Puerto Deseado Research Articles

Energetics and development modes of Asteroidea (Echinodermata) from the Southwestern Atlantic Ocean including Burdwood Bank/MPA Namuncurá

Reproduction is a highly expensive process that during gonadal development requires an important supply of nutrients. The allocation of energy can vary throughout the reproductive cycle, between sexes and development modes. During research cruise aboard the RV Puerto Deseado in April 2016, we collected fifteen species of sea stars from the southernmost region of Argentina. The main purposes of the present study were threefold: first, to revise and report novel information on the reproductive strategies and energetic density (ED) of body components from the asteroids of the southwestern Atlantic Ocean including Burdwood Bank/ MPA Namuncura; second, to compare the ED of these body components across species with contrasting reproductive strategies; third, to provide a tool to estimate the ED from dry mass of organs of the sea star species examined. Ovaries of Diplopteraster verrucosus (a brooder with a nidamental chamber) revealed a significantly greater ED than did the testes (29.81 ± 1.38 and 17.76 ± 1.59, respectively). In Glabraster antarctica (a broadcaster with yolky eggs and facultative planktotrophic larvae), the gonads had EDs of 25.78 ± 3.16 and 19.21 ± 0.52 (females and males, respectively). While in Peribolaster folliculatus (a broadcaster with eggs with low yolk content and inferred planktotrophic larvae) there was no significant difference in the ED values between sexes (females: 22.79 ± 1.10 and males: 20.46 ± 1.05). For the pyloric caeca, ED values did not reveal any difference between sexes, although in P. folliculatus, the ED was significantly higher than that for D. verrucosus and G. antarctica (25.90 ± 1.00, 23.03 ± 0.34, and 22.66 ± 0.65, respectively). The body wall had higher ED values in D. verrucosus and P. folliculatus than that for all the sea star species analyzed (46.48 ± 1.63, 51.17 ± 1.34, respectively). Higher ED values in the ovaries could be related to the nutrition of offspring, while differences found in the body wall may reflect the skeletal structure of this body component. This research provides basic information for understanding the differences on energetic allocation when contrasting development modes are considered.

Cormorant Pellets as a Tool for the Knowledge of Parasite-intermediate Host Associations and Nematode Diversity in the Environment.

SummaryAnisakids are usually acquired through the diet. Cormorant pellets are useful to detect both parasite larval stages, and prey items which could act as intermediate hosts in the environment. The current study provides information about the feeding habits of both birds and mammals, and the diversity of parasites circulating in the environment. The objective of the study was to identify Anisakidae larvae and prey items in pellets from the Imperial shag Phalacrocorax atriceps and the Red-legged cormorant P. gaimardi, suggesting possible parasite–prey associations. A total of 92 P. atriceps’ and 82 P. gaimardi’s pellets were collected from both Punta León, and Isla Elena bird colonies, respectively, during the period from 2006 to 2010. Pellets were preserved in ethanol and hard prey item remnants, and nematode larvae were studied using standard techniques. Prey item occurrence, nematode prevalence, and mean intensity were calculated. A correspondence analysis was performed to evaluate the larvae-prey association. Contracaecum spp., Pseudoterranova spp,, Anisakis spp., Terranova spp., and Hysterothylacium spp. third-stage larvae (L3) were identifi ed in pellets. Pseudoterranova spp. and Anisakis spp. L3 predominated in the environment of Punta León, whereas Contracaecum spp. and Hysterothylacium spp. L3 predominated in the Puerto Deseado area. The highest larvae-prey association was that of Contracaecum spp. L3 with Engraulis anchoita, followed by with Odontestes sp. in P. atriceps’ pellets. Contracaecum spp. L3 were significantly related to both sprats, Sprattus fueguensis and Ramnogaster arcuatta, in P. gaimardi’s pellets. It was verifi ed that E. anchovy is the main gateway of Contracaecum spp. L3 in P. atriceps. Odonthestes sp. might act as an intermediate/paratenic host of Contracaecum spp. L3 in the area. Both sprats might play a role as intermediate/paratenic hosts of C. australe, being the main gateway into P. gaimardi in the area. Thus, pellet analysis can be postulated as a good tool for indicating parasite-host associations between anisakids, and the prey items which act as intermediate hosts.

Challenges in relative sea-level change assessment highlighted through a case study: The central coast of Atlantic Patagonia

There are areas in the world where our understanding of past sea-level changes is less robust than in others. This is partly due to the difficulty past investigators had adopting i) high-resolution elevation measurement techniques (largely available only in the last decade) and ii) standardized methodological approaches to reconstruct past relative sea levels starting from field measurements. The central coast of Atlantic Patagonia (Argentina), preserves a unique succession of coastal landforms, which scientific investigations suggest to have been formed discontinuously since at least marine isotope stage 11 up to the Holocene. Patagonian coastal deposits (in particular raised beach ridges, marine terraces and river mouth terraces) and erosional landforms (slope angles, marine notches) were studied in the past with the aim of reconstructing relative sea-level changes and provide geological evidence to constrain geophysically based models for an area affected by significant vertical displacement due to isostatic adjustment and possibly by tectonic uplift. So far, there is no general agreement about the interpretation of Patagonia landforms and deposits in terms of sea-level index points. This is certainly a gap within a planetary scale overview of sea-level change and represents an obstacle for the construction of a sound model of glacial isostatic adjustment for the area. In this paper we critically analyse previous works on sea-level change along the central coast of Atlantic Patagonia and highlight the major sources of uncertainty, including choices about calculating past relative sea levels from the elevation of indicators and the vertical datum used. We also provide a comparison between different vertical datums (tidal, gravimetric and geodetic) at a real site (Puerto Deseado) where Differential Global Positioning System measurements were performed by our team in 2016, and address the problem from a trans-disciplinary point of view. In order to obtain accurate sea-level change estimates in the area, we suggest the use of a large spectrum of sea-level markers with well-defined indicative meanings and the adoption of specific technical choices capable of minimizing instrumental errors.

Coelosphaera (Coelosphaera) koltuni sp. nov. (Porifera: Demospongiae): a new species from South Orkney Islands, Antarctica

In this work, we describe a new sponge species belonging to the genus Coelosphaera Thomson, 1873. It was collected during an Argentinean Summer Antarctic Research Cruise onboard the Research Vessel “Puerto Deseado” in March 2014, near South Orkney Islands (Antarctica), 60° 53′ S 42° 35′ W, 487-m depth. Coelosphaera (Coelosphaera) koltuni sp. nov. is a globular, fistular and hollow-shaped sponge, with significantly larger megascleres (almost twice the length) than other Antarctic and New Zealand Coelosphaera species. We provide comparative data of all the described Coelosphaera species, especially those from nearby regions.

Gastropods of the genusAntistreptusas examples of persistent molluscan lineages in the Neogene of the southwestern Atlantic

AbstractGastropods of the southwestern Atlantic genusAntistreptusDall, 1902 from extant and Neogene deposits are reviewed. Fossil specimens come from the Punta Entrada Member of the Monte León Formation (50°21′25.4″S, 68°53′05.9″W). Extant samples are from museum collections and two expeditions on board the R/V “Puerto Deseado” to Burdwood Bank (54°13.934′S, 66°30.997′W) and surroundings. Dissection of soft parts and study of the type material ofA.magellanicusDall, 1902,Euthria(Glypteuthria)contrariaStrebel, 1908, andA.rolaniCastellanos, 1986 reveal that the latter two nominal species are synonymous. Neogene material assigned to the same genus could not be distinguished as a different species. According to the stratigraphic occurrence of the fossil material, the life-span of the genusAntistreptusDall, 1902 and the speciesA.magellanicusDall, 1902 is ~22 Myr, similar to that of the bivalveCyclochlamys argentinaPastorino and Griffin, 2018.

Reproduction and developmental stages in the crinoid Isometra vivipara Mortensen, 1917 from the southwestern Atlantic

Isometra vivipara Mortensen, 1917, which was described one hundred years ago, represents a particular case within the feather stars of the southwestern Atlantic Ocean. This is a dioecious species in which the oocytes are fertilized in the ovary and not externally as in other species. Some authors have pointed out that I. vivipara stores spermatozoa in the genital pinnules of the female, although there is still no detailed data on how they reach the pinnule. Besides, this species is characterized by possessing a second sexually dimorphic trait and presents two incubation stages: one in the genital pinnules, and the second one attached in the cirri of the mother. In the present work, the reproduction and developmental stages of the I. vivipara were studied. Samples were taken from two cruises aboard the B/O “Puerto Deseado” to Burdwood Bank/MPA Namuncura at 84–642 m depth, during March/April 2016 and April/May 2017. Four developmental stages were recognized: Embryo, Doliolaria larvae (inside the brood pouches), Cystidean, and Pentacrinoids (attached in the cirri of the mother). In addition, histological analysis showed that fertilization in I. vivipara could occur between the ovary and the marsupium. The egg measurements reached 0.35 mm in diameter—on of the largest egg size within South America and Antarctica comatulids—whereas for the larvae the largest registered diameter was 0.77 mm. These results are compared and discussed with all the available information of comatulids from South America and Antarctica.

Gastropods from the Burdwood Bank (southwestern Atlantic): an overview of species diversity.

This contribution provides novel information on the diversity of gastropods from the Burdwood Bank, based on the material collected in this area, as part of the 2013 Summer Antarctic Expedition ("CAV 2013"), conducted by the oceanographic vessel PUERTO DESEADO. As part of this study, a total of 50 species are recognized, from which 19 are reported for the first time from Burdwood Bank, and at least nine other are probably new to science. Each species is here described and illustrated. The results arising from this study are combined with the previously published records in an attempt to critically compile the information for this area, with view to determine the local diversity of the group. As a result of this study, the diversity of gastropods almost double with respected to the previously published information, reaching a total of 79 species of shelled gastropods.

Spawn and development of the gastropod Americominella longisetosa (Castellanos and Fernández, 1972) (Mollusca: Buccinidae) from the Southwestern Atlantic deep sea

The buccinid Americominella longisetosa (Castellanos and Fernández, 1972) is widely distributed along the Southwestern Atlantic shelf where it is found at 200–1,250 m depth. A total of 38 egg capsules of this species were collected by the Argentine ship R/V Puerto Deseado from the Burdwood Bank/MPA Namuncurá surroundings (~ 54°36'S, 61°30'W at 298 m depth and 53°56'S, 61°30′W at 185 m depth). Egg capsules occur individually, not clustered in egg masses, are globose in shape, translucid, with thin walls measuring about 20 µm in thickness and having a triangular stalk on the side by which the capsule is fixed to its substrate. The substrate to which the capsules were attached was the internal matrix of the poriferan Mycale magellanica (Ridley, 1881). In each capsule, only one embryo develops from an egg of about 150 µm in diameter. The embryo develops by ingesting about 9,000 nurse eggs. In distinct egg capsules we found embryos at different stages of development indicating several spawn events. Hatching takes place as a crawling juvenile measuring about 8 mm in shell length and with 4 ¼ whorls, indicative of a long embryonic development within the capsule.

Asteroidea of the southern tip of South America, including Namuncurá Marine Protected Area at Burdwood Bank and Tierra del Fuego Province, Argentina

In benthic communities, echinoderms are dominant in terms of abundance and diversity, and Asteroidea play an important role in the structure of communities. In the present study, Asteroidea were sampled in the recently created Namuncura Marine Protected Area (N MPA) at Burdwood Bank (which has an average of 50–200 m depth and is delimited by abrupt slopes), the surrounding shelf break and Tierra del Fuego Province, Argentina, at 24 stations at different depths and seabeds on board the oceanographic vessel ARA “Puerto Deseado.” A total of 32 Asteroidea species were identified. The bathymetric ranges were extended for two of them, and the geographic distribution was updated for seven of them, this being their first record in the N MPA. The N MPA showed higher asteroid richness than Tierra del Fuego Province and the surrounding shelf break. Moreover, this area presented species shared with Antarctica, which enhances the importance of the Malvinas Current (formed mainly by the contribution of Antarctic waters) in the larval dispersal of some species. On the other hand, a high percentage of the species found at the N MPA presented direct development with brooding females. The N MPA represents an important biodiversity hotspot. Thus, to contribute to the formulation of precise conservation strategies and enhance its protection, it is crucial to promote and continue the efforts to know more about the ecosystems at these latitudes.

Geochemical characteristics of the infilling of ground wedges at Puerto Deseado (Santa Cruz, Argentina): palaeoenvironmental and chronological implications

Ground wedge structures of cryogenic origin are common in the Quaternary sediments along the coast of the Patagonia, and their formation is related to climatic cold events experienced by this area in the Late Quaternary. The infilling sediments of two wedges generations were analyzed in the area of Puerto Deseado. Bulk chemistry (major elements), X-ray diffraction (XRD), morphoscopic observations with Scanning Electronic Microscope (SEM) and chemical analyses of volcanic glass shards were undertaken to provide indications about infilling sediment provenience, along with chronological constraint for wedge formation. Bulk chemistry and XRD patterns indicate a significant SiO2-enriched composition of the sediment infilling compared to the most of the loess deposits of the North Argentina and the present day dust originated in Patagonia. This was interpreted as due to the nature of the bedrock present over the Deseado Massif. SEM morphoscopic characteristics of glass shards evidence typical aeolian reworking features, with impact structures and indented edges of the volcanic fragments. Chemical analyses of the glass shards indicate that they were probably generated by the H0 eruption (17,300-17,400 cal yr BP) of the Hudson volcano. Volcanological data indicate that H0 eruption dispersed toward NE, but volcanic glasses were available for reworking due to a WNW component in the western wind direction. Over the Deseado Massif structural high the glass shards mixed with sediments enriched in SiO2, and were eventually deflated further to SE reaching the present coastal area and infilling the frost cracks. The age of the glass shards (17,300-17,400 cal yr BP) and that of the sandy layer affected by cryogenic structures (14,670±750 yr BP) well constrain to the Late Glacial both wedge generations.

Spawn in two deep-sea volute gastropods (Neogastropoda: Volutidae) from southwestern Atlantic waters

The gastropods Odontocymbiola pescalia and Provocator corderoi and their egg capsules were collected by the R/V Puerto Deseado from the Mar del Plata Submarine Canyon (~ 37°53′S, at depths of 291–1404m) and from Burdwood Bank (~ 54°27′S, 128–785m). Odontocymbiola pescalia egg capsules measured 15.67 ± 3.38mm in diameter. They were subspherical in shape with an external calcareous layer. Each egg capsule contained 3–5 embryos and white material as extra embryonic food. Embryos grew to a size of up to 9.3 ± 1.1mm in mean shell length before hatching as crawling juveniles. The spawn of P. corderoi consisted of a single dome shaped egg capsule of 14.17 ± 1.5mm in diameter, attached to hard substrata by a basal membrane with a rounded outline. A curved semilunar furrow (seam) on one side of the capsules was always present. The number of embryos per capsule was 2–6. Embryos hatched as crawling juveniles with a shell length of 5.9 ± 0.6mm.The size and number of whorls in the hatchling shell suggested a slow rate of development, akin to many other deep-sea invertebrates. The egg capsules and reproductive development strategies of both species were compared with those from other congeneric representatives.

Last Interglacial sea-level highstand deduced from notches and inner margins of marine terraces at Puerto Deseado, Santa Cruz Province, Argentina

Fil: Bini, Monica. Istituto Nazionale di Geofisica e Vulcanologia; Italia. Universita degli Studi di Pisa; Italia

Larval digenean preferences in two sympatric snail species at differing tidal levels off the Atlantic coast of Patagonia.

Larval stages of the trematodes Maritrema madrynense and Hemiuroidea fam. gen. et sp. differentially parasitized Siphonaria lessonii and S. lateralis, two sympatric pulmonate snail species on the rocky intertidal shore at Puerto Deseado, south-western Atlantic coast of Patagonia, Argentina. Snail specimens were collected at two sampling sites with contrasting physical-chemical characteristics. One site, in the upper intertidal, was exposed to sewage from fish-processing plants, greater hydrodynamic forcing and desiccation, a wider temperature range, longer exposure to ultraviolet radiation and higher abundance of birds. The second site, in the lower intertidal, was generally characterized by less stressful environmental conditions. At both sites, S. lateralis showed a markedly higher density than S. lessonii (55.13 vs. 5.87 snails/m2, respectively). Despite this, the prevalence of both digeneans was higher in S. lessonii (17.37% and 3.52% for M. madrynense and Hemiuroidea, respectively) than in S. lateralis (0.09% and 0% for M. madrynense and Hemiuroidea, respectively). This study demonstrates high parasite specificity for the host. Low densities of S. lessonii are attributed to castration of parasitized hosts and reduction of their physiological condition. The prevalence and intensity of infection of both digenean parasites were higher at the more stressful, upper intertidal site, thus suggesting that a higher abundance of birds and exposure to sewage pollution may promote the transmission of trematodes.

Redescription of the deep-sea colonial ascidian Synoicum molle (Herdman, 1886): first record since its original finding during the Challenger Expedition

The colonial ascidian Synoicum molle (Herdman, 1886) was recorded for the first time after its original description. The slope area where S. molle was discovered during the Challenger Expedition (1872-1876), located at the mouth off Rio de La Plata (Argentine Sea), still remains highly underexplored. During a series of deep-sea prospections along the SW Atlantic (A.R.A. Puerto Deseado, August 2012), 7 colonies of S. molle were collected few km from the type locality. The finding permitted to perform, for the first time, a complete morphological description of this species. The proper identification of marine species, especially deep-sea organisms, has implications for the general knowledge of biodiversity, a necessary tool for the conservation and study of ecosystem benefits that marine environments provide.

Análisis de la producción central y la entrega de hidrógeno, aplicado al Circuito Patagónico Austral

El departamento Deseado de la Provincia de Santa Cruz, Argentina, presenta la mayor potencialidad de producción de hidrógeno electrolítico del país, a partir de las tres fuentes de energías primarias sustentables: eólica, solar, biomásica. Allí, la Planta de Hidrógeno de Pico Truncado cuenta con capacidad de producción central de hidrógeno de 100m3 de H2/día, suficiente para abastecer 353 vehículos con combustible híbrido denominado HGNC, constituido por el corte 12% V/V de hidrógeno en GNC, (in situ) en cada estación.
 A partir del costo de producción, se analiza el costo de entrega de hidrógeno al circuito Patagónico Austral conformado por: Puerto Deseado, Fitz Roy, Caleta Olivia, Las Heras, Comodoro Rivadavia, Sarmiento y Los Antiguos. Considerando diversos parámetros locales, se determinó como forma de entrega más rentable el gasoducto virtual, con costo total de hidrógeno estimado en 6,5 USD/kg H2 y de HGNC despachado en la estación en 0,50 USD/Nm3.

Assessing levels of POPs in air over the South Atlantic Ocean off the coast of South America

The occurrence of persistent organic pollutants (POPs) in the atmosphere of the near-coast South Atlantic Ocean was studied. Air samples were collected using a high-volume air sampler (filter and polyurethane foam) on board the Argentinean research cruise R/V Puerto Deseado (CONICET). Samples were analyzed for 50 polychlorinated biphenyl (PCBs), 22 organochlorine pesticides (OCPs) and 14 polybrominated diphenyl ethers (PBDEs). These POPs classes showed a trend of decreasing levels from near-shore to open ocean sites. OCPs and PCBs were in the same order of magnitude (2.71–87.1pg/m3 and 9.56–130pg/m3, respectively) while PBDEs levels were significantly lower (0.69–2.58pg/m3). Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, chlordanes, hexachlorocyclohexanes (HCHs) and heptachlors were between 0.20 and 17.8pg/m3, while drines and hexachlorobenzene (HCB) were at lower levels (0.28–3.71pg/m3). The most frequently detected PCBs were congeners 32, 28, 44, 52, 95, representing >50% of the total. The PBDEs congener pattern was dominated by congener 209 (70%), followed by 47 and 99 (16% and 7%, respectively). Air parcel back trajectories for the study period provided few insights as trajectories mainly stemmed from the open ocean with limited inputs from continental sources. These results indicate that the concentration of POPs (namely PCBs, OCPs, and PBDEs) in air remain elevated in the near-shore environment and then drop-off substantially beyond a distance of about 400km. This has implications for the loading of POPs and delivery to the marine environment in the near coastal zone.

Southwestern Atlantic species of conoidean gastropods of the genus Aforia Dall, 1889.

A new species of the conoidean genus Aforia is described from the Southwestern Atlantic in Argentine deep waters. Detailed study of the type material of nominal species, Aforia goniodes (Watson, 1881) and its synonym Pleurotoma clara Martens, 1880, both described from deep waters off Argentina, allowed recognition of a new species. Aforia obesa sp. nov. was collected from 7 stations in 647 to 1,398 m depth during three cruises to the Mar del Plata submarine Canyon in the Argentine continental slope on the R/V "Puerto Deseado". Shells, radulae, penises and opercula of adults and juveniles of A. obesa n. sp. from several localities are illustrated, described and compared to other living congeners.

Hydroacoustical evidence of the expansion of pelagic swarms of Munida gregaria (Decapoda, Munididae) in the Beagle Channel and the Argentine Patagonian Shelf, and its relationship with habitat features

Squat lobsters are highly diversified and widespread decapods, of which only three species form pelagic swarms. Here we infer the expansion of Munida gregaria populations in the Beagle Channel and the Argentine Patagonian Shelf by means of acoustic surveys of pelagic swarms. We also describe the habitat characteristics in which these swarms occur. Acoustic data was collected during three multidisciplinary scientific cruises on board of the R/V Puerto Deseado during 2009, 2012 and 2014. Despite differences in the environmental conditions between the two surveyed areas, between 2009 and 2014 pelagic swarms increased their occurrence and abundance both in the Beagle Channel and on the Argentine Patagonian Shelf. Towards the end of the studied period, pelagic swarms of M. gregaria occurred in new locations, supporting the notion of a population expansion. Within the Beagle Channel swarm expansions were more marked than on the Patagonian Shelf. We here postulate that M. gregaria expansions occur in association with productive areas of the Argentine continental shelf, such as frontal zones, favoured by the squat lobster phenotypic plasticity that permit to exploit resources in both the neritic and benthic environments. At a regional scale on the Patagonian Shelf, three main groups of pelagic swarms of M. gregaria were clearly associated to respective frontal zones. The information presented here is necessary to understand fluctuations in both distribution and abundance patterns of a key species on the Argentine continental shelf. These fluctuations could be direct or indirect indicators of changes in the ecosystem.

Scleractinian corals recorded in the Argentinean Antarctic expeditions between 2012 and 2014, with comments on Flabellum (Flabellum) areum Cairns, 1982

In this contribution, we provide a list of the scleractinian corals recorded during the Argentinean Antarctic expeditions on board the oceanographic vessel Puerto Deseado (Argentina) in the austral summers in 2012, 2013 and 2014. The identified taxa consist of six solitary species ( Flabellum impensum, F. flexuosum, F. areum, Caryophyllia antarctica, Paraconotrochus antarcticus and Javania antarctica ), recorded from 19 sampling sites located off the Antarctic Peninsula and South Shetland and South Orkney islands. We also update the information of F. areum, previously known only from south-west Atlantic waters, extending its distribution range to Antarctic waters and its upper bathymetric range to 218 m. Keywords: cold-water corals; Antarctica; range extension; bathymetric range extension; Scleractinia. (Published. 4 July 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 29762, http://dx.doi.org/10.3402/polar.v35.29762

Structural study of the ovary, oogenesis and brooding inTonicia lebruni(Polyplacophora Chitonidae) from Patagonia

AbstractTonicia lebruni, a common, lower intertidal and subtidal chiton inhabiting Patagonian rocky shores, is a gonochoristic iteroparous species producing large eggs (≈ 400 μm in diameter), which are fertilized and brooded within the pallial groves until released as juveniles. A free larval stage is absent, despite this, T. lebruni is widely distributed along the south‐western Atlantic. At Puerto Deseado, T. lebruni has a marked seasonality in the reproductive cycle, reproducing only once a year. The reproductive period is quite short and defined in time: spawning and brooding take place during the late austral winter and beginning of spring. Recovery of the female gonad starts very soon after spawning. Oogenesis takes about 10–11 months for completion. Brood size is correlated with length of maternal individual. The number of embryos per brood varied between 785 and 5945. Extensive resorption of abortive eggs is viewed as related to limitation of space available for brooding. The egg hull is formed by a large number of minute pentagonal or hexagonal plates each one bearing a short spine bent onto the egg surface. The morphology and the surface of the hull could contribute to the cohesiveness of the brooded egg mass within the pallial grooves.