Lakes as climate change sensors: the case of La Alberca de Tacámbaro, Michoacán, México

Abstract

Lakes are excellent sensors of climate changes because their thermal behavior is controlled by the annual temperature patterns. Deep tropical lakes stratify during the warm part of the year, mixing during winter. This mixing pattern can be altered by warmer climatic conditions such as global warming and/or “El Niño”. In this article we aim to correlate climate variability with changes in the mixing pattern of lake Alberca de Tacámbaro, Michoacán, México during an interval that involved two “El Niño” events (2009-2010 and 2015-2016) and with changes in the diatom assemblages preserved in the sediments between 1988 to 2015. The lake showed a winter mixing pattern, with a shallower thermocline in spring that deepened towards the autumn. Temperature data show a warming trend since AD 2000 and the impact “El Niño” years is associated to nutrient limitation (phosphorus and nitrogen), that we associate to a reduced vertical mixing. These changes are linked with an increase in hypolimnion temperature in 2015 compared to 2019 and modifications in the diversity and species composition of the diatom community of this lake between 1988 to 2015. This study allowed to identify recent changes in the lake and its diatom assemblages that are linked with global warming trends and “El Niño” events.