Atypical, high-diversity assemblages of foraminifera in a mangrove estuary in northern Brazil

Sariaslan, Nisan; Langer, Martin R.

doi:https://doi.org/10.5194/bg-18-4073-2021

Articles | Volume 18, issue 13

https://doi.org/10.5194/bg-18-4073-2021

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

https://doi.org/10.5194/bg-18-4073-2021

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

Articles | Volume 18, issue 13

Research article

|

07 Jul 2021

Research article |

| 07 Jul 2021

Atypical, high-diversity assemblages of foraminifera in a mangrove estuary in northern Brazil

Nisan Sariaslan and Martin R. Langer

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Final revised paper (published on 07 Jul 2021)
Preprint (discussion started on 29 Mar 2021)

Interactive discussion

Status: closed

RC1:
'Comment on bg-2021-56', Johann Hohenegger, 18 Apr 2021

This is a very good paper about the atypical presence of mangrove foraminfera based on high salinity resistence in the mangrove areas of northeastern Brazil.

The methodology uses the common statistical methods, where I do not aggre with the counting of specimens resticted to around 300 specimens. The density (standing crop) depends in that case on the sample sizes and can be strongyl biased by different sample sizes. Nevertheless, this method is commonly used and does not really disturb the results even when sample sizes have been more or less equal.

The results and discusiion is clear and the paper should be printed with the few exceptions I send as an attached word file.

I did not correct the succesion of articles in the reference list not the correct citations. This is an editoral job

Citation: https://doi.org/10.5194/bg-2021-56-RC1
- AC2: 'Reply on RC1', Nisan Sariaslan, 20 May 2021
  
  Thank you for your positive reply and constructive comments.
  As you pointed out, the methodology and quantitative analysis follows the standard statistical methods in foraminiferal research (~300 specimens per sample). The total number of individuals picked and analyzed from each sample even exceeds the standard of 300 specimens (see Table 1 in the manuscript). To further standardize the number of individuals, picking was limited to a weight of 0.05 g of washed and dried sediment. The low amount of sediment picked to obtain more than 300 individuals shows that this mangrove material is particularly rich in benthic foraminifera, and is reflected in the atypical and high diversity assemblages. By providing the standard sample weight in the revised version, we eliminate a potential analytical bias and are grateful for bringing this to our attention. As outlined in the paper, the total number of picked specimens resulted in the highest diversity of benthic foraminifera recorded so far in true mangrove environments.
  
  Citation: https://doi.org/10.5194/bg-2021-56-AC2
RC2:
'Comment on bg-2021-56', Anonymous Referee #2, 18 May 2021

Attached please find the ms with minor revisions.

My only two concerns are:

1. It is not clear whether this ms deals with live or dead forams.

2. The autors used the small size fraction of 63 micron. The use of this particular fraction migth be the reason for the high diversity. This should be further discussed and compared with previous studies in the area.

Citation: https://doi.org/10.5194/bg-2021-56-RC2
- AC1: 'Reply on RC2', Nisan Sariaslan, 20 May 2021
  
  Please find below, our reply to your comments number 1 and 2:
  1. It is not clear whether this ms deals with live or dead forams.
  The analysis of the foraminiferal assemblages deals exclusively with thanatocoenosis. Details of the sampling procedure and time of collection are provided in the Material and Methods section.
  2. The autors used the small size fraction of 63 micron. The use of this particular fraction migth be the reason for the high diversity. This should be further discussed and compared with previous studies in the area.
  Almost all ecological studies on foraminiferal assemblages are based on the 63 micron sieve size, as recommended in standard textbooks (e.g. Murray, 2006). As clearly stated by Murray (2006): “The number of individuals and species will decrease with increasing sieve size and this may give misleading information…”, especially in terms of studies related to biodiversity and total species richness.
  
  Citation: https://doi.org/10.5194/bg-2021-56-AC1

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Publish subject to minor revisions (review by editor) (26 May 2021) by Hiroshi Kitazato

AR by Nisan Sariaslan on behalf of the Authors (31 May 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (01 Jun 2021) by Hiroshi Kitazato

AR by Nisan Sariaslan on behalf of the Authors (04 Jun 2021) Manuscript

Short summary

Analyses of foraminiferal assemblages from the Mamanguape mangrove estuary (northern Brazil) revealed highly diverse, species-rich, and structurally complex biotas. The atypical fauna resembles shallow-water offshore assemblages and are interpreted to be the result of highly saline ocean waters penetrating deep into the estuary. The findings contrast with previous studies, have implications for the fossil record, and provide novel perspectives for reconstructing mangrove environments.