Patagonian Region Research Articles

The role of temperature in shaping Culex acharistus mosquitoes life history traits in its southern limit of distribution (Patagonia-Argentina)

There is substantial evidence showing that temperature have a great impact on insects behavior, phenology and life histories. Because of mosquito global importance as disease vectors, in temperate regions where climatic conditions could be only borderline suitable for mosquito development, there is a growing interest in understanding the effect of temperature shifts on vital statistics to more accurately define how such changes could impact distribution and abundance patterns, as well as disease transmission cycles. We determined the role of ambient temperature under fluctuating conditions in shaping Culex acharistus (Diptera: Culicidae) life history traits, and estimated its development threshold and physiological time, in its southern limit of distribution in the Argentine Patagonia region. Four horizontal life tables were conducted under natural fluctuating temperature range in Esquel city (42°S – 71°W; 563 m a.s.l.), during spring-summer (17°C), summer (15.4°C), summer-autumn (12.7°C) and autumn-winter (5.6°C) seasons. Larvae, pupae and adult traits were recorded. The mean duration of the experiments varied between 28 to ≅100 days for spring-summer and autumn-winter seasons. Only during the cold season experiment pupae experienced the most severe temperatures and freeze-thaw cycles, and failed to reach adult stage. We found that larva and pupa development time, adult emergence time and longevity significantly increased with decreasing temperatures, while larval survival was greatest at an intermediate temperature and decreased toward low and high values. Also, protandry was observed and males emerge 2 days before females across seasons. Temperature development threshold and physiological time estimated for larva + pupa were 5.98°C and 211.24°C-days. Our study contributes to a growing body of knowledge by examining the effect of seasonal changes in temperature on mosquito life history traits. Results obtained here can be applied as useful parameters in the development of population dynamic models, improving current mosquito control strategies in cold-temperate regions.

Potential effects of climate change on the growth response of the toxic dinoflagellate Karenia selliformis from Patagonian waters of Chile

Northern Patagonia (41–44°S) is affected by climatic, hydrological and oceanographic anomalies, which in synergy with processes such as global warming and acidification of the coastal oceans may affect the frequency and intensity of harmful algal blooms (HABs). Greater frequency of HABs has been reported in the southeastern Pacific Ocean, including blooms of the toxic dinoflagellate Karenia selliformis, causing massive mortality of marine fauna in the oceanic and coastal areas of Patagonia. The objective of this study was to determine the effects of temperature and pH interaction on the growth of K. selliformis (strain CREAN_KS02), since these factors have wide seasonal fluctuations in the Patagonian fjord ecosystem. The CREAN_KS02 strain isolated from the Aysén Region (43°S) was used in a factorial experiment with five pH levels (7.0, 7.4, 7.7, 8.1 and 9.0) and two temperatures (12 and 17 °C) during a period of 18–21 days. Results indicated a significant effect of temperature and pH interaction on growth rate (range 0.22 ± 0.00 to 0.08 ± 0.01 d−1) and maximum density (range 13,710 ± 2,616 to 2,385 ± 809 cells mL−1) of K. selliformis. The highest density and growth of K. selliformis was found at 12 °C with a reduced pH (7.0–7.7). The results suggest that the current environmental conditions of coastal Patagonia, waters of low temperature and relatively low pH, may be favorable for the development of blooms of this species during autumn. We suggest that there is natural plasticity of K. selliformis in a wide pH range (7.0–8.1) but in a narrow low temperature range (10.6–12.9 °C), values that are typically recorded in the oceanic region of northern Patagonia. In contrast, in an extreme climate change scenario (ocean warming and coastal acidification) in northern Patagonia, a negative effect on the growth of K. selliformis may be expected due to amplification of the acidification effects caused by the thermal stress of high temperature water.

Unveiling species diversity within the toxic diatom genus Pseudo-nitzschia from the fjords and channels of Magallanes (48°- 51° S), Chile

Species of the potentially toxic diatom genus Pseudo-nitzschia are common components of the phytoplankton community in the fjords and channel systems of the Magallanes Subantarctic region. Despite Pseudo-nitzschia species forming recurrent harmful algal blooms (HABs) in this region, Chilean monitoring programs have historically simply grouped species of this genus into two groups (P. group seriata and P. group delicatissima) according to basic cell morphology under light microscopy, or as Pseudo-nitzschia spp. Based on ultrastructural features obtained from scanning electron microscopy (SEM), this study revealed more diversity within the genus than previously thought, identifying six Pseudo-nitzschia species in the Magallanes Subantarctic region (48°-56°S) from samples collected during a 11-year period (2006–2017). Most importantly, the study: 1) represent the first report on diversity and distribution of Pseudo-nitzschia species in this Patagonian region; 2) expanded the known distribution of P. australis and P. fraudulenta along the Chilean coast (down to 50° S); 3) confirmed previous records of P. pungens and P. cf. delicatissima; and 4) formally confirm the presence of P. heimii and P. calliantha in subantartic waters.

Coexistence of grasses and shrubs in Patagonian steppes. Norm or exception?

AbstractQuestions(1) Is the co‐dominance of grasses and shrubs a general feature of Patagonian steppes? (2) At a local scale, does it change with domestic grazing intensity or decadal changes in precipitation?LocationsQuestion 1. Patagonia region in southern South America. Question 2. Shrub–grass steppes (45°24′S, 70°17′W) subjected to different grazing intensity for decades.MethodsWe sampled vegetation to estimate perennial grass and shrub cover at two scales: regional and local. At the regional (phytogeographical) scale, we sampled grazed steppes under different climates and soils (n = 324 sites over ca. 487,000 km2). At the local scale, we sampled paddocks subjected to known grazing management, from commercial intensive densities of sheep to total (experimental) exclusion. Also, in the same site, we sampled permanent plots (25 years old) in a grazing exclosure to study the effects of precipitation variation.ResultsMixed communities are the predominant form of community organization in the Patagonia region. At the regional scale, shrub cover was negatively related to grass cover and communities where shrubs had higher cover than grasses represent 54% of the data set. At the local scale for an arid steppe, perennial grasses had higher cover than shrubs, regardless of grazing pressure. The shrub‐to‐grass ratio was increased only by intensive grazing. Permanent plots in a grazing‐excluded paddock indicate that decadal xeric or humid climate periods decrease or increase total cover, respectively. Surprisingly, the relative shrub‐to‐grass ratio did not change significantly.ConclusionsAlthough perennial grasses and shrubs cover are negatively correlated, they coexist in the Patagonian steppes under a wide range of climate, soil and grazing conditions. At a local scale, selective herbivory promotes species replacement but did not substantially change the life‐form covers. Water shortages, as well as periods of water surplus, similarly affect both life forms without compromising their coexistence.

EL LENGUAJE DE LOS HUESOS. DIÁLOGOS ENTRE PALEONTÓLOGOS Y ARQUEÓLOGOS EN EL MUSEO DE LA PLATA

This paper presents a historical outlook of the scientific and academic track of, at least, two disciplines that used to work together on the palaeoenvironment and its transformation since humans’ appearance. This inter and multidisciplinary practice became consolidated as the zooarchaeological research line that currently has great development not only in Argentina but also in the world. In this long academic history, Ameghino’s ideas have been proven steadily to the present. Our goal is to display the main concepts from the interdisciplinary production of biologists and archaeologists working in the Pampean and Patagonian regions.

Aerobiology in High Latitudes: Evidence of Bacteria Acting as Tracer of Warm Air Mass Advection reaching Northern Antarctic Peninsula.

Despite the extent use of geochemical tracers to track warm air mass origin reaching the Antarctic continent, we present here evidences that microorganisms being transported by the atmosphere and deposited in fresh snow layers of Antarctic ice sheets do act as tracers of air mass advection from the Southern Patagonia region to Northern Antarctic Peninsula. We combined atmospheric circulation data with microorganism content in snow/firn samples collected in two sites of the Antarctic Peninsula (King George Island/Wanda glacier and Detroit Plateau) by using flow cytometer quantification. In addition, we cultivated, isolated and submitted samples to molecular sequencing to precise species classification. Viable gram-positive bacteria were found and recovered in different snow/firn layers samples, among dead and living cells, their number concentration was compared to northern wind component, stable isotopes of oxygen, d18O, and the concentration of crustal elements (Fe, Ti and Ca). Use of satellite images combined with air mass back-trajectory analysis obtained from the NOAA/ HYSPLIT model corroborated the results.

Exploring the potential of Fabiana imbricata Ruiz et Pav. (“Pichi”) against pest insects and pathogenic microorganisms for crop protection

• Fabiana imbricata extracts represents green insecticides for fruit fly control • Scopoletin is the main constituent of Fabiana imbricata active extract • Leaf fractions show repellency activity against Acanthoscelides obtectus adults • The extract has effect on detoxifiying enzimes such as carbolxyl esterases and acetylcholinesterase of Tenebrio molitor . • the components of these fractions could not inhibit the expression of acid and alkaline phosphatase in the intestine of T. molitor The loss of agricultural products by pests and microorganisms is intensely fought with synthetic products that can pose a serious threat to the environment, health, and foods. The use of plant-derived products in the management of these organisms is a sustainable and safe alternative. In this study, we investigated Fabiana imbricata , a very well-known species of Solanaceae found in the Patagonian region. The toxicological effects of its fractions were tested against Drosophila melanogaster and Tenebrio molitor . These fractions were also screened for repellency on Acanthoscelides obtectus and antimicrobial activity. Additionally, the mortality assay of D. melanogaster larvae revealed higher activity for the stem (LC 50 value of 7.5 µg/mL) and leaf (LC 50 value of 19.8 µg/mL) petroleum benzine fractions. T. molitor larvae needed to be exposed to a high concentration of stem fractions (200 and 300 µg/mL) to observe about 50 and 90% mortality, respectively. Moreover, repellency after 4 h of exposure was mainly observed with the stem dichloromethane fraction (conc. 100 µg/mL). The acetate fraction of the stem (FE-C) was responsible for the greatest growth inhibition of the tested bacteria ( E. coli, L. monocytogenes, L. innocua, Salmonella sp., and S. aureus ). Based on the findings, stem fractions were selected for studies of toxicity in non-target organisms and systemic effects on proteins and detoxification enzymes from T. molitor larvae. The fractions tested against adult bees were safe up to 500 µg/mL for 4 h of exposure and 48 h of observation. Total proteins and enzymes AChE, GST/GSH, and Carboxylase were significantly reduced, mainly with FE-C. In contrast, ACP and ALP were up-regulated, with the same fraction as the major inducer. The chemical profiles of the fractions analyzed by GC-MS and NMR showed that FE-C had scopoletin as the main component. Therefore, we selected this compound for in silico analysis of AChE docking, qualitative and quantitative study of insecticide-likeness, and toxicity prediction. The results indicated that scopoletin efficiently docked with the active site of AChE. Due to the high values ​​of Relative Drug Likelihood (RDL) (2.77) and Gaussian Scoring Function (GAU) (4.19) values, ​​it can consider as potential insecticide-likeness and the toxicity prediction study showed that this compound has low toxicity to mammals. These results demonstrate that FE-C has potential as an insecticidal agent against insect pests and can be of help in combating pathogenic microorganisms present in food.

Thermal State of the Lithosphere of Patagonia Via Data of the Xenoliths

Ultramafic xenoliths and minerals present in intrusive rocks make it possible to infer the temperature and pressure of the upper mantle and lower crust, since they preserve their physical and chemical characteristics while being transported by magmatic processes. Thermal models incorporating thermo-barometric data have been developed to estimate the thermal field. Thus, the objective of this work is to use mineralogical temperature and pressure equilibrium information to estimate lithospheric thermal field in the Patagonian region bounded by latitudes 40º - 52º S and longitudes 67º - 71º W, these coordinates correspond to the Argentine provinces of Río Negro, Chubut and Santa Cruz. Experimental mineral temperature data indicate ranges of 917-1029 ºC in the Chubut province, 877-1253 ºC in the Río Negro region and 728-1196 ºC in the Santa Cruz province. The average heat flux and temperature values at the Moho depth are 40 mWm-2 and 734 ºC, respectively. Río Negro province has the highest temperature (760 ± 45 ºC) and the lowest thermal thickness value (75 ± 11 km), while Santa Cruz province has the highest heat flux (44 ± 7 mWm-2) at Moho depth, which indicates that there are possibly two plumes responsible for the deposition of xenoliths in the region: one in Río Negro province and the other in Santa Cruz.

Mapping Soil Organic Carbon Content in Patagonian Forests Based on Climate, Topography and Vegetation Metrics from Satellite Imagery

Soil organic carbon (SOC) content supports several ecosystem services. Quantifying SOC requires: (i) accurate C estimates of forest components, and (ii) soil estimates. However, SOC is difficult to measure, so predictive models are needed. Our objective was to model SOC stocks within 30 cm depth in Patagonian forests based on climatic, topographic and vegetation productivity measures from satellite images, including Dynamic Habitat Indices and Land Surface Temperature derived from Landsat-8. We used data from 1320 stands of different forest types in Patagonia, and random forest regression to map SOC. The model captured SOC variability well (R² = 0.60, RMSE = 22.1%), considering the huge latitudinal extension (36.4° to 55.1° SL) and the great diversity of forest types. Mean SOC was 134.4 ton C ha−1 ± 25.2, totaling 404.2 million ton C across Patagonia. Overall, SOC values were highest in valleys of the Andes mountains and in southern Tierra del Fuego, ranging from 53.5 to 277.8 ton C ha−1 for the whole Patagonia region. Soil organic carbon is a metric relevant to many applications, connecting major issues such as forest management, conservation, and livestock production, and having spatially explicit estimates of SOC enables managers to fulfil the international agreements that Argentina has joined.

Nutritional Composition and Bioactive Properties of Wild Edible Mushrooms from Native Nothofagus Patagonian Forests.

Nothofagus forests of the Andean Patagonian region are home to numerous wild edible mushroom (WEM) species with interesting organoleptic characteristics, although many of them have unknown nutritional and nutraceutical profiles. The proximal composition, fatty and organic acids, soluble sugars, phenolic compounds, ergosterol, as well as antioxidant and antimicrobial activity of 17 WEMs were analyzed. Carbohydrates, the most abundant macronutrients, varied between 49.00 g/100 g dw (C. magellanicus) and 89.70 g/100 g dw (F. antarctica). Significantly higher values were found for total fat in G. gargal (5.90 g/100 g dw) followed by A. vitellinus (4.70 g/100 g dw); for crude protein in L. perlatum (36.60 g/100 g dw) followed by L. nuda (30.30 g/100 g dw); and for energy in G. gargal (398 Kcal/100g) and C. hariotii (392 Kcal/100g). The most effective extracts regarding the TBARS antioxidant capacity were those of Ramaria. This is the first time that a study was carried out on the chemical composition of G. sordulenta, C. xiphidipus, F. pumiliae, and L. perlatum. The promotion of sustainable use of WEMs, including their incorporation in functional diets that choose WEMs as nutritious, safe, and healthy foods, and their use in an identity mycogastronomy linked to tourism development, requires the detailed and precise nutritional and nutraceutical information of each species.

Sisal wool skin disease in Merino sheep in the Argentine Patagonia region: Identification and molecular diagnosis of Corynebacterium bovis from skin lesions.

Sisal wool condition is a skin disease affecting Merino sheep in the Argentine Patagonia region. Corynebacterium spp. isolates have previously been isolated from skin swabs from lesions, while specific identification of the bacteria involved has not been reported. The aim of this work was to characterize the bacterial agent isolated from sisal wool lesions and to develop a diagnostic method for field surveillance. Molecular identification of a collection of 72 isolates obtained previously was performed using PCR and 16S rRNA and rpoB sequencing. A field survey was carried out on two farms in the Río Negro province of Argentine Patagonia. Swab samples from sheep with and without skin lesions were collected and analysed by PCR and culture. Isolates analysed were confirmed by sequencing as Corynebacterium bovis. Using a PCR test without culture step, all field samples from affected sheep were positive for C.bovis; samples from the healthy skin from the same animals or clinically healthy sheep all were negative. Sisal wool skin disease was associated with C.bovis infection based on culture and PCR methods; the latter may be useful for helping to pursue a disease control strategy.

Deep submarine infiltration of altered geothermal groundwater on the south Chilean Margin

Submarine groundwater discharge is increasingly recognized as an important component of the oceanic geochemical budget, but knowledge of the distribution of this phenomenon is limited. To date, reports of meteoric inputs to marine sediments are typically limited to shallow shelf and coastal environments, whereas contributions of freshwater along deeper sections of tectonically active margins have generally been attributed to silicate diagenesis, mineral dehydration, or methane hydrate dissociation. Here, using geochemical fingerprinting of pore water data from Site J1003 recovered from the Chilean Margin during D/V JOIDES Resolution Expedition 379 T, we show that substantial offshore freshening reflects deep and focused contributions of meteorically modified geothermal groundwater, which is likely sourced from a reservoir ~2.8 km deep in the Aysén region of Patagonia and infiltrated marine sediments during or shortly after the last glacial period. Emplacement of fossil groundwaters reflects an apparently ubiquitous phenomenon in margin sediments globally, but our results now identify an unappreciated locus of deep submarine groundwater discharge along active margins with potential implications for coastal biogeochemical processes and tectonic instability.

248.1: Hepatitis B virus Status of Organ Donors in Argentina

Background & Aims: Argentina is considered an area of a low prevalence of hepatitis B virus (HBV). However, the real prevalence of the disease is unknown. We aimed to study the prevalence of HBV in potential cadaveric donors. Methods: We performed a cross-sectional study to analyze data from the National Procurement of Transplantation (INCUCAI) in Argentina from 2006 to 2020. We included data from all donors, including tissue only, effective donors (those for whom transplantation was effectively done), and non-effective donors. HBV serologic tests included hepatitis B virus antigen (HBsAg), core antigen-antibody (HBcIgG), anti-HBs. These tests were performed on all donors during the procurement process. HBV status was defined as 1) active HBV: donors with positive HBsAg; 2) Past HBV infection or false positive: isolated positive HBcIgG; 3) Cured infection anti-HBs+/HBcIgG+. Results: Overall, 16140 deceased donors were denounced. Of these, 8627 (53.5%) were organ donors (7802 [90.4%] were effective) and 7513 (46.5%) were tissue donors. Demographic characteristics were age 42 ± 18 years; male/female ratio was 1.59/1. Overall, the prevalence of HBsAg was 0.37% (n=60) and of isolated HBcIgG+ was 3.6% (n=575). Among organ donors only, 328 (3.8%) presented isolated HBcIgG-positive serology. Of these, 252 (77%) were effective organ donors. Solid-organ transplants performed using isolated HBcIgG+ donors were 220 kidneys, 124 livers, and 27 intrathoracic organs. There was not significant 5-year graft and patient survival difference between HBcIgG+ receptor (kidney transplant 65% and 81%, and for liver 65% and 83% respectively) and general population (kidney transplant 67% (p0.58) and 92% (p0.77), and for liver 64% (p0.73) and 80% (p 0.83), respectively). Anti-HBs data were available in only 4455 donors of which 19% (N=847) were anti-HBs+. In those patients with positive anti-HBs, HBcIgG was positive in 8.3% (n=369). reflecting past HBV infection. Of the remaining 4086 AntiS available, only 11.7% were positive, that is, they were effectively vaccinated. The Patagonia region presented the highest prevalence of HBsAg, especially in the provinces of La Pampa (2.3%), Santa Cruz (2.2.%), and Tierra del Fuego (2.1.%). The prevalence ratio of HBsAg? among donors remained stable during the study period. Isolated HBc IgG-positive donors were only used for organ transplantation, among which 77% (252/328) were effective donors. Conclusions: The prevalence of HBsAg in deceased donors in Argentina is low. Since the probability of being a donor is random, the prevalence in this population could be close to the real one in the country.

Significant continental source of ice-nucleating particles at the tip of Chile's southernmost Patagonia region

Abstract. The sources and abundance of ice-nucleating particles (INPs) that initiate cloud ice formation remain understudied, especially in the Southern Hemisphere. In this study, we present INP measurements taken close to Punta Arenas, Chile, at the southernmost tip of South America from May 2019 to March 2020, during the Dynamics, Aerosol, Cloud, And Precipitation Observations in the Pristine Environment of the Southern Ocean (DACAPO-PESO) campaign. The highest ice nucleation temperature was observed at −3 ∘C, and from this temperature down to ∼-10 ∘C, a sharp increase of INP number concentration (NINP) was observed. Heating of the samples revealed that roughly 90 % and 80 % of INPs are proteinaceous-based biogenic particles at >-10 and −15 ∘C, respectively. The NINP at Punta Arenas is much higher than that in the Southern Ocean, but it is comparable with an agricultural area in Argentina and forestry environment in the US. Ice active surface site density (ns) is much higher than that for marine aerosol in the Southern Ocean, but comparable to English fertile soil dust. Parameterization based on particle number concentration in the size range larger than 500 nm (N>500 nm) from the global average (DeMott et al., 2010) overestimates the measured INP, but the parameterization representing biological particles from a forestry environment (Tobo et al., 2013) yields NINP comparable to this study. No clear seasonal variation of NINP was observed. High precipitation is one of the most important meteorological parameters to enhance the NINP in both cold and warm seasons. A comparison of data from in situ and lidar measurements showed good agreement for concentrations of large aerosol particles (>500 nm) when assuming continental conditions for retrieval of the lidar data, suggesting that these particles were well mixed within the planetary boundary layer (PBL). This corroborates the continental origin of these particles, consistent with the results from our INP source analysis. Overall, we suggest that a high NINP of biogenic INPs originated from terrestrial sources and were added to the marine air masses during the overflow of a maximum of roughly 150 km of land before arriving at the measurement station.

Provenance of pre- and Carboniferous sequences of the Esquel-Arroyo Pescado-Tepuel regions (Argentine Patagonia): A combined U–Pb and Hf isotope study of detrital zircon and constraints on depositional setting

Provenance and stratigraphic age of pre-Carboniferous or pre-glacial (Esquel and Arroyo Pescado formations) and Carboniferous glacial (Valle Chico Formation) metasedimentary units exposed in the southwestern sector of the North Patagonian Argentine region are analyzed by sedimentary petrology and combined U–Pb and Lu–Hf isotope on detrital zircons. Additionally, a sample of the Jaramillo Formation (Tepuel Group) allowed comparison and correlation to the Carboniferous deposits in the type area of the Tepuel-Genoa basin.Despite differences, samples of all units studied indicate deposition linked to an arc tectonic environment using ternary petrological diagrams. U–Pb detrital zircon age distribution of the Esquel Formation show a dominance of Famatinian, Pampean-Brazilian and Mesoproterozoic ages, whereas the Arroyo Pescado Formation displays a predominant Mesoproterozoic data cluster. On the other hand, the Valle Chico Formation records a main input of post-Famatinian or Chanic (Devonian) ages and minor Gondwanic (Carboniferous) ages. The Jaramillo Formation is unique due to the remarkable unimodal concentration of Gondwanic ages (Carboniferous) and the scarcity of older than Famatinian detrital zircon ages. The maximum sedimentation age is Lochkovian (Lower Devonian) for the Esquel Formation and, Tournaisian and Tournaisian-Visean (lower Carboniferous) for the Valle Chico and Jaramillo formations, respectively; the youngest records for the Arroyo Pescado Formation indicate a middle Cambrian to Middle Ordovician age. Most Mesoproterozoic zircon grains show a remarkable juvenile Hf isotopic character and a slight age difference between U–Pb and Hf TDM data. These records are equivalent to those identified in different units of the Paleozoic of the Patagonian region and the Malvinas/Falkland Islands, where the Mesoproterozoic detrital zircons with positive εHf (t) values indicative of a juvenile character are present. The conspicuous participation of Mesoproterozic zircons ages within the pre-Carboniferous units supports the probable existence of an unexposed Mesoproterozoic crust in the North Patagonian region, as mentioned by previous authors.The allochthonous or autochthonous character of South Patagonia is tested using combined U–Pb ages and initial Hf-isotope compositions of single zircons. The allochthonous alternative of South Patagonia in the pre-Carboniferous stage, favours contributions from eastern Antarctica, South Africa, Malvinas/Falkland Islands and local sources such as the Deseado Massif and the suspected Chaitenia terrane. An autochthonous scenario suggests that the North Patagonian, Deseado Massifs, Malvinas/Falkland Islands and local areas (Chaitenia terrane) were the main source for the pre-Glacial and Glacial studied units, with minor influence from distant regions of South America.

Indole-diterpenes alkaloid profiles of native grasses involved in tremorgenic syndromes in the Argentine Patagonia

One of the main intoxications to livestock in the Patagonia region of Argentina is the tremorgenic disease “Mal de Huecú", attributed to the consumption of the native grasses Poa huecu and/or Festuca argentina. In this report, five outbreaks of spontaneous intoxications were investigated. Several indole-diterpene alkaloids were identified in Poa huecu and Festuca argentina including the known tremorgen terpendole C and are likely the cause of “Mal de Huecú" disease.

Water evacuations in remote tourist regions: evaluating case studies from natural hazards in North Patagonian lakes, Argentina.

The remote North Patagonian region is a sparsely populated territory and a world famous tourist destination located on the leeward side of the Andes Mountains. Recent disasters triggered by various types of geoenvironmental hazards (including volcanic eruptions, mass-wasting processes and extreme weather events) heavily disrupted ground transport networks in a region with already limited territorial accessibilities. All these catastrophes prompted the need to evacuate or assist a number of secluded visitors, locals and livestock extemporaneously on board of coastguards and tourist passenger-ships from the shores of the many glacial lakes that make up part of the regional attraction. Despite the recurrence of these types of events, water evacuations in the region continue to be spontaneous, improvised and hazardous procedures. This contribution reconstructs and assesses a number of recent local-scale cases of lake evacuations and assistances from a number of Patagonian urban centers, rural areas and tourist sites. For each case study, we systematically elaborated on the prime components of an evacuation process, which enabled us to recognize key achievements, failures and conditioning factors for managing emergencies via water transport, most of them inherent to the studied region. Some of the complexities to emerge from case studies referred to: complex hazard-related scenarios; limited ground-based accessibilities and risk of isolation; various inter- and intra-organizational issues, incidental to natural reserves and tourist regions; a wide range of particular demographic features; and the availability and vulnerability of water transport resources. We suggested fundamental and replicable recommendations for developing water evacuation plans, also identifying forthcoming problems to solve in order to improve the management of emergencies through this alternative means of transport.Electronic supplementary materialSupplementary material (Appendix 1) is available in the online version of this article at 10.1007/s11629-021-7207-3

Associations between bacterial communities and microplastics from surface seawater of the Northern Patagonian area of Chile

The presence of microplastics in oceans and coastlines has increased during recent years due anthropogenic activities and represents a serious environmental problem. The establishment and assembly of microbial communities in these microplastics, specifically located near aquaculture activities, is not well understood. In this study, we analyzed unique and core members of bacterial communities attached to microplastics collected from three coastal environments of the South Pacific, which represent low, medium and high anthropogenic activity derived from the aquaculture industry. Microplastics were analyzed with Fourier-transform infrared spectroscopy, scanning electron microscopy, and next-generation sequencing to assess the prevailing microplastics types, and to characterize microbial communities attached to them. We identified four main types of microplastics (polypropylene, polyethylene, nylon and polystyrene) and 3102 Operational Taxonomic Units (OTUs) at the sampled sites, which were dominated by the phylum Cyanobacteria, Bacteroidetes and Proteobacteria (mainly Alpha and Gammaproteobacteria). Similarity index analysis showed that bacterial communities in microplastics differed from those found in the surrounding seawaters, and also that they varied among locations, suggesting a role of the environment and level of anthropogenic activities on the plastisphere taxa. Despite this difference, 222 bacterial OTUs were shared among the three sites representing between 34 and 51% of OTUs of each sampled site, and thus constituted a core microbiome of microplastics. Comparison of the core microbiome with bacterial communities of the surrounding seawater suggested that the plastisphere constituted a selective habitat for diverse microbial communities. Computational predictions also provided evidence of significantly enriched functions in the core microbiome. Co-occurrence networks revealed that putative ecological interactions among microplastics OTUs was dominated by positive correlations. To the best of our knowledge, this is the first study that evaluated the composition of microbial communities found in microplastics from the Patagonia region of the Southern Pacific Ocean.

The genus Pseudocleobis Pocock, 1900 (Solifugae: Ammotrechidae) in transitional Patagonia-Monte deserts, with descriptions of two new species.

Two new solifuge species of the genus Pseudocleobis (Solifugae, Arachnida) from northern Patagonia and southern Monte desert biogeographical regions are described: P. mauryi sp. nov. and P. profanus sp. nov. New records of P. huinca Maury, 1976, P. bardensis Maury, 1976 and P. solitarius Maury, 1976 are provided. The female of P. solitarius is described based on specimens from the type locality. SEM photographs, schemes of diagnostic characters, and maps of the known distributional records are provided for the five species treated here. Pseudocleobis profanus sp. nov. is closely related to P. huinca and P. bardensis, and the three species may form a species group characterized by the peculiar morphology of the male movable finger mucron and the flagellum. Ctenidia on male sternite III and IV are reported for the five species.

Emergent trophic interactions following the Chinook salmon invasion of Patagonia

AbstractIn their native range, Pacific salmon (Oncorhynchus spp.) have strong interactions with a multitude of species due to the annual pulse of marine‐derived nutrients that they deliver to streams and forests when they spawn and die. Over the past few decades, Chinook salmon (Oncorhynchus tshawytscha) has established non‐native populations throughout the Patagonia region of southern South America. Here, we provide the first assessment of the pathways through which salmon‐derived nutrients enter stream and forest food webs in Patagonia by surveying multiple streams in southern Chile to identify invertebrate and vertebrate consumers of salmon carcasses and summarizing all documented trophic interactions of Chinook salmon in Patagonia. Blowflies (Calliphoridae) were the dominant colonizer of carcasses in the riparian zone, and midge flies (Chironomidae) were the most common invertebrate on submerged carcasses. Camera trap monitoring in the riparian zone revealed consumption of carcasses or carcass‐associated invertebrates by the insectivorous passerine bird “chucao” (Scelorchilis rubecula), small rodents (black rat Rattus rattus, house mouse Mus musculus, and/or colilargo Oligoryzomys longicaudatus), the South American fox “culpeo” (Lycalopex culpaeus), and the invasive American mink (Neovison vison). A mink was filmed transferring a carcass from stream to streambank, indicating that vertebrate scavenging likely increases the degree to which marine‐derived nutrients enter terrestrial food webs. The native taxa that consume salmon are closely related to species that benefit from salmon consumption in North America, suggesting that the pathways of salmon nutrient incorporation in North American food webs have functionally re‐emerged in South America. Similarly, non‐native trout (Oncorhynchus mykiss and Salmo trutta) and mink consume salmon in Patagonia, and their eco‐evolutionary history of coexistence with salmon could mean that they are preadapted for salmon consumption and could thus be key beneficiaries of this invasion. Expanded monitoring of the abundance and impacts of salmon will be vital for understanding how these novel inputs of marine‐derived nutrients alter Patagonian food webs.