Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

Biogeosciences, Journal Year: 2015, Volume and Issue: 12(23), P. 7129 - 7167

Published: Dec. 8, 2015

Abstract. The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new ecosystems, while at same time modifying existing lakes, streams, and rivers that are impacted by thaw. Here, we describe current state knowledge regarding how affects lentic (still) lotic (moving) systems, exploring effects both thermokarst (thawing collapse ice-rich permafrost) deepening active layer (the surface soil thaws refreezes each year). Within thermokarst, further differentiate between in lowland areas vs. on hillslopes. For almost all processes explore, vary regionally, lake stream systems. Much this regional variation caused differences ground ice content, topography, type, coverage. Together, these factors determine (i) degree to which manifests as (ii) whether leads slumping or formation (iii) manner constituent delivery altered Differences thaw-enabled can be considerable, determining, for example, balance particulate dissolved constituents, inorganic organic materials. Changes composition thaw-impacted waters, coupled changes morphology, strongly affect physical optical properties lakes. ecology lakes streams also likely change; have unique microbiological communities, show respiration, primary production, food web structure largely driven sediment, matter, nutrient delivery. enables matter morphology stratification characteristics recipient will play an important role determining release greenhouse gases (CO2 CH4), its burial sediments, loss downstream. magnitude impacts aquatic ecosystems increasing, prevalence streams. There therefore urgent need quantify affecting across diverse landscapes, implications change climate warming.

Language: Английский

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Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol

Atmospheric chemistry and physics, Journal Year: 2017, Volume and Issue: 17(3), P. 2103 - 2162

Published: Feb. 13, 2017

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one important interactions between anthropogenic emissions related to combustion and natural from biosphere. This interaction has been recognized for more than 3 decades, during which time a large body research emerged laboratory, field, modeling studies. NO3-BVOC reactions influence air quality, climate visibility through regional global budgets reactive nitrogen (particularly nitrates), ozone, aerosol. Despite its long history significance this topic in atmospheric chemistry, number uncertainties remain. These include an incomplete understanding rates, mechanisms, aerosol yields reactions, lack constraints on role heterogeneous oxidative processes associated with NO3 radical, difficulty characterizing spatial distributions BVOC within poorly mixed nocturnal atmosphere, challenge constructing appropriate boundary layer schemes non-photochemical mechanisms use state-of-the-art chemical transport chemistry-climate models. review is result workshop same title held at Georgia Institute Technology June 2015. The first half summarizes current literature particular focus recent advances instrumentation models, secondary (SOA) formation chemistry. Building understanding, second outlines impacts chemistry quality climate, suggests critical needs better constrain improve predictive capabilities

Language: Английский

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Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions

Environmental Science & Technology, Journal Year: 2016, Volume and Issue: 51(3), P. 1074 - 1093

Published: Dec. 21, 2016

Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase compounds leading to formation particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources SOA precursors. They emit complex mixtures that vary in volatility molecular structure—factors influence their contributions urban SOA. However, relative importance each vehicle type with respect remains unclear due conflicting evidence recent laboratory, field, modeling studies. Both likely important, evolving location over short time scales. This review summarizes evidence, research needs, discrepancies between top-down bottom-up approaches used estimate focusing on inconsistencies molecular-level understanding regional observations. The effect emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) precursor emissions needs comprehensive evaluation, especially international perspective given heterogeneity regulations technology penetration. Novel studies needed identify quantify "missing" appear contribute substantially production, gasoline vehicles most advanced aftertreatment. Initial suggests catalyzed diesel particulate filters greatly reduce precursors along primary aerosol.

Language: Английский

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Chemistry and the Linkages between Air Quality and Climate Change

Chemical Reviews, Journal Year: 2015, Volume and Issue: 115(10), P. 3856 - 3897

Published: April 30, 2015

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTChemistry and the Linkages between Air Quality Climate ChangeErika von Schneidemesser*†, Paul S. Monks*‡, James D. Allan§∥, Lori Bruhwiler⊥, Piers Forster#, David Fowler∇, Axel Lauer†, William T. Morgan§, Pauli Paasonen○, Mattia Righi◆, Katerina Sindelarova¶□, Mark A. Sutton∇View Author Information† Institute for Advanced Sustainability Studies, 14467 Potsdam, Germany‡ Department of Chemistry, University Leicester, Leicester LE1 7RH, United Kingdom§ §School Earth, Atmospheric Environmental Sciences, ∥National Centre Science, Manchester, Manchester M13 9PL, Kingdom⊥ National Oceanic & Administration, Boulder, Colorado 80303, States# Leeds, Leeds LS2 9JT, Kingdom∇ Ecology Hydrology, Natural Environment Research Council, Edinburgh EH26 0QB, Kingdom○ Physics, Helsinki, 00100 Finland◆ Deutsches Zentrum für Luft- und Raumfahrt, Institut Physik der Atmosphäre, 82234 Oberpfaffenhofen, Germany¶ UPMC Univ. Paris 06, Université Versailles St-Quentin; CNRS/INSU; LATMOS-IPSL, UMR 8190 Paris, France□ Faculty Mathematics Charles University, 116 36 Prague, Czech Republic*E-mail: [email protected]*E-mail: protected]Cite this: Chem. Rev. 2015, 115, 10, 3856–3897Publication Date (Web):April 30, 2015Publication History Received10 February 2015Published online30 April inissue 27 May 2015https://doi.org/10.1021/acs.chemrev.5b00089Copyright © 2015 American Chemical SocietyRIGHTS PERMISSIONSACS AuthorChoicewith CC-BYlicenseArticle Views28841Altmetric-Citations260LEARN ABOUT THESE METRICSArticle Views are COUNTER-compliant sum full text article downloads since November 2008 (both PDF HTML) across all institutions individuals. These metrics regularly updated to reflect usage leading up last few days.Citations number other articles citing this article, calculated by Crossref daily. Find more information about citation counts.The Altmetric Attention Score is a quantitative measure attention that research has received online. Clicking on donut icon will load page at altmetric.com with additional details score social media presence given article. how calculated. Share Add toView InAdd Full Text ReferenceAdd Description ExportRISCitationCitation abstractCitation referencesMore Options onFacebookTwitterWechatLinked InReddit (22 MB) Get e-AlertscloseSUBJECTS:Aerosols,Atmospheric chemistry,Climate,Particulate matter,Redox reactions e-Alerts

Language: Английский

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Global distribution of particle phase state in atmospheric secondary organic aerosols

Nature Communications, Journal Year: 2017, Volume and Issue: 8(1)

Published: April 21, 2017

Secondary organic aerosols (SOA) are a large source of uncertainty in our current understanding climate change and air pollution. The phase state SOA is important for quantifying their effects on quality, but its global distribution poorly characterized. We developed method to estimate glass transition temperatures based the molar mass molecular O:C ratio components, we used chemistry model EMAC with aerosol module ORACLE predict atmospheric SOA. For planetary boundary layer, simulations indicate that mostly liquid tropical polar high relative humidity, semi-solid mid-latitudes solid over dry lands. find middle upper troposphere should be glassy state. Thus, slow diffusion water, oxidants molecules could kinetically limit gas-particle interactions free troposphere, promote ice nucleation facilitate long-range transport reactive toxic pollutants embedded

Language: Английский

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