Preliminary results on the evolution of proglacial ponds in the deglaciating Alps

Deglaciation is one of the most evident effects of the ongoing climatic changes on the Alpine environment. One of its common consequences is the formation of new water bodies in the proglacial area, where proglacial lakes and ponds are increasingly relevant ecosystems for the mountain landscape. The EVERLAKE project focuses on a recent system of proglacial ponds that originated from the retreat of the Zufall/Cevedale Glacier (Plima catchment, Central/Eastern Italian Alps). The aims of the project are to: (i) provide a first hydroecological characterisation of these pond ecosystems from a physical, chemical and biological point of view; (ii) understand their evolutionary trend during the process of deglaciation, with a space-for-time substitution approach. Here, we present data collected during the ice-free season 2022, showing the seasonal development occurring in three ponds located along a gradient of distance from the Cevedale Glacier terminus (i.e., at 2700-2900 m a.s.l.). We monitored water level, temperature and electrical conductivity and assessed the origin of water through analyses of stable isotopes (δ2H, δ18O). Bathymetric measurements were performed to estimate the residence time of each waterbody. We also analysed basic water chemistry, concentrations of trace elements, benthic and planktonic chlorophyll-a and organic content. The biological communities of these poorly known aquatic ecosystems were characterised by adopting an integrated approach combining morphological observations of microalgae and 16S and 18S rRNA metabarcoding of eDNA from both benthic and planktonic samples. The ponds showed different ecological conditions related to their distance from the glacier margins.