Claudia M Rojas Alvarado

• PhD Soil Science and Biogeochemistry, Penn State University
• Professor (Associate) at Universidad de O'Higgins, San Fernando

Acid mine drainage (AMD) barrens result from destruc- tion of vegetation within AMD flow paths. When exposed to air, soluble iron in AMD undergoes oxidation and hydrol- ysis to form ferric iron (oxyhydr)oxides which accumulate on soil surfaces. A restoration experiment was conducted at a 50-year-old AMD barrens created by discharge from an abandone...

Fires are common in Mediterranean soils and constitute an important driver of their evolution; however, their effects on the assembly rules of soil bacteria received limited attention. We reanalyzed the data from Aponte et al. (2022), retrieved from the NCBI database, to investigate fire-induced short term effects on β-diversity, abundance ranking,...

In drylands, where water scarcity limits vascular plant growth, much of the primary production occurs at the soil surface. This is where complex macro‐ and microbial communities, in an intricate bond with soil particles, form biological soil crusts (biocrusts). Despite their critical role in regulating C and N cycling in dryland ecosystems, there i...

The study aimed to develop a methodological framework to identify forest ecosystems affected by wildfires and evaluate their recovery chronologically. To do this remote sensing analysis, sites with burn scars were selected based on various criteria (fire severity, affected area, vegetation and soil type, slope, aspect, and one-time occurrence of wi...

Background The potential ecosystem collapse of forests in Mediterranean-type ecosystems (MTEs) by unprecedented droughts is worrisome due to the impacts on its exceptional biodiversity and human well-being. However, research integrating the impacts of global change drivers, forest resilience and the challenges facing human-nature relationships is s...

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 centra...

Soil quality assessments, rarely applied to contaminated soils with metal(loid)s, consider ecological topics such as multifunctionality, resistance and resilience of microbial communities to perturbations, in addition to ecosystem services. In this study, the effect of metal(loid) contamination was evaluated in soils based on physicochemical and bi...

Soil ecosystems are important reservoirs of biodiversity, as they are the most diverse habitat on Earth. Microbial biodiversity plays key roles in many ecosystem services, including the support to biogeochemical cycles. However, despite great advances in the understanding of the role of soil microbiota in providing benefits to nature and humankind,...

The management of mine tailings (MT) is commonly workload heavy, intrusive, and expensive. Phytostabilization offers a promising approach for MT management; however, it poses challenges due to the unfavorable physicochemical properties of these wastes. Nevertheless, native microorganisms capable of supporting plant growth and development could enha...

The 2022-2023 Chilean summer showed increased temperatures and similar burned area, compared to the 2016-2017 season, where more than 500,000 hectares were compromised, mainly in the rural areas. After a brief review, it is revealed that the effects of forest fires on soil and hydrological properties are barely debated in Chile. Here, we showed a c...

The root anatomical phenotype root cortical aerenchyma (RCA) decreases the metabolic cost of soil exploration and improves plant growth under drought and low soil fertility. RCA may also change the microenvironment of rhizosphere microorganisms by increasing oxygen availability or by reducing carbon rhizodeposition. We tested the hypothesis that pl...

The main organic input for the elaboration of growing media is peat (Sphagnum spp.), due to its physical and chemical characteristics. However, the mining of this material creates a considerable impact in the local ecosystems from which this is obtained, along with a global impact because of the emission of greenhouse gasses. Thus, sustainable mate...

Bioelectrochemical systems (BESs) have been extensively studied for treatment and remediation. However, BESs have the potential to be used for the enrichment of microorganisms that could replace their natural electron donor or acceptor for an electrode. In this study, Winogradsky BES columns with As-rich sediments extracted from an Andean watershed...

Understanding how soil chemical/physical and biological parameters behave after the increasingly common fires in Mediterranean Chilean ecosystems is critical to boost their recovery. Incorporating organic amendments in soil to support its post-fire recovery is promising; however, there are important gaps regarding the seasonal responses of soil par...

Forest fires alter soil microbial communities that are essential to support ecosystem recovery following land burning. These alterations have different responses according to soil abiotic pre-and post-fire conditions and fire severity, among others, and tend to decrease along vegetation recovery over time. Thus, understanding the effects of fires o...

El presente manual se desarrolló en el marco del proyecto “Técnicas silviculturales costo-efectivas para reducción de estrés hídrico de plantas en procesos de restauración de bosque esclerófilo” (Proyecto FIBN 034/2018), financiado por el Fondo de Investigación del Bosque Nativo (FIBN) y patrocinado por la Pontificia Universidad Católica de Chile....

Global climatic conditions have exacerbated the occurrence of fires, particularly in Mediterranean biomes. In Chile, during the 2016-2017 summer, a megafire affected more than 5,000 km2 in the nation’s southcentral area, compromising sclerophyllous forests characteristic of the Chilean mediterranean ecosystem. This work aims to evaluate the effect...

This study aimed to evaluate contrasting organic amendments as a strategy to promote the recovery of biotic and abiotic edaphic conditions central to the reestablishment of soil ecosystem functions at a site in south-central Chile affected by megafires in the 2016-2017 summer season. We analyzed the effects of the application of fresh (poultry and...

The monitoring of soil metal(loid) contamination is of global significance due to deleterious effects that metal(loid)s have on living organisms. Soil biological properties such as enzyme activities (EAs) are good indicators of metal(loid) contamination due to their high sensitivity, fast response, and low-cost. Here, the effect of metal(loid) cont...

Climate change and inappropriate landscape management have increased the intensity and severity of wildfires in Chilean Mediterranean ecosystems, including sclerophyllous forests. During the 2016-2017 summer, a megafire affected more than 5,000 km2 in the country, compromising these ecosystems. Despite advances on aboveground recovery following fir...

Transdisciplinary approaches that provide holistic views are essential to properly understand soil processes and the importance of soil to society and will be crucial in the future to integrate distinct disciplines into soil studies. A myriad of challenges faces soil science at the beginning of the 2020s. The main aim of this overview is to assess...

Understanding soil systems is critical because they form the structural and nutritional foundation for plants and thus every terrestrial habitat and agricultural system. In this paper, we encourage increased use of mathematical models to drive forward understanding of interactions in soil ecological systems. We discuss several distinctive features...

Revista de divulgación “Esta es una publicación financiada por el Fondo de Protección Ambiental del Ministerio del Medio Ambiente” Proyecto FPA 6-RE-002-2018: Recuperación de Salud de Suelos y su Implicancia en el Restablecimiento de Bosque Nativo Incendiado en Zonas del Secano de la VI Región 2019

Exoelectrogenic communities for bioelectrochemical systems such as microbial fuel cells (MFCs)are usually enriched from microbial consortia of municipal wastewater treatment plants and other circumneutral and mesophilic environments. Thus, the study of extreme environments offers an enormous potential to find new exoelectrogens and expand the funct...

El siguiente manual docente se enmarca en el Pro- grama de Educación Ambiental (PEA) del proyecto: Recuperación de salud de suelos y su implicancia en el restablecimiento de bosque nativo incendiado en zonas del secano de la VI Región (FPA 6-RE-002- 2018). Proyecto financiado por el Ministerio del Medio Ambiente, a través del concurso extraordi- na...

Understanding the factors that modulate bacterial community assembly in natural soils is a longstanding challenge in microbial community ecology. In this work, we compared two microbial co-occurrence networks representing bacterial soil communities from two different sections of a pH, temperature and humidity gradient occurring along a western slop...

Biological arsenic oxidation has been suggested as a key biogeochemical process that controls the mobilization and fate of this metalloid in aqueous environments. To the best of our know l-edge, only four aerobic chemolithoautotrophic arsenite-oxidizing (CAO) bacteria have been shown to grow via direct arsenic oxidation and to have the essential ge...

Green roofs have many benefits, but in countries with semiarid climates the amount of water needed for irrigation is a limiting factor for their maintenance. The use of drought-tolerant plants such as Sedum species, reduces the water requirements in the dry season, but, even so, in semiarid environments these can reach up to 60 L m⁻² per day. Conti...

A plant microbial fuel cell (PMFC) is a novel and sustainable bioelectrochemical technology that takes advantage of the organic compounds released through the plant roots (exudates) to produce power via electrochemically active bacteria. This technology has been implemented in flooded ecosystem; however, their use in arid or semiarid environments h...

The limited database of acidophilic or acidotolerant electrochemically active microorganisms prevents advancements on microbial fuel cells (MFCs) operated under low pH. In this study, three MFCs were used to enrich cathodic biofilms using acid mine drainage (AMD) sediments as inoculum. Linear sweep voltammetry showed cathodic current plateaus of 5....

Soil phosphorus (P) release is generally enhanced during anoxic conditions and is thought to occur mainly due to the reduction of iron oxides. However, other processes such as the P storage-release capacity of microbial cells has been overlooked. The goal of this study was to determine the roles of dissimilatory iron-reducing bacteria (DIRB) and po...

Microscopic investigations were undertaken to decipher the diversity in the lotic algal communities from acidic waters (pH 2.4-3.2) flowing overland in sheets and channels at an acid mine drainage (AMD) barrens near Kylertown, PA, USA. Microscopic observations, supplemented with taxonomic keys, aided in identification of the dominant algae, and mea...

The maturity of compost can be determined using sensitive species to phytotoxic metabolites by germination bioassays. In order to obtain a stabilized and non-phytotoxic product, the phytotoxic compounds must be biodegraded or immobilized during the maturity phase of composting. In this study the sensitivity of lettuce (Lactuca sativa, var. Four Sea...

Con el objeto de establecer la fitotoxicidad de diversos residuos orgánicos, se evaluó el índice de germinación (IG) de las especies de rabanito (cv. Cherry Bell) y pepino (cv. Marketer). Utilizando los residuos de: semilleros de hinojo (H), semilleros de puerro (Pu), semilleros de zapallo (Z), semilleros de lechuga (L), cáscara de almendra (Ca), c...