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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.

Due to the increasing emissions of carbon dioxide into the atmosphere, the absorption of this gas by the ocean is carried out at great speed, causing an increase in the acidity of seawater. This process, known as ocean acidification, leads to a reduction in the ability of many calcifying organisms to form their calcium carbonate structures. The objective of this research was to determine the net rates of calcium carbonate accretion (g CaCO3 cm-2 yr-1) of early successional taxa, in the marine-coastal ecosystem complex of Ensenada Rancho Luna, Cienfuegos. To quantify the net calcium carbonate accretion rates, 12 sampling devices were built based on the Vargas-Ángel et al. in 2015, positioning six of them in each ecosystem studied (mangrove and reef). The mean values of net calcium carbonate accretion rates were 0.87 ± 0.19 g CaCO3 cm-2 yr-1 in the reef and 0.59 ± 0.05 g CaCO3 cm-2 yr-1 in the mangrove swamp. Seven taxa were identified, corresponding to four early successional functional groups, grass (turf), CaCO3/sediment, Calcium-free functional group, and crusted coralline algae. The latter were the main contributors of CaCO3, being found mainly in the reef. Magnesite was determined as the dominant crystalline form of CaCO3, and crusty coralline algae, the group with the greatest vulnerability to the effect of ocean acidification. [ABSTRACT FROM AUTHOR]

Climatic signals preserved in the skeletal growth bands of massive corals offer a long-term perspective that allows understanding sea surface temperature changes at different time scales. In the Caribbean Sea and the Gulf of Mexico, coral species such as Orbicella faveolata present massive growth forms in shallow waters that facilitate dating of their skeleton, allowing to perform paleoenvironmental studies in coastal areas where instrumental records are scarce and cover short time periods. This study aimed to characterize coral geochemical records in the skeleton of a hermatypic coral O. faveolata collected in the Cayo Santa María (Cuba) reef and to reconstruct seawater surface annual temperatures for the last two centuries. Records of 230 years for Li/Ca, Sr/Ca, Mg/Ca, U/Ca, Li/Mg, and Sr-U were obtained. The Li/Ca indicator allowed the reconstruction of SST in the study area from 1778 to 2015, indicating an overall increase of 0.77 °C in the last 50 years. In addition, Li/Ca corroborated with high accuracy the characteristic warming and cooling periods reported for the Caribbean Sea and the Gulf of Mexico since 1778. Orbicella faveolata proved to contain a good multidecadal record of annual temperature and of the Atlantic Multidecadal Variability. These results are the first long-term reconstruction of SST in the Cuban coastal zone and provide relevant information to understand global warming in the Caribbean. [ABSTRACT FROM AUTHOR]

Green mussel, Perna viridis, was used to measure bioaccumulated levels of polycyclic aromatic hydrocarbons (PAHs) in Cienfuegos Bay. Mussels were collected from four sites between November 2009 and November 2010. Sixteen individual PAHs compound controlled by Environmental Protection Agency (EPA) were quantified using gas chromatography—mass spectrometry (GC—MS). Concentration for phenanthrene ranged from 22.14 to 43.04 μg/kg (wet weight), for fluorene 5.19—9.33 μg/kg (wet weight), and 3.47—15.97μg/kg (wet weight) for fluoranthene. The overall concentration levels of PAH in this study are comparable to sites with low pollution levels around the world and its composition suggests a contribution from petrogenic sources. According to European Regulation No. 835/2011, the concentration levels of PAHs found are safe for human consumption of mussels in Cienfuegos Bay. These results contribute to the database of the Caribbean region because the information about the contamination for PAHs is scarce in bivalves, in Cuba. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the community structure of meiofauna in subtidal sampling stations in Cienfuegos Bay, Cuba. Sampling was done in 16 subtidal stations in the bay during the months of February, May and September 2004 and September 2005 using scuba diving. Univariate and multivariate methods were used to analyse the data. BIOENV procedure and Pearson's Product-Moment correlation coefficient were also employed to explore the relationships between biotic and abiotic multivariate patterns. Meiofaunal communities identified include Nematoda, Copepoda, Kinorhyncha, Rotifera and Amphipoda. The study indicates a highly dynamic sedimentary environment in the bay.

In the framework of a program focusing on marine resource protection and management in the Caribbean, the objective of this work was to characterize As bioaccumulation in the common edible oyster Crassostrea virginica. Dissolved As (stable As + 73As as a tracer) was taken up according to saturation kinetics for all tested exposure concentrations (2-10 μg l-1), and steady-state was reached rapidly within ∼1 week. A slight decrease in uptake efficiency was observed for the higher concentration tested. Whole-body depuration kinetics showed that 73As was lost according to double exponential depuration kinetics that were characterized by short-lived biological half-lives (Tb1/2s) of 0.5-0.9 d and by long-lived Tb1/2l of 8-16 d. No significant difference in 73As retention was found among different initial exposure concentrations of As. Overall, our results indicate that C. virginica bioaccumulates As proportionally to the ambient dissolved As concentration, and retains it with similar efficiency regardless of the initial exposure level. Therefore C. virginica could be used as a reliable bioindicator species to monitor ambient levels of dissolved As contamination as well as to reveal short-term variations in As levels in seawater. [ABSTRACT FROM AUTHOR]

Several species of benthic dinoflagellates produce potent toxins that have negative impacts on the economy and human health of coastal zones. In a previous study carried out in a zone known to be prone to ciguatera, located at the eastern end of the Gulf of Batabanó, the species diversity of ciguatoxin producer organism, Gambierdiscus, was determined, however the presence and abundance of other potentially toxic benthic dinoflagellate genera was not considered. In present study, the samples obtained from artificial and natural substrates were re-analyzed to estimate the abundance of other genera of dinoflagellates in the area. The genera Prorocentrum and Ostreopsis were identified at all sampling points. In general, the abundance of these genera showed high variability between sites and were higher compared to the reported abundance of the genus Gambierdiscus. The results obtained by using both types of substrates were similar, which encourages the use of artificial substrates for quantifying benthic dinoflagellates in future studies. This work contributes to the available information about the presence and abundance of potentially toxic benthic dinoflagellates in the southern central region of Cuba and provides basic elements for risk assessment related to toxic blooms of these microalgae. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]