Los ibones del Pirineo: testigos de la historia climática y el cambio global

Wednesday, October 19
3-4PM EDT

Meet SYA Spain's environmental science faculty member Alfonso Pardo in this virtual class on the natural phenomenon.

Most high mountain lakes, located in the Pyrenees and other northern middle- to high-latitude mountain ranges, originated during the late Pleistocene glaciation pulses. Among the different glacial lakes, tarns (dubbed ibones in Aragón, Spain) are usually the most remote and isolated, due to their origin in the high mountain cirques, which constitute the main glacier accretion zones. There, glaciostatic pressure of the growing ice masses against the cirque bedrock, combined with glacial plucking of rock fragments, yielded depressions at the bottom of the cirques. Later, during the glacier retreat, most of those hollows were filled with thaw water producing these unusual lacustrine water bodies known as ibones. Today, their remoteness and isolation protect most tarns from intense human activities and impacts. Thus, many of these glacial lakes keep a near pristine status. Due to their high altitude and extreme environmental conditions, most tarn waterfronts have developed thin soils and scarce vegetation.

Water inputs in a remote Pyrenean glacial lake come mainly from direct or indirect (i.e., melting and flowing) atmospheric precipitation, whereas matter inputs come from atmospheric deposition and catchment loadings. Frequently, their water mass has a very low content in dissolved salts and nutrients. This is mainly due to the slow-weathering nature of the bedrock, the small size of their basins and catchment areas, and the limited soil development. As a result, relatively minor changes in the external environmental conditions can cause significant perturbations in the environmental conditions of tarns that may affect their chemical and biological dynamics.

Therefore, due to their good preservation and high sensibility, ibones are excellent ecosystems to study environmental responses and adaptations to external changes. The use of tarns as proxies of global environmental change implies a deep understanding of their natural processes and physicochemical dynamics.

Conversational skills in Spanish are recommended for this class. Supplemental lesson material (in English) to review in advance. To freshen up your Spanish, here's a video featuring Alfonso and former colleagues about their research in the ibones (don't worry, there are English subtitles.)

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