Volcanic eruptions and glacier recession: understanding the effects of particle inputs on planktonic communities of Andean-Patagonian lakes

Abstract

Lakes are particularly vulnerable to environmental changes and thus considered sentinels and integrators of processes that occur in the atmosphere and terrestrial environments. Individual up to ecosystemic metabolic pathways and nutrient cycling in lakes respond to both natural and human disturbances. Disentangling the effect of such different forces is a particular challenge for lake ecological studies. Here we present a conference paper based on previous studies carried out in Andean-Patagonian lakes under two important events: the Puyehue-Cordón Caulle eruption in 2011 and the glacial recession with a glacial lake outburst flood (GLOF) in 2009. We will discuss how biological variables respond to these two natural events that produce the input of minerogenic inorganic particles into the lakes. We will present the combination of observational and experimental research, including new molecular methods, that contributed to understanding the effects of these inorganic particles on aquatic ecosystems. Both events involved changes in the transparency of the lakes that affected phytoplankton parameters (biomass vertical distribution), bacteria composition, and community structuring process. Finally, in the same range of particle concentrations, both events have very contrasting effects on zooplankton. Particles from glacial melting are beneficial for Daphnids reducing the impact of ultraviolet radiation and increasing the quality of the food. In contrast, volcanic ashes are abrasive materials that have a deleterious effect for filtering zooplankton.