My PhD thesis focuses on the diversity and functioning of microbial communities associated with an arcto-alpine plant Oxyria digyna, common in pioneer plant communities. O. digyna harbours a diverse and partially plant specific bacterial community, and in our previous study, we identified several bacterial groups potentially involved in nitrogen fixation and cycling in the roots and rhizosphere of O. digyna in Kilpisjärvi, subarctic, and in Longyearbyen, high Arctic.
This goal of this work is to continue this work, and identify potential season specific bacterial communities responsible for nitrogen fixation and cycling associated with Oxyria digyna and their impact on soil and plant nitrogen budgets in the Arctic.
The field work includes four samplings in Isdammen near Longyearbyen. At each sampling, 12 plants root systems, rhizosphere and bulk soils will be harvested and processed. After field season, the samples will be analyzed by molecular methods to identify the overall community dynamics and comm unity members responsible for nitrogen fixation and cycling, and the impact of soil temperature and moisture and plant phenology on them. In addition, nitrogen budget and chemistry in plant tissues and soils will be analyzed.
The field work will be done by PhD student Manoj Kumar (the applicant), working in the group of Academy Researcher Riitta Nissinen at University of Jyväskylä, Finland, and by PhD student Sunil Mundra from the laboratory of Associate Professor Pernille Bronken Eidesen at University Centre of Svalbard, Longyearbyen. The data will be analyzed and published in collaboration between the two groups.