Carbonic anhydrase is involved in calcification by the benthic foraminifer <i>Amphistegina lessonii</i>

de Goeyse, Siham; Webb, Alice E.; Reichart, Gert-Jan; de Nooijer, Lennart J.

doi:https://doi.org/10.5194/bg-18-393-2021

Articles | Volume 18, issue 2

https://doi.org/10.5194/bg-18-393-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-18-393-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 2

Research article

|

18 Jan 2021

Research article |

| 18 Jan 2021

Carbonic anhydrase is involved in calcification by the benthic foraminifer Amphistegina lessonii

Siham de Goeyse, Alice E. Webb, Gert-Jan Reichart, and Lennart J. de Nooijer

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Final revised paper (published on 18 Jan 2021)
Supplement to the final revised paper
Preprint (discussion started on 23 Sep 2019)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Assessment of “Carbonic anhydrase is involved in benthic foraminiferal calcification”', Anonymous Referee #1, 14 Oct 2019
- AC1: 'Response to " 'Assessment of “Carbonic anhydrase is involved in benthic foraminiferal calcification”' "', Siham De Goeyse, 25 Dec 2019
RC2: 'reviewer comment', Anonymous Referee #2, 24 Oct 2019
- AC2: 'Response to 'reviewer comment',', Siham De Goeyse, 25 Dec 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to minor revisions (review by editor) (10 Feb 2020) by Hiroshi Kitazato

ED: Reconsider after major revisions (13 Feb 2020) by Hiroshi Kitazato

AR by Siham De Goeyse on behalf of the Authors (13 May 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (01 Jun 2020) by Hiroshi Kitazato

RR by Takashi Toyofuku (30 Jun 2020)

Suggestions for revision or reasons for rejection

I like this study very much.
This study is highly commendable because it an elaborate experimental design with reliable experimental techniques by well-established laboratory. The experimental results are robust. The results are novel and are of interest to many audiences.

Comments

L78-79: Could the authors show the size distribution of each experimental condition in the supplemental materials?

L94 Authors should indicate why they have quantified the amount of precipitation from DIC and alkalinity. It is clearly worth stating that there is no other way to estimate it precisely.

L114 Authors should explain the meaning of the color of the arrows and the dotted lines in the captions. The same manner in later figures 3 and 4.

Show the amount of calcification as a contour map in Fig. 2-4.

I would like to see the photos of individuals grown in the control, AZ, and DCMU conditions.

L184 As a previous reviewer pointed out, calcification is thought to require energy. It's hard to distinguish whether the problem is a shortage of energy or the insuffíciency of photosynthesis itself.

Given the dark conditions every 12 hours, I'm not sure that the competition for carbon between photosynthesis and calcification is a problem. It should also be pointed out that sharing the CO2 by time may be occurring.

For example, would calcification have been enhanced even if there were no dark conditions for 24-hour? Authors don't need to answer this question, but I think this sort of question would be helpful to sort out the really dominant factors

In the pre-experimental period when frozen algae were given, how much numbers of chambers were added?

L220 CA is an enzyme that is extremely universally found in the cytoplasm. I do not deny that CA is involved in calcification process, and I also believe so. However, the possibility that the activities of CAs of non-calcification site may also affect calcification. The possibility of widespread inhibition of the metabolic activity should be clearly described.

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RR by Anonymous Referee #4 (06 Jul 2020)

Suggestions for revision or reasons for rejection

A paper by de Goeyse et al. conducted a simple incubation experiment to test the role of carbonic anhydrase (CA) using the inhibitor acetazolamide on the calcification of symbiont-bearing foraminifer Amphistegina. Although the results clearly show the involvement of CA on calcification of the foraminifer, it is still a vague impression to me where CA is present at the surface of cell membrane or the site of calcification. I look forward to authors’ future cellular-scale studies to solve this question.

Some technical corrections are necessary prior to the acceptance of this paper.

L11: Symbiont>symbiont

L17: seawater is taken up > how?

L38: Hikami et al., 2011)) > delete the last )

L51: SOC > site of calcification (SOC). Spell in full when first mentioned in the text

L54: the conversion from HCO3- > the conversion from HCO3- outside the test/cell membraned?

L55: This process may be catalyzed by an enzymatic conversion by carbonic anhydrase (CA) > Does this process occur at SOC?

L79: similar size distribution (initial diameter: 140 to 1200 μm) > too broad initial diameter

L103: (Liu et al., 2015) > Liu et al. (2015)

L119: the first one is constant the second present > the first one is constant and the second one is present

L144: many specimens in the control vials added 2 or 3 chambers > According to Table 3, most specimens added 1 or 2 chambers; only one specimen added 3 chambers.

L152: 42 and 16 > 16 and 42

L153: only 22 (resp. 19) μmol·L−1 > only 19 and 22 μmol·L−1, respectively

L163: approximately 65 μmol·L−1 > Where does this figure comes from ?

L165: 60 μg·Ind.−1·day−1; > Delete ;

L168: 0.3-6.6 > Add unit

L173: Fig. 2 > Fig. 3?

L196: (Ter Kuile et al., (1989b, 1989a) > Ter Kuil et al. (1989a, 1989b), but no 1989a, b in References

L201-203, 210: Cited references are not listed in the References.

L205: in known as > delete in

L221: In for example > For example

L256: not light, but photosynthesis itself promotes calcification in perforate foraminifera. > better to say “… in symbiont-bearing perforate foraminifera”. I suggest that you should pay more attentions to differences between light and dark respirations to understand light-enhanced calcification.

Fig. 4 caption: Arrows show the calcification (red) and net respiration (blue) effects. > Add this sentence in Fig. 2 and 3 as well.

Table 3: I am wondering if these specimens are dead or alive after incubation.

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ED: Publish subject to minor revisions (review by editor) (06 Jul 2020) by Hiroshi Kitazato

AR by Siham De Goeyse on behalf of the Authors (04 Aug 2020) Author's response Manuscript

ED: Publish as is (18 Aug 2020) by Hiroshi Kitazato

AR by Siham De Goeyse on behalf of the Authors (28 Aug 2020)

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Short summary

Foraminifera are calcifying organisms that play a role in the marine inorganic-carbon cycle and are widely used to reconstruct paleoclimates. However, the fundamental process by which they calcify remains essentially unknown. Here we use inhibitors to show that an enzyme is speeding up the conversion between bicarbonate and CO₂. This helps the foraminifera acquire sufficient carbon for calcification and might aid their tolerance to elevated CO₂ level.