Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador
Oceanic prokaryotes are key players in the carbon cycle by consuming dissolved organic mat-ter (DOM) produced by primary producers. As this organic matter is highly complex with varying degree of bioavailability, prokaryotic communities are highly diverse and different taxa target certain types of or...
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fttriple:oai:gotriple.eu:10670/1.yjq2dw 2023-05-15T17:06:03+02:00 Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador Origin, composition and intended purpose of dissolved organic matter and its interactions with procaryot communities in the Labrador Sea LaBrie, Richard Maranger, Roxane 2021-01-26 http://hdl.handle.net/1866/24482 fr fre 10670/1.yjq2dw http://hdl.handle.net/1866/24482 undefined Thèses et mémoires de l'UdeM envir geo Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2021 fttriple 2023-01-22T17:40:53Z Oceanic prokaryotes are key players in the carbon cycle by consuming dissolved organic mat-ter (DOM) produced by primary producers. As this organic matter is highly complex with varying degree of bioavailability, prokaryotic communities are highly diverse and different taxa target certain types of organic compounds. By consuming this organic matter, prokary-otes reintroduce this carbon into the food web, a critical energy flow in oligotrophic gyres. However, this consumption is not perfect and they release a lot of carbon as CO2 through respiration, but also as recalcitrant DOM. Thus, they contribute to carbon sequestration in aquatic ecosystems. The objective of this thesis is to characterize DOM bioavailability and its influence on the composition and metabolism of prokaryotic communities in the Labrador Sea, described as one of the Earth’s climate system tipping elements. More precisely, we quantify for the first time how the spatial abundance distribution of prokaryotes influences ecosystem metabolism and organic matter association in the surface waters of the Labrador Sea. Lastly, we look at how DOM produced at the surface is transformed and sequestered following the Labrador Sea winter convective mixing. The oceanic carbon budget is still unbalanced. In order to better understand its carbon sources and bioavailability, we characterize DOM bioavailability across the aquatic contin-uum, from lakes to the open ocean. Using a meta-analysis, our results show that the propor-tion of labile organic matter, i.e. readily available for prokaryotes, is similar at around 6% in all aquatic ecosystems. However, the proportion of semi-labile organic matter, i.e requiring transformations to be consumed by prokaryotes, is highly related to terrestrial connectivity. The only ecosystems that did not follow these patterns were in a phytoplankton bloom pe-riod and had a high proportion of labile and semi-labile organic matter as their counterparts at equilibrium. Finally, we estimated that semi-labile organic matter could sustain ... Thesis Labrador Sea Unknown Mer du Labrador ENVELOPE(-55.998,-55.998,55.000,55.000) |
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envir geo |
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envir geo LaBrie, Richard Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
topic_facet |
envir geo |
description |
Oceanic prokaryotes are key players in the carbon cycle by consuming dissolved organic mat-ter (DOM) produced by primary producers. As this organic matter is highly complex with varying degree of bioavailability, prokaryotic communities are highly diverse and different taxa target certain types of organic compounds. By consuming this organic matter, prokary-otes reintroduce this carbon into the food web, a critical energy flow in oligotrophic gyres. However, this consumption is not perfect and they release a lot of carbon as CO2 through respiration, but also as recalcitrant DOM. Thus, they contribute to carbon sequestration in aquatic ecosystems. The objective of this thesis is to characterize DOM bioavailability and its influence on the composition and metabolism of prokaryotic communities in the Labrador Sea, described as one of the Earth’s climate system tipping elements. More precisely, we quantify for the first time how the spatial abundance distribution of prokaryotes influences ecosystem metabolism and organic matter association in the surface waters of the Labrador Sea. Lastly, we look at how DOM produced at the surface is transformed and sequestered following the Labrador Sea winter convective mixing. The oceanic carbon budget is still unbalanced. In order to better understand its carbon sources and bioavailability, we characterize DOM bioavailability across the aquatic contin-uum, from lakes to the open ocean. Using a meta-analysis, our results show that the propor-tion of labile organic matter, i.e. readily available for prokaryotes, is similar at around 6% in all aquatic ecosystems. However, the proportion of semi-labile organic matter, i.e requiring transformations to be consumed by prokaryotes, is highly related to terrestrial connectivity. The only ecosystems that did not follow these patterns were in a phytoplankton bloom pe-riod and had a high proportion of labile and semi-labile organic matter as their counterparts at equilibrium. Finally, we estimated that semi-labile organic matter could sustain ... |
author2 |
Maranger, Roxane |
format |
Thesis |
author |
LaBrie, Richard |
author_facet |
LaBrie, Richard |
author_sort |
LaBrie, Richard |
title |
Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
title_short |
Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
title_full |
Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
title_fullStr |
Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
title_full_unstemmed |
Origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du Labrador |
title_sort |
origine, composition et destinée de la matière organique dissoute et ses interactions avec les communautés de procaryotes dans la mer du labrador |
publishDate |
2021 |
url |
http://hdl.handle.net/1866/24482 |
long_lat |
ENVELOPE(-55.998,-55.998,55.000,55.000) |
geographic |
Mer du Labrador |
geographic_facet |
Mer du Labrador |
genre |
Labrador Sea |
genre_facet |
Labrador Sea |
op_source |
Thèses et mémoires de l'UdeM |
op_relation |
10670/1.yjq2dw http://hdl.handle.net/1866/24482 |
op_rights |
undefined |
_version_ |
1766060970135781376 |