Changes in ultrastructural features of the foraminifera Ammonia spp. in response to anoxic conditions: Field and laboratory observations

Karoliina Annika Koho, Charlotte LeKieffre, Hidetaka Nomaki, Iines Sandra Salonen, Emmanuelle Geslin, G. Mabilleau, Louise Sogaard Jensen, Gert-Jan Reichart

Forskningsoutput: TidskriftsbidragArtikelPeer review

Sammanfattning

The ultrastructure of the living foraminiferan, Ammonia sp. (phylotype unknown), collected from surficial and deeper, subsurface (anoxic) sediments from the Dutch Wadden Sea, was examined to provide information on the physiology of the foraminiferal cell and its adaptive strategies to low-oxygen conditions. The observed changes in cell ultrastructure under anoxia were further compared with the cell ultrastructure of Ammonia sp. (phylotype T6), from oxic and anoxic incubation experiments. The ultrastructural evidence indicates that under low-oxygen conditions Ammonia spp. may accumulate lipid droplets. In addition, the size of the lipid droplets may increase with the duration of anoxic conditions, becoming over 5 mu m in size, while the remaining cytosol of the foraminiferan become less electron dense. In some specimens, lipid droplets were also found in the space between the plasma membrane and the organic lining. We expect that the apparent increase in the number and size of the lipid droplets is indicative of a stress response of the foraminifera to the adverse anoxic conditions. Other ultrastructural changes in response to anoxia include the presence of intact bacteria and electron dense opaque bodies within the foraminiferal cytosol, and a possible thickening of the organic lining. The role of the bacteria remains enigmatic but they may be linked to foraminiferal dormancy in anoxia.

Originalspråkengelska
TidskriftMarine Micropaleontology
Volym138
Sidor (från-till)72-82
Antal sidor11
ISSN0377-8398
DOI
StatusPublicerad - jan 2018
MoE-publikationstypA1 Tidskriftsartikel-refererad

Vetenskapsgrenar

  • 1181 Ekologi, evolutionsbiologi
  • 2018 Ocean Sciences meeting

    Karoliina Koho (Närvarande)

    2018 → …

    Aktivitet: Typer för deltagande i eller organisering av evenemangArrangemang av och deltagande i konferens/workshop/kurs/seminarium

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