Elsevier

Quaternary Science Reviews

Volume 71, 1 July 2013, Pages 205-218
Quaternary Science Reviews

The last Glacial–Interglacial transition in Patagonia, Argentina: the stable isotope record of bulk sedimentary organic matter from Laguna Potrok Aike

https://doi.org/10.1016/j.quascirev.2012.05.025Get rights and content

Abstract

An investigation of stable isotope13CTOC and δ15NTN) and elemental parameters (TOC, TN contents and TOC/TN ratios) of bulk organic matter (<200 μm) from sediment cores recovered from the Patagonian lake Laguna Potrok Aike (Argentina) in the framework of the ICDP deep drilling project PASADO provided insights into past changes in lake primary productivity and environmental conditions in South Patagonia throughout the last Glacial–Interglacial transition. Stratigraphically constrained cluster analyses of all proxy parameters suggest four main phases. From ca 26,100 to 17,300 cal. years BP, lacustrine phytoplankton was presumably the predominant organic matter source in an aquatic environment with low primary productivity rates. At around 17,300 cal. years BP, abrupt and distinct shifts of isotopic and elemental values indicate that the lacustrine system underwent a rapid reorganization. Lake primary productivity (phytoplankton and aquatic macrophytes) shows higher levels albeit with large variations during most of the deglaciation until 13,000 cal. years BP. The main causes for this development can be seen in improved growing conditions for primary producers because of deglacial warming in combination with expedient availability of nutrients and likely calm wind conditions. After 13,000 cal. years BP, decreased δ13CTOC values, TOC, TN contents and TOC/TN ratios indicate that the lake approached a new state with reduced primary productivity probably induced by unfavourable growing conditions for primary producers like strengthened winds and reduced nutrient availability. The steady increase in δ15NTN values presumably suggests limitation of nitrate supply for growth of primary producers resulting from a nutrient shortage after the preceding phase with high productivity. Nitrate limitation and consequent decreased lacustrine primary productivity continued into the early Holocene (10,970–8400 cal. years BP) as reflected by isotopic and elemental values.

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)

  • R. Kilian et al.

    Palaeoecological contraints on late glacial and Holocene ice retreat in the Southern Andes (53°S)

    Global and Planetary Change

    (2007)
  • P. Kliem et al.

    Laguna Potrok Aike: Range and effects of lake-level oscillations in the Patagonian steppe

    Quaternary Science Reviews

    (2013)
  • P. Kliem et al.

    Lithology, absolute dating and hydrological interpretation of a 51,000 year old lacustrine record, Laguna Potrok Aike (Patagonia)

    Quaternary Science Reviews

    (2013)
  • F. Lamy et al.

    Modulation of the bipolar seesaw in the Southeast Pacific during termination 1

    Earth and Planetary Science Letters

    (2007)
  • E. Laws et al.

    Dependence of phytoplankton carbon isotopic composition on growth rate and CO2aq: theoretical considerations and experimental results

    Geochimica et Cosmochimica Acta

    (1995)
  • M. Lehmann et al.

    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

    (2002)
  • A. Lücke et al.

    Biogeochemical and micro-facial fingerprints of ecosystem response to rapid Late Glacial climatic changes in varved sediments of Meerfelder Maar (Germany)

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2004)
  • A. Lücke et al.

    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

    (2003)
  • V. Markgraf et al.

    Late and postglacial vegetation and fire history in Southern Patagonia and Tierra del Fuego

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2010)
  • J. Massaferro et al.

    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

    (2013)
  • C. Mayr et al.

    Precipitation origin and evaporation of lakes in semi-arid Patagonia (Argentina) inferred from stable isotopes (δ18O, δ2H)

    Journal of Hydrology

    (2007)
  • R. McCulloch et al.

    Late-glacial and Holocene palaeoenvironmental change in the central Strait of Magellan, southern Patagonia

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2001)
  • P. Meyers

    Preservation of elemental and isotopic source identification of sedimentary organic matter

    Chemical Geology

    (1994)
  • P. Meyers

    Applications of organic geochemistry to paleolimnological reconstructions: a summary of examples from the Laurentian Great Lakes

    Organic Geochemistry

    (2003)
  • P. Müller

    C/N ratios in Pacific deep-sea sediments: effect of inorganic ammonium and organic nitrogen compounds sorbed by clays

    Geochimica et Cosmochimica Acta

    (1977)
  • C. Ohlendorf et al.

    The PASADO core processing strategy – a proposed new protocol for sediment core treatment in multidisciplinary lake drilling projects

    Sedimentary Geology

    (2011)
  • C. Ohlendorf et al.

    Mechanisms of lake-level change at Laguna Potrok Aike (Argentina) – Insights from hydrological balance calculations

    Quaternary Science Reviews

    (2013)
  • T. Watanabe et al.

    Biological and environmental changes in Lake Baikal during the late Quaternary inferred from carbon, nitrogen and sulfur isotopes

    Earth and Planetary Science Letters

    (2004)
  • M. Wille et al.

    Vegetation and climate dynamics in southern South America: the microfossil record of Laguna Potrok Aike, Santa Cruz, Argentina

    Review of Palaeobotany and Palynology

    (2007)
  • B. Zolitschka et al.

    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

    (2006)
  • D. Aagesen

    Crisis and conservation at the end of the world: sheep ranching in Argentine Patagonia

    Environmental Conservation

    (2000)
  • F. Anselmetti et al.

    Environmental history of southern Patagonia unravelled by the seismic stratigraphy of Laguna Potrok Aike

    Sedimentology

    (2008)
  • B. Baruth et al.

    Climate and desertification processes in Patagonia

    Bamberger Geographische Schriften

    (1998)
  • N.H. Batjes

    Total carbon and nitrogen in the soils of the world

    European Journal of Soil Science

    (1996)
  • P. Blomqvist et al.

    Ammonium-nitrogen – a key regulatory factor causing dominance of non-nitrogen-fixing cyanobacteria in aquatic systems

    Archiv für Hydrobiologie

    (1994)
  • R. Cerveny

    Present climates of South America

  • M. Dokulil et al.

    Cyanobacterial dominance in lakes

    Hydrobiologia

    (2000)
  • J. Downing et al.

    Predicting cyanobacteria dominance in lakes

    Canadian Journal of Fisheries and Aquatic Sciences

    (2001)
  • EPICA community members

    One-to-one coupling of glacial climate variability in Greenland and Antarctica

    Nature

    (2006)
  • B. Fry

    Stable Isotope Ecology

    (2006)
  • C. Gebhardt et al.

    Seismic evidence of up to 200 m lake-level change in Southern Patagonia since MIS 4

    Sedimentology

    (2011)
  • T. Guilderson et al.

    Late Pleistocene sea level variations derived from the Argentine Shelf

    Geochemistry Geophysics Geosystems

    (2000)
  • T. Haberzettl et al.

    Lateglacial and Holocene wet-dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina

    The Holocene

    (2007)
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