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Research article2018Peer reviewedOpen access

Glacier dynamics influenced carbon flows through lake food webs: evidence from a chironomid delta δ13C-based reconstruction in the Nepalese Himalayas

Belle, Simon; Musazzi, Simona; Lami, Andrea

Abstract

Using a sediment core covering the last 3,500 years, we analysed photosynthetic pigments' concentrations in lake sediments and carbon stable isotopic composition of chironomid (Diptera, Chironomidae) remains (delta C-13(HC)). We aimed to reconstruct temporal changes in aquatic primary productivity and carbon resources sustaining chironomid larvae in a high mountain lake (Lake Pyramid Inferior; 5,067 m a.s.l.) located in the Nepalese Himalayas. Both pigments and delta C-13(HC) trends followed a similar fluctuating pattern over time, and we found significant positive relationships between these proxies, suggesting the strong reliance of benthic consumers on the aquatic primary production. Temporal trends matched well with main known climatic phases in the Eastern part of the Himalayan Mountains. Past glacier dynamics and associated in-lake solute concentrations appeared to be the main driver of autochthonous primary productivity, suggesting then the indirect impact of climate change on carbon processing in the benthic food web. During warm periods, the glacier retreat induced a rise in in-lake solute concentrations leading to an increasing primary productivity. Complementary investigations are still needed to strengthen our understanding about the response of past aquatic carbon cycling in CO2-limiting environments.

Keywords

Food webs; Carbon stable isotope; Subfossil chironomid; Sedimentary pigments; Paleolimnology

Published in

Hydrobiologia
2018, Volume: 809, number: 1, pages: 285-295
Publisher: SPRINGER

    Sustainable Development Goals

    SDG13 Climate action

    UKÄ Subject classification

    Oceanography, Hydrology, Water Resources

    Publication identifier

    DOI: https://doi.org/10.1007/s10750-017-3477-8

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/93867