Holocene limnological changes in saline and freshwater lakes, Lower Nhecolândia, Pantanal, Brazil

Giliane Gessica Rasbold, Luiz Carlos Ruiz Pessenda, Paulo Eduardo De Oliveira, Elton Eduardo Novais Alves, Dayana Rodrigues Silva, Hudson W. Carvalho, José Albertino Bendassolli, Célia Regina Montes, Adolpho Jose Melfi, Michael M. McGlue

Research output: Contribution to journalArticlepeer-review

Abstract

The lower Nhecolândia region, in the south of the Pantanal, contains thousands of shallow freshwater and saline-alkaline lakes isolated by sandy ridges. To understand the paleoenvironment, sediment cores from B02SR (freshwater) and 07SR (saline-alkaline) lakes were analyzed, employing a combination of 14C dating, microfossils, geochemical, elemental, and isotopic analyses. The 07SR core recovered Late Pleistocene sediments (~ 23,440 cal yrs BP), and the B02SR core Middle Holocene sediments (~ 6080 cal yrs BP). The base of the cores consists of bedded sands with no organic matter, sponge spicules, or diatoms. Phytoliths suggest the presence of cerrado vegetation with seasonal floods, suggestive of a periodically inundated distal floodplain. We interpret that the two lakes sustain perennial alkaline geochemical conditions between ~ 3080 and ~ 1330 cal yrs BP. The Lake B02SR transitioned to slightly acidic waters with low electrical conductivity from ~ 1330 cal yrs BP to the present, probably associated with a connection to ephemeral shallow or perennial channels. Lake 07SR maintained consistent water chemistry throughout the record, suggesting that an isolated drainage pattern remained unchanged creating persistent alkaline conditions. Our results suggest that lake chemical changes were spatially variable in lower Nhecolândia in the Holocene, which has implications for ecosystem services.

Original languageEnglish
Pages (from-to)1723-1739
Number of pages17
JournalHydrobiologia
Volume851
Issue number7
DOIs
StatePublished - Apr 2024

Bibliographical note

Publisher Copyright:
© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2023. corrected publication 2023.

Keywords

  • Diatoms
  • Phytoliths
  • Shallow lakes
  • Tropical paleoecology
  • Wetlands

ASJC Scopus subject areas

  • Aquatic Science

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