Organic carbon accumulation in oligotrophic coastal lakes in southern Brazil during the last century     

Bueno  Carolina  Sanders  Christian J.  Niencheski  Felipe Hax  Andrade  Carlos  Burnett  William  Santos  Isaac R. 《Journal of Paleolimnology》2021,66(1):71-82

Journal of Paleolimnology - We report organic carbon (OC) accumulation rates in three freshwater ecosystems in southern Brazil, along the largest shallow coastal lagoon ecosystem in the world, the...  相似文献   

Brazil beyond 2020: from deforestation to the energy challenge     

Emilio Lèbre La Rovere  Carolina Burle Dubeux  Amaro Olimpio Pereira Jr  William Wills 《Climate Policy》2013,13(2):70-86

The main assumptions and findings are presented on a comparative analysis of three GHG long-term emissions scenarios for Brazil. Since 1990, land-use change has been the most important source of GHG emissions in the country. The voluntary goals to limit Brazilian GHG emissions pledged a reduction in between 36.1% and 38.9% of GHG emissions projected to 2020, to be 6–10% lower than in 2005. Brazil is in a good position to meet the voluntary mitigation goals pledged to the United Nations Framework Convention on Climate Change (UNFCCC) up to 2020: recent efforts to reduce deforestation have been successful and avoided deforestation will form the bulk of the emissions reduction commitment. In 2020, if governmental mitigation goals are met, then GHG emissions from the energy system would become the largest in the country. After 2020, if no additional mitigation actions are implemented, GHG emissions will increase again in the period 2020–2030, due to population and economic growth driving energy demand, supply and GHG emissions. However, Brazil is in a strong position to take a lead in low-carbon economic and social development due to its huge endowment of renewable energy resources allowing for additional mitigation actions to be adopted after 2020.

Policy relevance

The period beyond 2020 is now relevant in climate policy due to the Durban Platform agreeing a ‘protocol, legal instrument or agreed outcome with legal force’ that will have effect from 2020. After 2020, Brazil will be in a situation more similar to other industrialized countries, faced with a new challenge of economic development with low GHG energy-related emissions, requiring the adoption of mitigation policies and measures targeted at the energy system. Unlike the mitigation actions in the land-use change sector, where most of the funding will come from the national budgets due to sovereignty concerns, the huge financial resources needed to develop low-carbon transport and energy infrastructure could benefit from soft loans channelled to the country through nationally appropriate mitigation actions (NAMAs).  相似文献   

Decadal predictability and prediction skill of sea surface temperatures in the South Pacific region     

Ramiro I. Saurral  Javier Garc&#;a-Serrano  Francisco J. Doblas-Reyes  Leandro B. D&#;az  Carolina S. Vera 《Climate Dynamics》2020,54(9):3945-3958

The South Pacific Ocean is a key driver of climate variability within the Southern Hemisphere at different time scales. Previous studies have characterized the main mode of interannual sea surface temperature (SST) variability in that region as a dipolar pattern of SST anomalies that cover subtropical and extratropical latitudes (the South Pacific Ocean Dipole, or SPOD), which is related to precipitation and temperature anomalies over several regions throughout the Southern Hemisphere. Using that relationship and the reported low predictive skill of precipitation anomalies over the Southern Hemisphere, this work explores the predictability and prediction skill of the SPOD in near-term climate hindcasts using a set of state-of-the-art forecast systems. Results show that predictability greatly benefits from initializing the hindcasts beyond the prescribed radiative forcing, and is modulated by known modes of climate variability, namely El Niño-Southern Oscillation and the Interdecadal Pacific Oscillation. Furthermore, the models are capable of simulating the spatial pattern of the observed SPOD even without initialization, which suggests that the key dynamical processes are properly represented. However, the hindcast of the actual phase of the mode is only achieved when the forecast systems are initialized, pointing at SPOD variability to not be radiatively forced but probably internally generated. The comparison with the performance of an empirical prediction based on persistence suggests that initialization may provide skillful information for SST anomalies, outperforming damping processes, up to 2–3 years into the future.  相似文献   

Does parameterization influence the performance of slope stability model results? A case study in Rio de Janeiro,Brazil     

Carolina de Lima Neves Seefelder  Sérgio Koide  Martin Mergili 《Landslides》2017,14(4):1389-1401

We produce factor of safety (FOS) and slope failure susceptibility index (SFSI) maps for a 4.4-km² study area in Rio de Janeiro, Brazil, in order to explore the sensitivity of the geotechnical and geohydraulic parameterization on the model outcomes. Thereby, we consider parameter spaces instead of combinations of discrete values. SFSI is defined as the fraction of tested parameter combinations within a given space yielding FOS <1. We repeat our physically based calculations for various parameter spaces, employing the infinite slope stability model and the sliding surface model of the software r.slope.stability for testing the geotechnical parameters and the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS) for testing the geohydraulic parameters. Whilst the results vary considerably in terms of their conservativeness, the ability to reproduce the spatial patterns of the observed landslide release areas is relatively insensitive to the variation of the parameterization as long as there is sufficient pattern in the results. We conclude that landslide susceptibility maps yielded by catchment-scale physically based models should not be interpreted in absolute terms and suggest that efforts to develop better strategies for dealing with the uncertainties in the spatial variation of the key parameters should be given priority in future slope stability modelling efforts.  相似文献   

Accumulation of lead and associated metals (Cu and Zn) at different growth stages of soybean crops in lead-contaminated soils: food security and crop quality implications     

Andrés Blanco  María J. Salazar  Carolina Vergara Cid  María L. Pignata  Judith H. Rodriguez 《Environmental Earth Sciences》2017,76(4):182

The Pb, Cu and Zn content, the physicochemical parameters in soils (EC, OM%, soil texture and pH) and the metal accumulation of Glycine max plants at different growth stages were evaluated. Topsoil and soybean samples were collected in the vicinity of a former battery-recycling plant, with the results showing that only the concentrations of Pb in soils corresponding to sites located near to the lead emission source were above the maximum permissible levels. However, soybean crops accumulated Pb above the permitted levels at all studied sites, revealing a potential toxicological risk for direct consumption. Thus, the accumulation of Pb in soybean was directly related to the translocation factor of the metal from roots to aerial parts of the plant. This was evidenced as a lower accumulation at early growth stages and a higher accumulation at maturity, with the distribution between organs coinciding with nutrient incorporation and remobilization in the plant. Moreover, the bioconcentration factor revealed that the bioaccumulation of lead in soybean was a consequence of the lead-recycling plant activity in the past. Taken together, results of the present study demonstrated that soybean crops can incorporate and accumulate potentially toxic metals, such as lead.  相似文献   

Effects of geomorphology and land use on stream water quality in southeastern Amazonia     

Hellen Kezia Silva Almada  Divino Vicente Silvério  Marcia Nunes Macedo  Leonardo Maracahipes-Santos  Elizabete Carolina Pinheiro Zaratim  Karina Pinheiro Zaratim 《水文科学杂志》2019,64(5):620-632

Water quality in streams is determined by several factors, including geology, topography, climate, and anthropogenic changes. This study aimed to assess the effects of watershed physical, morphology, and precipitation seasonality on the water quality of two streams that supply drinking water to rural settlements and urban areas in the Cerrado-Amazonia transition region. We monitored 16 physico-chemical attributes of water at six different sample locations over three years (2013–2016). Our results indicate that eight of these physico-chemical attributes did not meet the standards for safe drinking water established by Brazilian legislation. Precipitation seasonality, degradation of riparian zones, stream length, and watershed slope were the most important predictors of impaired water quality. Our results highlight the importance of restoring and conserving riparian forests in order to maintain drinking water quality.  相似文献   

Streamflow variability and its relationship with climate indices in western rivers of Argentina     

Carolina Lauro  Alberto I. J. Vich  Stella Maris Moreiras 《水文科学杂志》2019,64(5):607-619

The objective of this study was to examine the streamflow variability of Argentinean Andean basins (22°–52°S). Trends and step changes of seven hydrological variables were analysed. In addition, relationships between the hydrological variables and Pacific Decadal Oscillation (PDO), Niño 3.4, and Southern Annular Mode (SAM) indices were analysed. Most streamflow variables showed upward trends in the northwest and central-western basins, while downward trends were identified in the Patagonia (southwestern) region. Streamflow of the central-western and Patagonian basins was positively correlated with the Niño 3.4 index. Moreover, an inverse relationship with the SAM was found in watersheds south of 37°S. Positive step changes associated with the PDO phases in the north and central-western basins in the mid-1970s were detected, while negative step changes resulted in Patagonia between 1970 and 2000. This research provides new evidence of the influence of major climate modes on streamflow variability in the western rivers of Argentina.  相似文献   

Mineralogical signatures and sources of recent sediment in a large tropical lake     

Jorge Feliciano Ontiveros-Cuadras  Ana Carolina Ruiz-Fernández  Joan-Albert Sanchez-Cabeza  Libia Hascibe Pérez-Bernal  Michel Preda  Federico Páez-Osuna 《国际泥沙研究》2018,33(2):183-190

Two lead-210 (²¹⁰Pb) dated sediment cores from Chapala Lake were studied to identify the mineral composition of the sediments and to discuss its relation with trace metals. Minerals and trace metals reflected the domain of volcanic rocks (i.e. basalts, rhyolite and andesite) that characterize Chapala Lake and the Lerma River watershed. Redundancy analyses (RDA) were used to identify the sedimentary variables (magnetic susceptibility, organic matter, sand content, and mineral composition) that could be related to elemental composition. Despite the distance between the two cores (7.3 km) and hydrodynamic circulation the RDA showed that the main mechanism that controls the input of mineral species, and, therefore, element distributions in the lacustrine sediment of Chapala Lake, is related to the weathering of volcanic rocks in the Lerma-Chapala watershed, the consequent runoff and transport of fine grained catchment materials, and later in-lake processes. These findings highlight the importance of controlling watershed erosion to contribute to the improvement of the environmental quality of the lake.  相似文献   

Short contribution: A new method of analyzing and documenting micromorphological thin sections using flatbed scanners: Applications in geoarchaeological studies     

Trina L. Arpin  Carolina Mallol  Paul Goldberg 《Geoarchaeology》2002,17(3):305-313

Much of the information in micromorphological thin sections exists at the mesoscopic level. The use of flatbed scanners can improve analysis at this level and aid in preservation of the information. This article describes scanning in both plane and cross‐polarized light and discusses the hardware and software required. © 2002 Wiley Periodicals, Inc.  相似文献