mass accumulation rates (MAR), specially through the Anthropocene (i.e. since ~1950s) in most cases, attributed to deforestation and land erosion (one of the clearest indicators of global change), and the input of urban and industrial untreated wastes. The recent MAR decrease in Havana Bay (Cuba) was attributed to the implementation of environmental policies, which showed that 210Pb-derived reconstruction of environmental changes is also useful to verify the effectiveness of management programs to control land-derived erosion and siltation issues. Since siltation can be detrimental to valuable coastal resources around the world, retrospective evaluations of sedimentation rates, based on 210Pb-dated cores, are highly recommended to assist integrated coastal zone management programs in the region and elsewhere.

Ciguatoxin Occurrence in Food-Web Components of a Cuban Coral Reef Ecosystem: Risk-Assessment Implications.

In Cuba, ciguatera poisoning associated with fish consumption is the most commonly occurring non-bacterial seafood-borne illness. Risk management through fish market regulation has existed in Cuba for decades and consists of bans on selected species above a certain weight; however, the actual occurrence of ciguatoxins (CTXs) in seafood has never been verified. From this food safety risk management perspective, a study site locally known to be at risk for ciguatera was selected. Analysis of the epiphytic dinoflagellate community identified the microalga Gambierdiscus. Gambierdiscus species included six of the seven species known to be present in Cuba (G. caribaeus, G. belizeanus, G. carpenteri, G. carolinianus, G. silvae, and F. ruetzleri). CTX-like activity in invertebrates, herbivorous and carnivorous fishes were analyzed with a radioligand receptor-binding assay and, for selected samples, with the N2A cell cytotoxicity assay. CTX activity was found in 80% of the organisms sampled, with toxin values ranging from 2 to 8 ng CTX3C equivalents g-1 tissue. Data analysis further confirmed CTXs trophic magnification. This study constitutes the first finding of CTX-like activity in marine organisms in Cuba and in herbivorous fish in the Caribbean. Elucidating the structure-activity relationship and toxicology of CTX from the Caribbean is needed before conclusions may be drawn about risk exposure in Cuba and the wider Caribbean.

Morphology, toxicity and molecular characterization of Gambierdiscus spp. towards risk assessment of ciguatera in south central Cuba.

Ciguatera poisoning is caused by the consumption of reef fish or shellfish that have accumulated ciguatoxins, neurotoxins produced by benthic dinoflagellates of the genera Gambierdiscus or Fukuyoa. Although ciguatera constitutes the primary cause of seafood intoxication in Cuba, very little information is available on the occurrence of ciguatoxins in the marine food web and the causative benthic dinoflagellate species. This study conducted on the south-central coast of Cuba reports the occurrence of Gambierdiscus and Fukuyoa genera and the associated benthic genera Ostreopsis and Prorocentrum. Gambierdiscus/Fukuyoa cells were present at low to moderate abundances depending on the site and month of sampling. This genus was notably higher on Dictyotaceae than on other macrophytes. PCR analysis of field-collected samples revealed the presence of six different Gambierdiscus and one Fukuyoa species, including G. caribaeus, G. carolinianus, G. carpenteri, G. belizeanus, F. ruetzleri, G. silvae, and Gambierdiscus sp. ribotype 2. Only Gambierdiscus excentricus was absent from the eight Gambierdiscus/Fukuyoa species known in the wider Caribbean region. Eleven clonal cultures were established and confirmed by PCR and SEM as being either G. carolinianus or G. caribaeus. Toxin production in each isolate was assessed by a radioligand receptor binding assay and found to be below the assay quantification limit. These novel findings augment the knowledge of the ciguatoxin-source dinoflagellates that are present in Cuba, however further studies are needed to better understand the correlation between their abundance, species-specific toxin production in the environment, and the risk for fish contamination, in order to develop better informed ciguatera risk management strategies.

Radiocronología de sedimentos marinos y su aplicación en la comprensión de los procesos de contaminación ambiental en ecosistemas marinos cubanos / Radiochronology of marine sediments and its application to the knowledge of the process of environmental pollution in coastal Cuban ecosystems

En este trabajo se sistematizan algunos resultados alcanzados en la aplicación de la radiocronología de sedimentos marinos para la reconstrucción de bases de datos y el conocimiento de la evolución de la contaminación ambiental en cuatro ecosistemas costeros de relevancia nacional: las bahías de Cienfuegos y la Habana, así como los estuarios de los ríos Sagua y La Coloma en el Golfo de Batabanó. Se seleccionaron flujos de metales pesados y compuestos orgánicos persistentes que fueron discutidos para estos ecosistemas. Se mostró la eficacia de la radiocronología como herramienta para la gestión ambiental y el conocimiento de los procesos temporales de contaminación en el medio acuático

The results achieved in the implementation of the radiochronology of marine sediments for the reconstruction of databases and knowledge of the evolution of environmental pollution in four coastal ecosystems of national significance are presented in this paper Fluxes of selected heavy metals and persistent organic compounds are discussed for the Cienfuegos and Havana bays and Sagua and La Coloma estuaries. Finally, is showed the effectiveness of radiochronology of sediments as a useful tool for environmental management and knowledge of temporal processes of pollution in the aquatic environment

Mercury contamination of riverine sediments in the vicinity of a mercury cell chlor-alkali plant in Sagua River, Cuba.

Sediment is a great indicator for assessing coastal mercury contamination. The objective of this study was to assess the magnitude of mercury pollution in the sediments of the Sagua River, Cuba, where a mercury-cell chlor-alkali plant has operated since the beginning of the 1980s. Surface sediments and a sediment core were collected in the Sagua River and analyzed for mercury using an Advanced Mercury Analyser (LECO AMA-254). Total mercury concentrations ranged from 0.165 to 97 µg g(-1) dry weight surface sediments. Enrichment Factor (EF), Index of Geoaccumulation (Igeo) and Sediment Quality Guidelines were applied to calculate the degrees of sediment contamination. The EF showed the significant role of anthropogenic mercury inputs in sediments of the Sagua River. The result also determined that in all stations downstream from the chlor-alkali plant effluents, the mercury concentrations in the sediments were higher than the Probable Effect Levels value, indicating a high potential for adverse biological effects. The Igeo index indicated that the sediments in the Sagua River are evaluated as heavily polluted to extremely contaminated and should be remediated as a hazardous material. This study could provide the latest benchmark of mercury pollution and prove beneficial to future pollution studies in relation to monitoring works in sediments from tropical rivers and estuaries.

Two-year temporal response of benthic macrofauna and sediments to hypoxia in a tropical semi-enclosed bay (Cienfuegos, Cuba) / Respuesta temporal durante dos años de la macrofauna bentónica y sedimentos a la hipoxia en una bahía semi-cerrada tropical (Cienfuegos, Cuba)

AbstractHypoxia is the depletion of dissolved oxygen below 2 mg O2/L. Relatively few studies on hypoxia and its effects on benthic macrofauna have been done in tropical marine ecosystems. This study describes the temporal response of the water column, sediments and macrofauna to seasonal hypoxia in a semi-enclosed bay (Cienfuegos, Caribbean Sea). The Calisito site was sampled monthly from June 2010 until February 2012, yielding 21 sampling times. At each sampling event water and sediment samples were collected for measuring the abiotic variables (temperature, salinity, dissolved oxygen, nutrients, redox potential discontinuity, silt/clay and organic matter content) and macrofauna (abundance and species richness). Temperature and surface salinity followed a typical temporal pattern during the summer/rainy and the winter/dry periods. Salinity stratification occurred in the rainy period, lasting three months in 2010 and six months in 2011. The bottom water dissolved oxygen indicated hypoxic and anoxic events during the wet periods of 2010 and 2011 associated with salinity stratification, low hydrodynamics and oxidation of the accumulated organic matter. Over the study period, 817 individuals were collected and identified. Polychaetes were the dominant group in terms of abundance (57 % of total) followed by mollusks (41%). Hypoxia (and occasionally anoxia) caused strong deleterious effects on the abundance and species richness of macrofaunal communities in the study site. The most abundant polychaetes were opportunistic species with high tolerance to hypoxic conditions: Prionospio steenstrupi, Polydora sp.and Paraprionospio pinnata. Most of them colonized relatively fast once hypoxia ended. Persistent species such as Caecum pulchellum and Parvanachis obesa were present during hypoxia with fluctuating densities and apparently recover to higher abundances when normoxic conditions are re-established. Macoma tenta and Tellina consobrina colonized approximately 1-2 months later than the first polychaete peak during normoxia. Probably, the deleterious effects of hypoxia on the macrofauna were intensified by negative interspecific relationships such as competition by suitable space and predation. The recolonization of macrofauna depended possibly on local transport by currents within the bay because the connection with the Caribbean Sea is relatively limited. In summary, seasonal hypoxia in Cienfuegos Bay influences the water and sediment geochemistry and reduces both the abundance and diversity of macrofauna.

ResumenLa hipoxia es la disminución del oxígeno disuelto por debajo de 2 mg O2/L. Relativamente pocos estudios sobre la hipoxia y sus efectos en la macrofauna bentónica han sido realizados en ecosistemas marinos tropicales. Este estudio describe la respuesta temporal de la columna de agua, los sedimentos y la macrofauna a la hipoxia estacional en una bahía semicerrada en Cienfuegos, Mar Caribe. La estación de Calisito fue muestreada mensualmente de Junio 2010 a Febrero 2012, resultando en 21 eventos de muestreo. En cada oportunidad se recolectaron muestras de agua y sedimento para la medición de las variables abióticas (temperatura, salinidad, oxígeno disuelto, discontinuidad del potencial redox, contenido de limo/arcilla y materia orgánica) y macrofauna (abundancia y riqueza de especies). La temperatura y la salinidad superficial presentaron un patrón temporal típico durante los periodos de verano/ lluvia e invierno/seca. Ocurrió estratificación por salinidad en el periodo lluvioso, que duró tres meses en 2010 y seis en 2011. El oxígeno disuelto de fondo indicó eventos de hipoxia y anoxia durante los periodos lluviosos de 2010 y 2011 asociados con la estratificación de la columna de agua, la hidrodinámica lenta y la oxidación de la materia orgánica acumulada. Esto causó efectos deletéreos en la abundancia y diversidad de la macrofauna. Los poliquetos más abundantes fueron especies oportunistas con alta tolerancia a condiciones hipóxicas: Prionospio steenstrupi, Polydora sp. y Paraprionospio pinnata. La mayoría de estos colonizaron relativamente rápido una vez que terminó la hipoxia. Especies persistentes como Caecum pulchellum y Parvanachis obesa estuvieron presentes durante la hipoxia con densidades fluctuantes y aparentemente recuperaron sus abundancias cuando las condiciones normóxicas fueron re-establecidas. Macoma tenta y Tellina consobrina colonizaron 1-2 meses después que el primer pico de poliquetos durante la normoxia.Probablemente, los efectos deletéreos de la hipoxia en la macrofauna fueron intensificados por relaciones interespecíficas negativas como la competencia por espacio y la depredación. La recolonización de la macrofauna dependió probablemente del transporte local por las corrientes dentro de la bahía pues la conexión con el mar Caribe es relativamente limitada. En resumen, la hipoxia estacional en la bahía de Cienfuegos influencia la geoquímica del agua y los sedimentos y reduce la abundancia y diversidad de la macrofauna.

Two-year temporal response of benthic macrofauna and sediments to hypoxia in a tropical semi-enclosed bay (Cienfuegos, Cuba).

Hypoxia is the depletion of dissolved oxygen below 2 mg O(2)/L. Relatively few studies on hypoxia and its effects on benthic macrofauna have been done in tropical marine ecosystems. This study describes the temporal response of the water column, sediments and macrofauna to seasonal hypoxia in a semi-enclosed bay (Cienfuegos, Caribbean Sea). The Calisito site was sampled monthly from June 2010 until February 2012, yielding 21 sampling times. At each sampling event water and sediment samples were collected for measuring the abiotic variables (temperature, salinity, dissolved oxygen, nutrients, redox potential discontinuity, silt/clay and organic matter content) and macrofauna (abundance and species richness). Temperature and surface salinity followed a typical temporal pattern during the summer/rainy and the winter/dry periods. Salinity stratification occurred in the rainy period, lasting three months in 2010 and six months in 2011. The bottom water dissolved oxygen indicated hypoxic and anoxic events during the wet periods of 2010 and 2011 associated with salinity stratification, low hydrodynamics and oxidation of the accumulated organic matter. Over the study period, 817 individuals were collected and identified. Polychaetes were the dominant group in terms of abundance (57 % of total) followed by mollusks (41%). Hypoxia (and occasionally anoxia) caused strong deleterious effects on the abundance and species richness of macrofaunal communities in the study site. The most abundant polychaetes were opportunistic species with high tolerance to hypoxic conditions: Prionospio steenstrupi, Polydora sp.and Paraprionospio pinnata. Most of them colonized relatively fast once hypoxia ended. Persistent species such as Caecum pulchellum and Parvanachis obesa were present during hypoxia with fluctuating densities and apparently recover to higher abundances when normoxic conditions are re-established. Macoma tenta and Tellina consobrina colonized approximately 1-2 months later than the first polychaete peak during normoxia. Probably, the deleterious effects of hypoxia on the macrofauna were intensified by negative interspecific relationships such as competition by suitable space and predation. The recolonization of macrofauna depended possibly on local transport by currents within the bay because the connection with the Caribbean Sea is relatively limited. In summary, seasonal hypoxia in Cienfuegos Bay influences the water and sediment geochemistry and reduces both the abundance and diversity of macrofauna.

Organochlorine pesticides in green mussel, Perna viridis, from the Cienfuegos Bay, Cuba.

The green mussel, Perna viridis, was used to measure bioaccumulated levels of organochlorine pesticides in the marine environment of Cuba. Samples were collected in the Cienfuegos Bay between January and December 2010. The organochlorine pesticides (i.e. DDT, Dieldrin, Chlordane, Endosulfan, HCB, Aldrin, Heptachlor and Lindane) were quantified by gas chromatography. The sum of all organochlorine pesticides in P. viridis was 6.31 ng g(-1). The concentration ranged from 3.53 to 4.42 ng g(-1) dry weight (dw) for DDTs (i.e. sum of pp' DDT, pp' DDD, op' DDE and pp' DDE); 1.7-1.9 ng g(-1) dw for Dieldrin; 0.17-0.20 ng g(-1) dw for Chlordanes; 0.14-0.16 ng g(-1) dw for Endosulfan; 0.11-0.17 ng g(-1) dw for HCB; 0.07-0.11 ng g(-1) dw for Aldrin; 0.046-0.054 ng g(-1) dw for Heptachlor and 0.035-0.039 ng g(-1) dw for Lindane. These levels can be considered as low when compared to reported values from similar studies conducted elsewhere in the world. The concentrations of all organochlorines residues detected in this study fell below the EU Maximum Residue Limits.