Organic matter (OM) is comprised of a complex mixture of substrates, which are difficult to fully characterize. Therefore a range of analytical approaches is applied to provide a better understanding of the dynamics and biogeochemical cycling of aquatic system. One approach is UV-Visible spectroscopy, which includes measurements of spectral absorption and fluorescence of colored and fluorescent fractions of dissolved OM (DOM, CDOM and FDOM). In this study OM fluorescence is characterized by excitation-emission matrix spectroscopy on alkaline extracted DOM from a Baltic Sea sediment core that spanned 8500 years and fluctuating levels of hypoxia. Our results showed that three underlying fluorescence components had strong correlations with carbon, nitrogen content and δN. Our results demonstrate that optical properties of extracted OM from sediments reveal information about OM quality and quantity similar to those of biomarkers, which can be a useful additional tool for investigating OM deposition.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.scitotenv.2019.04.170 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
Heterotrophic denitrifiers play crucial roles in global carbon and nitrogen cycling. However, their inability to oxidize sulfide renders them vulnerable to this toxic molecule, which inhibits the key enzymatic reaction responsible for reducing nitrous oxide (NO), thereby raising greenhouse gas emissions. Here, we applied microcosm incubations, community-isotope-corrected DNA stable-isotope probing, and metagenomics to characterize a cohort of heterotrophic denitrifiers in estuarine sediments that thrive by coupling sulfur oxidation with denitrification through chemolithoheterotrophic metabolism.
View Article and Find Full Text PDFChemosphere
January 2025
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore; NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, 117411, Singapore. Electronic address:
Drinking water distribution systems face a multifaceted emerging concern, including in situ microplastic (MP) generation, chemical leaching from plastic pipes, and the formation of disinfection by-products (DBPs). This study investigated the co-release of MPs and chemical leachates from polyvinyl chloride (PVC) pipes exposed to different chlorine concentrations on a lab scale, as well as the subsequent formation of DBP. Results highlighted significant evidence of PVC-derived dissolved organic matter (PVC-DOM) and microplastic (PVC-MP) leaching at higher chlorine concentrations.
View Article and Find Full Text PDFNat Commun
January 2025
Laboratorio de Biodiversidad y Funcionamiento Ecosistémico. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS). Consejo Superior de Investigaciones Científicas (CSIC). Av. Reina Mercedes 10, E-41012, Sevilla, Spain.
Fires alter the stability of organic matter and promote soil erosion which threatens the fundamental coupling of soil biogeochemical cycles. Yet, how soil biogeochemistry and its environmental drivers respond to fire remain virtually unknown globally. Here, we integrate experimental observations and random forest model, and reveal significant divergence in the responses of soil biogeochemical attributes to fire, including soil carbon (C), nitrogen (N), and phosphorus (P) contents worldwide.
View Article and Find Full Text PDFLangmuir
January 2025
Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science (IISc), Bangalore 560012, India.
The enduring pathogenicity of can be attributed to its lipid-rich cell wall, with mycolic acids (MAs) being a significant constituent. Different MAs' fluidity and structural adaptability within the bacterial cell envelope significantly influence their physicochemical properties, operational capabilities, and pathogenic potential. Therefore, an accurate conformational representation of various MAs in aqueous media can provide insights into their potential role within the intricate structure of the bacterial cell wall.
View Article and Find Full Text PDFWater Sci Technol
January 2025
China Construction Fifth Engineering Division Co., Ltd, Changsha, Hunan 410004, China.
Road runoff underwent treatment using a filter filled with sludge from drinking water treatment plants to assess its capacity for removing dissolved organic matter (DOM). This evaluation utilized resin fractionation, gel permeation chromatography, three-dimensional excitation-emission matrix fluorescence spectroscopy, and UV-Visible spectroscopy. The filter demonstrated enhanced efficiency in removing dissolved organic carbon, achieving removal rates between 70 and 80%.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!