Biogeochemistry & Ecosystem Functioning
Work package 3
Lead Investigator: Prof Mark Trimmer
Lead Postdoctoral Researcher: Dr Sarah Harpenslager
Carbon and nitrogen are two core “building blocks” of all living organisms, including humans, plants and microbes. Both elements are constantly being cycled between sea, land, atmosphere and living organisms, mainly by microbial activity. This constant cycling can be seen as the flow of energy and resources through an ecosystem.
Groups of microbes specialise in different parts of the carbon or nitrogen cycles, and much of their activity depends strongly on temperature. The rate with which a microbe will perform its reactions varies with temperature, but while many will increase strongly, other rates may change only slightly or not at all. In other words, some processes are more temperature sensitive than others and this can create “imbalances” and inefficiencies in energy flux through the ecosystem.
Although individual responses of organisms and a few separate components of nutrient cycles to warming have already been studied, knowledge of the impact on multiple ecosystem processes is lacking. Our aim is to understand how the cycling of the most important elements of life, carbon and nitrogen, changes with temperature. To mimic the effects of long-term warming, we study these processes in our geothermally heated streams, outdoor experiments in pond mesocosms and also via lab experiments in microcosms – where there are close links to the other Work Packages.
This project will not only improve our understanding of temperature responses, but seeing as the terminal step both carbon and nitrogen cycle produces important greenhouse gasses (carbon dioxide, methane and nitrous oxide), will also give valuable information on potentially dangerous feedbacks with climate change.