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Monitoring study of chemical and isotopic composition of lake water and ostracods in the high Andes of SE Peru.
presentationposted on 2023-06-07, 17:15 authored by K P Boessenkool, A J Chepstow-Lusty, Mick FrogleyMick Frogley, E F Gil
We present the results of a years monitoring study (September 2002 to September 2003) of temperature and chemistry from both lake water and ostracods (bivalved Crustacea) from Lake Huacarpay (Lucre Basin), in the Cusco region of Peru. The project was carried out to provide a modern baseline for Holocene palaeoenvironmental reconstructions based on sequences obtained from a series of lakes in the high Andes of SE Peru. Terrestrial palaeoenvironmental reconstructions are often based on the chemical composition (e.g. [delta]18O, [delta]13C, Mg/Ca) of ostracod valves in lacustrine sediments. In controlled experiments, several authors have investigated the chemical composition of ostracod valves in relation to separate environmental parameters such as temperature or salinity. However, these relationships have only been established for a limited number of ostracod taxa. Hence, this monitoring study was carried out to determine the link between the chemical composition of ostracod valves and environmental parameters in their natural habitat. Water and ostracod samples were taken monthly from the northern side of Lake Huacarpay (71 4324"W; 13 3636"S; 3100 m a.s.l.), adjacent to a reed marsh, dominated by Typha dominguensis vegetation; water temperature was recorded every hour using a StarmonMini temperature logger. The climate of the research area is strongly seasonal: most precipitation falls between December and March, while dry and cold conditions (causing occasional freezing at night) occur from May-August. The chemical composition of the monthly water samples has been analysed, while the taxonomy of the ostracods is currently being resolved. Almost all measured major and trace elements show a clear annual trend with highest values between September and December. Stable oxygen isotopes in at least one common species of ostracod roughly follow this pattern. This is the first study of its kind from Peru integrating ostracod chemistry and annual temperature variability, and such investigations will be invaluable for interpreting palaeoecological records from this area.
Event nameEuropean Geophysical Union General Assembly
Event locationNice, France.
Department affiliated with
- Geography Publications
NotesConference presentation Abstract published in Gephysical Research Abstracts, volume 6.
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