Mahnala, Oona
- Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
Sammanfattning
Global climate change, leading to warming and increased precipitation in northern latitudes, is expected to increase the transfer of organic matter from soils to coastal waters. This inflow does not only bring particulate organic matter (POM) but also brown-coloured dissolved organic carbon (DOC), which darkens the water. Water darkening alters coastal food web structure and dynamics by affecting the system from bottom up, suppressing benthic primary production while favouring bacterial production and potentially also from the top down by hindering visual predators. Global climate warming further changes coastal food webs from the top down by increasing consumer metabolic rates, especially in large-bodied fish species, which increases costs for maintenance, consumption rates and thus body growth. This can lead to decreased fish biomass production and a shift towards dominance of smaller individuals. While the ecological consequences of warming and darkening are increasingly studied, their effects on contaminant transfer remain poorly understood. One likely outcome of water darkening is a shift from benthic to pelagic primary production, pushing omnivorous fish to rely more on pelagic resources, such as zooplankton. Such shifts in habitat use and species interactions are critical for contaminant transfer, as radionuclides such as 137Cs bioaccumulate mainly through diet. If fish switch from benthic prey with higher 137Cs concentration to zooplankton with lower contaminant levels, they may accumulate less radionuclides. In this essay, I review causes and consequences of warming and darkening of waters and discuss how coastal food web responses to these drivers may be key to predict radiocesium transfer and bioaccumulation, and thus important to risk assessment.
Nyckelord
Allochthonous carbon; 137Cs; radioactivity; Baltic Sea; climate change; terrestrial organic matter
Publicerad i
Aqua introductory research essay
2026, nummer: 2026:3
Utgivare: Department of Aquatic Resources, Swedish University of Agricultural Sciences
SLU författare
UKÄ forskningsämne
Ekologi
Miljövetenskap
Publikationens identifierare
- DOI: https://doi.org/10.54612/a.1stoao1uts
- eISBN: 978-91-8124-195-2
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/146515