Coast Of Argentina Research Articles

Paleozoic crustal blocks of onshore and offshore central Argentina: New pieces of the southwestern Gondwana collage and their role in the accretion of Patagonia and the evolution of Mesozoic south Atlantic sedimentary basins

The southwestern Gondwana basement block configuration in the central Argentinean offshore area was analyzed using gravimetric, magnetic and seismic data and existing onshore tectonic models. The resultant maps, the distribution of the Mesozoic and Cenozoic basins and Paleozoic structural features were used to validate the interpretations and to produce a new regional tectonic model. Pre-Carboniferous southwestern Gondwana of South America was interpreted as an open margin formed from east to west by the Dom Feliciano Belt, the Río de la Plata Craton, the Pampean Belt and the Pampia and Cuyania terranes. The collision of the Patagonia allochthonous terrane during the Late Paleozoic resulted in the development of the Ventania-Cape Fold Belt, which was mapped for the first time off the Argentinean coast out to 600 km from the shore. A strong change in the orientation of the Fold Belt is referred to as the Colorado Syntaxis, a mirror image of the Cape Syntaxis in South Africa. This change reflects the buttressing effect of the cratonic blocks that hamper the northward propagation of syncollisional deformation and resulted in a 180-km shift of the orogenic front. The Mesozoic basins and the basement block distribution were analyzed. The Pampean Belt, a deformed area produced by the Pampia accretion to the cratonic area, is the locus to two episutural basins, the General Levalle and Macachín basins. The Salado Basin was interpreted as an episutural basin controlled by a 2.1–2.0 Ga suture within the Rio de la Plata Craton. The Colorado Basin is composed of four segmented depocenters that reflect different emplacement controls: the location of the western Colorado Basin was controlled by the Upper Paleozoic orogen; the distributions of the central and eastern Colorado depocenters, orthogonal to the continental boundary, were also strongly influenced by the Upper Paleozoic structures and were offset by lineaments that reflect Dom Feliciano fabric; the Colorado Basin external depocenter that parallels the continental margin was also controlled by these lineaments. We interpret a time gap of some 50 Ma between the beginning of the evolution of the margin-orthogonal depocenters and the Atlantic breakup.

Environmental Factors Affecting the Distribution of the Red-Legged Cormorant in Argentina: A Regional Scale Approach

Red-legged Cormorants (Phalacrocorax gaimardi) breed along a broad stretch of the Pacific coast and a section of the Argentinian coast on the Atlantic Ocean. To understand factors that might determine the breeding range along Argentina, physical and environmental characteristics of cliffed coastlines used by Red-legged Cormorants were compared with those not used. Red-legged Cormorant colonies were found in longer cliffed coastlines (mostly longer than 250 m) with shallow waters (median depth =12 m) and high sea productivity close to the coast (median chlorophyll a concentration = 4.4 mg/m3). Within the Red-legged Cormorants' breeding range the probability of occurrence of their colonies increased with the length of the cliffed coastline and decreased with the median sea depth around the colony. Mixed colonies were found in coastal areas with cliffs where the seawater close to shore was deeper (deeper than = 13 m). North of its distribution, sea productivity close to the coast was lower (median chlorophyll a concentration = 1.6 mg/m3) than within its distribution, and cliff faces were more exposed to the strong prevailing winds, which can blow eggs and chicks from their nests. South of its distribution, the climatic characteristics were more adverse to breeding success: higher precipitation, lower ambient temperature, and higher wind speed than within its distribution. At this scale of study (regional), new aspects of habitat structure of the Red-legged Cormorant, such as sea primary production, water depths and climatic features, were indentified. All these aspects could be affecting habitat selections by this species.

Remarks on some scale worms (Polychaeta, Polynoidae) from the Southwest Atlantic with notes on the genus Eucranta Malmgren, 1866, and description of a new Harmothoe species

In a collection of polychaetes from the Southwest Atlantic, off the Argentinian coast, ten scale worm species of the family Polynoidae were found. The following nine species are already known to science and their synonymy, diagnostic characters, and distribution are given together with remarks on taxonomy and geographical distribution: Eucranta mollis (McIntosh, 1876), Eucranta notialis Monro, 1936, Harmothoe exanthema (Grube, 1858), Harmothoe magellanica (McIntosh, 1885), Polyeunoa laevis McIntosh, 1885, Halosydna patagonica Kinberg, 1856, Halosydnella australis (Kinberg, 1856), Lepidasthenia esbelta Amaral and Nonato, 1982 and Showapolynoe marmorata (Hartmann-Schroder, 1965) n. comb. Additionally, a new Harmothoe species was discovered and is described in detail. Differentiating characters of the new species and Harmothoe ciliata Monro, 1936 from the Magellan region are discussed. Since two species of Eucranta Malmgren, 1866 out of four known worldwide occur in the Southwest Atlantic and since the genus has never been revised in the past, we discuss the distinguishing characters of the species and present a synoptic table. Furthermore, we raise two subspecies to species level, i.e. Eucranta villosa notialis Monro, 1936 to E. notialis Monro, 1936 and Harmothoe brevipalpa ciliata Monro, 1936 to H. ciliata Monro, 1936. Two new junior synonyms are also recognised: Harmothoe fimbriata Hartmann-Schroder, 1965 is referred to H. ciliata Monro, 1936 and Halosydna brasiliensis Kinberg, 1857 to Halosydnella australis (Kinberg, 1856). An identification key is given to all species found in the considered area.

Schizymenia dubyi (Rhodophyta, Schizymeniaceae), a new introduced species in Argentina

Schizymenia dubyi (Chauvin ex Duby) J. Agardh is a red alga of the order Nemastomatales that is native to Europe, Asia and Oceania. The first specimen of this seaweed from the Argentinian coast was collected in the Chapadmalal intertidal wave-cut platform (38°12′S, 57°40′W) in September 2008. Taxonomic identification of the species was made on the basis of vegetative and reproductive characters and confirmed by DNA sequence analysis of the rbcL gene. The S. dubyi samples collected in the field were represented by foliose gametophytes as well as crustose tetrasporophytes. The gametophytes were distributed in patches of c. 50% coverage of the analysed quadrants (n = 20). Gametophyte abundance was 3.1±2.5 (mean±SD) plants per quadrant (0.04 m2). All these were fertile females. Molecular results placed the specimens from Argentina within the S. dubyi clade, closely related to S. dubyi from Japan and France.

Caracterización de la brisa de mar en el balneario de Monte Hermoso, Argentina

Sea breezes are local meteorological phenomena with an annual influence over the coast, however few studies have been performed on the argentine coast. The objective of this investigation is to characterize and establish the frequency of sea breezes in Monte Hermoso coastal city, located in the Southwest of Buenos Aires Province (61 o 15’ 55’’ W, 38 o 59’ 33’’ S). The study period was from December of 2007 to July of 2010. The methodology of Zubillaga and Piccolo (1977/78a) and Garcia and Piccolo (2004) was used to identify the occurrence of the sea breeze. Meteorological data obtained from a meteorological station located on the coastal city was used. Synoptical maps and satellite images were also used in the study. 40 days with sea breezes were identified. Their major frequency was in summer. July did not present any event. Their predominant direction was from ESE and SE and the average duration were two hours and a half. The average velocity was 4.5 m s-1.

The diet of the South American Tern: the Argentine Anchovy as key prey in the non-breeding season

The Argentine Anchovy (Engraulis anchoita) is one of the most important pelagic fishery resources of the Patagonian Shelf and is known to be an important prey item for several seabirds of the northern Argentine coast. The South American Tern (Sterna hirundinacea) is endemic to the Atlantic and Pacific coasts of South America and, on the Atlantic coast, breeds from central Brazil to southern Argentina. Large non-breeding flocks form during the austral winter and spring from southern Brazil to northern Patagonia. The diet of the South American Tern was studied over three consecutive non-breeding seasons through the analysis of regurgitated pellets. The Argentine Anchovy comprised >80% (index of relative importance) of fish prey in the diet, and remained important throughout the study period. Other important fish prey were Cornalito Silverside (Odonthestes incisa), Pejerrey Silverside (O. argentinensis) and Stripped Weakfish (Cynoscion guatucupa). The growing interest in commercially fishing Argentine Anchovies makes it important that studies are conducted to determine the potential effect of the harvest of Anchovies on South American Terns and other top predators.

Similarity in parasite community structure may be used to trace latitudinal migrations of Odontesthes smitti along Argentinean coasts

The aims of this study were to determine the existence of migratory movements and to identify ecological stocks of the silverside Odontesthes smitti along its distribution in the Southern Atlantic Ocean, using metazoan parasites as biological tags. Samples were obtained from San José Gulf (SJ) (42° 25' S; 64° 07' W) and Nuevo Gulf (NG) (42° 47' S; 65° 02' W) in north Patagonia during winter and summer and in waters off Mar del Plata (MDP) (38° 03' S; 57° 32' W), Bonaerense region, during winter. Fifteen parasite species were collected. Multivariate statistical procedures on parasite community data showed strong effect of host size on the structure of parasite assemblages. Taking into account the variations among samples due to host size, the differential structure of parasite communities between SJ and NG suggests that fish inhabiting these localities could belong to different ecological stocks. Fish from MDP and SJ caught in summer showed similar composition in their parasite assemblages, which is congruent with a migratory cycle that implies that fish caught in MDP during winter inhabit SJ during summer. Further evidence of the Patagonian origin of MDP O. smitti is the presence of the digenean Proctotrema bartolii in fish from both regions. Proctotrema bartolii is acquired by O. smitti only in the Magellanic province, where its intermediate host, Darina solenoides, is distributed. The analyses suggest that O. smitti inhabiting north Patagonian gulfs could belong to different ecological stocks and that O. smitti caught in MDP could have come from SJ.

Estuarine mesozooplankton dynamics on a short-term time scale: role of semidiurnal tidal cycle

Wageningen University Hydrology and Quantitative Water Management, Environmental Sciences Group (Atlas, Droevendaalsesteeg 4, 6708 PB, Wageningen, The Netherlands) Descriptors: Mesozooplankton, Acartia tonsa , Tidal variability, Estuaries, Argentina. Descritores: Mesozooplancton, Acartia tonsa , Ciclo de marea, Estuario, Argentina. In estuaries and coastal areas, planktonic organisms are subject to tidal, diurnal and seasonal environmental changes (MARQUES et al., 2009). Knowledge of the variability of zooplankton communities on different spatial and temporal scales is a prerequisite for the understanding of ecosystem dynamics. Tidal currents and estuarine circulation are well known phenomena that contribute to both vertical and horizontal redistribution of planktonic organisms (MORGADO et al., 2003. Moreover, biological mechanisms may also account for a significant part of the temporal variation in zooplankton community structure (MARQUES et al., 2009). Planktonic communities have presumably developed adaptations in order to compensate for or resist dispersive losses (LAM-HOAI et al., 2006), thus resulting in recurrent patterns of zooplankton distribution. The Bahia Blanca Estuary constitutes a mesotidal system with a semidiurnal tidal cycle, the tides being one of the most important sources of energy (PERILLO; PICCOLO, 1991). The temporal and spatial dynamics of the mesozooplankton in this estuary have been extensively investigated (e.g. HOFFMEYER 2004; HOFFMEYER et al., 2008) but none of these studies has considered the short-term variability associated with tidal cycles. The objectives of the present study were to describe the influence of the tidal cycle on mesozooplankton variability and to compare the mesozooplankton distribution of two zones in the main channel of the estuary: its northern margin and the deeper central zone. The Bahia Blanca Estuary is a coastal plain system (38°45´S; 62°22´W) on the Atlantic coast of Argentina (Fig. 1). It is formed by several NW to SE tidal channels separated by extensive intertidal flats, low marshes and islands (PICCOLO; PERILLO, 1990). The tides and winds have been considered the main factors controlling the water turbulence processes (PICCOLO; PERILLO, 1990), especially in the inner zone where the tidal height is maximal (tidal range of up to 3.6 m). Tidal currents are reversible with maximum surface velocities of about 1.3 m s

Morphodynamic characteristics in a tidal inlet: San Blas, Argentina

A tidal inlet on the Argentinean coast is studied. An integrated approach of combining detailed bathymetry survey, seabed sampling and tidal current measurements was used to characterize the tidal inlet morphodynamics. A Phase Measuring Bathymetric System (PMBS) “GeoSwath Plus” from GeoAcoustics Ltd. with centimetric precision and a mean swath coverage of 160 m, was used to recognize bedform morphologies and to determine bedform dynamics by comparison of successive surveys . Tidal velocities were recorded during a complete tidal cycle using an ADCP mounted on a ship operating at a frequency of 650 kHz. Maximum tidal currents, of the order of 2 m s − 1 , exhibit different patterns across the channel. While maximum ebb currents dominate in the central and southern area of the channel, flood maximum currents dominate on the northern flank. The complex morphology of a dune field in an inlet and the resulting 3-D dune movement mechanism are also presented. In the middle of San Blas channel, a field with symmetrical large dunes (10–100 m in spacing) and very large dunes (> 100 m in spacing) 4.5 to 5 m in height was found. Dune migration rates were measured by comparing two successive morphological maps of the field, reaching a rate up to 21 m year − 1 toward the ocean. In contrast, the smaller dunes present on the northern border of the field migrate in an inward direction at a rate of 15.7 m year − 1 .

Southernmost occurrence of Syngnathus folletti on a temperate coastal lagoon of Argentina

We report the occurrence of a mature male Syngnathus folletti in the inlet channel of Mar Chiquita coastal lagoon (37°44′S 57°25′W, Buenos Aires, Argentina). This record constitutes the southernmost report for the species. Mar Chiquita coastal lagoon is characterized by mudflats surrounded by a large cord-grass area but not by grass beds which are seen to be a suitable habitat for S. folletti. Therefore, oceanic winds that allow warmer northern waters to approach the coast of Argentina could be the cause of the presence of the species.

The energy cycle and structural evolution of cyclones over southeastern South America in three case studies

[1] In this paper, the Lorenz energy cycle over a limited area was applied for three cyclones with different origins and evolutions, where each of them was formed in an important cyclogenetic region near southeastern South America. The synoptic conditions and energetics were analyzed during each system's life cycle and showed important relationships between their energy cycle and the evolution of their vertical structure. In the case of the weak baroclinic cyclone which formed on Brazil's south-southeastern coast, the analysis showed that it originated through a midlevel cutoff low with contribution from barotropic instability. Its evolution would indicate potential transition to a hybrid system if the convective activity were stronger. The system that occurred in the La Plata River mouth had features of an oceanic bomb-type cyclogenesis and showed an important contribution from the available potential energy generation term through the latent heat release by the convection. Meanwhile, the system of the southern Argentina coast presented a classical baroclinic development of extratropical cyclogenesis in the energy cycle, from the wave amplification up to the final occlusion of the associated frontal system. These analyses revealed that the development of some cyclones that occur in eastern South America can present different mechanisms that are not related to the classical extratropical cyclogenesis.

CELL WALL VARIABILITY IN THE GREEN SEAWEED CODIUM VERMILARA (BRYOPSIDALES CHLOROPHYTA) FROM THE ARGENTINE COAST(1).

Cell wall chemistry in the coencocytic green seaweed Codium vermilara (Olivi) Delle Chiaje (Bryopsidales, Chlorophyta) is well understood. These cell walls are composed of major amounts of neutral β-(1→4)-D-mannans (Mn), sulfated polysaccharides (SPs), which include pyranosic arabinan sulfates (ArpS), pyruvylated galactan sulfates (pGaS), and mannan sulfates (MnS); also minor amounts of O-glycoproteins are present. In this study, cell wall samples of C. vermilara were investigated with regard to their monosaccharide composition and infrared spectra (using Fourier transform infrared spectroscopy coupled to principal component [FTIR-PC] analysis). Samples from three different populations of C. vermilara from the Argentine coast showed: (i) an important variation in the relative arabinan content, which increases from north to south, and (ii) a measurable degree of cell wall variability in the sulfate distribution between the different sulfated polysaccharides, independent of the amount of each polysaccharide present and of total sulfate content. When cell wall composition was analyzed over three consecutive years in a single geographic location, the quantity of Mn and overall sulfate content on SPs remained constant, whereas the pGaS:ArpS molar ratio changed over the time. Besides, similar cell wall composition was found between actively growing and resting zones of the thallus, suggesting that cell wall composition is independent of growth stage and development. Overall, these results suggest that C. vermilara has developed a mechanism to adjust the total level of cell wall sulfation by modulating the ArpS:pGaS:MnS molar ratio and also by adjusting the sulfation level in each type of polymer, whereas nonsulfated Mn, as the main structural polysaccharide, did not change over the time or growing stage.

Latitudinal gradients in macroalgal biodiversity in the Southwest Atlantic between 36 and 55°S

Different groups of marine benthic organisms show contrasting latitudinal patterns of biodiversity. The widely accepted paradigm of increasing biodiversity towards the tropics does not seem to be valid for macroalgal floras of the Southern Hemisphere. We compiled a database summarizing the distributional ranges of macroalgae along the coast of Argentina to test whether biodiversity decreases towards lower latitudes, as in the Pacific coast of South America, and whether breaking points in the geographical distribution can be recognized in one or more areas of the Southwest Atlantic south of 36°S. We found a clear trend of decreasing biodiversity with decreasing latitude. The interpretation of some biodiversity declines is confounded by changes in the intensity of the sampling effort. A 51% reduction in algal species richness between 42 and 41°S coincides with the boundary between the Argentine and Magellanic Zoogeographic Provinces. This sharp breaking point is related to a thermal anomaly caused by long residence times of water masses within San Matias Gulf, suggesting an upper thermal tolerance limit for most Antarctic/sub-Antarctic seaweeds. A further reduction occurs at 38–37°S. This breaking point can be explained by the disappearance of suitable hard substrata, since rocky outcrops give place to wide extensions of sandy beaches. The impoverished algal assemblage inhabiting the northern coast of Argentina is mainly related to the reduction or disappearance of the Antarctic/sub-Antarctic floristic component. This area is characterised by a predominance of widely distributed species, Chlorophytes and opportunistic filamentous or foliose algae.

Relationships between the spatial distribution of oligochaetes (Annelida, Clitellata) and environmental variables in a temperate estuary system of South America (Río de la Plata, Argentina)

The oligochaete assemblage on the Argentine coast of the Río de la Plata estuary was sampled seasonally within environments having different types of disturbances. Three habitats were sampled: sediments free of vegetation, sediments within bullrush stands and substrates with Limnoperna fortunei. The species richness, evenness and Shannon–Wiener diversity values were different among those habitats. The only dominant species (according to the Kownacki index) was Nais variabilis. Mean density values varied between 400 and 199,500 ind./m2. Organic matter, ammonium and phosphates correlated positively with the mean oligochaete abundance, but not with the granulometry. Physicochemical variables and nutrient levels were measured and their relation to the sampling sites assessed through a principal component analysis (41.8% cumulative variance). The canonical correspondence analysis (41.2% cumulative variance) indicated that the oligochaetes distributed along both a eutrophication–pollution gradient and a turbidity–conductivity gradient. These results would be useful for assessing the ecological status of estuaries for a subsequent implementation of appropriate sustainability-management policies.

Plastic ingestion in Franciscana dolphins, Pontoporia blainvillei (Gervais and d’Orbigny, 1844), from Argentina

Plastic debris (PD) ingestion was examined in 106 Franciscana dolphins (Pontoporia blainvillei) incidentally captured in artisanal fisheries of the northern coast of Argentina. Twenty-eight percent of the dolphins presented PD in their stomach, but no ulcerations or obstructions were recorded in the digestive tracts. PD ingestion was more frequent in estuarine (34.6%) than in marine (19.2%) environments, but the type of debris was similar. Packaging debris (cellophane, bags, and bands) was found in 64.3% of the dolphins, with a lesser proportion (35.7%) ingesting fishery gear fragments (monofilament lines, ropes, and nets) or of unknown sources (25.0%). PD ingestion correlated with ontogenetic changes in feeding regimes, reaching maximum values in recently weaned dolphins. Because a simultaneous increase in gillnet entanglement and the bioaccumulation of heavy metals take place at this stage, the first months after trophic independence should be considered as a key phase for the conservation of Franciscana dolphin stocks in northern Argentina.

Far from home: Record of a vagrant striped dolphin in Patagonia with notes on diet, parasites and age determination

The striped dolphin, Stenella coeruleoalba ( Meyen, 1833), is a pelagic small cetacean with primary distribution in tropical and subtropical waters. Here, we present a record of a vagrant individual of striped dolphin in Patagonia, out of its distribution range. The animal was 1 year old, measured 148 cm. and weighted 35 Kg. The specimen was classified as immature due to the small development of the epididym and the absence of spermatozoa in testicular smear. Helminths found belong to two families of Cestoda: cysts of Phyllobothrium delphini (Phyllobothriidae) and Tetrabothrius sp. (Tetrabothriidae). In addition, 1 Pholeter gastrophilus (Digenea: Pholeteridae) was collected. In the stomach we found two cephalopod beaks, identified as argentine shortfin squid and lesser shining bobtail and 6 crystallines of non-identified small fishes. This stranding event constitutes the most southern record for the species at the Argentine coast and highlights the importance of systematically recording strandings as an integral part of any program aimed at monitoring the well-being of local cetacean communities.

Biomasss and microzooplankton seasonal assemblages in the Bahía Blanca Estuary, Argentinean Coast

We investigated the occurrence and seasonal variation of the biomass of rotifers, tintinnids, the heterotrophic dinoflagellate Gyrodinium fusus and copepod nauplii in the Bahía Blanca Estuary (38°42′S61°50 ′W), Argentina, during an annual cycle. The rotifers fauna comprised three species, while the tintinnids were represented by sixteen species. The biomass of the rotifers fluctuated between 0.62 and 8.90 µgC l−1. The biomass of the tintinnids fluctuated between 0.13 and 9.37 µgC l−1, the biomass of the nauplii stages between 1.78 and 7.65 µgC l−1; while the biomass of G. fusus varied from 0.26 and 7.94 µgC l−1, these results are compared to estimates of microzooplankton in other regions. We analysed the presence of the different groups in relation to the environmental variables, based on point-biserial correlation. Salinity fluctuated between 25.14 and 36.64; temperature between 7.5 and 23.2°C, solar radiation between 0.9 and 30.8 MJ m−2d−1 and Secchi distance between 0.25 and 1.43 m. Rotifers were correlated positively with temperature, chlorophyll-a and Secchi depth and negatively with salinity. The tintinnids were positively correlated with salinity. Gyrodinium fusus was positively correlated with Secchi depth, and chlorophyll-a, and negatively with temperature and solar radiation. Nauplii stages were negatively correlated with chlorophyll-a. Based on the occurrence of the microzooplankters in relation to the physico-chemical variables, it was possible to establish two seasonal assemblages: (a) the co-occurrence of the rotifers and the heterotrophic dinoflagellate G. fusus during the winter–spring; and (b) the tintinnids and nauplii larvae during the summer. We conclude that, in this estuary, physico-chemical variables are the forcing factors that directly, or indirectly, influence the seasonal assemblages of the microzooplankton.

Like a "Helpless Animal" ( D 41)? Like a Cautious Woman: Joyce's "Eveline," Immigration, and the Zwi Migdal in Argentina in the Early 1900s

Like a "Helpless Animal" (D 41)? Like a Cautious Woman:Joyce's "Eveline," Immigration, and the Zwi Migdal in Argentina in the Early 1900s Laura Barberan Reinares (bio) In his 1972 essay "Molly's Masterstroke," Hugh Kenner challenges the "conventional and superficial" readings of "Eveline" that suggest this (anti)heroine remains paralyzed in the end, unable to embrace a promising future with Frank in Buenos Aires.1 Katherine Mullin, for her part, presents compelling evidence on the discourses of white-slave trafficking circulating in Europe around the time Joyce was writing and revising "Eveline" for publication.2 In this note, I will provide further key facts supporting Kenner's and Mullin's reading of the story, since a historical look at the circumstances of Frank's tales further reinforces questions about the sailor's honesty. "Eveline" was first published in The Irish Homestead on 10 September 1904. One month later, on 8 October, Joyce moved to Pola for a brief period and later to Trieste, where he began his permanent exile. By that time, heavy immigration from Europe to Argentina had already started; as H. S. Ferns observes, "in the early 1820's, Argentina excited interest as a new Eldorado in Liverpool and London, and attracted both people and capital."3 Between 1830 and 1930, sporadic waves of Irish immigrants reached Argentinean coasts in search of a better future, tempted by the "spectacularly rapid economic and cultural development" happening during those years.4 These groups, however, constituted a noticeable minority when compared to the influx from other nations such as Spain, Italy, France, and Germany (to a lesser degree). By 1914, "around one-third of the country's population was foreign-born, and around 80 percent of the population comprised immigrants and those descended from immigrants since 1850," with Italians and Spaniards encompassing the greatest slice of the foreign community.5 Thomas F. McGann explains that, in fact, "one-half of the total of economically active people in the country in 1914 were foreigners."6 As Sidney Feshbach suggests in his response to Kenner's argument, it sounds credible that Frank could have attempted a new life in Buenos Aires,7 but a deeper look at the historical context raises questions about the successful picture he paints of himself and thus [End Page 529] about his intentions. The most obvious of Frank's fabrications lies in the seductive "stories of the terrible Patagonians" he tells the young girl (D 39). A quick look at any Argentinean history book can confirm 1) that the Patagonians had long been wiped out by the time Frank traveled around the world, and 2) that they were not nearly as "terrible" as Frank portrays them. Don Gifford notes that "[i]n late Victorian times little was known of [the Patagonians] except that they were said to be the tallest of human races," while he further observes that "[l]egend took over from there and created a race of near monsters."8 In reality, Jonathan C. Brown explains, the native Patagonians were "quite small . . . families or clans" of hunters who "moved mainly on foot and set camps based on the seasons and hunting opportunities"; their "tools were simple, usually bone and stone weapons and scrapers, products of their Stone Age existence."9 When the Spaniards arrived in the sixteenth century, the conquistadores set in motion a systematic crusade of annihilation against the native aborigines in Argentina, which was relatively easy to accomplish because the tribes were scattered around the territory and never managed to constitute strong empires such as the Incas in Peru or the Aztecs and Mayans in Mexico. This near genocide continued for centuries until General Julio A. Roca's infamous "Conquest of the Desert" in 1879, where he completed "the end of indigenous resistance [by extermination]" and, therefore, the "southern Pampas and Patagonia became open for settlement," according to Brown (287). Unlike most of the rest of South America, Argentina had very few of its native inhabitants left by 1879.10 From a historical standpoint, then, the "terrible Patagonians" Frank describes to Eveline were clearly a myth, while one can speculate that the author possibly knew that the monstrous Patagonians only existed in...

Southernmost records of bottlenose dolphins, Tursiops truncatus

Bottlenose dolphins (Tursiops spp.) are cosmopolitan animals widely distributed in waters of both hemispheres. The taxonomy of Tursiops has long been controversial, with over 20 specific names being published, and subspecies and inshore/offshore forms being proposed. In the southwestern South Atlantic, subspecies T. truncatus truncatus and T. truncatus gephyreus were proposed for specimens along the coasts of Brazil, Uruguay, and Argentina. Sightings of bottlenose dolphins are common along the coast of Argentina as far south as the Province of Chubut (ca. 46°S). Here, we summarize and discuss the southernmost records of bottlenose dolphins. We cannot make inferences about the species or subspecies to which these animals belong given the small number of specimens. Future studies of external measurements, pigmentation, DNA, and isotopes from both sides of the continent should help clarify the situation off southern South America. Furthermore, research is needed to explore a possible link between an effect of general global warming and the Tursiops specimens found this far south. The sighting and specimens described here, at 53°S–nearly 55°S, are the southernmost records for the genus and extend the range of the species in the southern South Atlantic.

Organotin compounds in sediments of three coastal environments from the Patagonian shore, Argentina

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 Bahia 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.