Centennial hydroclimatic and anthropogenic processes of South East South America modulate interannual and decadal river discharge

Pérez, Laura; Barreiro, Marcelo; Etchevers, Ismael; Crisci, Carolina; García-Rodríguez, Felipe

doi:10.1016/j.scitotenv.2021.146733

Cited by 18 publications

(10 citation statements)

References 112 publications

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“…The interannual rainfall variability is linked to the high-frequency SAM and ENSO, with positive phases (El Niño) related to humid conditions, and negative phases (La Niña) to dry episodes (Nunes et al 2009). Furthermore, the low frequency forcing i.e., PDO and AMO were linked to changes observed in the decadal to multidecadal precipitation regimes throughout SESA (Perez et al 2021a). In this regard, signi cant Spearman correlations were recorded between the standardized rainfall time series and the standardized climate variability modes (i.e., SOI and PDO) for the last century (ρ = -0.5 and 0.2, respectively, n = 117, p < 0.05).…”

Section: Hydroclimatic Featuresmentioning

confidence: 98%

“…Such conditions of higher precipitations after the middle of the 19th century were recorded in the Pampa plain lakes as well (e.g.,Córdoba et al 2014). For instance, the Mar Chiquita Lake exhibited elevated lake levels, while the RdlP mud depocenter displayed signi cant continental input onto the shelf(Piovano et al 2009;Perez et al 2021a). These conditions were associated with the onset of CWP, during which we inferred higher temperatures and precipitations for the SESA region (Fig.7, Piovano et al 2009; Córdoba et al 2014; Guerra et al 2019; Lopez-Blanco et al 2020; Perez et al 2021a, b).…”

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confidence: 99%

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Late Holocene lake level changes are modulated by centennial hydroclimatic variability of southeastern South America, a case study of Laguna de las Nutrias, Uruguay

Perez,

Cuña-Rodríguez,

Córdoba

et al. 2023

Preprint

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Laguna de las Nutrias is a small/enclosed shallow lake located within an environmentally protected area under negligible anthropogenic impact in Southeastern South America (SESA). It holds a high-resolution sedimentary record that allowed us to infer the hydrological response to the regional climatic variability during the last 700 year linked to different climate variability modes. We performed 2 mm-µXRF-scanning analyses on an 88-cm long sediment core, which was dated by both 14C and 210Pb techniques. We utilized Ti/Al, Ti/Ca, Fe/Mn, Ti/K, S/Ti, Br/Ti, and Si/Ti as proxies for catchment runoff, lake level, redox conditions, grain size, organic matter, storms/extreme events, and trophic state, respectively. The lowest sedimentation rate, lake level, runoff values, highest trophic state and grain size were recorded between 1360–1800 CE, assigned to the Little Ice Age (LIA), under low humidity conditions related to the weakening of the South American Low-Level Jet (SALLJ). Subsequently, the highest sedimentation rate values, runoff and lake level were recorded up to the present. Concomitant lowest trophic state conditions were inferred and interpreted as dilution processes associated with higher lake levels. This stage was assigned to the onset of the Current Warm Period (CWP), which was characterized by higher humidity conditions leading to the highest sedimentation rate, lake level and runoff values after 1980 CE, associated with the noticeable increase in rainfall during “1970´s climatic shift”. By performing time series analyses, we determined centennial, multi-decadal, decadal, and inter-annual cyclicity in lake level related to the hydroclimatic variability. Furthermore, a high significant positive/negative Spearman correlation was observed between runoff and lake level/trophic state proxies and the El Niño Southern Oscillation (ENSO) reconstruction. ENSO modulates both long and short-term frequency of SALLJ, leading to an increase in rainfall during positive phases, which determined high lake level and runoff and a decreased trophic state due to dilution processes. The reconstructed hydrological variability herein is synchronic with other SESA lacustrine systems and the increased Rio de la Plata discharge, indicating similar long-term limnological responses to the regional climatic patterns.

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Section: Hydroclimatic Featuresmentioning

confidence: 98%

mentioning

confidence: 99%

Late Holocene lake level changes are modulated by centennial hydroclimatic variability of southeastern South America, a case study of Laguna de las Nutrias, Uruguay

Perez,

Cuña-Rodríguez,

Córdoba

et al. 2023

Preprint

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“…Here we discuss MGB-SA results for river discharge recent alteration and trend by comparing them with other studies over South America. Many authors have assessed past and recent trends in hydrology time series over different South American basins and regions (Bartiko, 2020;Castino et al, 2017;Fleischmann, 2021;Perez et al, 2021;Wongchuig Correa et al, 2017).…”

Section: Recent Discharge Alterationmentioning

confidence: 99%

Density and classification of the rainfall network and spatiotemporal analysis of rain in the upper Parana river region, Brazil

Tokuda

Lima

Sobrinho

et al. 2023

RBRH

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Water management aims to ensure the water availability necessary to meet the current and future demand for water resources. For which it is essential to implement monitoring networks that support the investigation of events that interfere with the rainfall regime of watersheds, such the phases of the ocean-atmospheric phenomenon El Niño – Southern Oscillation (ENSO). The classification of the rainfall network was proposed according to the World Meteorological Organization (WMO) for 14 management watersheds in the Upper Parana River (UPR) region, Brazil. On the other hand, the spatial and temporal variability of annual rainfall was analyzed using geostatistical techniques and confronted with ENSO data. To this purpose, data from 408 stations were collected via the Hidroweb portal, for the period from 1990 to 2020. The low representativeness of data in the region was verified from the observational network. The areas with the lowest and highest rainfall reduction were the north and northwest regions of the UPR, and the areas surrounding the Paraná River, respectively. The years 2019 and 2020 were identified as the most critical period of the last 3 decades with below-average rainfall (-13.21%) in 49.55% of the studied area, indicating a persistence in the drought scenario.

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“…During the last decades, natural grasslands supporting extensive livestock production have been replaced with large‐scale croplands, causing degradation of ecosystem services (de Vasconcelos et al, 2014; Modernel et al, 2016). High‐resolution palaeoceanographic studies in the Río de la Plata demonstrated the effect of continental human activities on the aquatic ecosystems (Pérez, Barreiro, et al, 2021; Pérez, Crisci, et al, 2021) attributed to land‐use intensification and dam construction leading to significant soil erosion and transport/deposition into the inner shelf, enhanced by the El Niño Southern Oscillation (ENSO) events (Bonachea et al, 2010; Pérez, Barreiro, et al, 2021; Pérez, Crisci, et al, 2021). The Uruguay river holds 10 large dams (>10 km 2 ), and there are more than 90 further dams either planned or under construction (http://globaldamwatch.org) (Pérez, Barreiro, et al, 2021; Pérez, Crisci, et al, 2021), which cause strong modifications to its hydrological cycle (Depetris & Pasquini, 2007a, 2007b; Milliman et al, 2008; Tucci & Clarke, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…South America is one of the regions most affected by global agriculture, where large‐scale cash crops have replaced natural vegetation (Doughty, 2010; Graesser et al, 2018; Pérez, Barreiro, et al, 2021; Pérez, Crisci, et al, 2021; Tucci & Clarke, 1998). Large proportions of land are dedicated to agricultural production with annual crops, such as soybean, maize, wheat and rice (Giller et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Rise of toxic cyanobacterial blooms is promoted by agricultural intensification in the basin of a large subtropical river of South America

Kruk

Segura²,

Piñeiro

et al. 2023

Global Change Biology

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Toxic cyanobacterial blooms are globally increasing with negative effects on aquatic ecosystems, water use and human health. Blooms' main driving forces are eutrophication, dam construction, urban waste, replacement of natural vegetation with croplands and climate change and variability. The relative effects of each driver have not still been properly addressed, particularly in large river basins. Here, we performed a historical analysis of cyanobacterial abundance in a large and important ecosystem of South America (Uruguay river, ca 1900 km long, 365,000 km2 basin). We evaluated the interannual relationships between cyanobacterial abundance and land use change, river flow, urban sewage, temperature and precipitation from 1963 to the present. Our results indicated an exponential increase in cyanobacterial abundance during the last two decades, congruent with an increase in phosphorus concentration. A sharp shift in the cyanobacterial abundance rate of increase after the year 2000 was identified, resulting in abundance levels above public health alert since 2010. Path analyses showed a strong positive correlation between cyanobacteria and cropland area at the entire catchment level, while precipitation, temperature and water flow effects were negligible. Present results help to identify high nutrient input agricultural practices and nutrient enrichment as the main factors driving toxic bloom formation. These practices are already exerting severe effects on both aquatic ecosystems and human health and projections suggest these trends will be intensified in the future. To avoid further water degradation and health risk for future generations, a large‐scale (transboundary) change in agricultural management towards agroecological practices will be required.

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Centennial hydroclimatic and anthropogenic processes of South East South America modulate interannual and decadal river discharge

Cited by 18 publications

References 112 publications

Late Holocene lake level changes are modulated by centennial hydroclimatic variability of southeastern South America, a case study of Laguna de las Nutrias, Uruguay

Late Holocene lake level changes are modulated by centennial hydroclimatic variability of southeastern South America, a case study of Laguna de las Nutrias, Uruguay

Density and classification of the rainfall network and spatiotemporal analysis of rain in the upper Parana river region, Brazil

Rise of toxic cyanobacterial blooms is promoted by agricultural intensification in the basin of a large subtropical river of South America

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