Article
Environmental Sciences
Erin N. MacDonald, Suzanne E. Tank, Steven Kokelj, Duane G. Froese, Ryan H. S. Hutchins
Summary: This study used ultrahigh-resolution mass spectrometry to characterize DOM derived from different permafrost end-member types in the western Canadian Arctic, revealing significant variation in DOM composition among the permafrost end-member types. The unique compound characteristics of DOM from various permafrost end-member types are primarily influenced by the parent materials of the permafrost.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Engineering, Environmental
Derrick R. Vaughn, Anne M. Kellerman, Kimberly P. Wickland, Robert G. Striegl, David C. Podgorski, Jon R. Hawkings, Jaap H. Nienhuis, Mark M. Dornblaser, Edward G. Stets, Robert G. M. Spencer
Summary: Anthropogenic conversion of forests and wetlands to agricultural and urban landcovers impacts dissolved organic matter (DOM) within streams draining these catchments, but research on how it affects DOM molecular composition and bioavailability is lacking. In a study of the Upper Mississippi River Basin, it was found that streams draining urban areas had higher bioavailable DOC (BDOC) concentrations compared to streams draining agricultural and forested areas. The conversion of forested landcover to urban had a greater impact on stream DOM bioavailability than conversion to agricultural landcover.
Article
Environmental Sciences
Jennifer A. Rogers, Valier Galy, Anne M. Kellerman, Jeffrey P. Chanton, Nikita Zimov, Robert G. M. Spencer
Summary: Research has shown that the input of dissolved organic matter from permafrost in Arctic rivers like the Kolyma River is overwhelmed by the export of modern terrestrial organic matter.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2021)
Article
Environmental Sciences
Sarah Ellen Johnston, Joanna C. Carey, Anne Kellerman, David C. Podgorski, Jonathan Gewirtzman, Robert G. M. Spencer
Summary: Climatic changes in high-latitude watersheds are transforming the source and reactivity of riverine dissolved organic matter (DOM), with terrain characteristics playing a major role in determining DOM composition. Northern watersheds export less DOC with relatively more aliphatic DOM, while southern basins have more aromatic DOM with higher lignin concentrations. Shifting vegetation and thawing permafrost are expected to continue impacting DOM characteristics in changing Arctic environments.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2021)
Article
Environmental Sciences
M. R. N. Moore, S. E. Tank, M. R. Kurek, M. Taskovic, A. M. McKenna, J. L. J. Smith, S. V. Koklej, R. G. M. Spencer
Summary: The Arctic is experiencing rapid warming, causing the thawing of permafrost and releasing organic carbon. This study found that the thawed permafrost inputs can be observed in streams, with higher concentrations of dissolved organic carbon and lower aromaticity. The unique molecular fingerprints of permafrost inputs can be tracked downstream in the aquatic network.
Article
Environmental Sciences
Meilian Chen, Chaoliu Li, Robert G. M. Spencer, Nagamitsu Maie, Jin Hur, Amy M. McKenna, Fangping Yan
Summary: Alpine rivers in the Tibetan Plateau exhibit a decreasing trend of dissolved organic matter (DOM) quantity and an increasing trend of aromaticity from the northern to southern plateau, influenced by dust load, precipitation, and vegetation. Proglacial streams are dominated by tyrosine-like fluorescent DOM, while main stems of rivers within larger catchment areas are controlled by humic-like fluorescent DOM. The presence of condensed aromatics in riverine DOM suggests anthropogenic black soot pollution, and seasonal variations in DOM amount and characteristics indicate heterogeneous land cover, anthropogenic activities, and climatic factors at play on the highest plateau on Earth.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Anne M. Kellerman, Jorien Vonk, Stephanie McColaugh, David C. Podgorski, Elise van Winden, Jon R. Hawkings, Sarah Ellen Johnston, Munir Humayun, Robert G. M. Spencer
Summary: Glaciers and ice sheets store significant amounts of dissolved organic matter (DOM) and their rapid mass loss may increase fluxes of DOM into proglacial environments. Research on the molecular composition of glacially derived DOM is limited, but findings from Arctic glacial environments show differences in DOM between Greenland and Svalbard, suggesting varied sources of DOM. Supraglacial meltwater samples contain abundant aliphatic and peptide-like formulae, indicating energy-rich sources that contribute to microbial degradation in coastal systems as glaciers lose mass.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Engineering, Civil
Yanqiu Tao, Yao Du, Yamin Deng, Teng Ma, Yanxin Wang
Summary: This study reveals that phosphorus-containing dissolved organic matter (DOM) is an important factor controlling groundwater phosphorus enrichment. Through the degradation of DOM, an accumulation and retention process of phosphorus is observed at the molecular level, eventually becoming the predominant phosphorus pool in groundwater.
JOURNAL OF HYDROLOGY
(2023)
Article
Chemistry, Analytical
Qiong Pan, Wenya Hu, Ding He, Chen He, Linzhou Zhang, Quan Shi
Summary: High-resolution mass spectrometry provides compositional information of dissolved organic matter through isotopic assignment, but multiple possible solutions often occur due to measurement deviation and resolving power limitation. To improve result accuracy in an automated manner, a machine-learning-based algorithm was developed, which showed a significant improvement in formula assignment compared to traditional methods.
Article
Engineering, Environmental
Yun Kyung Lee, Wei He, Huaming Guo, Tanju Karanfil, Jin Hur
Summary: UV irradiation promotes the leaching of dissolved organic matter (MP-DOM) from both commercial and polymer microplastics (MPs), but polymer MPs release more. Commercial MP-DOM is characterized by protein/phenol-like components, while polymer MP-DOM is dominated by humic-like components. The presence of unsaturated structures generated in sunlit environments indicates the high environmental reactivity of polymer MPs and fully weathered plastics.
Article
Agricultural Engineering
Gang Tang, Binrui Li, Bowei Zhang, Chen Wang, Guangci Zeng, Xing Zheng, Chongxuan Liu
Summary: Using FT-ICR MS and fluorescence spectroscopy, this study examined the transformation of DOM and DON during A2O processes, showing that anaerobic degradation reduced the mass of influent DOM/DON, anoxic denitrified DON and generated DOM, and oxic processes led to DOM mineralization and ammonia nitrogen-DON conversion. Increases in aromaticity and unsaturation degree after A2O processes were associated with Proteobacteria (positively) and Bacteroidetes (negatively), providing important insights into DOM/DON dynamics in wastewater treatment plants.
BIORESOURCE TECHNOLOGY
(2021)
Article
Environmental Sciences
Huixia Han, Yujie Feng, Jing Chen, Qiaorong Xie, Shuang Chen, Ming Sheng, Shujun Zhong, Wan Wei, Sihui Su, Pingqing Fu
Summary: The study found that after acidification, the quantity and intensity of aromatic compounds with high oxygen content in soil, seawater, and atmospheric aerosol samples were significantly enhanced, while highly saturated compounds were reduced or absent. The effect of acidification on the molecular composition of DOM depends on the original environmental media of the samples.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Environmental Sciences
Derrick R. Vaughn, Anne M. Kellerman, Kimberly P. Wickland, Robert G. Striegl, David C. Podgorski, Jon R. Hawkings, Jaap H. Nienhuis, Mark M. Dornblaser, Edward G. Stets, Robert G. M. Spencer
Summary: Landcover changes have impacted the natural carbon cycle, with differences in dissolved organic carbon concentrations and molecular compositions in streams draining forest, agriculture, and urban landcovers. Forest and urban streams have higher DOC concentrations, while agricultural and urban streams show higher abundances of N-,S- heteroatomic formulae. The differences likely result from carbon sourcing, microbial processing, soil disturbance, and anthropogenic inputs.
Review
Engineering, Environmental
Most Shirina Begum, Ji-Hyung Park, Liyang Yang, Kyung Hoon Shin, Jin Hur
Summary: This review focused on the indicators of biodegradable dissolved organic carbon (BDOC) and CO2 production potential in inland waters. Optical and molecular indices were used to track the changes in BDOC during biodegradation. The study identified four methods for measuring BDOC and discussed the potential of using optical and molecular indices as proxies for estimating BDOC and CO2 production. The results showed that certain optical and molecular indices had consistent relationships with BDOC, providing useful indicators for predicting BDOC and CO2 emissions.
Article
Engineering, Environmental
Jun Chen, Na Wan, Kewei Li, Hu Aibin, Hang He, Dongsheng Wang, Weijun Zhang
Summary: This study used FT-ICR-MS to investigate the molecular characteristics and biological effects of microplastics dissolved organic matter (MP-DOM) leached from sludge hydrothermal treatment (HTT) at different temperatures. The results showed that the molecular richness and diversity of MP-DOM increased with rising temperature, accompanied by molecular transformation. The MP-DOM influenced the root development of Brassica rapa by affecting gene expression, with lignin-like compounds inhibiting Phenylpropanoids biosynthesis and CHNO compounds promoting nitrogen metabolism. The optimal HTT temperature for the further treatment of sludge was found to be 180℃.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Environmental Sciences
M. Behnke, J. B. Fellman, D. D'Amore, S. M. Gomez, R. G. M. Spencer
Summary: This study investigates the composition of terrestrial dissolved organic matter (DOM) in different landscape types of Southeast Alaska's temperate rainforest. The results show that both the source and processing of DOM play a significant role in determining its composition. Furthermore, climate change is predicted to have an impact on DOM export to the coastal ocean.
Article
Geochemistry & Geophysics
J. T. Sliwinski, O. Kost, L. Endres, M. Iglesias, N. Haghipour, S. Gonzalez-Lemos, H. M. Stoll
Summary: Fluorescent laminations in stalagmites from Asturias, Spain are annual and coincide with peaks in yttrium and troughs in strontium concentrations, which are reliable seasonality markers. Strontium concentrations are positively correlated with stalagmite growth rate and controlled by solution supersaturation, influenced by seasonal variations in cave ventilation. Yttrium concentrations are controlled by drip water flux, surface retention time, and dilation within the matrix. The persistent anti-correlation between strontium and yttrium can be explained as an interplay between their individual controls.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Ecology
Juan Jia, Zongguang Liu, Negar Haghipour, Lukas Wacker, Hailong Zhang, Carlos A. Sierra, Tian Ma, Yiyun Wang, Litong Chen, Ao Luo, Zhiheng Wang, Jin-Sheng He, Meixun Zhao, Timothy I. Eglinton, Xiaojuan Feng
Summary: Climate projection requires accurate understanding of SOC decomposition and its response to warming. This study provides direct evidence of the rapid turnover of lignin-derived phenols compared to slower-cycling components of SOC, and reveals that temperature mainly regulates lignin turnover while slow-cycling components are strongly influenced by mineral association. These findings suggest that warming may greatly accelerate lignin decomposition, especially in soils with weak mineral associations.
Article
Soil Science
Maxime Thomas, Arthur Monhonval, Catherine Hirst, Lisa Broder, Scott Zolkos, Jorien E. Vonk, Suzanne E. Tank, Kirsi H. Keskitalo, Sarah Shakil, Steven Kokelj, Jurjen van der Sluijs, Sophie Opfergelt
Summary: In northern high latitudes, rapid warming can enhance permafrost thaw and the transformation of soil organic carbon. However, a significant portion of permafrost soil organic carbon is stabilized by interactions with the soil mineral pool. Understanding mineral-organic carbon interactions is crucial for constraining permafrost-carbon-climate feedbacks.
Article
Multidisciplinary Sciences
Megan I. Behnke, Suzanne E. Tank, James W. McClelland, Robert M. Holmes, Negar Haghipour, Timothy I. Eglinton, Peter A. Raymond, Anya Suslova, Alexander Zhulidov, Tatiana Gurtovaya, Nikita Zimov, Sergey Zimov, Edda A. Mutter, Edwin Amos, Robert G. M. Spencer, Andrea Rinaldo
Summary: Arctic rivers are important channels for transmitting signals of change from the changing landscape to the ocean. This study reveals a previously overlooked contribution from aquatic biomass in the particulate organic matter (POM) flux. It also suggests that climate change-induced warming and increasing CO2 concentrations could enhance soil destabilization and aquatic biomass production, leading to increased POM fluxes to the ocean.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Environmental Sciences
Nadav S. Bendavid, Heather D. Alexander, Sergei P. Davydov, Heather Kropp, Michelle C. Mack, Susan M. Natali, Seth A. Spawn-Lee, Nikita S. Zimov, Michael M. Loranty
Summary: In post-fire Siberian larch forests, shrubs play a significant role in the vegetation canopy, especially in areas with varying tree density. The study examined the leaf area index (LAI) of trees and tall shrubs in a mature Siberian larch forest that regenerated after a fire. The results showed that tree LAI increased with tree density, while tall shrub LAI decreased. Additionally, there was a positive correlation between tall shrub LAI and NDVI/EVI from satellite imagery.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Environmental Sciences
M. I. Behnke, J. B. Fellman, D. V. D'Amore, R. G. M. Spencer
Summary: This study used advanced technology to investigate the production and transport of dissolved organic matter (DOM) in small watersheds in the northeast Pacific coastal temperate rainforest. The results showed that DOM generation is influenced by vegetation and soil, and can be transported from land to the ocean. Hydrologic and temperature variables were better predictors of DOM inputs from soil sources, while antecedent conditions played a role in the availability of DOM from vegetation sources. The study also found that wetlands contribute nitrogen-containing molecular formulae to DOM and that climate change may affect DOM sources, transport, and fate in these watersheds.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Geosciences, Multidisciplinary
G. McNicol, E. Hood, D. E. Butman, S. E. Tank, I. J. W. Giesbrecht, W. Floyd, D. D'Amore, J. B. Fellman, A. Cebulski, A. Lally, H. McSorley, S. G. Gonzalez Arriola
Summary: The rivers in the northeast Pacific Coastal Temperate Rainforest export 3.5 Tg-C yr(-1) of dissolved organic carbon (DOC) to the ocean. Over 56% of this DOC flux comes from small coastal watersheds, which make up only 22% of the total drainage basin. The average DOC yield from these coastal watersheds is roughly three times higher than that from tropical regions worldwide. These findings suggest that the export of DOC from these watersheds plays a significant role in regional-scale heterotrophy within near-shore marine ecosystems in the northeast Pacific.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
J. Blake Clark, Antonio Mannino, Robert G. M. Spencer, Suzanne E. Tank, James W. Mcclelland
Summary: Long-term increases in Arctic river discharge have been observed, and there are positive correlations between dissolved organic carbon (DOC) concentration, river discharge, and chromophoric dissolved organic matter (CDOM) content in the largest Arctic rivers. The study estimated chromophoric DOC (CDOC) concentrations in six Arctic rivers using data collected from 2009 to 2019. The modeled results showed an increase in DOC and CDOC exports, with CDOC increasing at a faster rate than total DOC.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Environmental Sciences
L. M. Thompson, M. Low, R. Shewan, C. Schulze, M. Simba, O. Sonnentag, S. E. Tank, D. Olefeldt
Summary: Climate change and permafrost thaw can affect the mobilization of terrestrial dissolved organic carbon (DOC), mercury (Hg), and neurotoxic methylmercury (MeHg) into aquatic ecosystems. The study found that the peatland catchment had higher concentrations of DOC and dissolved MeHg, but lower concentrations of total Hg compared to the mixed catchment. In the mixed catchment, analyte concentrations increased with discharge, while in the peatland catchment, they were not primarily associated with discharge. The study also suggests that climate change may enhance the production and transport of MeHg in boreal-Arctic catchments, especially during warmer periods.
WATER RESOURCES RESEARCH
(2023)
Article
Ecology
Eric B. Borth, Heather D. Alexander, Nikita Zimov, Ryan W. McEwan
Summary: The goal of this project was to assess sources of regeneration limitation in L.cajanderi forests in northeastern Siberia. We focused on the regeneration potential of stands varying in tree density and analyzing seedling establishment patterns in relation to microsite conditions. The results showed that tree density was negatively related to cone production, and moderate density stands produced more cones. Safe sites in the landscape facilitated L.cajanderi seedling establishment, particularly in lowland areas. These findings suggest complex linkages between forest density, propagule availability, fire, safe sight colonization, and seedling establishment in the understudied L.cajanderi forests of the Siberian Arctic.
Article
Environmental Sciences
Ryan H. S. Hutchins, Suzanne E. Tank, David Olefeldt, William L. Quinton, Christopher Spence, Nicole Dion, Samson G. Mengistu
Summary: Wildfires in northern regions are causing changes in water quality, but the effects are relatively small compared to other factors such as climate and watershed characteristics. Variability in stream water chemistry is driven by watershed-specific properties, overshadowing the influence of wildfires. Future impacts on streams are likely more substantially driven by climate change and altered hydrology than increasing wildfire frequency.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Ecology
Dirk Jong, Lisa Broder, Tommaso Tesi, Kirsi H. Keskitalo, Nikita Zimov, Anna Davydova, Philip Pika, Negar Haghipour, Timothy I. Eglinton, Jorien E. Vonk
Summary: Arctic rivers are increasingly affected by thawing permafrost, and the fate of permafrost-derived organic carbon (OC) depends on complex processes along the source-to-sink system. A study on the Kolyma River and East Siberian Sea investigates the composition and degradation state of riverine OC compared to marine sediments. The results suggest that old permafrost-OC is mainly associated with sediments, while autochthonous primary production contributes to particulate OC.