Abstract

Climate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (<40 mu m) and larger sized plankton (microplankton; 40-200 mu m), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

Published in

Scientific Reports
2021, Volume: 11, number: 1, article number: 16859
Publisher: NATURE PORTFOLIO

SLU Authors

• Wu, Pianpian

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Dartmouth College

• Bishop, Kevin

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

Associated SLU-program

Non-toxic environment
Lakes and watercourses


Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all
Take urgent action to combat climate change and its impacts


UKÄ Subject classification

Climate Research
Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1038/s41598-021-95742-9

Permanent link to this page (URI)

https://res.slu.se/id/publ/113603