Late Quaternary palaeoenvironmental evolution and sea level oscillation of the Santa Catarina Island (southern Brazil)

Aumond Kuhn, Lidia; Zonneveld, Karin A. F.; Alves Souza, Paulo; Rodrigues Cancelli, Rodrigo

doi:https://doi.org/10.5194/bg-2023-11

Preprints

https://doi.org/10.5194/bg-2023-11

Preprints

01 Feb 2023

| 01 Feb 2023

Status: a revised version of this preprint is currently under review for the journal BG.

Late Quaternary palaeoenvironmental evolution and sea level oscillation of the Santa Catarina Island (southern Brazil)

Lidia Aumond Kuhn, Karin A. F. Zonneveld, Paulo Alves Souza, and Rodrigo Rodrigues Cancelli

Abstract. Sea level oscillation during the Quaternary played a major role in the geomorphology and vegetation dynamics of coastal areas in southern Brazil, encompassing ecosystems that often have a unique biodiversity. Understanding the natural evolution of these areas is essential for decision-making of land use regulations towards sustainable development as well as to preserve the uniqueness of the coastal ecosystems. The southern Brazil coastal plain is formed by marine, transitional and continental Quaternary deposits controlled by relative past variations of the sea level. These variations shaped the coastal landscape and influenced the development of different Atlantic Rainforest formations, such as mangroves and restingas. In particular, the restinga formation corresponds to a specific ecosystem that covers sandy soils of marine and fluvial-marine origin formed during the Quaternary on the Brazilian coastal plain. In this contribution, we present high-resolution palynological and stable isotope data from a Holocene core retrieved from the coastal plain of the Santa Catarina Island (southern Brazil). We were able to identify four different environmental zones in the last 6500 yr BP. The first zone (6500–2820 cal yr BP) is characterized by a lagoon with large marine water influence. Notably, the observed dinoflagellate cyst association suggests that marine waters entering the region had its origin in the relatively warm saline Brazil Current waters. During the second zone (2820–1480 cal yr BP), marine water contribution to the lagoon decreased until it became disconnected with the sea. The third zone (1480–520 cal yr BP) was marked by the decrease of the water level until it dried out and led to the colonization of herbaceous vegetation over the palaeo-lagoon. The last zone (520 cal yr BP–recent) is characterized by the consolidation of the coastal plain Atlantic Rainforest (restinga vegetation). Our results form an example of the strong sensitivity of southern Brazilian ecosystem change caused by relative sea level variations. As such, it might contribute to the debate about potential effects of current climate change induced by global sea level variations.

Received: 20 Jan 2023 – Discussion started: 01 Feb 2023

Lidia Aumond Kuhn et al.

Status: final response (author comments only)

RC1:
'Comment on bg-2023-11', Hermann Behling, 14 Feb 2023

The manuscript by Lidia A. Kuhn and co-authors provides important new results on vegetation and environmental changes in the coastal region of southern Brazil since the last about 6500 years. This multi-proxy study is of high international interest from the coastal region which has been poorly studied. The manuscript is well prepared. Following smaller points should be considered.
Line 13: Take “relative” out
Line 17: Change “in” to for
Line 46: “paleo…” should be palaeo…. , be consistent with UK English, see also other parts of the manuscript
Line 55: “only” ? There is also a marine core studied off Santa Catarina State: Gu, F., Zonneveld, K.A.F., Chiessi, C.M., Arz, H..W., Pätzold, J., Behling, H., 2017. Long-term vegetation, climate and ocean dynamics inferred from a 73,500 years old marine sediment core (GeoB2107-3) off southern Brazil. Quaternary Science Reviews, 172C, 55-71. DOI information: 10.1016/j.quascirev.2017.06.028
There are also more studies from the coastal region in Santa Catarina. See e.g. Behling, H., 1995. Investigations into the Late Pleistocene and Holocene history of vegetation and climate in Santa Catarina (S Brazil). Vegetation History and Archaeobotany, 4, 127-152.
Line 163: Does it make sense to have a sum of all palynomorphs? Such a curve is not meaningful.
Line 167: “total sum” of all palynomorphs? Does it make sense to use all, as they reflect very different environments?
Line 307: Should be Chenopodiaceae.
It would be good to indicate the number of counted dinoflagellate cysts for each sample.

Citation: https://doi.org/10.5194/bg-2023-11-RC1
- AC1: 'Reply on RC1', Lidia Kuhn, 15 Mar 2023
  
  We are happy to learn that Dr Hermann Behling recognized the relevance of our contribution and we thank him for his relevant comments and suggestions. We carefully modified the manuscript and indicated in detail our actions to the reviewer's comments below.
  Line 13: Take “relative” out
  Ans.: Corrected as suggested.
  Line 17: Change “in” to for
  Ans.: Changed as suggested.
  Line 46: “paleo…” should be palaeo…. , be consistent with UK English, see also other parts of the manuscript
  Ans.: Corrected as suggested.
  Line 55: “only”? There is also a marine core studied off Santa Catarina State: Gu, F., Zonneveld, K.A.F., Chiessi, C.M., Arz, H..W., Pätzold, J., Behling, H., 2017. Long-term vegetation, climate and ocean dynamics inferred from a 73,500 years old marine sediment core (GeoB2107-3) off southern Brazil. Quaternary Science Reviews, 172C, 55-71. DOI information: 10.1016/j.quascirev.2017.06.028
  There are also more studies from the coastal region in Santa Catarina. See e.g. Behling, H., 1995. Investigations into the Late Pleistocene and Holocene history of vegetation and climate in Santa Catarina (S Brazil). Vegetation History and Archaeobotany, 4, 127-152.
  Ans.: We added the respective references and modified the manuscript to:
  “However, the Santa Catarina coastal plain sector is geomorphologically distinct and similar studies are scarce, located only in the continental portion (Behling, 1995; Behling and Negrelle, 2001; Amaral et al., 2012; Cancelli, 2012; Kuhn et al., 2017; França et al., 2019; Val-Péon et al., 2019; Cohen et al., 2020; Silva et al., 2021) and at the continental slope at the western South Atlantic (ca. 200 km north of the Santa Catarina Island; Gu et al., 2017).”
  Line 163: Does it make sense to have a sum of all palynomorphs? Such a curve is not meaningful.
  Ans.: We determined the relative abundances of the individual palynomorphs groups from terrestrial and marine origin by dividing of with the total palynomorph sum to obtain insight into the relative change of marine and terrestrial derived elements over time. To obtain insight into the contemporaneous vegetation changes on land and the marine environmental changes we determined the relative abundances of the individual pollen/spore species and dinoflagellate cyst species by dividing by the total pollen/spores sum and the dinoflagellate cyst sum respectively.
  We realized that the text was quite confusing written in this respect and therefore adapted the text such that it is clearer.
  We modified the text to:
  “To obtain information about what part of the palynomorph association consist of terrestrial derived elements (pollen/spores, freshwater algae), fungi and marine elements (acritarchs, dinoflagellate cysts and microforaminiferal linings), we used the total sum of all palynomorphs to determine the relative abundances of these groups. Relative abundances of pollen/spores are determined by dividing the pollen counts by the pollen sum referring the total amount of pollen grains. The relative abundances of dinoflagellates were calculated by dividing their counts by the total dinoflagellate cyst sum.”
  Line 167: “total sum” of all palynomorphs? Does it make sense to use all, as they reflect very different environments?
  Ans.: See previous point.
  Line 307: Should be Chenopodiaceae.
  Ans.: Corrected as suggested.
  It would be good to indicate the number of counted dinoflagellate cysts for each sample.
  Ans.: We included information about the total amount of dinoflagellate cysts counted in Figure 8 and we will provide all palynological data as an appendix file.
  
  Citation: https://doi.org/10.5194/bg-2023-11-AC1
RC2:
'Comment on bg-2023-11', Aline Freitas, 01 Mar 2023

Page 17, line 302 you cite Botryococcus as freshwater algae that tolerate little salinity, but by the way of a complementary information and discussion, Batten & Grenfell (1996)* cite its occurrence in calm or stagnant waters, such as lakes, swamps, marshes, marshes, although it can withstand relatively higher salinity from other environments such as mangroves and estuaries. It can be found in shallow or deep bodies of water.
Page 17, line 310 the presence of Celtis and Trema (Zone I, Fig. 7), pioneer taxa in this phase, helps the inference of an unstable environment, subject to ecological succession. And together with the shrub-tree taxa (Alchornea, Myrtaceae and Arecaceae) and halophytes (Amaranthaceae-Chenopodiaceae and others) it indicates seasonally flooded open restinga, with sandy soils subject to salinity (see Allagoptera that occurs in the Holocene coastal sediments of Armação dos Búzios, in Southeastern Brazil**). The presence of Botryococcus confirms this hypothesis.
Page 17, line 313 the presence of indeterminate pollen in this phase may be related to the transport of organic particles and the granulometry of sediments (fine sands and silts), in the very redeposition of lacustrine-lagoonal sediments configuring a high-energy and oxygenated environment, under greater influence of currents marine (mentioned in the Fig. 2) than continental (terrestrial biomass) contribution. What the assemblage of dinoflagellates and other marine organic microfossils attest this inferences.
Page 18, lines 336 for complementation purposes, the expressive presence of Botryococcus may indicate marine water inputs in the lake/lagoonal body, even with a tendency to clog, since these microalgae are indicators of lake-lagoon environments, with a certain tolerance to salinity (Batten & Grenfell, 1996).
Page 18, lines 344 and 350 dispite ecological data of Zygnema spores, they are cosmopolitan in oligotrophic lacustrine, shallow and clear freshwater environments. Also present in fertile soils, and lakes and peat bog margins. A few members of Zygnemataceae can withstand more adverse environmental conditions, such as seasonal droughts and higher temperatures during winter (van Geel & Grenfell 1996***). Cyperaceae it is an emergent aquatic plant common in shallow or deep lagoons or salt marshes.
Page 20, lines 384 I would add that the Botryococcus microalgae in Phase/Zone III indicate the salinity pulses in the lacustrine-lagoon body.
References:
*Batten DJ, Grenfell HR. 1996. Botryococcus. In: Jansonius J, McGregor DC. (eds.) Palynology: principles and applications. Dallas, American Association of Stratigraphic Palynologists Foundation. Vol. 1. p. 205-214.
**Freitas & Carvalho, 2012 Freitas AG, Carvalho MA. 2012. Análise morfológica e inferências ecológicas de grãos de pólen e esporos (últimos ~8.000 anos) da Lagoa da Ferradura, Armação dos Búzios, RJ, Brasil. Revista Brasileira de Paleontologia 15: 300-318.).
***Van Geel B, Grenfell HR. 1996. Spores of Zygnemataceae. In: Jansonius J, McGregor DC. (eds.) Palynology: principles and applications. Dallas, American Association of Stratigraphic Palynologists Foundation. Vol 1. p. 173-179.

Citation: https://doi.org/10.5194/bg-2023-11-RC2
- AC2:
  'Reply on RC2', Lidia Kuhn, 15 Mar 2023
  
  We thank Dr Aline Freitas for her relevant comments and suggestions. We carefully modified the manuscript and indicated in detail our comments to the reviewer's observations below.
  Page 17, line 302 you cite Botryococcus as freshwater algae that tolerate little salinity, but by the way of a complementary information and discussion, Batten & Grenfell (1996)* cite its occurrence in calm or stagnant waters, such as lakes, swamps, marshes, marshes, although it can withstand relatively higher salinity from other environments such as mangroves and estuaries. It can be found in shallow or deep bodies of water.
  Ans.: We included these comments in the manuscript and modified the manuscript to: “The presence of freshwater algae indicates freshwater influence despite the significant marine contribution. In addition, Botryococcus is a euryhaline freshwater algae that may have its photosynthetic activity inhibited, directly or indirectly, by the water salinity (Tyson, 1995). Also, Batten and Grenfell (1996) cite Botryococcus occurrence in calm or stagnant waters, such as lakes, swamps, marshes, although it can withstand relatively higher salinity from other environments such as mangroves and estuaries. Therefore, the low concentrations of this freshwater algae during this zone might be caused by the presence of marine influence. The observed palynomorph association suggests that calm conditions and mixing of marine and freshwater prevailed typical for a lagoon environment.”
  Page 17, line 310 the presence of Celtis and Trema (Zone I, Fig. 7), pioneer taxa in this phase, helps the inference of an unstable environment, subject to ecological succession. And together with the shrub-tree taxa (Alchornea, Myrtaceae and Arecaceae) and halophytes (Amaranthaceae-Chenopodiaceae and others) it indicates seasonally flooded open restinga, with sandy soils subject to salinity (see Allagoptera that occurs in the Holocene coastal sediments of Armação dos Búzios, in Southeastern Brazil**). The presence of Botryococcus confirms this hypothesis.
  Ans.: We included these comments in the manuscript and changed the manuscript to: “In this zone, the pollen of the trees and shrubs taxa are mainly composed by Alchornea, Arecaceae, Myrtaceae and Celtis. The presence of Celtis and Trema, pioneer taxa, suggests an unstable environment, subject to ecological succession. These pioneer taxa together with the trees and shrubs taxa (Alchornea, Myrtaceae and Arecaceae) and the halophytes herbs taxa (e.g., Amaranthus/Chenopodiaceae) indicate seasonally flooded open restinga in the surrounding area, with sandy soil subject to salinity (Freitas and Carvalho, 2012)”.
  Page 17, line 313 the presence of indeterminate pollen in this phase may be related to the transport of organic particles and the granulometry of sediments (fine sands and silts), in the very redeposition of lacustrine-lagoonal sediments configuring a high-energy and oxygenated environment, under greater influence of currents marine (mentioned in the Fig. 2) than continental (terrestrial biomass) contribution. What the assemblage of dinoflagellates and other marine organic microfossils attest this inferences.
  Ans.: We included the reviewer comment as a possible interpretation and modified the manuscript to: “Indeterminate pollen grains occur at higher concentrations at this and the subsequent zone II in comparison to the two upper zones. This can be explained by the input of pollen grains transported by streams and wind into the lagoon partly damaging some of the grains. Alternatively, the presence of indeterminate pollen in this phase may be related to the transport of organic particles and the granulometry of sediments (fine sands and silts), in the very redeposition of lacustrine-lagoonal sediments configuring a high-energy and oxygenated environment, under greater influence of marine currents than continental (terrestrial biomass) contribution. However, the predominance of fine sand, silt and clay sediment, as well as the presence of preserved calcareous shells in living position, could indicate deposition in a predominantly calm water body. Therefore, we interpret that the water body was likely calm with sporadic higher energy events (e.g., storms)”.
  Page 18, lines 336 for complementation purposes, the expressive presence of Botryococcus may indicate marine water inputs in the lake/lagoonal body, even with a tendency to clog, since these microalgae are indicators of lake-lagoon environments, with a certain tolerance to salinity (Batten & Grenfell, 1996).
  Ans.: In this phase the increase in Botryococcus algae coincides with the decrease in marine palynomorphs and the level that there are the highest percentages of Botryococcus almost there aren´t marine palynomorphs (see figure 6). Dinoflagellate cysts are no longer present in this phase. In addition, there is an increase in Botryococcus in the middle of this zone and a decrease in the end of zone I and beginning of zone II. So, it doesn’t look like salinity pulses in the lagoon body.
  Page 18, lines 344 and 350 dispite ecological data of Zygnema spores, they are cosmopolitan in oligotrophic lacustrine, shallow and clear freshwater environments. Also present in fertile soils, and lakes and peat bog margins. A few members of Zygnemataceae can withstand more adverse environmental conditions, such as seasonal droughts and higher temperatures during winter (van Geel & Grenfell 1996***). Cyperaceae it is an emergent aquatic plant common in shallow or deep lagoons or salt marshes.
  Ans.: We included the reviewer comment regarding Cyperaceae and modified the manuscript to: “High percentages of Poaceae and Cyperaceae taxa and δ¹³C enrichment from the beginning of this zone up to 140 cm of depth can be observed in this zone (Figs. 3, 7). In particular, Cyperaceae is an emergent aquatic plant common in restinga vegetation in lagoon environments, marshes and swampy lowlands (Falkenberg, 1999). This suggests that the herbs that previously occupied the margins of the lagoon advanced and colonized the palaeo-lagoon area and the environment of ongoing humid soil condition.” However, we did not include the comment about Zygnema because this taxa was not recorded in this zone and in the previous zone it was recorded in a low percentages.
  Page 20, lines 384 I would add that the Botryococcus microalgae in Phase/Zone III indicate the salinity pulses in the lacustrine-lagoon body.
  Ans.: We understand the reviewer’s comments and we acknowledge that Botryococcus withstands saline waters. However, given the trend of disappearance of marine palynomorphs followed by a terrestrial environment we consider that it is more likely that the increase in Botryococcus algae in zone II is related to a decrease of the water level in a lake.
  
  Citation: https://doi.org/10.5194/bg-2023-11-AC2
  - RC3: 'Reply on AC2', Aline Freitas, 16 Mar 2023
    
    I am grateful for the considerations on the part of the authors and I consider the paper strongly suitable for publication.
    
    Citation: https://doi.org/10.5194/bg-2023-11-RC3
    
    AC3: 'Reply on RC3', Lidia Kuhn, 18 Mar 2023
    
    We thank Dr. Aline Freitas for recognizing the relevance of our contribution and we thank her for her careful review.
    
    Citation: https://doi.org/10.5194/bg-2023-11-AC3

Lidia Aumond Kuhn et al.

Viewed

Total article views: 251 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
180	53	18	251	1	2

HTML: 180
PDF: 53
XML: 18
Total: 251
BibTeX: 1
EndNote: 2

Views and downloads (calculated since 01 Feb 2023)

Month	HTML	PDF	XML	Total
Feb 2023	114	34	7	155
Mar 2023	66	19	11	96

Cumulative views and downloads (calculated since 01 Feb 2023)

Month	HTML	PDF	XML	Total
Feb 2023	114	34	7	155
Mar 2023	66	19	11	96

Viewed (geographical distribution)

Total article views: 256 (including HTML, PDF, and XML) Thereof 256 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 24 Mar 2023

Short summary

This study investigated changes in coastal ecosystem that reflect environmental changes over the past 6500 years on Brazil's largest oceanic island. This study was motivated by the need to understand the natural evolution of coastal areas to predict future changes. The results highlight the sensitivity of this ecosystem to changes caused by relative sea level variations. As such, it contributes to the debate about potential effects of current climate change induced by global sea level changes.


Total:	0
HTML:	0
PDF:	0
XML:	0