Pan-arctic trends in terrestrial dissolved organic matter from optical measurements
Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical pr...
Published in: | Frontiers in Earth Science |
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/26135/ https://doi.org/10.3389/feart.2016.00025 https://nrl.northumbria.ac.uk/id/eprint/26135/1/171139_Mann_ProvisionalPDF.pdf |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:26135 2023-05-15T14:25:40+02:00 Pan-arctic trends in terrestrial dissolved organic matter from optical measurements Mann, Paul Spencer, Robert Hernes, Peter Six, Johan Aiken, George Tank, Suzanne McClelland, James Butler, Kenna Dyda, Rachael Holmes, Robert 2016-03-17 text https://nrl.northumbria.ac.uk/id/eprint/26135/ https://doi.org/10.3389/feart.2016.00025 https://nrl.northumbria.ac.uk/id/eprint/26135/1/171139_Mann_ProvisionalPDF.pdf en eng Frontiers https://nrl.northumbria.ac.uk/id/eprint/26135/1/171139_Mann_ProvisionalPDF.pdf Mann, Paul, Spencer, Robert, Hernes, Peter, Six, Johan, Aiken, George, Tank, Suzanne, McClelland, James, Butler, Kenna, Dyda, Rachael and Holmes, Robert (2016) Pan-arctic trends in terrestrial dissolved organic matter from optical measurements. Frontiers in Earth Science, 4. p. 25. ISSN 2296-6463 cc_by_4_0 CC-BY F700 Ocean Sciences F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2016 ftunivnorthumb https://doi.org/10.3389/feart.2016.00025 2022-09-25T06:03:37Z Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275-295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of ‘terrestrial humic-like’ versus ‘marine humic-like’ fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our ... Article in Journal/Newspaper Arctic Arctic Arctic Ocean Climate change permafrost Northumbria University, Newcastle: Northumbria Research Link (NRL) Arctic Arctic Ocean Frontiers in Earth Science 4 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F700 Ocean Sciences F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F700 Ocean Sciences F800 Physical and Terrestrial Geographical and Environmental Sciences Mann, Paul Spencer, Robert Hernes, Peter Six, Johan Aiken, George Tank, Suzanne McClelland, James Butler, Kenna Dyda, Rachael Holmes, Robert Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
topic_facet |
F700 Ocean Sciences F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275-295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of ‘terrestrial humic-like’ versus ‘marine humic-like’ fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our ... |
format |
Article in Journal/Newspaper |
author |
Mann, Paul Spencer, Robert Hernes, Peter Six, Johan Aiken, George Tank, Suzanne McClelland, James Butler, Kenna Dyda, Rachael Holmes, Robert |
author_facet |
Mann, Paul Spencer, Robert Hernes, Peter Six, Johan Aiken, George Tank, Suzanne McClelland, James Butler, Kenna Dyda, Rachael Holmes, Robert |
author_sort |
Mann, Paul |
title |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_short |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_full |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_fullStr |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_full_unstemmed |
Pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
title_sort |
pan-arctic trends in terrestrial dissolved organic matter from optical measurements |
publisher |
Frontiers |
publishDate |
2016 |
url |
https://nrl.northumbria.ac.uk/id/eprint/26135/ https://doi.org/10.3389/feart.2016.00025 https://nrl.northumbria.ac.uk/id/eprint/26135/1/171139_Mann_ProvisionalPDF.pdf |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Arctic Ocean Climate change permafrost |
genre_facet |
Arctic Arctic Arctic Ocean Climate change permafrost |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/26135/1/171139_Mann_ProvisionalPDF.pdf Mann, Paul, Spencer, Robert, Hernes, Peter, Six, Johan, Aiken, George, Tank, Suzanne, McClelland, James, Butler, Kenna, Dyda, Rachael and Holmes, Robert (2016) Pan-arctic trends in terrestrial dissolved organic matter from optical measurements. Frontiers in Earth Science, 4. p. 25. ISSN 2296-6463 |
op_rights |
cc_by_4_0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.3389/feart.2016.00025 |
container_title |
Frontiers in Earth Science |
container_volume |
4 |
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1766298113402732544 |