Preprints
https://doi.org/10.5194/bg-2021-62
https://doi.org/10.5194/bg-2021-62

  12 Apr 2021

12 Apr 2021

Review status: this preprint is currently under review for the journal BG.

Permanent ectoplasmic structures in deep-sea Cibicides/oides taxa – long-term observations at in situ pressure

Jutta Wollenburg, Jelle Bijma, Charlotte Cremer, Ulf Bickmeyer, and Zora Mila Colomba Zittier Jutta Wollenburg et al.
  • Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, D-27570, Germany

Abstract. Deep-sea Cibicidoides pachyderma (forma mundulus) and related Cibicidoides spp. were cultured at in situ pressure for 1-2 days, or 6 weeks to 3 months. During that period, fluorescence analyses following BCECF-AM (2’,7’-bis(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester) or Calcein AM (4,5-Bis((N,N-bis(carboxymethy)amino)methyl)fluorescein acetoxymethylester) labelling, revealed a persisting cytoplasmic sheet or envelope surrounding the Cibicidoides tests. Thus, the Cibicidoides shell can be considered rather as an internal than an external cell structure. A couple of days to a week after being transferred into high-pressure aquaria and adjusted to a pressure of 115 bar, the foraminifera changed from a mobile to a more or less sessile living mode. During this quasi sessile way of life, a series of comparably thick static ectoplasmic structures developed that were not resorbed or remodelled but, except for occasional further growth, remained unchanged throughout the experiments. Three different types of these ‘permanent structures’ were observed: A) Ectoplasmic ‘roots’ were common in adult C. pachyderma, C. lobatulus and C. wuellerstorfi specimens. In our experiments single ectoplasmic ‘roots’ grew to maximum 700 times the individuals shell diameter and were presumably used to anchor the specimen in an environment with strong currents. B) Ectoplasmic ‘trees’ describe rigid ectoplasmic structures directed into the aquarium’s water body and were used by the foraminifera to climb up and down these ectoplasmic structures. Ectoplasmic ‘trees’ were so far only observed in C. pachyderma and enabled the ‘tree’-forming foraminifera to elevate itself above ground. C) Ectoplasmic ‘twigs’ were used to guide and hold the more delicate pseudopodial network when distributed into prevailing currents, and were, in our experiments, also only developed in C. pachyderma specimens. Relocation of a specimen usually required to tear apart and leave behind the rigid ectoplasmic structures, eventually also the envelope surrounding the test. Apparently, these rigid structures could not be resorbed or reused.

Jutta Wollenburg et al.

Status: open (until 24 May 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on bg-2021-62', Susan T. Goldstein, 19 Apr 2021 reply
    • AC1: 'Reply on RC1', Jutta Wollenburg, 16 May 2021 reply
  • RC2: 'Comment on bg-2021-62', Anonymous Referee #1, 03 May 2021 reply
    • AC2: 'Reply on RC2', Jutta Wollenburg, 16 May 2021 reply

Jutta Wollenburg et al.

Jutta Wollenburg et al.

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Short summary
Cultured at in Situ high-pressure conditions Cibicid/-es/-oides taxa develop lasting ectoplasmic structures that cannot be retracted or resorbed. An ectoplasmic envelope surrounds their test and may protect the shell e.g. versus carbonate aggressive bottom water conditions. Ectoplasmic roots likely anchor the specimens in areas of strong bottom water currents, trees enable them to elevate themselves above ground, and twigs stabilize and guide the retractable pseudopodial network.
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