Abrupt rise in the contribution of CH4-derived carbon to benthic secondary production of a shallow hemiboreal/boreal lake

Abstract

Understanding long-term carbon flows through aquatic food webs is essential to assess impact of climatic and environmental changes on lake ecosystems. We reconstructed temporal changes in carbon sources fuelling chironomid biomass in a small and shallow hemiboreal/boreal lake over the last 11 000 years. Results were compared with temporal dynamics of known potential controlling factors: summer air temperature, human activities, phytoplankton assemblages and organic matter composition. We report an abrupt rise in the contribution of methane-derived carbon to chironomid biomass. However, this sudden increase was not the consequence of drastic changes in the composition of sedimentary organic matter, mean air temperature, lake trophic state or human activities in the catchment area. Our results suggest that shallowing of the lake caused by sedimentary infilling processes was a possible driver of the expansion of anoxic zones, enhancing CH4 cycling in lake sediments. However, complementary studies are needed to better understand the mechanisms by which lake shallowing could affect carbon flows to aquatic consumers, and then better assess the natural dynamics of past carbon processing in the benthic food web of shallow lakes.

Keywords

benthic food web; carbon stable isotope; Holocene; methane-derived carbon; subfossil chironomid

Published in

Journal of Quaternary Science
2018, Volume: 33, number: 8, pages: 969-976 Publisher: WILEY

SLU Authors

• Belle, Simon

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Estonian University of Life Sciences

Sustainable Development Goals

SDG15 Life on land


UKÄ Subject classification

Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.1002/jqs.3075

Permanent link to this page (URI)

https://res.slu.se/id/publ/97556