¿Qué es el estuario de Bahía Blanca?

El estuario de Bahía Blanca es uno de los accidentes geográficos menos conocidos de la costa atlántica de la provincia de Buenos Aires (Argentina). Se pueden apreciar interesantes y hasta excepcionales características biológicas, geomorfológicas y oceanográficas. Es un área de algo más de 3000 km2 que, en su tipo, es sólo superada en extensión en la Argentina por el estuario del Plata. Este artículo de divulgación científica se pregunta por qué este notable desconocimiento de uno de los accidentes costeros más llamativos del país; incluye información sobre diversos tipos de estuarios, detalles sobre cangrejales y otros temas, así como lecturas sugeridas

Dinámica de aguas superficiales de tres períodos continuos de Landsat; diferencias subregionales en llanuras argentinas

[EN] The Pampean region in Argentina is an extensive plain characterized by abundant shallow lakes that fulfill many environmental, ecological, and social functions. This study aims to detect the multiannual lake area changes in this region during 2001-2009 using remote sensing, including lakes as small as ≥10,000 m2 or 1 ha. Landsat scenes of the wet (2008-2009), normal (2006), and dry (2008-2009) seasons were obtained, and using remote sensing techniques, the number and area of shallow lakes were calculated. The spatiotemporal variation of shallow lakes was studied in different climate periods in eight singular subregions. Spatial associations between annual precipitation and lake number and area were analyzed through the development of a Geographic Information System (GIS) at a subregional scale. During the study period the total lake area in the Pampean region decreased by 5257.39 km2 (62 %), but each subregion showed different responses to climatic events. In seven of them, the differences between climate periods prove to be statistically significant (P>0.01). The relationship between precipitation and lake number and area revealed the domain of positive association. We conclude that climate factors play a dominant role in lake changes across the Pampean plains. However, other factors such as origin, topographic and edaphic characteristics intensify or mitigate changes in surface hydrology.[ES] La Región Pampeana en Argentina es una extensa planicie caracterizada por abundantes lagunas que cumplen numerosas funciones ambientales, ecológicas y sociales. Este estudio tiene como objetivo detectar los cambios plurianuales del área lagunar en esta región durante el período 2001-2009 utilizando la teledetección, incluidos lagos tan pequeños como ≥ 10.000 m2 o 1 ha. Se obtuvieron escenas Landsat de las estaciones húmeda (2008-2009), normal (2006) y seca (2008-2009) y, mediante técnicas de teledetección, se calculó el número y el área de las lagunas. Se estudió su variación espacio-temporal en diferentes períodos climáticos en ocho subregiones singulares. Se analizaron las correlaciones espaciales entre la precipitación anual y el número y el área de los lagos mediante el desarrollo de un Sistema de Información Geográfica (SIG). Durante el período de estudio el área total de lagos en la región pampeana disminuyó en 5.257,39  km2 (62 %), pero cada subregión mostró diferentes respuestas a los eventos climáticos. En siete de ellos, las diferencias entre periodos climáticos resultan estadísticamente significativas (P>0,01). La relación entre la precipitación con el número y área de las lagunas reveló el dominio de asociaciones positivas. Si bien el clima juega un papel dominante en los cambios en las lagunas de planicie, otros factores, como el origen, las características topográficas y edáficas, intensifican o mitigan los cambios en la hidrología superficial.Authors would like to thank the Consejo Nacional de Investigaciones Científicas y Técnicas for supporting this study. Besides, to the United States Geological Survey for supplying the information analyzed in this study. This work was carried out with the aid of a grant from the Inter-American Institute for Global Change Research (IAI) CRN3038, which is supported by the US National Science Foundation (Grant GEO-1128040)Aliaga, VS.; Piccolo, M.; Perillo, G. (2021). Surface water extent dynamics from three periods of continuous Landsat time series; subregional differences across Argentine plains. Revista de Teledetección. 0(58):131-145. http://hdl.handle.net/10251/169769OJS13114505

The Holocene evolution of Caleta de los Loros, NE Patagonia, Argentina

Geomorphological and sedimentary records from coastal lagoon and beach-ridge systems may serve as valuable archives for the local reconstruction of key parameters influencing past shoreline configuration and trends in long-term coastal evolution. We here present observations on the sedimentology, chronology and surface properties of a modern swash-arrested macrotidal lagoon located on the northern shore of San Matías Gulf, NE Patagonia, Argentina. The study is based on remotely sensed data, GPS-RTK measurements, shallow vibracorings and a large number of samples dated using optically stimulated luminescence (OSL). Caleta de los Loros is composed of a tide-dominated, mature coastal lagoon, several sets of wave-built beach ridges, and a large field of transgressive parabolic dunes. The system is located in a morphological depression within an elongated stretch of cliffed shoreline composed of friable sand and gravel stones. Despite the prevalence of favorable conditions for the formation of prograded coastal deposits since the mid Holocene transgression, the OSL chronology established in this study yielded surprisingly young ages. Sedimentary successions in the distal part of the system formed prior to c. 2300 a BP, while the larger and more exposed western part of the system and the lagoon formed over the last c. 1000 a BP. A c. 4 km wide strandplain prograded rapidly between c. 1000 - 450 a BP, while most lagoonal deposits yielded younger, though subrecent ages between c. 600 – 70 a BP. The chronology and spatial arrangement of landforms evidence a large-scale switch-over in the directional component of sediment supply likely triggered by shifts in climate regime. The new observations fit well with recent paleoenvironmental and archaeological reconstructions from the area suggesting an association of the timing of local coastal development with global climate signals in the late Holocene. Even though we were not able to identify or benchmark the precise triggers of geomorphological change at Caleta de los Loros, our study presents a striking illustration of the potential importance of sensible environmental changes on the rapid and non-linear sedimentary development of a natural coastal system