scholarly journals Using Geochemical Fingerprints for Assessing Sediment Source Apportionment in an Agricultural Catchment in Central Argentina

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3632
Author(s):  
Yanina Garcias ◽  
Romina Torres Astorga ◽  
Guillermo Ojeda ◽  
Sergio de los Santos Villalobos ◽  
Samuel Tejeda ◽  
...  
Keyword(s):  
Sediment Accumulation ◽  
Natural Ecosystems ◽  
Small Catchment ◽  
Geochemical Tracers ◽  
Central Argentina ◽  
San Luis ◽  
Geomorphological Units ◽  
Semi Arid Region ◽  
Erosion Hotspots ◽  
Unmixing Model

In the hilly semi-arid region of central Argentina, where the agricultural frontier expands at the expense of natural ecosystems, soil erosion is one of the most alarming environmental problems. Thus, obtaining knowledge about the dynamics of erosive processes and identifying erosion hotspots constitutes a primary scientific objective. This investigation is focused on estimating the apportionments of main sources of sediments, at the mouth of a small catchment called Durazno del Medio, located in the province of San Luis, Argentina. Elemental Analysis, measured by Energy Dispersive X-ray Fluorescence (EDXRF), was used to select potential geochemical fingerprints of sediment. The unmixing model MixSIAR was applied to approximate the contribution of each identified source in the sediment accumulation areas at the mouth of the catchment. Potential sediment sources were selected using two criteria: (i) a hierarchical approach to identify the main geomorphological units (GUs) and (ii) the main land uses (LU), recognized by examining satellite images and field recognitions. The selected geochemical tracers were able to distinguish sources located in the Crystalline basement hills with loess-patched (CBH) as the main sediment contributors.

scholarly journals Xenodon histricus (Jan, 1863) (Squamata: Dipsadidae): distribution extension and new province record in Argentina

Check List ◽  
2015 ◽  
Vol 11 (5) ◽  
pp. 1737
Author(s):  
Julia Soledad D'Angelo ◽  
Federico Lisandro Agnolín ◽  
Florencia Anyelen Godoy
Keyword(s):  
South America ◽  
San Jose ◽  
Central Argentina ◽  
San Luis

Xenodon histricus is probably the least known species of its genus in South America. In Argentina it has not been collected since 1937, and most records were restricted to the northeastern forests of the country. We report finding this species in 1995 at San José del Morro, San Luis province, Central Argentina. This report fills a gap in the distribution of this taxon, and constitutes the most recent record of the species for the country.

scholarly journals Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints

2011 ◽  
Vol 62 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Dario Gioia ◽  
Claudio Martino ◽  
Marcello Schiattarella
Keyword(s):  
Sediment Accumulation ◽  
Radiometric Dating ◽  
Sedimentation Rates ◽  
Southern Apennines ◽  
Short Term ◽  
Small Catchment ◽  
Fluvial Terraces ◽  
Denudation Rates ◽  
Land Surfaces

Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints Age constraints of geomorphological markers and consequent estimates of long- to short-term denudation rates from southern Italy are given here. Geomorphic analysis of the valley of the Tanagro River combined with apatite fission track data and radiometric dating provided useful information on the ages and evolution of some significant morphotectonic markers such as regional planated landscapes, erosional land surfaces and fluvial terraces. Reconstruction of paleotopography and estimation of the eroded volumes were perfomed starting from the plano-altimetric distribution of several orders of erosional land surfaces surveyed in the study area. Additional data about denudation rates related to the recent and/or active geomorphological system have been obtained by estimating the amount of suspended sediment yield at the outlet of some catchments using empirical relationships based on the hierarchical arrangement of the drainage network. Denudation rates obtained through these methods have been compared with the sedimentation rates calculated for two adjacent basins (the Pantano di San Gregorio and the Vallo di Diano), on the basis of published tephrochronological constraints. These rates have also been compared with those calculated for the historical sediment accumulation in a small catchment located to the north of the study area, with long-term exhumation data from thermochronometry, and with uplift rates from the study area. Long- and short-term denudation rates are included between 0.1 and 0.2 mm/yr, in good agreement with regional data and long-term sedimentation rates from the Vallo di Diano and the Pantano di San Gregorio Magno basins. On the other hand, higher values of exhumation rates from thermochronometry suggest the existence of past erosional processes faster than the recent and present-day exogenic dismantling. Finally, the comparison between uplift and denudation rates indicates that the fluvial erosion did not match the tectonic uplift during the Quaternary in this sector of the chain. The axial zone of the southern Apennines should therefore be regarded as a landscape in conditions of geomorphological disequilibrium.

scholarly journals Sobre la presencia de Amaranthus palmeri (Amaranthaceae) en Argentina On the presence of Amaranthus palmeri (Amaranthaceae) in Argentina

1970 ◽  
Vol 48 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Sergio Morichetti ◽  
Juan José Cantero ◽  
Cesar Núñez ◽  
Gloria E. Barboza ◽  
Andrea Amuchastegui ◽  
...  
Keyword(s):  
Geographical Distribution ◽  
Amaranthus Palmeri ◽  
Central Argentina ◽  
San Luis ◽  
First Time

Summary: On the presence of Amaranthus palmeri (Amaranthaceae) in Argentina. Amaranthus palmeri, a species native from USA and Mexico, is cited for the first time for the Argentinean adventitious flora mainly in the Córdoba province and also in San Luis and La Pampa provinces. The species is described and illustrated and their geographical distribution is mentioned.Key words: Amaranthus palmeri, Central Argentina, adventitious flora.Resumen: Amaranthus palmeri, especie nativa de Estados Unidos de Norte América y México, se cita por primera vez para la flora adventicia argentina sobre la base de ejemplares coleccionados principalmente en la provincia de Córdoba, además de San Luis y La Pampa. Se describe e ilustra la especie y se menciona su distribución geográfica.Palabras clave: Amaranthus palmeri, Argentina central, flora adventicia.

scholarly journals The Morelloid clade of Solanum L. (Solanaceae) in Argentina: nomenclatural changes, three new species and an updated key to all taxa

PhytoKeys ◽  
2020 ◽  
Vol 164 ◽  
pp. 33-66
Author(s):  
Sandra Knapp ◽  
Franco Chiarini ◽  
Juan J. Cantero ◽  
Gloria E. Barboza
Keyword(s):  
New Species ◽  
New Taxa ◽  
High Elevation ◽  
San Juan ◽  
Distribution Maps ◽  
Central Argentina ◽  
San Luis ◽  
Three New Species ◽  
La Rioja

Since the publication of the Solanaceae treatment in “Flora Argentina” in 2013 exploration in the country and resolution of outstanding nomenclatural and circumscription issues has resulted in a number of changes to the species of the Morelloid clade of Solanum L. (Solanaceae) for Argentina. Here we describe three new species: Solanum hunzikeri Chiarini & Cantero, sp. nov., from wet high elevation areas in Argentina (Catamarca, Salta and Tucumán) and Bolivia (Chuquisaca and Tarija), S. marmoratum Barboza & S. Knapp, sp. nov., from central Argentina in Catamarca, La Pampa, La Rioja, San Juan and San Luis, and S. tiinae Barboza & S. Knapp, sp. nov., from the mountains of Jujuy, La Rioja, Salta and Tucumán. We provide descriptions, illustrations and distribution maps for all new taxa. A table of nomenclatural changes and additional taxa now known to occur in Argentina summarizes additions and changes since the “Flora Argentina”. We also provide an updated key, including all new taxa for the country, to facilitate identification and further exploration.

scholarly journals Satellite-based analysis of recent trends in the ecohydrology of a semi-arid region

2013 ◽  
Vol 17 (10) ◽  
pp. 3779-3794 ◽  
Author(s):  
M. Gokmen ◽  
Z. Vekerdy ◽  
W. Verhoef ◽  
O. Batelaan
Keyword(s):  
Arid Region ◽  
Potential Evapotranspiration ◽  
Natural Ecosystems ◽  
Management Interventions ◽  
Supplementary Irrigation ◽  
Spatially Distributed ◽  
Recent Trends ◽  
Semi Arid Region ◽  
Year 2000 ◽  
Semi Arid

Abstract. We present a regional framework for an integrated and spatiotemporally distributed assessment of human-induced trends in the hydrology and the associated ecological health of a semi-arid basin where both human activities (i.e. agriculture) and natural ecosystems are highly groundwater dependent. To achieve this, we analysed the recent trends (from year 2000 to 2010) in precipitation, evapotranspiration (actual and potential) and vegetation greenness (i.e. NDVI) using a combination of satellite and ground-based observations. The trend assessment was applied for the semi-arid Konya Basin (Turkey), one of the largest endorheic basins in the world. The results revealed a consistent increasing trend of both yearly evapotranspiration (totally 63 MCM yr−1 from croplands) and mean NDVI (about 0.004 NDVI yr−1 in irrigated croplands), especially concentrating in the plain part of the basin, while no significant trends were observed for the precipitation and potential evapotranspiration variables. On the contrary, a consistent decreasing trend of both yearly evapotranspiration (totally −2.1 MCM yr−1) and mean NDVI (−0.001 NDVI yr−1) was observed in the wetlands, which also cannot be explained by trends in precipitation and potential evapotranspiration. The emerging picture suggest that the greening trend of the vegetation and increasing of evapotranspiration in the plain are related to land cover changes (i.e. conversion into irrigated croplands) and to the intensification of the supplementary irrigation for agriculture, which in turn caused drying out of some wetlands and the natural vegetation which mostly depend on the groundwater, the main source of irrigation water as well. Our study presented an example of the utility of spatially and temporally continuous RS data in assessing the regional trends in hydrological and ecological variables and their interactions in a spatially distributed manner in a semi-arid region, which can also be adapted to other regions. Such spatiotemporally distributed analysis at the basin level is particularly important considering that most of the water management interventions also take place at this scale.

Early juvenile pterosaurs (Pterodactyloidea: Pterodaustro guinazui) from the Lower Cretaceous of central Argentina

2004 ◽  
Vol 41 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Laura Codorniú ◽  
Luis M Chiappe
Keyword(s):  
Lower Cretaceous ◽  
Early Stage ◽  
Allometric Growth ◽  
Lack Of Fusion ◽  
Lacustrine Deposits ◽  
Central Argentina ◽  
San Luis ◽  
Caudal Vertebrae ◽  
New Material ◽  
Anatomical Information

We report on two juvenile specimens of Pterodaustro guinazui, a medium-sized, filter-feeding pterodactyloid pterosaur from the Lower Cretaceous (Albian) lacustrine deposits of the Lagarcito Formation of central Argentina (Sierra de Las Quijadas, San Luis Province). Both specimens lack the skull, but one is otherwise nearly complete and articulated, and the other is more fragmentary. Their small size (~300 mm of wingspan), the lack of fusion of several postcranial bones, the minimal epiphyseal ossification, and the porous appearance of the periosteal surfaces indicate the specimens died at a very early stage of postnatal development. The presence of derived characters unique, within Pterodactyloidea, to P. guinazui (e.g., caudal vertebrae exceeding 16 elements) supports the proposed specific identification of the specimens. The new material provides anatomical information previously unknown for P. guinazui and sheds light on allometric transformations during the growth of this pterosaur. Comparisons with more mature and much larger individuals support two major allometric trends: (i) the negative allometric growth of the proximal portion of the forelimb, and (ii) the positive allometric growth of the metacarpal IV.

Dormancy and germination in three Acacia (Fabaceae) species from central Argentina

2006 ◽  
Vol 16 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Guillermo Funes ◽  
Paula Venier
Keyword(s):  
Arid Region ◽  
Temperature Pattern ◽  
Optimal Temperature ◽  
Seed Colour ◽  
Central Argentina ◽  
Temperature Regimes ◽  
Semi Arid Region ◽  
Colour Morphs ◽  
Semi Arid ◽  
Germination Requirements

We studied dormancy and germination requirements of seeds of Acacia aroma, A. caven and A. furcatispina from a semi-arid region of central Argentina. Imbibition experiments were performed to determine the rate of water uptake in seeds. To determine optimal temperature for germination, seeds were incubated at three temperature regimes (15/5, 25/15 and 35/20°C) with a 12/12 h daily photoperiod or in total darkness. Additionally, differences in dormancy and germination in seed colour morphs of A. aroma were studied. Seeds of A. aroma and A. caven had impermeable coats, while those of A. furcatispina did not. Seeds of the three species showed the same pattern of germination. Germination percentages were significantly lower at 15/5°C than at 25/15 or 35/20°C. The germination temperature pattern found for these species is probably related to the summer seasonal nature of rainfall in the study area. In A. aroma, seeds of the two colour morphs showed a similar pattern of dormancy and germination.

scholarly journals Satellite based analysis of recent trends in the ecohydrology of a semi-arid region

2013 ◽  
Vol 10 (5) ◽  
pp. 6193-6235 ◽  
Author(s):  
M. Gokmen ◽  
Z. Vekerdy ◽  
W. Verhoef ◽  
O. Batelaan
Keyword(s):  
Arid Region ◽  
Potential Evapotranspiration ◽  
Natural Ecosystems ◽  
Management Interventions ◽  
Supplementary Irrigation ◽  
Spatially Distributed ◽  
Recent Trends ◽  
Semi Arid Region ◽  
Year 2000 ◽  
Semi Arid

Abstract. We present a regional framework for an integrated and spatiotemporally distributed assessment of human-induced trends in the hydrology and the associated ecological health of a semi-arid basin where both human activities (i.e. agriculture) and natural ecosystems are highly groundwater dependent. To achieve this, we analysed the recent trends (from year 2000 to 2010) in precipitation, evapotranspiration (actual and potential) and vegetation greenness (i.e. NDVI) using a combination of satellite and ground-based observations. The trend assessment was applied for the semi-arid Konya basin (Turkey), one of the largest endorheic basins in the world. The results revealed a consistent increasing trend of both yearly evapotranspiration (totally 63 MCM yr−1 from croplands) and mean NDVI (about 0.004 NDVI yr−1 in irrigated croplands), especially concentrating in the plain part of the basin, while no significant trends were observed for the precipitation and potential evapotranspiration variables. On the contrary, a consistent decreasing trend of both yearly evapotranspiration (totally −2.1 MCM yr−1) and mean NDVI (−0.001 NDVI yr−1) was observed in the wetlands, which also cannot be explained by trends in precipitation and potential evapotranspiration. The emerging picture suggest that the greening trend of the vegetation and increasing of evapotranspiration in the plain are related to land cover changes (i.e. conversion into irrigated croplands) and to the intensification of the supplementary irrigation for agriculture, which in turn caused drying out of the some of the wetlands and the natural vegetation which mostly depend on the groundwater, the main source of irrigation water as well. Our study presented an example of the utility of spatially and temporally continuous RS data in assessing the regional trends in hydrological and ecological variables and their interactions in a spatially distributed manner in a semi-arid region, which can also be adapted to other regions. Such spatiotemporally distributed analysis at the basin level is particularly important considering that most of the water management interventions also take place at this scale.

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