Zobrazeno 1 - 10
of 18
pro vyhledávání: '"John R, Helms"'
Autor:
John R. Helms, Xiaoyan Cao, Pu Duan, Klaus Schmidt-Rohr, Peter W. Bernhardt, Margaret R. Mulholland, Jingdong Mao
Publikováno v:
Analytical Chemistry. 89:11990-11998
Dissolved organic nitrogen (DON) comprises the largest pool of fixed N in the surface ocean, yet its composition has remained poorly constrained. Knowledge of the chemical composition of this nitrogen pool is crucial for understanding its biogeochemi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::335bd65f45332de8a2b0ae019ddef8e3
https://doi.org/10.1021/acs.analchem.7b02335
https://doi.org/10.1021/acs.analchem.7b02335
Autor:
Robert J. Kieber, J. David Felix, G. Brooks Avery, Katherine M. Mullaugh, Fernanda F. Giubbina, John M. Cala, Rachel K. Thomas, M. Lucia A.M. Campos, Ralph N. Mead, John R. Helms, Joan D. Willey
Publikováno v:
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
Universidade de São Paulo (USP)
instacron:USP
The global wet deposition flux of ethanol is estimated to be 2.4 ± 1.6 Tg/yr with a conservative range of 0.2–4.6 Tg/yr based upon analyses of 219 wet deposition samples collected at 12 locations globally. This estimate calculated by using observe
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c5bf1d5af5188c840d98d635c519e337
https://doi.org/10.1002/2016gb005516
https://doi.org/10.1002/2016gb005516
Autor:
J. David Felix, Robert J. Kieber, Hugh D. Rainey, Jennifer L. Harfmann, Ralph N. Mead, G. Brooks Avery, John R. Helms, Stephen A. Skrabal, David C. Podgorski
Publikováno v:
Organic Geochemistry. 151:104164
Photochemically-released dissolved organic matter (PR-DOM) from resuspended sediments is an understudied flux of dissolved organic carbon (DOC) and nutrients with the potential to influence estuarine microbial food webs. There is currently limited kn
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9fe950875df1e0637cf2c0c76b5110c4
https://doi.org/10.1016/j.orggeochem.2020.104164
https://doi.org/10.1016/j.orggeochem.2020.104164
Autor:
Ralph N. Mead, Laura Foley, Katherine M. Mullaugh, G. Brooks Avery, Amanda Guy, J. David Felix, Angela L. Carroll, Robert J. Kieber, John R. Helms, Jesse Alan Roebuck, Stephen A. Skrabal, Joan D. Willey
Publikováno v:
Chemosphere. 144:360-365
This study reports the first ethanol concentrations in fresh and estuarine waters and greatly expands the current data set for coastal ocean waters. Concentrations for 153 individual measurements of 11 freshwater sites ranged from 5 to 598 nM. Concen
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cc535edc907d5827e0c51f900b2d8365
https://doi.org/10.1016/j.chemosphere.2015.08.080
https://doi.org/10.1016/j.chemosphere.2015.08.080
Autor:
Jingdong Mao, Aron Stubbins, Nelson W. Green, Kenneth Mopper, Patrick G. Hatcher, John R. Helms, E. Michael Perdue, Hongmei Chen
Publikováno v:
Marine Chemistry. 177:278-287
Oceanic dissolved organic matter (DOM) is one of the largest pools of reduced carbon on Earth, yet DOM remains poorly chemically characterized. Studies to determine the chemical nature of oceanic DOM have been impeded by the lack of efficient and non
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::d943698e810035b883efd3c7973f413f
https://doi.org/10.1016/j.marchem.2015.07.007
https://doi.org/10.1016/j.marchem.2015.07.007
Autor:
Stephen A. Skrabal, John R. Helms, Ralph N. Mead, Emily E. Probst, G. Brooks Avery, Robert J. Kieber
Publikováno v:
Rapid Communications in Mass Spectrometry. 28:2455-2460
RATIONALE Karenia brevis, a marine dinoflagellate, biosynthesizes a unique class of polyether toxins called brevetoxins that produce significant health, environmental and economic impacts in and along coastal waters. Previous application of liquid ch
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c200a289b726532e92f1531957d3be58
https://doi.org/10.1002/rcm.7032
https://doi.org/10.1002/rcm.7032
Publikováno v:
Environmental Toxicology and Chemistry. 33:2240-2245
The photodegradation rate of the anti-histamine cetirizine (Zyrtec®) was investigated in various water matrices. The average observed first-order photodegradation rate coefficient (kobs), obtained by linear regression of the logarithmic-transformed
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8adae844177deaae3f2646ab56aab2f4
https://doi.org/10.1002/etc.2691
https://doi.org/10.1002/etc.2691
Autor:
Robert J. Kieber, Stephen A. Skrabal, John R. Helms, Melissa W. Southwell, Ralph N. Mead, G. Brooks Avery, Donna A. Glinski
Publikováno v:
Organic Geochemistry. 73:83-89
Sediments exposed to simulated solar radiation release dissolved organic carbon (DOC). However, it is unclear how the provenance of sedimentary organic matter (OM) impacts this photorelease. In the first geographically extensive study of this kind, t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::44b3f0f1f8208f64dc05b813d388362f
https://doi.org/10.1016/j.orggeochem.2014.05.011
https://doi.org/10.1016/j.orggeochem.2014.05.011
Autor:
Kenneth Mopper, Hongmei Chen, E. Michael Perdue, John R. Helms, Patrick G. Hatcher, Nelson W. Green, Aron Stubbins
Publikováno v:
Marine Chemistry. 164:48-59
A high-recovery technique of dissolved organic matter (DOM) isolation – reverse osmosis coupled with electrodialysis (RO/ED) – was used to isolate DOM from the North Atlantic Senegal-Mauritanian upwelling area surface water (5 m), North Atlantic
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::4a7cacf652626ebc6105dbda9f209fe5
https://doi.org/10.1016/j.marchem.2014.06.002
https://doi.org/10.1016/j.marchem.2014.06.002
Publikováno v:
Estuarine, Coastal and Shelf Science. 149:273-282
This study presents the first extensive examination of the controls on optical properties of chromophoric dissolved organic matter (CDOM) within the Cape Fear River Estuary (CFRE) utilizing spectral slope ratios (SR). The application of SUVA254 value
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::cecda9742acc286988f19efded75a7d7
https://doi.org/10.1016/j.ecss.2014.08.026
https://doi.org/10.1016/j.ecss.2014.08.026