Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification
The common cuttlefish, Sepia officinalis, is a coastal cephalopod known for its eco physiological performance supported by a wide repertoire of behaviors that allows it, despite its short life cycle, to play a central role in food webs. However, it is also known to efficiently accumulate metallic el...
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ftunivrochelle:oai:HAL:tel-04145265v1 2024-02-11T10:07:31+01:00 Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification Bioaccumulation et effets du mercure chez la seiche dans le contexte de l’acidification des océans Minet, Antoine LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Université de La Rochelle Paco Bustamante Christelle Jozet-Alves Thomas Lacoue-Labarthe 2022-09-23 https://theses.hal.science/tel-04145265 https://theses.hal.science/tel-04145265/document https://theses.hal.science/tel-04145265/file/2022Minet192409.pdf en eng HAL CCSD NNT: 2022LAROS039 tel-04145265 https://theses.hal.science/tel-04145265 https://theses.hal.science/tel-04145265/document https://theses.hal.science/tel-04145265/file/2022Minet192409.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-04145265 Animal biology. Université de La Rochelle, 2022. English. ⟨NNT : 2022LAROS039⟩ Cephalopod IHg/MeHg PH Kinetics Organotropism Brain Behavior GABA Céphalopode Cinétique Organotropisme Cerveau Comportement [SDV.BA]Life Sciences [q-bio]/Animal biology [SDV.SA]Life Sciences [q-bio]/Agricultural sciences info:eu-repo/semantics/doctoralThesis Theses 2022 ftunivrochelle 2024-01-23T23:34:09Z The common cuttlefish, Sepia officinalis, is a coastal cephalopod known for its eco physiological performance supported by a wide repertoire of behaviors that allows it, despite its short life cycle, to play a central role in food webs. However, it is also known to efficiently accumulate metallic elements such as mercury (Hg), a neurotoxic contaminant in its organic form (methylmercury; MeHg). Moreover, in the context of global changes, ocean acidification (OA) induced by the increase of CO2 emissions, can impact metabolism, development and the central nervous system, especially in young life stages. The present work therefore aims to study the effects of OA on Hg bioaccumulation and the effects of these two neurotoxicants (Hg and CO2) on behavior and cognitive performance in juvenile cuttlefish. In the first place, in-situ measurements showed that Hg accumulated in the brain of cephalopods in methylated form (MeHg). Moreover, experimental approaches using isotopic tracers (stable and radioactive) of Hg have shown that the accumulation of total Hg comes mainly from the assimilation of MeHg present in preys, compared to the accumulation of inorganic mercury (iHg) dissolved in seawater. This MeHg is then very strongly retained despite evidence of Hg demethylation processes in the digestive gland. Surprisingly, OA has no effect on the bioaccumulation efficiencies and metabolism of Hg. In terms of effect, behavioral assays showed that Hg and CO2, alone or in combination, did not impact visual acuity and predation performance in juveniles. However, both induced an increase in locomotor activity, compromised defensive behavior through, in particular, an alteration of disruptive coloration and a non-alignment of lateralization. Among the neural processes likely to be impacted by Hg and CO2, the GABAergic system was analyzed in the optic lobes but showed no obvious link with behavioral responses suggesting more complex effect processes. All of this work therefore questions the effects of future ocean conditions on ... Doctoral or Postdoctoral Thesis Ocean acidification HAL - Université de La Rochelle |
institution |
Open Polar |
collection |
HAL - Université de La Rochelle |
op_collection_id |
ftunivrochelle |
language |
English |
topic |
Cephalopod IHg/MeHg PH Kinetics Organotropism Brain Behavior GABA Céphalopode Cinétique Organotropisme Cerveau Comportement [SDV.BA]Life Sciences [q-bio]/Animal biology [SDV.SA]Life Sciences [q-bio]/Agricultural sciences |
spellingShingle |
Cephalopod IHg/MeHg PH Kinetics Organotropism Brain Behavior GABA Céphalopode Cinétique Organotropisme Cerveau Comportement [SDV.BA]Life Sciences [q-bio]/Animal biology [SDV.SA]Life Sciences [q-bio]/Agricultural sciences Minet, Antoine Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
topic_facet |
Cephalopod IHg/MeHg PH Kinetics Organotropism Brain Behavior GABA Céphalopode Cinétique Organotropisme Cerveau Comportement [SDV.BA]Life Sciences [q-bio]/Animal biology [SDV.SA]Life Sciences [q-bio]/Agricultural sciences |
description |
The common cuttlefish, Sepia officinalis, is a coastal cephalopod known for its eco physiological performance supported by a wide repertoire of behaviors that allows it, despite its short life cycle, to play a central role in food webs. However, it is also known to efficiently accumulate metallic elements such as mercury (Hg), a neurotoxic contaminant in its organic form (methylmercury; MeHg). Moreover, in the context of global changes, ocean acidification (OA) induced by the increase of CO2 emissions, can impact metabolism, development and the central nervous system, especially in young life stages. The present work therefore aims to study the effects of OA on Hg bioaccumulation and the effects of these two neurotoxicants (Hg and CO2) on behavior and cognitive performance in juvenile cuttlefish. In the first place, in-situ measurements showed that Hg accumulated in the brain of cephalopods in methylated form (MeHg). Moreover, experimental approaches using isotopic tracers (stable and radioactive) of Hg have shown that the accumulation of total Hg comes mainly from the assimilation of MeHg present in preys, compared to the accumulation of inorganic mercury (iHg) dissolved in seawater. This MeHg is then very strongly retained despite evidence of Hg demethylation processes in the digestive gland. Surprisingly, OA has no effect on the bioaccumulation efficiencies and metabolism of Hg. In terms of effect, behavioral assays showed that Hg and CO2, alone or in combination, did not impact visual acuity and predation performance in juveniles. However, both induced an increase in locomotor activity, compromised defensive behavior through, in particular, an alteration of disruptive coloration and a non-alignment of lateralization. Among the neural processes likely to be impacted by Hg and CO2, the GABAergic system was analyzed in the optic lobes but showed no obvious link with behavioral responses suggesting more complex effect processes. All of this work therefore questions the effects of future ocean conditions on ... |
author2 |
LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Université de La Rochelle Paco Bustamante Christelle Jozet-Alves Thomas Lacoue-Labarthe |
format |
Doctoral or Postdoctoral Thesis |
author |
Minet, Antoine |
author_facet |
Minet, Antoine |
author_sort |
Minet, Antoine |
title |
Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
title_short |
Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
title_full |
Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
title_fullStr |
Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
title_full_unstemmed |
Bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
title_sort |
bioaccumulation and effects of mercury in cuttlefish in the context of ocean acidification |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://theses.hal.science/tel-04145265 https://theses.hal.science/tel-04145265/document https://theses.hal.science/tel-04145265/file/2022Minet192409.pdf |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
https://theses.hal.science/tel-04145265 Animal biology. Université de La Rochelle, 2022. English. ⟨NNT : 2022LAROS039⟩ |
op_relation |
NNT: 2022LAROS039 tel-04145265 https://theses.hal.science/tel-04145265 https://theses.hal.science/tel-04145265/document https://theses.hal.science/tel-04145265/file/2022Minet192409.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1790606117520277504 |