Time filter

Source Type

Bayer M.S.,CONICET | Bayer M.S.,National University of Cordoba | Morsan E.,Institute Biologia Marina y Pesquera Almirante Storni | Gordillo S.,CONICET | And 2 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2015

Amiantis purpurata shells from the San Matías Gulf (SMG) were analysed in order to compare both morphology and size throughout the late Quaternary in relation to environmental changes. Shells from modern beaches, Holocene marine assemblages (late Holocene, 3630 ± 100 years bp) and interglacial Pleistocene marine assemblages (MIS 5, 100 ka years bp) were studied by measuring the height and length, and using the elliptic Fourier analysis (EFA) to take an outline contour. The Pleistocene shells were smaller, more elliptical and with a deeper lunule than the Holocene and modern ones. No significant differences were recorded in the allometry index throughout the late Quaternary. The variation in size and shape of the A. purpurata shells could be related to the phenotypic plasticity of this species as a response to the environmental changes registered in the SMG during the Quaternary. These changes include variations in sea surface temperatures, salinities and substrates, and also water circulation changes, which would have modified nutrient availability. Morphological changes imply burrowing activity, mechanical stability, nutrient uptake and defence response to predation. Copyright © Marine Biological Association of the United Kingdom 2015

Delucchi F.,CONICET | Narvarte M.A.,Institute Biologia Marina y Pesquera Almirante Storni | Amin O.,CONICET | Tombesi N.B.,National University of the South | And 2 more authors.
International Journal of Environment and Waste Management | Year: 2011

One of the most toxic compounds that have been introduced into the marine environment is Tributyltin (TBT) used as a biocide in antifouling paints. The aim of this study was to obtain the first information of TBT pollution in sediments of three environments of the Argentinean coastline. Sediments from the Bahía Blanca estuary, San Antonio Bay and Ushuaia Bay were sampled to determine TBT and dibutyltin (DBT) concentration. The butyltin compounds were identified and quantified by gas chromatography and mass spectrometry (GC-MS). The different amount of organotin compounds detected shows dissimilar pollution levels and degradation processes along the Argentinean coasts. Copyright © 2011 Inderscience Enterprises Ltd.

Garaffo G.V.,University of the Sea | Dans S.L.,CONICET | Dans S.L.,Brown University | Pedraza S.N.,CONICET | And 8 more authors.
Marine Ecology Progress Series | Year: 2011

Several species of small cetaceans inhabit the coastal area of Patagonia (Argentina), but little is known about their distribution and the degree of overlap between them. The goal of the present study was to build habitat-selection models for small cetaceans in order to assess areas of particular importance for the different species. These models were constructed using physiographic and remotely sensed variables. From 1994 to 2007, 13 aerial surveys were conducted along the Patagonian coast (from Golfo San Matías: 40° 40'-42°14' S, 65° 00'-63°47' W to Bahía de los Nodales: 48°00' S, 65°35' W). A grid of 0.5° × 0.5° cells was constructed for the study area. Each cell was characterized by environmental variables and by the encounter rate (ER) for each cetacean species. The ER of each species was investigated in relation to environmental variables using generalized linear models, and model averaging (multimodel inference) was used to obtain a predicted ER for the different species. The correlation between the ER of different species was analyzed by Spearman rank correlation. The environmental variables that were found to be significant predictors of species distribution differed between species. The ERs of dusky dolphin Lagenorhynchus obscurus and Peale's dolphin L. australis showed a positive relationship. Commerson's dolphin Cephalorhynchus commersonii presented a more coastal distribution than the other species, and individuals were more often found feeding in estuarine zones. Knowledge of the patterns of distribution of small cetaceans along the Patagonian coast provides baseline knowledge of how these species interact with each other and their environment. Such information should be considered when managing potential areas of conflict between coastal small cetaceans and human activities. © Inter-Research 2011.

Luzzatto D.C.,Institute Biologia Marina y Pesquera Almirante Storni | Luzzatto D.C.,CONICET | Sieira R.,CONICET | Pujol M.G.,Museo Municipal de Ciencias Naturales Lorenzo Scaglia | De Diaz Astarloa J.M.,CONICET
Cybium | Year: 2012

This study aimed at sequencing the mitochondrial cytochrome b gene (cyt b) of seahorses morphologically identified as Hippocampuspatagonicus Piacentino & Luzzatto, 2004 from the two known localities where the species occur in the Argentine Sea (San Antonio Oeste and Mar del Plata). Based on the lack of substitutions within cyt b found between the individuals of both localities, the geographical range of H. patagonicus was extended up to the Northern limit of the Argentine Sea. A phylogenetic analysis comparing the cyt b sequences of Hippocampus species revealed that H. patagonicus together with H. hippocampus and H. erectus belong to a monophyletic group of species. The comparison of the cyt b sequence of Hippocampus cf. erectus from Southern Brazil with that one of H- patagonicus resulted in scarce differences. This could suggest the presence of H, patagonicus in southern Brazil, although further investigation is needed to resolve the taxonomie status of H, erectus in the South Western Atlantic.

Firstater F.N.,CONICET | Firstater F.N.,Institute Biologia Marina y Pesquera Almirante Storni | Hidalgo F.J.,CONICET | Lomovasky B.J.,CONICET | Iribarne O.O.,CONICET
Journal of Experimental Marine Biology and Ecology | Year: 2012

Bottom-up and top-down forces simultaneously influence benthic communities. However, their relative strength may vary with environmental conditions. In the Peruvian coast, the periwinkles are conspicuous grazers able to control both biofilm abundance and barnacle recruitment. Moreover, even in upwelling areas, algae living in the high intertidal may be nutrient-limited. Here we tested, in a nutrient-rich system, the relative effects of grazing and nutrient on the early succession of the high rocky intertidal. For this, we experimentally manipulated grazing and nutrient combined in a completely crossed design. Since nutrient and grazing seem to alter benthic community at different temporal scales, their effects were tested over the long-term (14. months) and the short-term (1. months). Over the long-term, barnacle cover increased throughout time, but was neither affected by grazing nor fertilization. At all sampling times fertilization increased biofilm cover and reduced bare rock, while exclusion of grazers also enhanced biofilm. The effect of grazing on bare rock varied through the succession. Macroalgae reached a maximum cover of 6.88%. Over the short-term, chlorophyll-a content was not affected by nutrient addition but was always higher in plots where grazer were excluded. Our results suggest that biofilm might be nutrient-limited in the high intertidal, despite being located in an upwelling area. However, the effects of grazers and nutrients on the biofilm are not reflected in macroalgae or barnacles, probably because of the occurrence of other structuring factors. In the short-term, grazing seems to have greater effect on biofilm, irrespective of the nutrient level, whereas over the longer-term, biofilm can take advantage of nutrient enhancement only in the absence of grazers. © 2012 Elsevier B.V..

Discover hidden collaborations