Project Details
Projekt
Subseafloor life and carbon cycling in the Bengal Fan (IODP Exp. 354)
Applicant
Dr. Rishi Ram Adhikari
Subject Area
Palaeontology
Mineralogy, Petrology and Geochemistry
Mineralogy, Petrology and Geochemistry
Term
from 2016 to 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 320209155
This proposal seeks support for post-cruise research of Dr. Rishi Ram Adhikari (PI), who has sailed as shipboard scientist on IODP Expedition 354 (February-March 2015, Singapore-Colombo, Sri Lanka). During the expedition seven sites were drilled across the Bengal Fan along 8°N to study interactions between tectonics, climate change and the global carbon cycle. The expedition provided a much longed-for opportunity to conduct deep biosphere research in the Indian Ocean. High-quality samples were obtained for dedicated deep biosphere research with state-of-the-art techniques aiming to (a) investigate how the size, composition and activity of subseafloor microbial communities in the Bengal Fan are related to long- and short-term changes in sediment flux and OM quality during the evolution of the fan, (b) elucidate relationships between the sources of OM, dissolved organic matter (DOM) quality and metabolic processes in the deep biosphere and (c) reduce the large data gap regarding the deep biosphere in the Indian Ocean. The proposed study will test five hypotheses related to fundamental challenges identified in the IODP Science Plan (ISP) for the period 2013-2023, i.e.: What are the origin, composition, and global significance of subseafloor communities? (Challenge 5), How sensitive are ecosystems and biodiversity to environmental change? (Challenge 7), and What properties and processes govern the flow and storage of carbon in the subseafloor? (Challenge 13). To this end, the project will determine biomass, activity and composition of microbial communities as well as carbon turnover in the deep subseafloor with both cultivation independent methods and laboratory based experiments. Investigations will encompass enumeration of microbial cells and endospores, determination of hydrogenase enzyme activity as proxy for microbial activity, and stable isotopic investigation of organic metabolites. The composition of DOM will be elucidated using 3D fluorescence spectroscopy and microbial community compositions will be characterized using intact polar membrane lipids and DNA. Moreover, selected sediment samples will be incubated with stable isotope labeled (13-C) organic matter to study carbon turnover and storage in the Bengal Fan. The proposed research will be conducted in the Organic Geochemistry Group of Prof. Dr. Kai-Uwe Hinrichs (host and collaborator) at MARUM/University of Bremen and in the laboratory of Dr. Fumio Inagaki (collaborator) at the Kochi Institute for Core Sample Research/JAMSTEC in Japan.
DFG Programme
Infrastructure Priority Programmes
International Connection
Japan
Cooperation Partners
Professor Dr. Kai-Uwe Hinrichs; Dr. Fumio Inagaki
