Abstract
The objective of this research is to examine the history of lentic ecosystem salinity in the southern Pantanal wetlands (Brazil). The timing and controls on hydrochemical changes were inferred using sponge spicule and diatom paleoecology on a Holocene-aged sediment core from Nhecolândia, a lake district situated on a fossil lobe of the Taquari megafan. The oldest portion of the core contains Heterorotula fistula spicules, indicative of an ephemeral freshwater lake that existed until ~ 4.6 cal ka BP. Benthic diatoms of the genus Gomphonema and Eunotia appeared ~ 3.2 cal ka BP, indicating a shallow and dystrophic environment. A transition to a more permanent lake that hosted freshwater sponges (e.g., Corvoheteromeyenia spp.), and diatom assemblages (e.g., Cyclotella meneghiniana, Aulacoseira pantanalensis) endured until ~ 1.3 cal year BP; after this time, most sponges and planktic diatoms disappear from the sedimentary record. High abundances of Anomoeoneis sphaerophora and Craticula guaykuruorum in the latest Holocene reflect a transition to a hyperalkaline, saline lake environment. The results suggest that Nhecolândia’s saline lakes may evolve from freshwater precursors due to local (biochemical) and regional (geo-climatic) controls on water availability, which has implications for patterns of biodiversity and ecosystems services in Pantanal.
Original language | English |
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Journal | Hydrobiologia |
Volume | 815 |
Issue number | 1 |
DOIs | |
State | Published - Jun 1 2018 |
Bibliographical note
Publisher Copyright:© 2017, Springer International Publishing AG, part of Springer Nature.
Funding
Acknowledgements The authors are grateful to the São Paulo Research Foundation (FAPESP) for financial support of this project (Grant #2014/06889-2). We thank the National Council for Scientific and Technological Development (CNPq) for research grants to LVW and MLA (grant #308563/2013-1) and to SAFSC (Grant #476020/2013-1), Coordenac¸ão de Aperfeic¸oamento de Pessoal de Nível Superior (Capes) for a doctorate scholarship to RLG, the University of Kentucky Vice President for Research for a seed grant to MM. We are grateful to the Luminescence and Gamma Spectrometry Laboratory at the University of São Paulo for access to optically stimulated luminescence dating facilities. We thank EMBRAPA-Pantanal for facilitating fieldwork. Dr. Fabiano Pupim (USP) and Dr. Aguinaldo Silva (UFMS) are gratefully acknowledged for their collaboration. We thank Dr. Karlyn Westover for assistance with constrained cluster analyses of the diatom data. The authors appreciate comments by the reviewers on an early version of the manuscript.
Funders | Funder number |
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University of Kentucky Executive Vice President for Research | |
Fundação de Amparo à Pesquisa do Estado de São Paulo | 2014/06889-2 |
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior | |
Conselho Nacional de Desenvolvimento Científico e Tecnológico | 476020/2013-1, 308563/2013-1 |
Keywords
- Diatoms
- Paleolimnology
- Pantanal wetlands
- Saline lakes
- Sponge spicules
ASJC Scopus subject areas
- Aquatic Science