Constraints on microbial growth and carbon mineralization in marine sediments
Microorganisms are found all around the world facing a broad range of temperature regimes from perennial subzero conditions at the Earth's poles to tropical environments with stable temperatures above 35°C. In the mid-latitudes microorganisms cope with large (~20°C) annual temperature variations. Seemingly regardless of the thermal conditions, microorganisms actively metabolize and thereby drive re-mineralization of organic carbon in the seabed. Re-mineralization should however scale with temperature, as all microbial activity is temperature dependent. How temperature dependent microbial processes in the seabed are, we investigate with the help of long-term temperature exposure experiments.
In these experiments we follow the changes in metabolic rates with temperature over time. As a result we can detect growth as a consequence of increasing rates and determine the temperature dependence of the microbial growth in marine sediments. The understanding of limitations of growth in marine sediments will help us predict how rising temperatures will affect microbial activity and ultimately carbon mineralization in the range of temperature regimes on Earth.