Full Name

Ketil Koop-Jakobsen

My research focus on the spatial and temporal dynamics of chemical gradients in soils and sediments, and their importance for ecosystem functions and services.  

In aquatic ecosystems, many important biogeochemical processes occur below the sediment surface and are controlled by complex interactions between plants, animals, sediment and microbes. These processes are important for the control of essential ecosystem services and functions, such as carbon sequestration, nutrient retention, and greenhouse gas production. Plant traits, such as plant-mediated sediment oxygenation and root exudation, and infauna activities, such as bioturbation and bioirrigation, generate chemical gradients that continuously change in time and space. Inside the sediment, specialized microbial communities often evolve around these gradients, which are found, for example, around roots and burrows. This generates a patchy distribution in abundance, functionality and activity of the microbial community in the sediment, which vary over time in response to diurnal, tidal and seasonal changes. The importance of the spatiotemporal variation for nutrient turnover, carbon storage and GHG emissions may not be captured using conventional analytical methods, and spatiotemporal variation of microbial and chemical processes are often overlooked in aquatic sediments. My research focus on plant and animal traits that alter sediment chemistry and microbial communities in time and space, and aim to elucidate the impact it has on major ecosystem functions such as nutrient turnover, carbon storage and GHG emissions.  

My research specifically targets the small-scale chemical gradients in sediments that build up as a result of the interaction between plants, animals, sediment and microbes. For this purpose, I apply a variety of analytical tools for imaging, profiling and monitoring the accumulation and turnover of essential elements and molecules. The toolbox includes planar- and needle-optode systems for capturing the distribution of O2, pH and CO2, microelectrodes for profiling of O2, N2O, H2S and redox gradients and soil-zymography for determining the spatial orientation of the microbial activity in the sediment. These techniques enable the analysis of rapidly changing small-scale (<mm) gradients in the sediment chemistry.