globalchange  > 过去全球变化的重建
DOI: 10.1016/j.palaeo.2014.03.013
论文题名:
Holocene paleolimnological reconstruction of a high altitude Colombian tropical lake
作者: Cardozo A.Y.V.; Gomes D.F.; da Silva E.M.; Duque S.R.E.; Rangel J.O.C.; Sifeddine A.; Turcq B.; Albuquerque A.L.S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2014
卷: 415
起始页码: 127
结束页码: 136
语种: 英语
英文关键词: Diatoms ; Lake Tota ; Late Holocene ; Organic geochemistry ; Paleohydrology ; Sedimentary
英文摘要: Aquatic environments in the high-Andean may be quite vulnerable to climatic conditions and hydrological processes (precipitation/evaporation) that have the potential to alter water levels and chemistry. This study reconstructs the paleohydrological history of Lake Tota, Colombia, to provide a record of environmental changes in the eastern flank of the Colombian Andes during the late Holocene. A 54. cm core was collected at the margin of the lake at a depth of 1.5. m, and the paleohydrological reconstructions were based on changes in diatom assemblages, granulometry, and bulk organic geochemical parameters. The core was subdivided into 5 biozones by assessing the significance of the variance among the CONISS clusters. Biozone T5 (base, 4000. calibrated. years BP) was dominated by the planktonic diatom Discostella stelligera and was deposited in a period of high-water level. Sedimentation during this period was rich in carbon due to phytoplanktonic production; the granulometry data suggests that the lake was under high to moderate hydrological dynamic conditions, indicating active deposition at the river delta front. Biozone T4, beginning at 3600. cal.yrs BP, was dominated by three species D. stelligera, Cocconeis placentula var. lineata and Fragilaria sensu lato, and this association could indicate that the lake was under the influence of large fluctuations in water level. This interpretation is supported by granulometry and geochemical data, particularly by the low levels of total organic carbon (TOC). In biozone T3, corresponding to 3000. cal.yrs BP, we found a lowering of the water level, suggested by low levels of TOC. Poor granulometric sorting and higher carbon/nitrogen (C/N) ratios suggest a macrophyte influence on the sedimentation, avoiding direct deltaic influence. In this biozone the benthic diatom F. sensu lato group was dominant. In biozone T2, starting 2400. cal.yrs BP, the proxies indicate that the lake experienced increasing water levels and that stronger circulation patterns occurred in the water column than in the preceding periods, as inferred by the presence of Aulacoseira granulata a ticoplanktonic species. The sediment in this biozone is well sorted and finer, indicating a greater depth. Biozone T1 at the top of the core and since 2000. cal.yrs BP to the present, evidence for a recent reduction in water level of Lake Tota can be deduced by the presence of Achnanthidium minutissimum var. minutissimum. © 2014 Elsevier B.V. All rights reserved.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69173
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作者单位: Instituto de Biologia, Departamento de Botânica, Universidade Federal da Bahia, Rua Barão de Jeremoabo 147, Salvador, Bahia, Brazil; Unidad de Ecologia en Sistemas Acuáticos, Escuela de Ciencias Biológicas, Universidad Pedagógica y Tecnológica de Colombia, Avenida Central del Norte, Tunja, Boyacá, Colombia; Instituto Amazónico de Investigaciones Imani, Universidad Nacional, Km 2 via Tarapacá, Leticia, Amazonas, Colombia; Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Ciudad Universitaria, Cra 30 #45-03, Bogotá, Cundinamarca, Colombia; Instituto de Química, Departamento de Geoquímica Ambiental, Universidade Federal Fluminense, Rua Outeíro de São João Baptísta, Niterói, Rio de Janeiro, Brazil; Institut de Recherche pour le Développement, France; IRD LOCEAN (UPMC, CNRS, IRD, MNHN), 32 av Henri Varagnat, Bondy Cedex, France

Recommended Citation:
Cardozo A.Y.V.,Gomes D.F.,da Silva E.M.,et al. Holocene paleolimnological reconstruction of a high altitude Colombian tropical lake[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2014-01-01,415
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