Titre :

Foraminiferal community response to seasonal anoxia in Lake Grevelingen (the Netherlands)

Auteur(s) :

Richirt, Julien [Auteur]
Évolution, Écologie et Paléontologie (Evo-Eco-Paleo) - UMR 8198 [Evo-Eco-Paléo (EEP)]
Riedel, Bettina [Auteur]
Mouret, Aurélia [Auteur]
Environnements et Paléoenvironnements OCéaniques [EPOC]
Schweizer, Magali [Auteur]
Bio-Indicateurs Actuels et Fossiles [BIAF]
Langlet, Dewi [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Bio-Indicateurs Actuels et Fossiles [BIAF]
Seitaj, Dorina [Auteur]
Meysman, Filip [Auteur]
Royal Netherlands Institute for Sea Research [NIOZ]
Slomp, Caroline [Auteur]
Jorissen, Frans [Auteur]
Bio-Indicateurs Actuels et Fossiles [BIAF]

Titre de la revue :

Biogeosciences Discussions

Éditeur :

European Geosciences Union

Date de publication :

2019-10-01

ISSN :

1810-6277

Discipline(s) HAL :

Sciences de l'environnement/Biodiversité et Ecologie

Résumé en anglais : [en]

Over the last decades, hypoxia in marine coastal environments have become more and more widespread, prolonged and intense. These hypoxic events have large consequences for the functioning of benthic ecosystems. They ...
Lire la suite >Over the last decades, hypoxia in marine coastal environments have become more and more widespread, prolonged and intense. These hypoxic events have large consequences for the functioning of benthic ecosystems. They profoundly modify early diagenetic processes involved in organic matter recycling, and in severe cases, they may lead to complete anoxia and presence of toxic sulphides in the sediment and bottom water, thereby severely affecting biological compartments of benthic 20 marine ecosystems. Within these ecosystems, benthic foraminifera show a high diversity of ecological responses, with a wide range of adaptive life strategies. Some species are particularly resistant to hypoxia/anoxia and consequently, it is interesting to study the whole foraminiferal community as well as species specific responses to such events. Here we investigated the temporal dynamics of living benthic foraminiferal communities (recognised by CellTracker™ Green) at two sites in the saltwater Lake Grevelingen in the Netherlands. These sites are subject to seasonal anoxia with different durations and are 25 characterised by the presence of free sulphide (H2S) in the uppermost part of the sediment. Our results indicate that foraminiferal communities are impacted by the presence of H2S in their habitat, with a stronger response in case of longer exposure times. At the deepest site (34 m), one to two months of anoxia and free H2S in the surface sediment resulted in an almost complete disappearance of the foraminiferal community. Conversely, at the shallower site (23 m), where the duration of anoxia and free H2S was shorter (one month or less), a dense foraminiferal community was found throughout the year. 30 Interestingly, at both sites, the foraminiferal community showed a delayed response to the onset of anoxia and free H2S, suggesting that the combination of anoxia and free H2S does not lead to increased mortality, but rather to strongly decreased reproduction rates. At the deepest site, where highly stressful conditions prevailed for one to two months, the recovery time of the community takes about half a year. In Lake Grevelingen, Elphidium selseyense and Elphidium magellanicum are much 2 less affected by anoxia and free H2S than Ammonia sp. T6. We hypothesise that this is not due to a higher tolerance of H2S, 35 but rather related to the seasonal availability of food sources, which could have been less suitable for Ammonia sp. T6 than for the elphidiids.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Collections :

• Évolution, Écologie et Paléontologie (Evo Eco Paleo) - UMR 8198

Source :

Harvested from HAL