Influencia de los procesos ambientales predominantes en la cuenca y el embalse Hanabanilla sobre la composición de su sedimento

The Hanabanilla reservoir was built in 1960 in the center-south of Cuba and is used for human supply and power generation. This research was aimed at identifying the important processes affecting sediment composition, through the analysis of particle size, and organic carbon (OC), nutrients, and major trace elements concentrations in sediment samples taken at the outlet point of the reservoir. The documentary review allowed us to identify how the nature and management of the basin and the operation of the reservoir affected sediment quality. The application of principal components analysis (PCA), and the determination of ionic relationships and correlations between the sediment quality variables, allowed for the identification of influential processes on sediment quality. Anthropic activities in the period 1960-2012 produced residues rich in OC, total phosphorus (TP) and total nitrogen (TN) that were stored in reservoir sediments. During the first years of the reservoir (1964-1976) the highest concentrations of sediment TP were recorded and the sediments functioned as a sink. The OC and TN mean concentrations were higher in the last stage of the study (2006-2012). The main influential processes on sediment composition were the operation of the reservoir, the geochemical cycle of P, the mineralization of the substances in the water column, and the weathering of silicates and the contribution of organic matter from the basin. Sediment quality data indicate that OC and TN were of allochthonous origin and TP was of autochthonous origin. Levels of sediment OC and TN also corresponded with an increase in anthropic activities in the basin.El embalse Hanabanilla fue construido en 1960 en el centro-sur de Cuba y sus usos principales son el abastecimiento humano y la generación de energía eléctrica. Esta investigación tuvo como objetivo identificar los procesos fundamentales que afectan la composición del sedimento, mediante el análisis del tamaño de las partículas, y el contenido de carbono orgánico (OC), nutrientes y elementos traza mayoritarios en muestras de sedimento tomadas en la obra de toma del embalse. La revisión documental permitió identificar cómo afectan la naturaleza y el manejo de la cuenca, y la operación del embalse a la calidad del sedimento. El análisis de componentes principales (PCA), las relaciones iónicas, y las correlaciones entre las variables de calidad del sedimento, permitieron identificar los procesos influyentes en la calidad del sedimento. Las actividades antrópicas en el período 1960-2012 produjeron residuos ricos en OC, fósforo total (TP) y nitrógeno total (TN) que se almacenaron en los sedimentos del embalse. Durante los primeros años del embalse (1964-1976), se registraron las más altas concentraciones de TP en el sedimento que actuó como sumidero. Las concentraciones medias de OC y TN fueron más altas en la última etapa del estudio (2006-2012). Los principales procesos que influyeron en la composición del sedimento fueron: la operación del embalse, el ciclo geoquímico del P, la mineralización de las sustancias en la columna de agua, y el lavado de los silicatos, unido a la contribución de la materia orgánica de la cuenca. Los datos indicaron un origen alóctono para el OC y el TN, y autóctono para el TP. Los niveles de OC y TN en el sedimento también se correspondieron con un incremento en la actividad antrópica en la cuenca.Fil: Labaut Betancourt, Yeny. Centro de Estudios Ambientales de Cienfuegos; Cuba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Betancourt, Carmen R.. Universidad de Cienfuegos Carlos Rafael Rodriguez; CubaFil: Díaz Asencio, Misael. Centro de Estudios Ambientales de Cienfuegos; CubaFil: Beutel, Marc W.. University of California; Estados Unido

Variaciones espaciales y temporales de las comunidades de la meiofauna en la bahía de Cie, Cubanfuegos

The community structure of meiofauna was studied in 16 subtidal sampling stations and in four months in Cienfuegos Bay, Cuba for describing their patterns of distribution, as well as their possible causes. Silt/clay (S/C) and organic matter (OM) contents in sediment were positively correlated, and their changes were related to spatial variation of sedimentary environment across stations. The narrow range of interstitial salinity suggests a slight effect on meiofauna even when changes of surficial salinity occurred. Density and number of taxa changed among dry and wet seasons plausibly as a response to hypoxic conditions due to water stratification in the wet season. Negative relationships were recorded among S/C and OM with meiofaunal densities possibly due to restrictive effects of accumulation and oxidation of organic matter. Physical disturbance appears to be a main process affecting meiofauna in some shallow stations subjected to strong waving and tidal currents. No any single ecological factor explains the large spatial variability of meiofaunal communities in the whole bay; a combination of several processes like distribution of primary production, stratification/mixing of the water column and physical disturbance probably is occurring in the bay.Se estudió la estructura de la comunidad de la meiofauna en 16 estaciones submareales y en cuatro meses, en la bahía de Cienfuegos, Cuba, para describir sus patrones de distribución así como sus posibles causas. Los contenidos de limo/arcilla (S/C) y materia orgánica (OM) en los sedimentos estuvieron positivamente correlacionados y sus cambios se relacionaron con la variación espacial del ambiente sedimentario a través de las estaciones. El restringido intervalo de salinidad intersticial sugiere un efecto pequeño sobre la meiofauna aún cuando ocurrieron cambios en la salinidad superficial. La densidad y el número de taxa cambiaron entre la estaciones seca y húmeda como respuesta a las condiciones hipóxicas causadas por la estratificación del agua en la estación húmeda. Se determinaron relaciones negativas entre los contenidos de limo/arcilla y materia orgánica con las densidades de la meiofauna, debido posiblemente a los efectos restrictivos causados por la acumulación y oxidación de la materia orgánica. El disturbio físico parece ser un proceso principal que afecta a la meiofauna en algunas estaciones someras sujetas a fuerte oleaje y corrientes de marea. Ningún factor ecológico por sí solo explica la gran variabilidad espacial de las comunidades de la meiofauna en la bahía; probablemente una combinación de varios procesos como la distribución de la producción primaria, la estratificación/mezcla de la columna de agua y el disturbio físico está ocurriendo en la bahía

Correction to: A 50-year sediment record of algal assemblage changes in Hanabanilla Reservoir, Cuba

Unfortunately, several plots in Fig. 3 labels are missed in the original version of this article. The author has provided the figure with the labels that were missed during editing.Fil: Labaut Betancourt, Yeny. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Centro de Estudios Ambientales de Cienfuegos; CubaFil: Macchi, Pablo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Comas, Augusto A.. Centro de Estudios Ambientales de Cienfuegos; CubaFil: Betancourt, Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad de Cienfuegos Carlos Rafael Rodriguez; CubaFil: Díaz Asencio, Misael. Centro de Estudios Ambientales de Cienfuegos; Cuba. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; Méxic

One century of sedimentation and Hg pollution at the mouth of the Sagua la Grande River (Cuba)

The Sagua la Grande River is the largest of northern Cuba. The socioeconomic development in this region during the last 100 years has caused changes in its natural conditions, such as an increase in Hg levels. In 1981, a chlor-alkali plant with mercury-cell technology was built on the river bank and has released several contaminants to the environment. Sedimentation along the river and the nearby coastal zone was reconstructed using the radionuclides 210Pb, 226Ra, 137Cs, and 239,240Pu in sediment cores. The changes in sediment accumulation were related to important changes in the river basin after 1950, such as the channeling of the river in 1955 and the construction of the Alacranes Dam in 1972. Maximum sediment accumulation rates were attributed to large floods in 1933, 1948, and 1985 (Hurricane Kate). The 210Pb chronology allowed the reconstruction of Hg pollution during the last four decades. In the locations with greatest fluvial influence, Hg concentrations increased since the early 1980s exceeding the Effects Range-Median (0.71 mg kg–1). The accumulated Hg inventories released from the plant were one order of magnitude larger than those due to other sources. These results show the impact of Hg releases from this industry on the estuary, especially in the coastal zone close to the river mouth.

210Pb and 137Cs as tracers of recent sedimentary processes in two water reservoirs in Cuba.

Hanabanilla and Paso Bonito Reservoirs are the main fresh water sources for about half a million inhabitants in central Cuba. Prior to this investigation precise information about the losses of storage capacity was not available. Sedimentation is the dominant process leading to reduction in water storage capacity. We investigated the sedimentation process in both reservoirs by analyzing environmental radionuclides (e.g. 210Pb, 226Ra and 137Cs) in sediment cores. In the shallow Paso Bonito Reservoir (mean depth of 6.5 m; water volume of 8 x 106 m3), we estimated a mean mass accumulation rate (MAR) of 0.4 ± 0.1 g cm-2y-1 based on 210Pb chronologies. 137Cs was detected in the sediments, but due to the recent construction of this reservoir (1975), it was not possible to use it to validate the 210Pb chronologies. The estimated MAR in this reservoir is higher than the typical values reported in similar shallow fresh water reservoirs worldwide. Our results highlight a significant loss of water storage capacity during the past 30 years. In the deeper and larger Hanabanilla Reservoir (mean depth of 15.5 m; water volume of 292 x 106 m3), the MAR was investigated in three different sites of the reservoir. The mean MARs based on the 210Pb chronologies varied between 0.15 and 0.24 g cm -2y-1. The MARs calculated based on the 137Cs profiles further validated these values. We show that the sediment accumulation did not change significantly over the last 50 years. A simple empirical mixing and sedimentation model that assumes 137Cs in the water originated from both, direct atmospheric fallout and the catchment area, was applied to interpret the 137Cs depth profiles. The model consistently reproduced the measured 137Cs profiles in the three cores (R2 \u3e 0.9). Mean residence times for 137Cs in the water and in the catchment area of 1 y and 35-50 y, respectively were estimated. The model identified areas where the catchment component was higher, zones with higher erosion in the catchment, and sites where the fallout component was quantitatively recorded in the sediments

210Pb and 137Cs as tracers of recent sedimentary processes in two water reservoirs in Cuba.

Hanabanilla and Paso Bonito Reservoirs are the main fresh water sources for about half a million inhabitants in central Cuba. Prior to this investigation precise information about the losses of storage capacity was not available. Sedimentation is the dominant process leading to reduction in water storage capacity. We investigated the sedimentation process in both reservoirs by analyzing environmental radionuclides (e.g. 210Pb, 226Ra and 137Cs) in sediment cores. In the shallow Paso Bonito Reservoir (mean depth of 6.5 m; water volume of 8 x 106 m3), we estimated a mean mass accumulation rate (MAR) of 0.4 ± 0.1 g cm-2y-1 based on 210Pb chronologies. 137Cs was detected in the sediments, but due to the recent construction of this reservoir (1975), it was not possible to use it to validate the 210Pb chronologies. The estimated MAR in this reservoir is higher than the typical values reported in similar shallow fresh water reservoirs worldwide. Our results highlight a significant loss of water storage capacity during the past 30 years. In the deeper and larger Hanabanilla Reservoir (mean depth of 15.5 m; water volume of 292 x 106 m3), the MAR was investigated in three different sites of the reservoir. The mean MARs based on the 210Pb chronologies varied between 0.15 and 0.24 g cm -2y-1. The MARs calculated based on the 137Cs profiles further validated these values. We show that the sediment accumulation did not change significantly over the last 50 years. A simple empirical mixing and sedimentation model that assumes 137Cs in the water originated from both, direct atmospheric fallout and the catchment area, was applied to interpret the 137Cs depth profiles. The model consistently reproduced the measured 137Cs profiles in the three cores (R2 \u3e 0.9). Mean residence times for 137Cs in the water and in the catchment area of 1 y and 35-50 y, respectively were estimated. The model identified areas where the catchment component was higher, zones with higher erosion in the catchment, and sites where the fallout component was quantitatively recorded in the sediments

Gulf of Mexico (GoM) Bottom Sediments and Depositional Processes: A Baseline for Future Oil Spills

The deposition/accumulation of oil on the seafloor is heavily influenced by sediment/texture/composition and sedimentary processes/accumulation rates. The objective of this chapter is to provide a baseline of Gulf of Mexico sediment types and transport/depositional processes to help guide managers where oiled sediments may be expected to be deposited and potentially accumulate on the seafloor in the event of a future oil spill. Based solely on sediments/processes/accumulation rates, regions most vulnerable to oil deposition/accumulation include the deep eastern basin, followed by the western/southwestern basin, and north and west continental margins. The least vulnerable regions include the northwest Cuban shelf and the carbonate-dominated west Florida shelf and Campeche Bank. This is intended to be used as a general, “first cut” tool and does not consider local variations in sediments/processes