Historical eruptions of Lautaro Volcano and their impacts on lacustrine ecosystems in southern Argentina

Abstract

Lacustrine sequences were obtained from Laguna Verde and Laguna Gemelas Este, two small lakes 43 located east of the southern Patagonian Ice Field and close to the village of El Chaltén in Argentinian 44 Patagonia. Four tephra layers were identified in each of these short sedimentary sequences and 45 characterised using individual glass-shard tephra chemistry to determine provenance. In order to 46 understand the impact of the tephra deposits on lake ecosystems, bulk sediment geochemistry and 47 diatom assemblages were analysed. Age-depth models for the cores were established by radiometric 48 dating using 137 Cs and 210 Pb measurements. 49

Geochemical and mineralogical characterization of sediments from Lake Futalaufquen (42.8°S, Andean Patagonia) to evaluate their potential as paleoclimatic proxies

“…It is possible to find low isotope variation with tephra layers (Haberzettl et al, 2008), lower δ 13 C values after some (but not all) tephra deposits associated with a decrease in lake productivity (Bertrand et al, 2010), and variable responses in close environments. As an example, in one small lake studied on southernmost Patagonia, δ 15 N values were 2.1‰ lower in tephra deposits than in normal sediment (with no variation in δ 13 C values), which is explained by higher turbidity during volcanic activity that restricted nitrogen assimilation in the ecosystem; in another nearby small lake, such δ 15 N variation was not observed (Mayr et al, 2019).…”

“…It has been observed, however, that tephra deposition can cause changes in lakes and their catchment, with significant physical (sedimentation rate, light availability, habitat alteration), chemical (soluble compounds, nutrient availability, heavy metals), and biological (composition of lacustrine communities) effects (Telford et al, 2004; Ayris and Delmelle, 2012) that mask climatic impacts. Although distal tephra layers are more frequent and geographically more dispersed, little is known about the effects of the deposition, and records can be contradictory (Mayr et al, 2019). Despite the fact that records can be variable, it is important to recognize tephra layers in lake sequences to prevent misinterpretation in paleolimnological reconstructions (Telford et al, 2004).…”

Review of Local and Global Impacts of Volcanic Eruptions and Disaster Management Practices: The Indonesian Example

“…Volcanic ash deposits in a lake system can increase water toxicity to living biota [50]. Tephra and ashfall can contaminate the lacustrine ecosystem [51], e.g., in Lake Van (Eastern Anatolia, Turkey) [52]. However, hazards and managements related to volcanic lake's water quality are poorly developed [49].…”

Responses of testate amoebae assemblages (Amoebozoa: Arcellinida) to recent volcanic eruptions, inferred from the sediment record in Laguna Verde, southern Patagonia, Argentina

“…Depending on tephra composition and limnological characteristics, dissolution of tephra can alter water chemistry, modify the lake ecosystem, and change the sediment composition (Hutchinson et al 2019;Massaferro and Corley 1998;Telford et al 2004). In many cases, ashfall increases turbidity in lakes, reduces light penetration and modifies biotic communities (Barker et al 2000;Hutchinson et al 2019;Lotter and Birks 1993;Mayr et al 2019).…”

“…To address this knowledge gap, we studied the paleoecology of lacustrine testate amoebae in a 61-cm-long sediment core from Laguna Verde, southern Patagonia, a lake located in a region that has been impacted by frequent volcanic activity since the Late Glacial (Fontijn et al 2014;Mayr et al 2019;Stern et al 2007). This information enabled us to identify the response of lacustrine testate amoebae assemblages to four volcanic events during the past * 300 years.…”