Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques
To understand, characterize, and predict the evolution of oceanic biogeochemical cycles in relation to the global climate change, it is necessary to better understand the dynamics of organic matter (OM). In this context, the overall objective of this thesis was to get more insights chromophoric diss...
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fttriple:oai:gotriple.eu:10670/1.tfpym0 2023-05-15T15:18:26+02:00 Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques Para, Julien Aix-Marseille 2 Sempéré, Richard Charrière, Bruno 2011-06-17 http://www.theses.fr/2011AIX22041/document fr fre 10670/1.tfpym0 http://www.theses.fr/2011AIX22041/document other Theses.fr Uvr Cdom Interface océan/continent Cycle du carbone Phototransformation Land/sea interface Carbone cycle envir geo Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2011 fttriple 2023-01-22T18:32:24Z To understand, characterize, and predict the evolution of oceanic biogeochemical cycles in relation to the global climate change, it is necessary to better understand the dynamics of organic matter (OM). In this context, the overall objective of this thesis was to get more insights chromophoric dissolved fraction of OM (CDOM) dynamics in surface Mediterranean and Arctic coastal waters and to determine the impact on attenuation of ultraviolet (UVR) and visible (PAR) underwater radiation. For this, the study of optical properties of absorbance and fluorescence of CDOM, coupled with atmospheric and underwater radiometric measurements, were made during a seasonal cycle in the Bay of Marseille (SOFCOM station), and in the Beaufort Sea during summer 2009. The Bay of Marseilles is characterized by low amounts of CDOM (aCDOM(350) = 0.10 ± 0.02 m-1), particularly in end summer stratification period due to the intensity of the solar irradiance, enriched in UVR-B, which degrades and bleaches CDOM (SCDOM = 0.023 ± 0.003 nm-1). In this highly urbanized coastal area, the dynamics of CDOM are driven by biotic processes (in situ biological production and within the Rhône River plume) and abiotic (photo-bleaching and mixing). Our results showed that CDOM is mostly of autochthonous origin, even during Rhône plume intrusion events (photo-degradation of terrestrial CDOM during the transit). During bloom periods, the CDOM consists mainly of a recent type protein (peak T), which preferentially absorbs in the short UVR. These pulses of recent CDOM are superimposed on a persistent background of CDOM mainly composed of aged material, humic-type (peaks M and C), which absorbs UVR and PAR. Over the Canadian shelf of the Beaufort Sea, CDOM is highly abundant (aCDOMmax (350) = 6.36 m-1) and strongly influenced by allochthonous inputs from the Mackenzie (peaks A-C and M) decreasing conservatively with salinity. In marine waters (salinity> 25), CDOM had lower concentrations (aCDOM(350) = 0.21 ± 0.13 m-1) and originated from a recent in ... Thesis Arctic Beaufort Sea Climate change Unknown Arctic |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
French |
topic |
Uvr Cdom Interface océan/continent Cycle du carbone Phototransformation Land/sea interface Carbone cycle envir geo |
spellingShingle |
Uvr Cdom Interface océan/continent Cycle du carbone Phototransformation Land/sea interface Carbone cycle envir geo Para, Julien Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
topic_facet |
Uvr Cdom Interface océan/continent Cycle du carbone Phototransformation Land/sea interface Carbone cycle envir geo |
description |
To understand, characterize, and predict the evolution of oceanic biogeochemical cycles in relation to the global climate change, it is necessary to better understand the dynamics of organic matter (OM). In this context, the overall objective of this thesis was to get more insights chromophoric dissolved fraction of OM (CDOM) dynamics in surface Mediterranean and Arctic coastal waters and to determine the impact on attenuation of ultraviolet (UVR) and visible (PAR) underwater radiation. For this, the study of optical properties of absorbance and fluorescence of CDOM, coupled with atmospheric and underwater radiometric measurements, were made during a seasonal cycle in the Bay of Marseille (SOFCOM station), and in the Beaufort Sea during summer 2009. The Bay of Marseilles is characterized by low amounts of CDOM (aCDOM(350) = 0.10 ± 0.02 m-1), particularly in end summer stratification period due to the intensity of the solar irradiance, enriched in UVR-B, which degrades and bleaches CDOM (SCDOM = 0.023 ± 0.003 nm-1). In this highly urbanized coastal area, the dynamics of CDOM are driven by biotic processes (in situ biological production and within the Rhône River plume) and abiotic (photo-bleaching and mixing). Our results showed that CDOM is mostly of autochthonous origin, even during Rhône plume intrusion events (photo-degradation of terrestrial CDOM during the transit). During bloom periods, the CDOM consists mainly of a recent type protein (peak T), which preferentially absorbs in the short UVR. These pulses of recent CDOM are superimposed on a persistent background of CDOM mainly composed of aged material, humic-type (peaks M and C), which absorbs UVR and PAR. Over the Canadian shelf of the Beaufort Sea, CDOM is highly abundant (aCDOMmax (350) = 6.36 m-1) and strongly influenced by allochthonous inputs from the Mackenzie (peaks A-C and M) decreasing conservatively with salinity. In marine waters (salinity> 25), CDOM had lower concentrations (aCDOM(350) = 0.21 ± 0.13 m-1) and originated from a recent in ... |
author2 |
Aix-Marseille 2 Sempéré, Richard Charrière, Bruno |
format |
Thesis |
author |
Para, Julien |
author_facet |
Para, Julien |
author_sort |
Para, Julien |
title |
Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
title_short |
Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
title_full |
Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
title_fullStr |
Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
title_full_unstemmed |
Etude de la Matière Organique Dissoute Chromophorique et du rayonnement solaire (UV-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
title_sort |
etude de la matière organique dissoute chromophorique et du rayonnement solaire (uv-visible) dans les eaux de surfaces côtières méditerranéennes et articques |
publishDate |
2011 |
url |
http://www.theses.fr/2011AIX22041/document |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Beaufort Sea Climate change |
genre_facet |
Arctic Beaufort Sea Climate change |
op_source |
Theses.fr |
op_relation |
10670/1.tfpym0 http://www.theses.fr/2011AIX22041/document |
op_rights |
other |
_version_ |
1766348626127224832 |