Paleoecology explains Holocene chemical changes in lakes of the Nhecolandia (Pantanal-Brazil)

Autor(es)

Guerreiro, Renato Lada ^[1] ; McGlue, Michael M. ^[2] ; Stone, Jeffery R. ^[3] ; Bergier, Ivan ^[4] ; Parolin, Mauro ^[5] ; da Silva Caminha, Silane A. F. ^[6] ; Warren, Lucas V. ^[7] ; Assine, Mario L. ^[7]

Afiliação do(s) autor(es)

^[1] Inst Fed Parana Campus Assis Chateaubriand, 475 Ave Civ, BR-85935000 Assis Chateaubriand, Parana - Brazil

^[2] Univ Kentucky, Dept Earth & Environm Sci, 121 Washington Ave, Lexington, KY 40506 - USA

^[3] Indiana State Univ, Dept Earth & Environm Syst, 600 Chestnut St, Terre Haute, IN 47809 - USA

^[4] Embrapa Pantanal, CPAP, Lab Biomass Convers, PO 109, Corumba, MS - Brazil

^[5] Fac Estadual Ciencias & Letras Campo Mourao, Lab Estudos Paleoambientais Fecilcam Lepafe, 733 Ave Comendador Norberto Marcondes, BR-87303100 Campo Mourao, Parana - Brazil

^[6] Univ Fed Mato Grosso, Fac Geociencias, Lab Palinol Mato Grosso, 2367 Ave Fernando Correia da Costa, BR-78060900 Cuiaba, Mato Grosso - Brazil

^[7] Unesp Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Ave 24-A, BR-13506900 Rio Claro, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Hydrobiologia; v. 815, n. 1, p. 1-19, JUN 2018.
• Citações Web of Science: 4

Resumo

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 Nhecolandia, 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 similar to 4.6 cal ka BP. Benthic diatoms of the genus Gomphonema and Eunotia appeared similar to 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 similar to 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 Nhecolandia'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. (AU)

• Processo FAPESP: 14/06889-2 - Mudanças paleo-hidrológicas, cronologia de eventos e dinâmica sedimentar no quaternário da Bacia do Pantanal
• Beneficiário: Mario Luis Assine
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular