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- Adhikari, Rishi
Dr. Rishi Adhikari
Archived PageThis web page has not been updated since the former colleague left MARUM. |
Hinrichs Lab
Current project
Subseafloor life and carbon cycling in the Bengal Fan (IODP Exp. 354)
DFG Project AD 511/2-1
Bengal Fan is one of the largest sediment reservoirs in the world which provides a geological record for Himalayan orogeny and tectonics-climate interactions. In order to elucidate the impact of Himalayan orogeny on the global carbon cycle, it is therefore important to understand how the microbial activity of the deep biosphere is intertwined with the preservation or remineralization of sedimentary OM as well as with changes in sediment supply. Variations in organic carbon accumulation rate over geological time scales affect the energy supply of the deep biosphere as well as the amount of CO2 in the atmosphere, and thus climate. In addition, Himalayan orogeny might have shaped the development of the deep biosphere in the Bengal Fan by riverine transport of terrestrial sediments and associated nutrients and microorganisms from the Ganga-Brahmaputra catchment into the Bay of Bengal. [more...]
DFG Project AD 511/2-1
Bengal Fan is one of the largest sediment reservoirs in the world which provides a geological record for Himalayan orogeny and tectonics-climate interactions. In order to elucidate the impact of Himalayan orogeny on the global carbon cycle, it is therefore important to understand how the microbial activity of the deep biosphere is intertwined with the preservation or remineralization of sedimentary OM as well as with changes in sediment supply. Variations in organic carbon accumulation rate over geological time scales affect the energy supply of the deep biosphere as well as the amount of CO2 in the atmosphere, and thus climate. In addition, Himalayan orogeny might have shaped the development of the deep biosphere in the Bengal Fan by riverine transport of terrestrial sediments and associated nutrients and microorganisms from the Ganga-Brahmaputra catchment into the Bay of Bengal. [more...]
Research interest
Subsurface biogeochemical cycling is still largely unknown and needs extensive investigations. Due to the limitation of energy supply/availability in subsurface environments, microbial quantification of extremely low metabolic activity is still a big challenge. My research focuses in microbial activity measurements using radiotracer based hydrogenase enzyme assay. This enzyme facilitates hydrogen metabolism which is the most essential substrate in the deep biosphere. However, a single tool could not be sufficient to explore a dynamic system such as the deep biosphere. Therefore, I apply different approaches (prokaryotic cell and endospore abundances, hydrogen metabolism, intact polar membrane lipids etc.) to understand microbial interactions with a complex geochemical environment.
Career
2016 - 2018 DFG – ‘own position’, MARUM, University of Bremen Bremen, Germany
DFG Project AD 511/2-1 Subseafloor life and carbon cycling in the Bengal Fan (IODP Exp. 354)
2013 - 2016 Postdoc, Organic Geochemistry, MARUM, University of Bremen Bremen, Germany
Funded through Leibniz Prize of Prof. Dr. Kai-Uwe Hinrichs
2008 - 2013 Research Assistant (PhD Student), University of Potsdam, Germany
Funded through BMBF Forschungsverbundvorhaben GeoEn (Grant 03G0671A/B/C)
Quantification of microbial biomass and activity in subsurface sediments (Supervisor: Dr. Jens Kallmeyer)
DFG Project AD 511/2-1 Subseafloor life and carbon cycling in the Bengal Fan (IODP Exp. 354)
2013 - 2016 Postdoc, Organic Geochemistry, MARUM, University of Bremen Bremen, Germany
Funded through Leibniz Prize of Prof. Dr. Kai-Uwe Hinrichs
2008 - 2013 Research Assistant (PhD Student), University of Potsdam, Germany
Funded through BMBF Forschungsverbundvorhaben GeoEn (Grant 03G0671A/B/C)
Quantification of microbial biomass and activity in subsurface sediments (Supervisor: Dr. Jens Kallmeyer)
Seagoing
- 2015 Singapore – Colombo, D/V JOIDES Resolution
IODP Expedition 354 - Neogene and late Paleogene record of Himalayan orogeny and climate: a transect across the Middle Bengal Fan - 2012 Sasebo (Japan) – Ugata (Japan), D/V Chikyu
JAMSTEC Chikyu Expedition 906 - The Kumano Mud-Volcano Drilling II - 2009 Costa Rica – Hawaii, R/V Knorr
Expedition KNR195-III - Equatorial Pacific
Publications
Evans, T.W., Könneke, M., Lipp, J.S., Adhikari, R.R., Taubner, H., Elvert, M., and Hinrichs, K.-U. (2018). Lipid biosynthesis of Nitrosopumilus maritimus dissected by lipid specific radioisotope probing (lipid-RIP) under contrasting ammonium supply. Geochimica et Cosmochimica Acta 242:51-63 DOI: 10.1016/j.gca.2018.09.001
Ijiri, A., Inagaki, F., Kubo, Y., Adhikari, R.R., Hattori, S., Hoshino, T., Imachi, H., Kawagucci, S., Morono, Y., Ohtomo, Y., Ono, S., Sakai, S., Takai, K., Toki, T., Wang, D.T., Yoshinaga, M.Y., Arnold, G.L., Ashi, J., Case, D.H., Feseker, T., Hinrichs, K.U., Ikegawa, Y., Ikehara, M., Kallmeyer, J., Kumagai, H., Lever, M.A., Morita, S., Nakamura, K.I., Nakamura, Y., Nishizawa, M., Orphan, V.J., Roy, H., Schmidt, F., Tani, A., Tanikawa, W., Terada, T., Tomaru, H., Tsuji, T., Tsunogai, U., Yamaguchi, Y.T., and Yoshida, N. (2018). Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex. Science Advances 4 DOI: 10.1126/sciadv.aao4631
Glombitza C., Adhikari R.R., Riedinger N., Gilhooly W.P. III, Hinrichs K.-U. and Inagaki F. (2016) Microbial Sulfate Reduction Potential in Coal-Bearing Sediments Down to ~2.5 km below the Seafloor off Shimokita Peninsula, Japan. Frontiers in Microbiology 7:1576 DOI: 10.3389/fmicb.2016.01576
France-Lanord, C., Spiess, V., Klaus, A., Schwenk, T., and the Expedition 354 Scientists (2016). Bengal Fan. Proceedings of the International Ocean Discovery Program, 354: College Station, TX (International Ocean Discovery Program) DOI: 10.14379/iodp.proc.354.2016
Adhikari, R.R., Glombitza, C., Nickel, J.C., Anderson, C.H., Dunlea, A.G., Spivack, A.J., Murray, R.W., D'Hondt, S. and Kallmeyer, J. (2016) Hydrogen Utilization Potential in Subsurface Sediments. Frontiers in Microbiology 7:8 DOI: 10.3389/fmicb.2016.00008
France-Lanord, C., Spiess, V., Klaus, A., and the Expedition 354 Scientists (2015) Neogene and late Paleogene record of Himalayan orogeny and climate: a transect across the Middle Bengal Fan. International Ocean Discovery Program Expedition 354 Preliminary Report DOI: 10.14379/iodp.pr.354.2015
Kallmeyer, J., Pockalny, R., Adhikari, R.R., Smith D.C., D’Hondt, S. (2012) Global distribution of microbial abundance and biomass in subseafloor sediment. Proceedings of the National Academy of Sciences (PNAS) 109, 40, 16213-16216 DOI: 10.1073/pnas.1203849109
Røy, H., Kallmeyer, J., Adhikari, R.R., Pockalny, R., Jørgensen, B.B., D’Hondt, S. (2012) Aerobic Microbial Respiration in 86-Million-Year-Old Deep-Sea Red Clay. Science 336, 6083, 922-925 DOI: 10.1126/science.1219424
Adhikari, R.R., Kallmeyer, J. (2010) Detection and quantification of microbial activity in the subsurface. Chemie der Erde - Geochemistry 70, 135 DOI: 10.1016/j.chemer.2010.05.003
Conference / Meeting Contributions
Adhikari, R.R., Heuer, V., Hinrichs, K.-W., France-Lanord, C., Spieß, V., Schwenk, T., Klaus, A. and the Expedition 354 Scientists (2016). Deep Biosphere in Bengal Fan Sediments (IODP Expedition 354). Abstract presented at IODP/ICDP Colloquium Heidelberg, Germany
Adhikari, R.R. (2015). Hydrogenase enzyme activity in deep coalbed off Shimokita. The Second Post-cruise Meeting of the Integrated Ocean Drilling Program (IODP) Expedition 337, April 11-15, at National sun Yat-Sen University, Kaohsiung, Taiwan
Adhikari, R.R., Nickel, J., Glombitza, C., Spivack, A.J., D'Hondt, S. L., Kallmeyer, J., (2013). Distribution and activity of hydrogenase enzymes in subsurface sediments. Abstract B23G-07, AGU Fall Meeting, San Francisco, California
Adhikari, R.R., Nickel, J., Kallmeyer, J., (2012). Quantifying microbial activity in deep subsurface sediments using a tritium based hydrognease enzyme assay. Abstract B43G-0485, AGU Fall Meeting, AGU, San Francisco, California
Kallmeyer, J., Pockalny, R.A., Adhikari, R.R., Smith D.C., D’Hondt, S.L., (2012). Global Distribution of Microbial Abundance and Biomass in Subseafloor Sediment. Abstract B42C-01, AGU Fall Meeting, San Francisco, California
Adhikari, R.R., Nickel, J., Kallmeyer, J., (2012). Quantification of microbial activity in subsurface environments using a hydrogenase enzyme assay. Geophysical Research Abstracts[nbsp] Vol. 14, EGU2012-7959, EGU General Assembly, Vienna
Adhikari, R.R., Kallmeyer, J., (2011). Hydrogenase enzyme assay for the quantification of microbial activity in subsurface environments. Mineralogical Magazine, Volume 75, Number 3, 408, Goldschmidt Conference Abstracts, Prague
Røy, H., Kallmeyer, J., Adhikari, R.R., Gribsholt, B., Jørgensen, B.B., D’Hondt, S., (2011). Aerobic microbial respiration in ancient oxic sediments below the Subtropical Gyres. Geophysical Research Abstracts Vol. 13, EGU2011-8714, EGU General Assembly, Vienna
Adhikari, R.R., Kallmeyer J., (2011). Hydrogenase enzyme assay: a promising technique for the quantification of microbial activity in subsurface environment. IODP/ICDP Workshop on Geological Carbon Capture & Storage, Oman
Adhikari, R.R., Kallmeyer J., (2010). Hydrogenase enzyme assay: a promising technique for the quantification of microbial activity in subsurface environment. International GeoEn Meeting, Potsdam
Kallmeyer, J., Pockalny, R.A., D’Hondt, S.L., Adhikari, R.R., (2009). A New Estimate of Total Microbial Subseafloor Biomass, Eos Trans. AGU, 90(52), Fall Meet. Suppl., Abstract B23C-0381, California
Adhikari, R.R. (2015). Hydrogenase enzyme activity in deep coalbed off Shimokita. The Second Post-cruise Meeting of the Integrated Ocean Drilling Program (IODP) Expedition 337, April 11-15, at National sun Yat-Sen University, Kaohsiung, Taiwan
Adhikari, R.R., Nickel, J., Glombitza, C., Spivack, A.J., D'Hondt, S. L., Kallmeyer, J., (2013). Distribution and activity of hydrogenase enzymes in subsurface sediments. Abstract B23G-07, AGU Fall Meeting, San Francisco, California
Adhikari, R.R., Nickel, J., Kallmeyer, J., (2012). Quantifying microbial activity in deep subsurface sediments using a tritium based hydrognease enzyme assay. Abstract B43G-0485, AGU Fall Meeting, AGU, San Francisco, California
Kallmeyer, J., Pockalny, R.A., Adhikari, R.R., Smith D.C., D’Hondt, S.L., (2012). Global Distribution of Microbial Abundance and Biomass in Subseafloor Sediment. Abstract B42C-01, AGU Fall Meeting, San Francisco, California
Adhikari, R.R., Nickel, J., Kallmeyer, J., (2012). Quantification of microbial activity in subsurface environments using a hydrogenase enzyme assay. Geophysical Research Abstracts[nbsp] Vol. 14, EGU2012-7959, EGU General Assembly, Vienna
Adhikari, R.R., Kallmeyer, J., (2011). Hydrogenase enzyme assay for the quantification of microbial activity in subsurface environments. Mineralogical Magazine, Volume 75, Number 3, 408, Goldschmidt Conference Abstracts, Prague
Røy, H., Kallmeyer, J., Adhikari, R.R., Gribsholt, B., Jørgensen, B.B., D’Hondt, S., (2011). Aerobic microbial respiration in ancient oxic sediments below the Subtropical Gyres. Geophysical Research Abstracts Vol. 13, EGU2011-8714, EGU General Assembly, Vienna
Adhikari, R.R., Kallmeyer J., (2011). Hydrogenase enzyme assay: a promising technique for the quantification of microbial activity in subsurface environment. IODP/ICDP Workshop on Geological Carbon Capture & Storage, Oman
Adhikari, R.R., Kallmeyer J., (2010). Hydrogenase enzyme assay: a promising technique for the quantification of microbial activity in subsurface environment. International GeoEn Meeting, Potsdam
Kallmeyer, J., Pockalny, R.A., D’Hondt, S.L., Adhikari, R.R., (2009). A New Estimate of Total Microbial Subseafloor Biomass, Eos Trans. AGU, 90(52), Fall Meet. Suppl., Abstract B23C-0381, California