North-Patagonian Andean deep lakes: Impact of glacial recession and volcanic eruption

BALSEIRO, E. G.; MODENUTTI, B. E.; BASTIDAS NAVARRO, MARCELA; MARTYNIUK, N.; SCHENONE, LUCA; LASPOUMADERES, C.

Freshwater and wetlands of patagonia

Springer

Año: 2022;

North- Patagonian Andean deep lakes(>100 m depth) are ultraoligotrophic, and thus high light-low nutrientenvironments.  In this chapter, we willpresent examples and discuss the effect of particles input due to climatechange (changes in glacial clay due to glacial recession) and volcanic eruption(volcanic ashes) in the water column of these lakes. The best descriptor ofwater column functioning was the vertical position of the deep chlorophyllmaximum that was very sensitive to changes in underwater light and may be usedas a simple variable to track changes in the dynamics of lakes. Mixotrophy isparticularly important in the plankton of these lakes, and here we show howglacier recession affect, through the glacier clay, the bacterivory of theseprotists. Finally, we present results on how volcanic ashes triggered thedisappearance of cladoceran populations, and changes in glacier clay affectzooplankton filter feeders, modifying the food quality (C:P ratio) that drivesthe coexistence between cladocerans and copepods.