José Luis Esteves

Hydrocarbons in Coastal Sediments of Patagonia, Argentina: Levels and Probable Sources

Intertidal superficial sediment from the Patagonian coastal zone were analysed to determine the concentration and probable source of aromatic and aliphatic hydrocarbons. Concentrations of aromatic and aliphatic hydrocarbons ranged from non-detected to 737.6 μg/g and non-detected to 1304.7 μg/g of dry sediment, respectively. High concentrations were observed in San Jorge Gulf, where the main economic activities are based on crude oil production. The highest aromatic and aliphatic hydrocarbon concentrations were present at Faro Aristizabal, 200 km away from oil charging areas. As suspected, hydrocarbon levels in harbour areas were generally more important than at nearby zones. Lower or non-detected hydrocarbon levels were recorded at locations with low or non-anthropogenic activity. Alkane distribution indices and hydrocarbon distribution patterns were used to identify natural and anthropogenic inputs. The results showed recent crude oil inputs and contribution from remaining weathered residues at various locations, whereas biogenic compounds or biogenic in combination with anthropogenic hydrocarbons predominated in others.

Enhancement of hydrocarbon wastebiodegradation by addition of a biosurfactantfrom Bacillus subtilis O9

A non-sterile biosurfactant preparation (surfactin)was obtained from a 24-h culture of Bacillussubtilis O9 grown on sucrose and used to study itseffect on the biodegradation of hydrocarbon wastes byan indigenous microbial community at theErlenmeyer-flask scale. Crude biosurfactant was addedto the cultures to obtain concentrations above andbelow the critical micelle concentration (CMC). Lowerconcentration affected neither biodegradation normicrobial growth. Higher concentration gave highercell concentrations. Biodegradation of aliphatichydrocarbons increased from 20.9 to 35.5% and in thecase of aromatic hydrocarbons from nil to 41%,compared to the culture without biosurfactant. Theenhancement effect of biosurfactant addition was morenoticeable in the case of long chain alkanes. Pristaneand phytane isoprenoids were degraded to the sameextent as n-C17 and n-C18 alkanes and, consequently,no decrease in the ratios n-C17/pri and n-C18/phy wasobserved. Rapid production of surfactin crudepreparation could make it practical for bioremediationof ship bilge wastes.

Metales pesados en organismos marinos de la zona costera de la Patagonia argentina continental

Se analizaron los contenidos de Hg, Cd, Pb, Cu y Zn en moluscos, crustaceos (tejido blando - µg/g peso seco), aves y mamiferos marinos (rinon, higado y musculo - µg/g peso humedo), procedentes de la zona costera de Patagonia argentina. Los niveles de Hg fueron no detectables o muy bajos. Se encontraron niveles de Cd mas elevados que los permitidos para consumo humano en algunos moluscos (hasta 6,75 µg/g), aunque su origen seria fundamentalmente natural. Las concentraciones de Pb en crustaceos de la Bahia San Antonio (10,00 ? 13,20 µg/g) fueron relacionadas con una antigua actividad minera. Los contenidos de Cu y Zn estuvieron en la mayoria de los casos, dentro del rango informado en la literatura.

Biosurfactant-enhanced degradation of residual hydrocarbons from ship bilge wastes

The use of Bacillus subtilis O9 biosurfactant (surfactin) and of bioaugmentation to improve the treatment of residual hydrocarbons from ship bilge wastes was studied. A biodegradation experiment was conducted in aquaria placed outdoors under non-aseptic conditions. Three treatments were examined: culture medium plus bilge wastes, bioaugmentation with microorganisms from bilge wastes, and bioaugmentation plus biosurfactant. Samples were analyzed for viable counts, aliphatic and aromatic hydrocarbon concentrations, n-C17/pristane and n-C18/phytane ratios. While the addition of biosurfactant stimulated hydrocarbon degradation, bioaugmentation did not produce any remarkable effect. At day 10, the remaining percentages of aliphatic and aromatic hydrocarbons in aquaria, which received biosurfactant, were 6.8 and 7.2, respectively, while it took 20 days to reach comparable results with the other treatments. The biosurfactant did not affect the preferential biodegradation of n-C17/pristane and n-C18/phytane. This biosurfactant, which can be produced in a relatively simple and inexpensive process, is a promising alternative in the optimization of hydrocarbon waste treatment. Journal of Industrial Microbiology & Biotechnology (2000) 25, 70–73.

Distribution and ecology of Pseudo-nitzschia species (Bacillariophyceae) in surface waters of the Weddell Sea (Antarctica)

The distribution of six Pseudo-nitzschia species and their relationship with environmental conditions were studied for the first time in a vast zone of the Weddell Sea (∼61–77°S, Antarctica). Both qualitative and quantitative phytoplankton samples, collected during summer 2004, were examined using light and scanning electron microscopy. Phytoplankton abundance and composition showed great variability along our study area. Diatoms were the most conspicuous phytoplankton group in the northern area while small flagellates were generally dominant in the southern stations. The genus Pseudo-nitzschia was broadly distributed and significantly contributed to total diatom densities. A marked contrast in Pseudo-nitzschia species distribution was observed in three main zones divided by the Weddell Front (WF) and the Antarctic Slope Front (ASF). P. subcurvata and P. turgiduloides were the most abundant species in the neritic Weddell Sea zone, south of the ASF, mainly near the ice-edge in shallower waters and in conditions of long photoperiod. In contrast, P. prolongatoides and P. lineola dominated north of the ASF; the first was associated with deeper and nutrient-rich waters whereas the latter showed a weak relation with environmental variables examined. Finally, P. turgidula and P. heimii were mostly observed in the Weddell–Scotia Confluence Zone in the warmest and far from ice covered waters, north of the WF. A brief morphological Pseudo-nitzschia species description is given in the Appendix, including morphometrics and pictures.

Hydrocarbon levels in sediments and bivalve mollusks from Bahía Nueva (Patagonia, Argentina) : An assessment of probable origin and bioaccumulation factors

Effects of crude oil and its derived products on marine ecosystems are well known. Both aliphatic and aromatic fractions possess toxic properties that can affect marine organisms. Particularly, sixteen unsubstituted PAHs have been recognized as priority pollutants for the Word Health Organization, the Economic European Community, and the USA Environmental Protection Agency (Hellow et al., 1994). Many PAHs have been found to be carcinogenic in mammals and, consequently, there is concern over the mobilization of PAHs and their metabolites into marine food chains via bioaccumulation and trophic transfer from benthic fauna (Ferguson and Chandler, 1998). Determination of PAHs in marine organism tissues is necessary because of their carcinogenic and mutagenic properties (Noreña-Barroso et al., 1999). Mussels have been considered as pollution sentinels by many authors (i.e. Hellow et al., 2002) because of their bioaccumulation capacity, and the National Status and Trends Program (NOAA, 1993) recommended them as a foreground matrix to environment monitoring. Sediments are also ideal matrices for chemical analysis, as they are the final fate for a variety of lipophilic pollutants (Hellow et al., 2002), and reflect long-term deposition. Coastal environments of Patagonia, Argentina, are threatened by petroleum residues resulting from port activities as well as crude oil transport. Studies of intertidal sediments along this coast showed anthropogenic hydrocarbon pollution in several areas (Commendatore et al., 2000; Esteves et al., 2006; Commendatore and Esteves, 2007). However, there is scarce information about hydrocarbon levels at many sites of the Patagonian coast due to its large extension and limited resources to conduct evaluations ( 3000 Km). Bahía Nueva (BN) (42.75 S, 65.00 W Fig. 1) is a bay located in western Golfo Nuevo, at southern limit of Peninsula Valdés, UNESCO World Heritage Site. It has an area of 58 km and a mean depth of 30 m. Water temperature varies from 10 C in winter to 17.5 C in summer. Puerto Madryn city ( 80,000 inhabitants) located in this bay has tourism, fisheries and aluminum production as the most important economic activities. The city has two ports with an important maritime traffic. In addition, a high population growth rate and an increase in tourism during the last decade have augmented domestic sewage and groundwater drainage. Due to the lack of a complete sewage system, it is also very likely that polluted groundwater reaches the coast (Gil and Esteves, 2000). The main wastewater discharges into the Bay derive from fishery plant effluents; although the aluminum plant does not produce liquid effluents, pollutants likely to enter the sea through atmospheric deposition. These activities are potential sources of anthropogenic hydrocarbons which could affect economic resources and marine biodiversity. Water circulation inside the Bay flows northwards (Esteves et al., 1997) and is less than 2.5 cm s , depending mainly on the wind (Lanfredi, 1974; Krepper and Rivas, 1979; Rivas, 1983). Twelve and eight stations to obtain sediments and organisms, respectively, were sampled in areas close to petroleum hydrocarbon sources (ports, stations 7 and 10), groundwater drainage areas (stations 3–5), fishery effluents (station 11), previous urban sew-

A toxic dinoflagellate bloom and PSP production associated with upwelling in Golfo Nuevo, Patagonia, Argentina

In 1980 Paralytic Shellfish Poison (PSP) was detected for the first time in Patagonia (Argentina), and has been recurring since during spring and summer.Human intoxicantions were recorded during the 1987/88 sumer due to ingestion of mussles. In January, concentrations of 750 000 cell l−1 were observed, decreasing to 3100 cells l−1 twenty days later. At the same time, values of 66 150.Mouse Unit (MU) 100 g−1 of meat were measured in Aulacomya ater (a bivalve mollusk). A decrease in the concentration of toxic plankton resulted in a concomitant decrease in MU values. The mean detoxification time was 7.6 days. However, mussels retained toxicity up to 50 days after the disappearance of cells.The upwelling of cold waters at the beginning of summer, could have been one of the causes that favoured a bloom of Alexandrium excavatum and of Prorocentrum micans. In March, an abundance of the diatom Skeletonema costatum coincided with high concentrations of silicate.

Cross-frontal distribution of inorganic nutrients and chlorophyll-a on the Patagonian Continental Shelf of Argentina during summer and fall

Datos oceanograficos recolectados durante 2001-2003 en la Plataforma Continental Patagonica Argentina fueron analizados para estudiar las principales caracteristicas quimicas en esta gran plataforma. Se presenta la variacion de los nutrientes inorganicos y de la clorofila-a a una distancia de 40 a 60 km de la costa. El nitrato es el nutriente limitante en la region y esta negativamente correlacionado con la clorofila-a. Todas las variables presentan variaciones localizadas en verano, las cuales pueden ser relacionadas con los frentes de marea a traves de la comparacion de nuestros datos con el parametro critico de estabilidad de Simpson (50 J m-3). En otono, la concentracion de nutrientes en la plataforma continental fue mas uniforme y generalmente mayor que en verano debido a la disrupcion de dichos frentes.

Comparison of AVHRR and SeaWiFS imagery with fishing activity and in situ data in San Matías Gulf, Argentina

Seven years (January 2000 to December 2006) of AVHRR and SeaWiFS data were used to estimate monthly climatological means and to present SST and chlorophyll-a seasonal evolution in San Matías Gulf, located between 40° 47′ S and 42° 13′ S on the Argentine coast. SST and chlorophyll-a satellite maps corresponding to spring–summer showed two well differentiable sectors: the southern zone presented colder waters and higher chlorophyll-a concentration while the northern one showed warm water and lower chlorophyll-a. Hake (Merluccius hubbsi) is the most important resource in terms of landings and economic revenues of the San Matías Gulf. Fishing activity data gathered by a Vessel Monitoring System (2004–2006) were linked with SST and chlorophyll-a maps showing that the fishing vessels operated on the thermal front from November to March and had the maximum hake yields. In addition, AVHRR-SST and SeaWiFS-chlorophyll-a data were compared with temperature and chlorophyll-a measured in oceanographic surveys carried out in 2007.

Assessment of recent sediment influence in an urban polluted subantarctic coastal ecosystem. Beagle Channel (Southern Argentina).

In this study, baseline information about the environmental status of Ushuaia (UB) and Golondrina (GB) bays is presented. Surface and bottom seawater and freshwater discharged from land were evaluated. Multivariate analysis identified different water quality zones within the bays, two of them located next to the north and northwest coastlines of UB, where the majority of human activities are developed. Porosity, total organic matter, biochemical components, ammonium, and phytopigments were determined in sediment samples from each quality zone. Benthic fluxes of nutrients and dissolved oxygen were assessed in situ using opaque chambers. In northwest zone of UB, carbon equivalents of proteins and carbohydrates in surficial sediments were the same order as in hypertrophic ecosystems, whereas ammonium and phosphate released from sediment greatly exceeded the allochthonous sources. Management of municipal wastewater is required to remediate this chronic pollution.