Skip to main content
Dryad

Data from: Effects of advancing treelines and melting glaciers on alpine lake ecosystems: A mesocosm experiment

Data files

Jul 09, 2025 version files 34.89 KB

Abstract

Climate warming promotes the upward advance of mountain treelines, thereby increasing allochthonous inputs of terrestrial organic matter into alpine lakes. Higher temperatures also accelerate glacial ablation, altering inputs of finely eroded rock particles, termed “glacial flour”. Organic matter (OM) and glacial flour (GF) both affect aquatic ecosystems; however, a knowledge gap exists concerning their combined impact. To test for the direct and interactive effects of OM and GF, we conducted a crossed two-factor outdoor mesocosm experiment. We hypothesized that GF sequesters OM through adsorption, thus reducing its effects on the abiotic environment and phytoplankton community. Addition of GF decreased underwater attenuation of ultraviolet radiation by the OM amendment (i.e., a GF-OM interaction), but not the pronounced positive effects of OM on nutrients and phytoplankton chlorophyll. GF did mediate the effect of OM on phytoplankton community composition by suppressing diatoms. These findings highlight the potential for future shifts in allochthonous inputs away from GF and towards OM to stimulate high-elevation lake ecosystems as glaciers ablate and treeline vegetation migrates to higher elevations under a warming climate.