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Validation of water reflectance using in situ data is essential to ensure the quality of ocean colour satellite-derived products useful for water quality monitoring, like turbidity and chlorophyll-a concentration. Since December 2021, the HYPERNETS automated hyperspectral system has been collecting data in the optically complex and highly turbid waters of the Río de la Plata, an ideal scenario for testing atmospheric correction algorithms' performance. The site, located 60 km south of Buenos Aires (Argentina), is described in relation to the water reflectance spectral features and variability using high spatial resolution imagery and a methodology is proposed to objectively select a sensor-specific location of a reference pixel for satellite validation. Six months of data is used to evaluate surface water reflectance operational products from multi-spectral systems like Landsat 8&9/OLI (L89/OLI), Sentinel-2/MSI (S2/MSI) & Sentinel-3/OLCI (S3/OLCI), and PlanetScope SuperDoves (PS/SD), and also non standard products for Aqua/MODIS (Aqua/MODIS) and SNPP&JPSS1/VIIRS (SJ/VIIRS) missions. Moreover, the standard surface water reflectance product from the hyperspectral PRISMA mission could also be evaluated. The matchups show general good results when in situ measurements are compared to L2 standard products of high spatial resolution sensors that use land-based atmospheric correction approach, if sun glint contamination is avoided. Low mean relative percentage difference was found for S2/MSI (2.45%) and L89/OLI (-3.52%), but higher for PS/SD (30.7%). In turn, S3/OLCI medium resolution also showed low mean relative differences (2.31%), while SJ/VIIRS and Aqua/MODIS showed larger and negative differences (-16.35 for SJ/VIIRS and -35.6% for Aqua/MODIS) which showed a clear increase towards the shortest blue bands. The results show the great potential of the HYPERNETS automated system to provide high quality and quantity of data for validation of satellite data at all visible and near infrared (VNIR, 400-900 nm) wavelengths in a multi-mission perspective. [ABSTRACT FROM AUTHOR]

Estuaries are characterized by steep biogeochemical gradients that are often overlooked by discrete water sampling which is especially critical for large ecosystems like the Río de la Plata estuary (RLP). To overcome this limitation, high-resolution in situ measurements of salinity, temperature, pH, turbidity, chlorophyll a (Chl-a), colored dissolved organic matter (CDOM) complemented by laboratory analysis of Chl-a and suspended particle (SPM) grain size distribution were employed to characterize the fluvio-marine transition along seven legs covering 1500 km in the RLP. In situ records performed each 400 m permitted to detect the anthropogenic discharge of CDOM in the upper freshwater Buenos Aires–La Plata metropolitan sector (1.7–3.6 mg C l−1) and the sharp turbidity increase at the beginning of the saline intrusion (S: 0.2–2) resulting in a consistent turbidity maximum zone formation (TMZ: 180–350 NTU). High-resolution data at the TMZ also revealed a significant positive covariation of Chl-a with turbidity indicating the retention of freshwater algae. The relative increase of phaeopigments in the South TMZ sector supported the detrital signature of the Paraná River load contrasting with the less turbid and fresher signal of the North corridor influenced by the Uruguay River flow. CDOM showed an opposite pattern and decreased with turbidity at the TMZ suggesting partial colloid precipitation from the surface's 50-cm layer sampled by the boat, followed by a rapid recovery and a linear decrease with salinity (2.9 ± 0.7 to 0.3 ± 0.4 mg C l−1). Turbidity and SPM grain size measurements also reflected the North–South asymmetry of the estuary with lower turbidities enriched in finer fractions along the Northern corridor. A consistent transport pathway of partially mixed, turbid waters enriched in Chl-a, CDOM, and clays concentrated in the TMZ with intermediate salinities was traced downstream along the South shore as a significant transport pathway of suspended solids to the sea. [ABSTRACT FROM AUTHOR]

Copyright of Arte, Individuo y Sociedad is the property of Universidad Complutense de Madrid and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Trabajos y Comunicaciones is the property of Universidad Nacional de La Plata and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Boletin de Geologia is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the Argentine Pampa fertile soils were originally covered by grasslands, but at present are intensively cultivated. We assessed the specific composition of the fish assemblage of El Pescado stream and compared it with that recorded in 1991–1993, when land use in the watershed consisted in natural pastures. The persistence of the fish assemblage between the two studies was rather high: 0.76. Abundance, biomass and species richness were higher during drought periods. Connectivity with the huge Río de la Plata hydrographic system seems the most important contribution to the high and stable species richness of El Pescado stream. [ABSTRACT FROM AUTHOR]

Settling particles (SPs) and sediments collected in the Buenos Aires sewer area were analyzed for dioxin like polychlorinated biphenyls (dlPCBs) and polybrominated diphenyl ethers (PBDEs) to follow early diagenetic changes during transport and deposition of organic matter. SP showed a temporal trend of higher total organic carbon (TOC) and fresher dlPCBs and PBDEs signatures during warm-rainy months related to more efficient washout of residues. TOC-normalized sediment trap concentrations suggest a diagenetic magnification of dlPCBs during cold-dry months due to enhanced decomposition of TOC, whereas most labile PBDEs appear to follow TOC decay. The diagenetic behavior of individual congeners along seasonal changes (cold/warm) and during deposition (bottom sediment/SP) shows the selective preservation of heavier, more persistent congeners with a positive relationship with sediment half-lives. The 3-4 times diagenetic magnification of heavier congeners observed in bottom sediments would be a prevailing long-term pathway for dlPCBs and PBDEs bioaccumulation in detritus feeding organisms. [ABSTRACT FROM AUTHOR]

Copyright of Estudos Ibero-Americanos is the property of EDIPUCRS - Editora Universitaria da PUCRS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Superficial sediments and settling material collected in Buenos Aires coastal area were analyzed to evaluate the accumulation and sources of trace metals. Residual elements showed homogeneous sedimentary concentrations (Fe: 23,846 ± 4,367; Ni: 10 ± 2.7; Mn: 706 ± 314 μg g−1) whereas anthropogenic metals presented exponentially decreasing offshore gradients (Zn: 98 ± 69; Cr: 28 ± 21; Cu: 19 ± 15; Pb: 18 ± 13 μg g−1). Anthropogenic impact was evaluated through metal-Fe relationships, Fe-normalized enrichment factors and sediment quality guidelines. The slopes of metal-Fe regressions from background sites were comparable to upper crust metal ratios, excepted Cr which is impoverished, and Mn which is diagenetically enriched. Metal-Fe relationships also hold for most 2.5 km offshore sites but with higher slopes denoting human influence, and are completely lost in 1–2.5 km sediments and trap material which plot over the regressions and exceed sediment quality guidelines. [ABSTRACT FROM AUTHOR]

The article examines the war of independence in Spanish colonies of Latin America during the early 19th century. This article focuses in particular on politics and collective identity formation in the former vice-royalty of Río de la Plata, near present day Argentina. The role of the city of Buenos Aires in the war against Spanish royalists is described. The author argues that the people of Buenos Aires and Río de la Plata were able to form a collective identity as enemies of the Spanish royalists. The weak role of native peoples in military campaigns against Spanish royalists is mentioned.

The temporal variability and bioaccumulation dynamics of individual PCBs were studied in a detritivorous fish (Sábalo: Prochilodus lineatus) collected from 1999 to 2005 in the polluted Buenos Aires coastal area. Fish muscles contain high concentrations of total PCBs (11±7.2, 4.6±3.4 or 19±13μgg−1, dry, fresh and lipid weight, respectively) reflecting chronic bioaccumulation from sewage-industrial particulates. On a temporal basis, lipid normalized PCBs concentrations peaked by the end of 2001–2002 coincident with the rainiest period over the last four decades and shortly after PCB prohibition in the country, reflecting massive discharges to the coastal ecosystem. PCB composition in fish muscles show a prevailing contribution of hexachlorobiphenyls (35±4.2%), followed by hepta (23±3.0%), penta (20±3.6%), tri-tetra (16±4.8%) and minor proportions of octa-decachlorobiphenyls (5.7±3.1%) similar to an Aroclor 1242–1254–1260 1:2:4 mixture. During 2001–2002 maxima fish showed an enrichment in tri-tetrachlorobiphenyls (∼1242–1254–1260 1:1:1 mixture) denoting a fresher signature. Fish/settling material lipid-organic carbon accumulation factors (BSAFs: 2.4–46, average: 21±10) plotted against kow showed a parabolic trend (BSAFs=−0.38 log kow2+5.16log kow-15.85; R2 =0.46) maximizing at hexa, hepta and octachlorobiphenyl 203 with reduced bioaccumulation of a few hepta (170, 191) and most octa-decachlorobihenyls suggesting limited intestinal absorption. [Copyright &y& Elsevier]