The last Glacial–Interglacial transition in Patagonia, Argentina: the stable isotope record of bulk sedimentary organic matter from Laguna Potrok Aike
Introduction
Stable isotope analysis of bulk organic matter has been widely used in ecological research (e.g. Fry, 2006; Michener and Lajtha, 2007). However, these variables not only provide present day environmental information, but the isotopic composition of e.g. sedimentary organic matter preserves also evidence of past environmental changes (Meyers, 1994). Stratigraphic changes in carbon and nitrogen isotope composition of organic matter contained in lake sediments thus help trace histories of environmental and climate change (e.g. Meyers and Lallier-Vergès, 1999; Meyers, 2003; Lücke and Brauer, 2004).
Although several lacustrine isotope records have provided evidence for climate changes during the last deglaciation in the northern hemisphere (e.g. Yu and Eicher, 1998;; von Grafenstein et al., 1999;; Lücke et al., 2003;; Parplies et al., 2008) and in the mid-latitudes of the southern hemisphere (e.g. Valero-Garcés et al., 2005; Bertrand et al., 2010), understanding of late Quaternary climate changes in the southern hemisphere higher latitudes is still incomplete because of the lack of long, continuous and high-resolution terrestrial records. Hence, due to its unique geographic location, records from southernmost Patagonia can offer new palaeoclimatic insights and an important linkage with marine records from southern oceans and ice core records from Antarctica. The sediment archive of Laguna Potrok Aike, further developed by the Potrok Aike maar lake sediment archive drilling project (PASADO) within the framework of the International Continental Scientific Drilling Program (ICDP), has initiated interdisciplinary multiproxy investigations to advance the understanding of past environmental and climatic changes in South Patagonia throughout the last Glacial–Interglacial cycle (e.g. Recasens et al, in press; Hahn et al., 2013). Here we report on the results of high-resolution carbon and nitrogen isotope analyses of bulk sedimentary organic matter from Laguna Potrok Aike for a time window from 26,075 to 8400 cal. years BP, including the last Glacial Maximum (LGM) and the glacial–Interglacial transition period, and discuss their paleoenvironmental significance. Our investigation builds on the earlier studies of surface and older sediments as well as core catcher samples (Mayr et al., 2009; Kastner et al., 2010; Lücke et al., 2010) and expands their scope with respect to temporal resolution and depositional history.
Section snippets
Site description
Laguna Potrok Aike is located at 113 m above sea level in the Pali Aike Volcanic Field in southern Patagonia, Argentina (51° 58′ S, 70° 23′ W, Fig. 1A) and originated from a phreatomagmatic explosion (Zolitschka et al., 2006). A detailed description about geomorphological characters and landscape evolution of the Laguna Potrok Aike area can be found in Coronato et al. (2013). During the last Glacial the catchment of the lake was not covered by the Patagonian glaciers (Zolitschka et al., 2006).
Material and methods
A total of 533 m of sediment cores was recovered from two drilling sites in Laguna Potrok Aike in 2008 in the framework of the ICDP deep drilling project PASADO (Zolitschka et al., 2009; Ohlendorf et al., 2011, Fig. 1B). In this study, we used the samples collected from the 106 m long Site 2 composite profile 5022-2CP (Ohlendorf et al., 2011) that covers the last 51,000 years according to the age–depth model (version 3) of Kliem et al. (2013b). The profile consists of undisturbed pelagic
Geochemistry
For all measured samples, TOC contents range from 0.02 to 9.87% (mean 1.00%, n = 737) and TN contents from 0.01 to 0.66% (mean 0.12%, n = 700) (Fig. 2). TOC/TN ratios range between 1.73 and 29.44 (mean 7.33, n = 696). Carbon and nitrogen isotope compositions vary from −28.1 to-22.3‰ (mean −25.6‰, n = 741) and 1.3–7.6‰ (mean 3.4‰, n = 685), respectively. Below 18.73 m (cd) most samples show comparably low and stable values of TOC and TN contents and TOC/TN ratios. δ13CTOC values here are almost
Nitrogen proxies and inorganically bound nitrogen
One of the geochemical proxies frequently used in environmental studies is the nitrogen content, for example to determine the carbon to nitrogen ratio. Nitrogen in aquatic sediments is a constituent of organic matter as well as bound to inorganic matter, mainly clay minerals (Müller, 1977). Normally, their carbon to nitrogen ratio is expressed as the TOC to TN ratio due to difficulties in the separation between the organic and the inorganic fraction of total nitrogen. However, especially in
Conclusions
Based on high-resolution measurements of the TOC, TN contents, TOC/TN ratios, δ13CTOC and δ15NTN values from bulk sediments (<200 μm) of Laguna Potrok Aike, insights into the paleoenvironment in southern Patagonia during the last Glacial–Interglacial transition are provided. Under full glacial conditions, from ca 26,000 to 17,300 cal. years BP, the lake had a very low primary productivity with a dominant organic matter source from lake algae. At around 17,300 cal. years BP, the lake underwent a
Acknowledgement
We thank H. Vos (Research Center Jülich) for providing the software of CONISS cluster analysis und for helpful discussions. We thank D. Dumitrescu for support in sample preparation in the laboratory. This research used samples provided by the International Continental Scientific Drilling Program (ICDP) in the framework of the “Potrok Aike Maar Lake Sediment Archive Drilling Project” (PASADO). Funding for drilling was provided by the ICDP, the German Science Foundation (DFG), the Swiss National
References (86)
- et al.
Bulk organic geochemistry of sediments from Puyehue Lake and its watershed (Chile, 40°S. Implications for paleoenvironmental reconstructions
Palaeogeography, Palaeoclimatology, Palaeoecology
(2010) - et al.
Effects of growth rate, CO2 concentration, and cell size on the stable carbon isotope fractionation in marine phytoplankton
Geochimica et Cosmochimica Acta
(1999) - et al.
Glacial, fluvial and volcanic landscape evolution in the Laguna Potrok Aike maar area, Argentina
Quaternary Science Reviews
(2013) - et al.
Early diagenesis of organic matter from sediments of the eastern subtropical Atlantic: evidence from stable nitrogen and carbon isotopes
Geochimica Cosmochimica Acta
(2001) - et al.
Present-day South American climate
Palaeogeography, Palaeoclimatology, Palaeoecology
(2009) CONISS: a fortran 77 program for stratigraphically constrained cluster analysis by the method of the incremental sum squares
Computers and Geosciences
(1987)- et al.
Climate induced changes in the carbonate and organic content of Laguna Potrok Aike sediments during the past 50 ka inferred from infrared spectroscopy
Quaternary Science Reviews
(2013) - et al.
The last glacial maximum and deglaciation in southern South America
Quaternary Science Reviews
(2002) - et al.
Microsedimentological characterization using image analysis and XRF as indicators of sedimentary processes and climate changes during Late Glacial at Laguna Potrok Aike, Santa Cruz, Argentina
Quaternary Science Reviews
(2013) - et al.
Southern Patagonian glacial chronology for the last glacial period and implications for Southern Ocean climate
Quaternary Science Reviews
(2008)
Palaeoecological contraints on late glacial and Holocene ice retreat in the Southern Andes (53°S)
Global and Planetary Change
Laguna Potrok Aike: Range and effects of lake-level oscillations in the Patagonian steppe
Quaternary Science Reviews
Lithology, absolute dating and hydrological interpretation of a 51,000 year old lacustrine record, Laguna Potrok Aike (Patagonia)
Quaternary Science Reviews
Modulation of the bipolar seesaw in the Southeast Pacific during termination 1
Earth and Planetary Science Letters
Dependence of phytoplankton carbon isotopic composition on growth rate and CO2aq: theoretical considerations and experimental results
Geochimica et Cosmochimica Acta
Preservation of organic matter and alternation of its carbon and nitrogen isotope composition during simulated and in situ early sedimentary diagenesis
Geochimica et Cosmochimica Acta
Biogeochemical and micro-facial fingerprints of ecosystem response to rapid Late Glacial climatic changes in varved sediments of Meerfelder Maar (Germany)
Palaeogeography, Palaeoclimatology, Palaeoecology
A lateglacial and Holocene organic carbon isotope record of lacustrine palaeoproductivity and climatic change derived from varved lake sediments of Lake Holzmaar, Germany
Quaternary Science Revews
Late and postglacial vegetation and fire history in Southern Patagonia and Tierra del Fuego
Palaeogeography, Palaeoclimatology, Palaeoecology
Major lake level fluctuations and climate changes for the past 16,000 years as reflected by diatoms and chironomids preserved in the sediments of Laguna Potrok Aike, southern Patagonia
Quaternary Science Reviews
Precipitation origin and evaporation of lakes in semi-arid Patagonia (Argentina) inferred from stable isotopes (δ18O, δ2H)
Journal of Hydrology
Late-glacial and Holocene palaeoenvironmental change in the central Strait of Magellan, southern Patagonia
Palaeogeography, Palaeoclimatology, Palaeoecology
Preservation of elemental and isotopic source identification of sedimentary organic matter
Chemical Geology
Applications of organic geochemistry to paleolimnological reconstructions: a summary of examples from the Laurentian Great Lakes
Organic Geochemistry
C/N ratios in Pacific deep-sea sediments: effect of inorganic ammonium and organic nitrogen compounds sorbed by clays
Geochimica et Cosmochimica Acta
The PASADO core processing strategy – a proposed new protocol for sediment core treatment in multidisciplinary lake drilling projects
Sedimentary Geology
Mechanisms of lake-level change at Laguna Potrok Aike (Argentina) – Insights from hydrological balance calculations
Quaternary Science Reviews
Biological and environmental changes in Lake Baikal during the late Quaternary inferred from carbon, nitrogen and sulfur isotopes
Earth and Planetary Science Letters
Vegetation and climate dynamics in southern South America: the microfossil record of Laguna Potrok Aike, Santa Cruz, Argentina
Review of Palaeobotany and Palynology
Crater lakes of the Pali Aike Volcanic Field as key sites for paleoclimatic and paleoecological reconstructions in southern Patagonia, Argentina
Journal of South American Earth Sciences
Crisis and conservation at the end of the world: sheep ranching in Argentine Patagonia
Environmental Conservation
Environmental history of southern Patagonia unravelled by the seismic stratigraphy of Laguna Potrok Aike
Sedimentology
Climate and desertification processes in Patagonia
Bamberger Geographische Schriften
Total carbon and nitrogen in the soils of the world
European Journal of Soil Science
Ammonium-nitrogen – a key regulatory factor causing dominance of non-nitrogen-fixing cyanobacteria in aquatic systems
Archiv für Hydrobiologie
Present climates of South America
Cyanobacterial dominance in lakes
Hydrobiologia
Predicting cyanobacteria dominance in lakes
Canadian Journal of Fisheries and Aquatic Sciences
One-to-one coupling of glacial climate variability in Greenland and Antarctica
Nature
Stable Isotope Ecology
Seismic evidence of up to 200 m lake-level change in Southern Patagonia since MIS 4
Sedimentology
Late Pleistocene sea level variations derived from the Argentine Shelf
Geochemistry Geophysics Geosystems
Lateglacial and Holocene wet-dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina
The Holocene
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2015, Palaeogeography, Palaeoclimatology, PalaeoecologyCitation Excerpt :Zhu et al. (2013) observed a significant shift in isotopic records of bulk organic matter for the period between 17.30 and 13.00 ka cal. BP, which also points to increased lake primary productivity, and which Zhu et al. (2013) attribute to warmer temperatures and increased nutrient input. Small benthic Fragilaria sensu lato taxa have been described as pioneer species, since they are often found with great abundance in the initial lake phases following deglaciation (Pienitz et al., 1991; Saulnier-Talbot et al., 2003).
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2013, Quaternary Science ReviewsCitation Excerpt :The more notable rock-magnetic change is a sharp diminution in the concentration of magnetic minerals at 17.3 ka cal BP, and is observed in all concentration-dependant parameters (kLF, NRM, ARM, IRM) (Fig. 4). The concentration change at 17.3 ka cal BP is coeval with a sharp increase of the total organic carbon (TOC) (Hahn et al., 2013; Recasens et al., 2011; Zhu et al., 2013) and it represents the limit between the lithological units C-1 and B (Fig. 4), where plant macro remains and gastropods become abundant (Kliem et al., 2013). Hence the diminution in the magnetic concentration proxies most likely reflects the dilution of magnetic minerals by increased organic sediments.
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PASADO Science Team as listed at http://www.icdp-online.org/front_content.php?idcat=1494.