Applicant

Dr. Karen Krüger
Universität Bremen
Fachbereich 02 - Biologie und Chemie
Arbeitsgruppe Mikrobielle Ökophysiologie
Leobener Straße 
28359 Bremen

Project description

The effects of climate change in the Antarctic strongly impact the biogeochemical cycling of elements in coastal sediments. Increased glacial ice melting supplies large amounts of suspended minerals into sediments, which affects the underlying microbial-driven processes and their communities. The microbial community in marine coastal surface sediments drives two key processes: sulfate reduction and metal oxide reduction. These processes are essential for completing the final stages of organic matter oxidation to CO2 within the sediments. Several bacterial groups assumed to be involved in dissimilatory iron and sulfate reduction have been detected in polar coastal sediments through 16S ribosomal RNA analysis, as well as enrichment and stable isotope probing experiments. Among these clades is the Sva1033 clade from the Desulfuromonadales, identified as a keystone species for iron reduction through near in situ analysis of this key biogeochemical process. Temperature gradient experiments clearly showed the plasticity and resilience of the Sva1033 clade over a wide temperature spectrum. Despite their crucial role in these ecosystems, the genetic characteristics of Sva1033 and other keystone species remain to be fully understood. Overall, Antarctic genetic data of the microbial community remains underrepresented in public databases and we know little detail about the gene repertoire and individual function of keystone guilds and species. In the planned project, we aim to address these gaps by 16S amplicon, metagenome-assembled genome and metagenome data mining to identify keystone microorganisms in Antarctic marine sediments and elucidate their essential functions. Data mining is the extraction of knowledge from large datasets that helps to answer specific research questions. It is used to find associations, patterns or trends. This project aims to: 1) identify keystone microbial species in Antarctic coastal sediments using network analysis, 2) investigate the genetic repertoire of these keystone species to understand their eco-physiological roles and distribution in Antarctic coastal sediments through data mining, and 3) compare the phylogeny and genetic repertoire of key clades from Antarctic sediments with those from other polar regions. In the light of future changes, it is essential to understand the current functions of keystone microorganisms to gain insights into the biodiversity, the resilience of these microbial communities to environmental change, and their genetic connectiveness to other polar regions. Such information is urgently needed as we want to predict possible future responses of the microbial community to anticipated environmental change.

DFG Programme Infrastructure Priority Programmes

Term since 2026