Instituto Argentino Of Oceanografia

Bahía Blanca, Argentina

Instituto Argentino Of Oceanografia

Bahía Blanca, Argentina
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Batabyal P.,Indian National Institute of Cholera and Enteric Diseases | Einsporn M.H.,Leibniz Center for Tropical Marine Ecology | Mookerjee S.,Indian National Institute of Cholera and Enteric Diseases | Palit A.,Indian National Institute of Cholera and Enteric Diseases | And 6 more authors.
Science of the Total Environment | Year: 2014

This study deals with the influence of water physico-chemical properties, tides, rainfall and fecal pollution on the abundance of enteropathogens in a main distributary of the Ganges, in the endemic cholera belt of West Bengal. Between January and June 2011, water and sediments were sampled from two sites of the Hooghly River by Kolkata and Diamond Harbour. Counts of cultivable Vibrio (CVC, from~102 to~105CFU/L) and total bacteria (TBC, from~105 to~109CFU/L) increased with water temperature (17°C to 37°C). A combination of variations in tidal height, salinity and turbidity had a distinct influence on CVC, TBC and coliform counts. At Diamond Harbour, a salinity increase from 0.6 to 7.9 was accompanied by a 1000-fold amplification of initial CVC~102CFU/L, whereas higher prevalence of coliforms in Kolkata was related to greater disposal of untreated sewage into the river. Turbidity-dependent variation of CVC was noteworthy, particularly at Diamond Harbour, where CVC in intertidal surface sediments showed an analogous trend as in surface waters, suggesting bentho-pelagic coupling of Vibrio dynamics. Besides the influence of salinity variation with tidal cycles, sediment re-suspension from tidal flats can play a role on Vibrio abundance in aquatic ecosystems. © 2013 Elsevier B.V.

Kopprio G.A.,Leibniz Center for Tropical Marine Ecology | Freije R.H.,National University of the South | Strussmann C.A.,Tokyo University of Marine Science and Technology | Kattner G.,Alfred Wegener Institute for Polar and Marine Research | And 3 more authors.
Journal of Fish Biology | Year: 2010

The vulnerability of the pejerrey Odontesthes bonariensis population in Lake Chasicó was assessed under different climate change conditions. During the sampling period, the water temperature was adequate for fish reproduction and to sustain an adequate sex ratio. Climate-driven higher temperatures, however, may severely distort population structure and cause drastic reduction or local extinction of stocks. Lake Chasicó can be classified as eutrophic with clear waters and cyanobacteria that regularly cause fish mortality were identified as Nodularia spumigena and Oscillatoria sp. Global warming may strengthen the effects of eutrophication (e.g. toxic blooms or anoxia). Since many Cyanophyta species tolerate higher temperatures better than other algae, toxic blooms could increase. Furthermore, cyanobacteria have low nutritional value and could decouple the low-diversity food web. Lake Chasicó has currently the salinity optimum (c. 20) for the development of the early life-history stages of O. bonariensis. Climate change, however, is likely to amplify the intensity of droughts or inundations. Floods can endanger O. bonariensis development due to its sub-optimal growth at low salinity and droughts could increase lake salinity and also temperature and nutrient concentration. In order to reduce some of the effects of climate change on the O. bonariensis population in Lake Chasicó, integrated basin management based on an eco-hydrological approach is proposed. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Fiori S.M.,Instituto Argentino Of Oceanografia | Fiori S.M.,National University of the South | Carcedo M.C.,Instituto Argentino Of Oceanografia
Journal of Shellfish Research | Year: 2015

The yellow clam Amarilladesma mactroides (Reeve, 1854), is an intertidal species that prospers mainly on dissipative sandy beaches along the temperate Atlantic coast of South America, from Brazil to Argentina (24-41° S). This large clam is considered a fast burrower, which lives buried in the sediment, migrating seasonally into the intertidal zone. The present study explores the effect of sediment grain size on the burrowing performance of this species, to elucidate the influence of granulometry on the alongshore distribution of the A. mactroides population. Laboratory trials were performed with clams of different sizes, to study the influence of grain size on the burial rate. Clam distribution was analyzed along a 32 km coastal fringe whose granulometric composition varies from very fine to coarse sand. The values of the mean burrowing rate index, a measurement of clam mobility, suggest that burrowing is fast to very fast in fine and medium sand and becomes slower toward areas with extreme particle size (very fine and coarse sand). The burial time of A. mactroides was positively correlated with shell length: small animals can burrow into substrates that may exclude larger animals. Adults clams burrowed in a very limited range of sand grain sizes. They displayed fastest burial times in grain sizes typical of dissipative beaches, i.e., fine to medium sand. Patchy distribution and density variation of A. mactroides alongshore reflect the relation between grain size and burrowing performance: the population is absent in sites with the highest proportion of coarse sands, its density increases in patches with the highest proportion of fine and medium sand and peaks at a site with the highest proportion of fine sand. Results indicate that the discontinuous distribution of A. mactroides along its range could be due to a postsettlement process. Clams can potentially recruit on a wide morphodynamic range, but only may thrive in beaches which sand grain size allows them a rapid reburial during migratory and local movements.

Negrin V.L.,Instituto Argentino Of Oceanografia | de Villalobos A.E.,National University of the South | Trilla G.G.,Institute Investigaciones e Ingenieria Ambiental 3iA | Botte S.E.,Instituto Argentino Of Oceanografia | And 4 more authors.
Chemistry and Ecology | Year: 2012

In order to examine the role of position in the tidal range on biomass production and nutrient pools in Spartina alterniflora in an Argentinian estuary, we estimated productivity, the concentration of C, N and P in tissues and pools (concentration×biomass) of these elements in low (LM) and high (HM) zones. Aboveground biomass of S. alterniflora was higher in HM than in LM. Aboveground primary productivity was 106 and 439 g dry wt m-2 year-1 in LM and HM, respectively. Belowground biomass was similar in LM and HM. Belowground primary productivity was 526 and 744 g dry wt m-2 year-1 for LM and HM, respectively. Nutrient pools were higher in HM than in LM. Biomass and productivity values were low, which makes nutrient pools low. The lower values of the parameters analysed in LM than in HM indicate that position in the tidal range is an important factor in this system, possibly due to the effect of flooding. Moreover, this pattern is opposite to the general one observed in the northern hemisphere, meaning that studying marshes from different environments is worth doing. Because pools were higher in HM, this zone would be more important for nutrient input to the estuary. © 2012 Copyright Taylor and Francis Group, LLC.

Fiori S.M.,Instituto Argentino Of Oceanografia | Fiori S.M.,National University of the South | Simonetti P.,Instituto Argentino Of Oceanografia | Dos Santos E.P.,Instituto Argentino Of Oceanografia
Aquatic Invasions | Year: 2012

The present work reports the finding of an exotic bivalve, Barnea (Anchomasa) truncata, in the intertidal zone of the Bahía Blanca Estuary Argentina (38° Lat S), more than 2000 km south from the edge of its native range in South America (21° Lat S, Brazil). Lines of evidence suggest that larval transport by shipping is the probable entry route of this species. The most apparent modification created by the introduction of this species is the generation of greater complexity and habitat heterogeneity in the mud tidal plain of the estuary; the consequent effects on the local biota should therefore be evaluated. © 2012 The Author(s).

The life cycle and growth of the mud-snail Heleobia australis was studied in the Bahía Blanca estuary (Argentina) from April 2008 to April 2010. Four age classes were identified. This species recruits once a year, during summer. In general, the recruits (< 2.5 mm) represented a small percentage of the total population. The growth rate of H. australis declined with increasing animal size and showed a marked seasonal pattern for the population under study: lower rate during winter and higher rate in summer. A life cycle of approximately 30 months (~2.5 years) was estimated for the population of H. australis in the Bahía Blanca estuary. This population shows variations in growth rate, abundance of recruits, and shell size in relation to more northerly populations. Several factors like parasitism, predation, environmental features, and anthropogenic action may be interacting to produce these differences. This work constitutes the first long-term study of the life cycle of cochliopids. Heleobia australis appears to be a long-lived species and exhibits variations in its life cycle that seem to be influenced by biological and physical variables. Long-term studies that include biological interactions and spatial features of the microhabitats are needed to elucidate patterns in life-history traits of H. australis along its distribution range.

Cohen M.C.L.,Federal University of Pará | Lara R.J.,Instituto Argentino Of Oceanografia | Cuevas E.,University of Puerto Rico at San Juan | Oliveras E.M.,University of Puerto Rico at San Juan | Da Silveira Sternberg L.,University of Miami
Catena | Year: 2016

We evaluated the response to sea level rise and climatic changes of the northeastern Caribbean by establishing a palaeoenvironmental reconstruction of the Flamenco Lagoon, located in the coastal side of the Guanica Dry Forest, a MAB/UNESCO reserve in the semi-arid southwestern coast of Puerto Rico (17°57'10.31″N, 66°50'39.30″W). The reconstruction was based on pollen records, sediments analysis, δ13C, δ15N, C/N data and AMS 14C dating of one sediment core. The geology of the area is rocky calcareous karst with rocky outcrops and canyons, with intermittent streams that move water during periods of high run-off conditions. The present lagoon is surrounded by rocky outcrops where dry forest vegetation is present on the terrestrial sides, and sand dunes on the coastal side. We propose that the studied lagoon developed after the stabilization of sea level rise in the region following three main stages: (1) before ~5400 cal yr BP, sediments were accumulated according to small channels dynamics and trees, shrubs and herbs were present. The sedimentary organic matter was mainly sourced from terrestrial C3 and C4 plants. (2) Between ~5400 and ~4400 cal yr BP, tidal flats were established and mangroves, mainly represented by Rhizophora trees, migrated landward with sea level rise and established in the area, and the sedimentary organic matter was sourced from terrestrial C3 plants. (3) Around 4400 cal yr BP, sea level was near the stabilization, the endorheic minibasin was closed when a coastal sand dune was established as a result of drier climatic conditions. Mangroves were eliminated from the system as a result of the closure of the area by sand dunes and increased salinity in water due to high evaporative demand of the climate. The pollen dominance of herbaceous and shrubby vegetation prevails until present. Throughout the lagoon development, sedimentary organic matter was sourced from C3 and C4 plants, as well as phytoplankton organic matter. The closure of the lagoon and the drier conditions prevalent in the region during the late Holocene, which lasts until the present day, and increased the contribution of salinity tolerant phytoplankton that characterizes the current conditions of the Flamenco Lagoon. © 2016 Elsevier B.V.

Bustos M.L.,Instituto Argentino Of Oceanografia | Piccolo M.C.,Instituto Argentino Of Oceanografia | Perillo G.M.E.,Instituto Argentino Of Oceanografia
Cuadernos de Investigacion Geografica | Year: 2011

The effect of strong winds on the erosion and geomorphological changes in Pehuen Co beach (Buenos Aires, Argentina) were analyzed. Although four different sectors of the coast with variable orientations were identified, in all cases the beach is dissipative with two or three parallel bars. The West Zone (ZW) is an extensive beach composed of medium to fine sand, backed by dunes covered with tamarisx gallica and a coastal road that artificially modified the dunes resulting in a cliffy backshore. The Center Zone (ZC), more urbanized, has beach less extense and dominated by fine sand; dunes covered with tamarisx gallica. The East Zone (ZE) has the widest beaches and medium sand; it coincides with the end of the urbanization. Finally the Reserve Zone (ZR), where there are trace fossils, is the most extensive and widest beach with fine sand and dunes naturally vegetated; it has no roads or infrastructure. Wind data from a meteorological station located on the coast and related to the monthly beach profiles during the period 2007-2009 were analyzed. The events offshore winds (SE and SW quadrants) were identified. It was determined that 40 km h -1 is threshold of wind speed and durations greater than 6 h are required to significantly affect coastal geomorphology. The results showed that different wind directions generate erosion and/or accretion in each sector. 91 events were recorded, most of the SW quadrant. The West and Central zones were the most vulnerable to events from SW quadrant. The East zones were eroded (13 m 3) by the winds from the SE quadrant. Based on this analysis, a map of coastal vulnerability was developed showing that the western and central zones were the most vulnerable. The other two zones had a middle and lower vulnerability most likely due their natural stages not affected anthropogenic factors. © Universidad de La Rioja.

Escapa M.,Institute Investigaciones Marinas y Costeras | Perillo G.M.E.,Instituto Argentino Of Oceanografia | Iribarne O.,Institute Investigaciones Marinas y Costeras
Geomorphology | Year: 2015

Salt-marshes are under increasing threat, particularly from sea-level rise and increased wave action associated with climate change. The development and stability of these valuable habitats largely depend on complex interactions between biotic and abiotic processes operating at different scales. Also, interactions between biotic and abiotic processes drive internal morphological change in salt-marshes. In this paper we used a biogeomorphological approach to assess the impact of biological activities and interactions on salt pan formation in Sarcocornia-dominated salt marshes. Salt pans represent a key physiographic feature of salt-marshes and recent studies hypothesized that biogeomorphic processes could be related to salt pan formation in SW Atlantic salt-marshes. The glasswort Sarcocornia perennis is one of the dominant plants in the salt-marshes of the Bahía Blanca Estuary (Argentina) where they form patches up to 8m in diameter. These salt-marshes are also inhabited in great densities by the burrowing crab Neohelice (Chasmagnathus) granulata whose bioturbation rates are among the highest reported for salt-marshes worldwide. A set of biological interactions between N. granulata and S. perennis appears to be responsible for salt pan development in these areas which has not been described elsewhere. The main objective of this work was to determine the ecological interactions occurring between plants and crabs that lead to salt pan formation by using field-based sampling and manipulative experiments. Our results showed that S. perennis facilitated crab colonization of the salt-marsh by buffering otherwise stressful physical conditions (e.g., temperature, desiccation). Crabs preferred to construct burrows underneath plants and, once they reach high densities (up to 40 burrowsm-2), the sediment reworking caused plant die-off in the central area of patches. At this state, the patches lose elevation and become depressed due to the continuous bioturbation by crabs. Thus, salt pans are generated in this case by a set of biogeomorphic processes that include pure ecological interactions such as plant facilitation of crab settlement and also indirect negative effects of crabs on plant survival. Furthermore, crab bioturbation affects sediment structure due to concentration of burrowing activity under plant canopies promoting elevation loss and leading, after a few years, to salt pan formation in a previously vegetated substrate. © 2014 Elsevier B.V.

Beltrame M.O.,Instituto Argentino Of Oceanografia | Beltrame M.O.,FASTA University | De Marco S.G.,FASTA University | De Marco S.G.,University of the Sea | And 3 more authors.
Archives of Environmental Contamination and Toxicology | Year: 2010

Cadmium, chromium, copper, and manganese concentrations were determined in hepatopancreas of both sexes as well as in eggs at different embryonic development stages of the burrowing crab Neohelice granulata (Brachyura, Varunidae) from Mar Chiquita Coastal Lagoon, a biosphere reserve from Argentina, during a period of 1 year, to assess the bioaccumulation of metals associated with sex and seasonality. Furthermore, metal levels in associated superficial sediment samples were also determined. Two different "cangrejales," one in a mudflat and another one in a salt marsh, were studied. The results showed high concentrations of copper within the hepatopancreas, which was considered a strong reflection of high exposure of N. granulata to this metal. Metal accumulation in hepatopancreas from both study sites and sexes did not present significant differences, as did seasonality. In this sense, both spring and summer metal levels in hepatopancreas were the greatest. Eggs did not present differences in metal accumulation, with the exception of manganese, between sites or between crabs at different embryonic stages. For this metal, eggs from female crabs inhabiting mudflats showed higher levels than those from inhabiting salt marshes. Moreover, eggs in the late embryonic stage also showed the highest manganese concentrations. Metal levels in sediments, however, were similar in both sites. These are the first results of metal level in biota and sediments in this particular environment. Such results could be used as a baseline for the monitoring of metal levels in future studies in Mar Chiquita Coastal Lagoon. © 2009 Springer Science+Business Media, LLC.

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