Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
ACS Earth Space Chem ; 8(4): 630-653, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38654896

RESUMO

Colloid generation, stability, and transport are important processes that can significantly influence the fate and transport of nutrients and contaminants in environmental systems. Here, we critically review the existing literature on colloids in redox-dynamic environments and summarize the current state of knowledge regarding the mechanisms of colloid generation and the chemical controls over colloidal behavior in such environments. We also identify critical gaps, such as the lack of universally accepted cross-discipline definition and modeling infrastructure that hamper an in-depth understanding of colloid generation, behavior, and transport potential. We propose to go beyond a size-based operational definition of colloids and consider the functional differences between colloids and dissolved species. We argue that to predict colloidal transport in redox-dynamic environments, more empirical data are needed to parametrize and validate models. We propose that colloids are critical components of element budgets in redox-dynamic systems and must urgently be considered in field as well as lab experiments and reactive transport models. We intend to bring further clarity and openness in reporting colloidal measurements and fate to improve consistency. Additionally, we suggest a methodological toolbox for examining impacts of redox dynamics on colloids in field and lab experiments.

2.
mSystems ; 9(7): e0031424, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38940520

RESUMO

We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling-particularly methane-cycling-microorganisms in montane riparian floodplain sediments. We generated 1,233 MAGs (>50% completeness and <10% contamination) from 50- to 150-cm depth below the sediment surface capturing the transition between oxic, unsaturated sediments and anoxic, saturated sediments in the Slate River (SR) floodplain (Crested Butte, CO, USA). We recovered genomes of putative methanogens, methanotrophs, and methylotrophs (n = 57). Methanogens, found only in deep, anoxic depths at SR, originate from three different clades (Methanoregulaceae, Methanotrichaceae, and Methanomassiliicoccales), each with a different methanogenesis pathway; putative methanotrophic MAGs originate from within the Archaea (Candidatus Methanoperedens) in anoxic depths and uncultured bacteria (Ca. Binatia) in oxic depths. Genomes for canonical aerobic methanotrophs were not recovered. Ca. Methanoperedens were exceptionally abundant (~1,400× coverage, >50% abundance in the MAG library) in one sample that also contained aceticlastic methanogens, indicating a potential C1/methane-cycling hotspot. Ca. Methylomirabilis MAGs from SR encode pathways for methylotrophy but do not harbor methane monooxygenase or nitrogen reduction genes. Comparative genomic analysis supports that one clade within the Ca. Methylomirabilis genus is not methanotrophic. The genetic potential for methylotrophy was widespread, with over 10% and 19% of SR MAGs encoding a methanol dehydrogenase or substrate-specific methyltransferase, respectively. MAGs from uncultured Thermoplasmata archaea in the Ca. Gimiplasmatales (UBA10834) contain pathways that may allow for anaerobic methylotrophic acetogenesis. Overall, MAGs from SR floodplain sediments reveal a potential for methane production and consumption in the system and a robust potential for methylotrophy.IMPORTANCEThe cycling of carbon by microorganisms in subsurface environments is of particular relevance in the face of global climate change. Riparian floodplain sediments contain high organic carbon that can be degraded into C1 compounds such as methane, methanol, and methylamines, the fate of which depends on the microbial metabolisms present as well as the hydrological conditions and availability of oxygen. In the present study, we generated over 1,000 MAGs from subsurface sediments from a montane river floodplain and recovered genomes for microorganisms that are capable of producing and consuming methane and other C1 compounds, highlighting a robust potential for C1 cycling in subsurface sediments both with and without oxygen. Archaea from the Ca. Methanoperedens genus were exceptionally abundant in one sample, indicating a potential C1/methane-cycling hotspot in the Slate River floodplain system.


Assuntos
Sedimentos Geológicos , Metagenoma , Metano , Rios , Metano/metabolismo , Sedimentos Geológicos/microbiologia , Rios/microbiologia , Archaea/genética , Archaea/metabolismo , Archaea/classificação , Bactérias/genética , Bactérias/classificação , Bactérias/metabolismo , Bactérias/isolamento & purificação , Filogenia , Genoma Arqueal , Genoma Bacteriano/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA