Paleoclimate and paleoecology of the northern lowland Neotropics, Phase I and II: Limnological survey of modern aquatic environments and paleoclimate reconstructions from fossil species assemblages recovered by the Lago Petén Itzá Scientific Drilling Project (PISDP)
Zusammenfassung der Projektergebnisse
The lack of limnological data on aquatic ecosystems from remote areas and quantitative ecological information for most lacustrine bioindicators preclude their use in paleolimnological studies in the Neotropics. Information on ecological preferences of 29 extant ostracode species collected in 63 aquatic ecosystems on the Yucatán Peninsula was determined. Ostracodes of the Yucatán Peninsula respond sensitively to climate and environmental fluctuations, making them excellent bioindicators for inferring late Quaternary paleoenvironmental changes in the lowland Neotropics. Ostracodes were collected along a steep, increasing NW-S precipitation gradient and across a large altitudinal range. Ostracode autecology was characterized by relating species abundances to physical and chemical properties of host waters and in surface sediments. Cluster analysis of water chemistry variables distinguished between highland and lowland lakes, and indicated that geological setting, groundwater influence, and sea spray were important factors contributing to the difference. Multivariate statistics indicated that conductivity and water chemical composition are the most important factors in shaping ostracode communities. Ostracodes in surface-sediment samples taken along a N-S transect in Lago Petén Itzá provided information about the water-depth-related distribution of 11 ostracode species. Taxonomy of the extant ostracode fauna was refined using analysis of soft and hard body parts. Paleoenvironmental reconstruction was accomplished using ostracode assemblages in sediment cores from Lago Petén Itzá, and relied on (1) a regional training data set, (2) multivariate statistics to determine the principal environmental factors that affect ostracode distributions, and (3) development of ostracode-based transfer functions to infer shifts in conductivity and water depth, using WA-PLS and BC. These transfer functions were applied to (1) fossil ostracode assemblages in Last Glacial Maximum (LGM, 24-19 ka BP) and Deglacial-early Holocene (19-10 ka BP) sediments in long core PI- 6 from Lago Petén Itzá, taken under the auspices of the Lake Petén Itzá Scientific Drilling Project, and to (2) assemblages in short core PI-SC-1-10m, which spans the last ~500 yr. Inferences suggest a cold and wet climate during the LGM. Alternating dry and wet conditions characterized the Deglacial. The LGM displayed conductivity as low as 188 μS cm-1, and these fresh conditions suggest high rainfall and lake levels. The Deglacial displayed higher conductivities, up to 555 μS cm-1, suggesting greater ion concentrations and lower lake levels. During the Post-Columbian era, lake levels were 5 m higher than today in the early 17th century, and in the late 20th century. Cultural eutrophication began in the 1930s and has increased, along with urban pollution since ~1970. These transfer functions for inferring past lake water conductivity and water depth can now be applied to late Quaternary lake records from Central America, and may be applicable to lacustrine records from the entire Neotropical region. Similar analyses using chironomids and diatoms are underway. A future multi-proxy study using bioindicators, sedimentological data, pollen and geochemical proxies will enable to discern the role of the tropics as a driver of global climate change.
Projektbezogene Publikationen (Auswahl)
- 2006. Paleoclimate and paleoecology of the northern lowland Neotropics, Phase I: Limnological survey of modern aquatic environments of the Peninsula Yucatán, a contribution to the Lake Petén-Itzá, Guatemala, Drilling Project. Abstract Volume IODP-ICDP Kolloquium, Greifswald, Germany: 9
Pérez, L., E. Vinogradova, W. Riss, B. Scharf, A. Schwalb
- 2007. Paleoclimate and paleoecology of the northern lowlands Neotropics: Limnological survey of modern aquatic environments of Peninsula Yucatán, a contribution to the Lake Petén Itzá Drilling Project. 4th International Limnogeology Congress (ILIC 4), Barcelona, Spain: 184
Pérez, L., B. Scharf, R. van Geldern, P. Steeb, A. Schwalb
- 2007. Proyecto Paleoambiental en el Lago Petén Itzá. CONVERCIENCIA. Guatemala city, Guatemala
Pérez, L., B. Scharf, A. Schwalb
- 2008. Modern ostracodes from aquatic habitats of Yucatán Peninsula (Guatemala, Mexico and Belize) as indicators of climate and environmental Change. Geophysical Research Abstracts, Vol. 10, EGU2008-A-00354, Vienna, Austria
Pérez, L., B. Scharf, J. Lorenschat, D. Samol, M. Lorenz, R. Bugja, P. Steeb, R. van Geldern, A. Schwalb
- 2008. Paleoclima y paleoecología de las tierras bajas del norte de los neotrópicos: investigación limnológica y extracción de sedimentos del lago Petén Itzá (Guatemala). Revista Universidad del Valle de Guatemala 18: 65-83
Pérez, L., G. Alfaro, M. Palmieri, M. Dix, M. Maldonado, G. Islebe, B. Scharf, A. Schwalb
- 2009. Comparison of aquatic habitats in the Lowlands and Highlands of Southern Guatemala using Recent Freshwater Ostracodes. 11th International Paleolimnology Symposium, Guadalajara, México. Programme and Abstract Volume: 92
Lorenschat, J., B. Scharf, R. Bugja, L. Pérez, A. Schwalb
- 2009. Living and fossil ostracode species assemblages from the Yucatán Peninsula as indicators of environmental change, a contribution to the Lago Petén Itzá Drilling Project. Abstract Volume IODP/ICDP Kolloquium, Potsdam, Germany
Pérez, L., B. Scharf, A. Schwalb
- 2009. Modern ostracode species assemblages from the northern lowland Neotropics (Yucatán Peninsula) and Guatemalan highlands. 16th International Symposium on Ostracoda, Brasilia, Brazil
Pérez, L., J. Lorenschat, B. Scharf, A. Schwalb
- 2009. Ostracode species assemblages from lacustrine sediments as proxies of climatic and environmental change in the lowland Neotropics. International Conference and 99th Annual Meeting of the Geologische Vereinigung, Göttingen, Germany: 111
Pérez, L., J. Lorenschat, B. Scharf, A. Schwalb
- 2009. Quaternary ostracode species assemblages from Lago Petén Itzá, Guatemala, and aquatic environments of the Yucatán Peninsula. 11th International Paleolimnology Symposium, Guadalajara, México, Programme and Abstract Volume: 111
Pérez, L., J. Lorenschat, B. Scharf, A. Schwalb
- 2010. Distribution, diversity and ecology of modern freshwater ostracodes (Crustacea), and hydrochemical characteristics of Lago Petén Itzá, Guatemala. Journal of Limnology 69 (1): 146-159
Pérez, L., J. Lorenschat, R. Bugja, M. Brenner, B. Scharf, A. Schwalb
- 2010. Environmental history of Lago Petén Itzá, Guatemala during the Deglacial and Last Glacial Maximum. Abstract volume IODP/ICDP Kolloquium, Frankfurt, Germany
Pérez, L., J. Lorenschat, M. Brenner, B. Scharf, A. Schwalb
- 2010. Extant freshwater ostracodes (Crustacea) from Lago Petén Itzá, Guatemala. International Journal of Tropical Biology and Conservation 58 (3): 871-895
Pérez, L., J. Lorenschat, M. Brenner, B. Scharf, A. Schwalb
