Browsing by Author "Rojas, Claudia"

Now showing 1 - 5 of 5
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    A new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed
    (2018) Anguita, Javiera M.; Rojas, Claudia; Pastén González, Pablo Arturo; Vargas Cucurella, Ignacio Tomás; CEDEUS (Chile)
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    Current understanding, knowledge gaps, and challenges of mountain permafrost research in the Chilean and Argentinean Andes
    (2024) Fernandez-Navarro, Hans; Baldis, Carla Tapia; Rojas, Claudia; Derrien, Morgane; Villasenor, Tania
    Mountain permafrost extends over a vast area throughout the Chilean and Argentinean Andes, making it a key component of these mountain ecosystems. To develop an overview of the current state of knowledge on southern Andean permafrost, it is essential to outline appropriate research strategies in a warmer climate context. Based on a comprehensive review of existing literature, this work identifies eight main research themes on mountain permafrost in the Chilean and Argentinean Andes: paleoenvironmental reconstructions, permafrost-derived landforms inventories, permafrost distribution models, internal structure analysis, hydrogeochemistry, permafrost dynamics, geological hazards, and transitional landscape studies. This extensive review work also highlights key debates concerning the potential of permafrost as a water resource and the factors influencing its distribution. Furthermore, we identified several challenges the scientific community must address to gain a deeper understanding of mountain permafrost dynamics. Among these challenges, we suggest tackling the need to broaden spatial focus, along with the use of emerging technologies and methodologies. Additionally, we emphasize the importance of developing interdisciplinary approaches to effectively identify the impacts of climate change on mountain permafrost. Such efforts are essential for adequately preparing scientists, institutional entities, and society to address future scenarios.
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    Drought and Wildfire Trends in Native Forests of South-Central Chile in the 21st Century
    (2024) Duarte, Efrain; Rubilar, Rafael; Matus, Francisco; Garrido-Ruiz, Claudia; Merino, Carolina; Smith-Ramirez, Cecilia; Aburto, Felipe; Rojas, Claudia; Stehr, Alejandra; Dorner, Jose; Najera, Francisco; Barrientos, Guillermo; Jofre, Ignacio
    Over the last decades, Chile has experienced a long-term drought with significant consequences for water availability, forest productivity, and soil degradation, ultimately dramatically increasing the surface of burned area. Here, we quantify the Palmer Drought Severity Index (PDSI) to ascertain the extent of "moisture deficiency" across the central-southern region of Chile from 2000 to 2023 to assess the drought's relationship with the frequency of wildfires focusing on the impact of native forests. Our methodology quantifies the PDSI from the burned area data using MODIS MCD64A1 satellite imagery, validated by in situ wildfire occurrence records. The findings indicate that 85.2% of fires occurred under moderate to severe drought conditions. We identified 407,561 ha showing varying degrees of degradation due to wildfires, highlighting the critical areas for targeted conservation efforts. A significant increase in both the frequency of wildfires and the extent of the affected area in native forests was observed with the intensification of drought conditions in the 21st century within mesic to humid Mediterranean climatic zones where drought explains up to 41% of the variability in the burned area (r(2) = 0.41; p < 0.05). This study highlights the relationship between drought conditions and wildfire frequency, showing the paramount need to adopt comprehensive wildfire mitigation management in native forests.
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    Long-term evaluation of soil-based bioelectrochemical green roof systems for greywater treatment
    (2024) Tapia, Natalia; Gallardo-Bustos, Carlos; Rojas, Claudia; Vargas, Ignacio T.
    Water scarcity has generated the need to identify new sources. Due to its low organic contaminant load, greywater reuse has emerged as a potential alternative. Moreover, the search for decentralized treatment systems in urban areas has prompted research on using green roofs for greywater treatment. However, the performance of organic matter removal is limited by the type of substrate and height of the growing media. Bioelectrochemical systems (BESs) improve treatment performance by providing an additional electron acceptor (the electrode). In this study, nine reactors under three different conditions, i.e., open circuit (OC), microbial fuel cell (MFC), and microbial electrolysis cell (MEC), were built to evaluate the treatment of synthetic greywater in a substrategrowing medium composed of perlite and coconut fiber and operated in batch-cycle mode for 397 days. The results suggested that using BESs enables greywater treatment and the removal of pollutants to levels that allow their reuse for irrigation. Furthermore, electrical conductivity was reduced from 732.4 +/- 41.2 mu S/cm2 in OC to 637.32 +/- 22.73 mu S/cm2 and 543.15 +/- 19.69 mu S/cm2 in MEC and MFC, respectively. The soluble chemical oxygen demand in the latter treatments reached 76% removal, compared to levels above the OC, which only reached approximately 67%. Microbial community analysis revealed differences, mainly in the cathodes, showing a higher development of Flavobacterium, Azospirillum, and Zoogloea in MFCs, which could explain the higher levels of organic matter removal in the other conditions, suggesting that the BES could produce an enrichment of beneficial bacterial groups for treatment. Therefore, implementing BESs in green roofs enables sustainable longterm greywater treatment.
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    Structure and co-occurrence patterns in microbial communities under acute environmental stress reveal ecological factors fostering resilience
    (2018) Mandakovic, Dinka ; Rojas, Claudia; Maldonado, Jonathan ; Latorre, Mauricio ; Travisany, Dante ; Delage, Erwan ; Bihouée, Audrey ; Díaz, Francisca P. ; Latorre, Claudio ; Navarrete, Sergio A.