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Project: Will the microbial filter prevent methane emissions from Baltic Sea coasts in a warmer future?

In a warmer future, there will be more methane production in sediments in coastal areas. Anaerobic oxidation of methane (microbial filter) will potentially increase its efficiency and consume part of the excess of methane. But will that increase be enough? Or will methane be released to the water and potentially the atmosphere? A unique, full-size experiment may bring some answers.

Project information

Project manager
Marcelo Ketzer
Other project members
Mark Dopson, Anders Forsman, Samuel Hylander, Linnaeus University; Satoko Owari, Tokyo University of Marine Science and Technology
Participating organizations
Linnaeus University; Tokyo University of Marine Science and Technology
1 Jan 2023–31 Dee 2025
Environmental science (Department of Biology and Environmental Science, Faculty of Health and Life Sciences)

More about the project

Anaerobic oxidation of methane via sulphate reduction is the main microbial process preventing the seafloor release of large quantities of CH4 from sediment to the water column and potentially the atmosphere. This process, also known as the microbial filter, is controlled by temperature and sulphate concentration in seawater. Climate change will affect the efficiency of this filter by reducing the sulphate concentration and increasing temperature of Baltic Sea waters. The precise effects are still, however, poorly understood. A failure of the microbial filter will potentially be associated with widespread methane release along Baltic Sea coasts amplifying trends in anoxia and climate change.

Here we plan to study the changes in methane production and consumption via sulphate reduction in the sediments and water column of a bay in the Baltic Sea that has been heated (ca. 5- 10°C) by the discharge of the cooling waters of a powerplant for 50 years. We will compare data from this bay (an analogue for the future warmer Baltic Sea) with an adjacent, unaffected bay. We will test the impact of long (50 years) and short (seasonal, daily) term changes in temperature in the formation and consumption of methane and the efficiency of the microbial filter, in addition to changes in microbial communities and metabolic pathways during methanogenesis.

The project is part of: