Dr. Christian Hansen

Research

until 2023 / currently as a consultant:

Investigating the seafloor as a reactor (Ocean Floor Cluster of Excellence - MARUM)

The seafloor represents the key interface between the oceans and the ocean crust. Driven by steep geothermal gradients, major geochemical mass and heat transfer occurs as seawater circulates through the crust and participates in metasomatic water-rock reactions. Abundant heat, reduced chemicals and reworked carbon substrate fuel unique biological communities at hydrothermal vents, an environment considered a likely contender for the origin of life on earth. But the impact of this seafloor reactor on the global carbon cycle, the global climate, the long-term evolution of ocean chemistry and the diversity of life is still poorly constraint, let alone properly quantified. In an integrated approach, we will use samples and data acquired from natural systems and experiments conducted under precisely controlled conditions as well as coupled thermodynamic-kinetic models to further elucidate these processes.

The emphasis in this project lies on using batch and flow-through experiments to investigate a variety of different processes that occur within marine hydrothermal systems. (Hydrothermal Lab)

Publications (peer-reviewed journals)

Victoria K, Hansen CT, Strauss H, Wu S, Bach W (2023): Experimental evidence for the hydrothermal formation of native sulfur by synproportionation. Frontiers in Earth Science Geochemistry, 11, 1–13.
| doi:10.3389/feart.2023.1132794 |

Hansen CT, Kleint C, Böhnke S, Klose L, Adam‐Beyer N, Sass K, Zitoun R, Sander SG, Indenbirken D, Dittmar T, Koschinsky A, Perner M (2022): Impact of high Fe‐concentrations on microbial community structure and dissolved organics in hydrothermal plumes: an experimental study. Scientific Reports12:20723.
| doi:10.1038/s41598-022-25320-0 |

Wilckens FK, Hansen CT, Diehl A, Bach W, Kasemann SA (2022): Sources of Mg enrichments in Vent Fluids from the Kermadec Arc recorded by Li, B and Mg Isotopes. Geochemistry, Geophysics, Geosystems23(11), e2022GC010471.
| doi:10.1029/2022GC010471 |

Hansen CT, Lissenberg CJ, Kahl W-A, Bach W (2022): Hydrothermal troctolite alteration at 300 and 400°C – Insights from flexible Au-reaction cell batch experimental investigations. American Mineralogist107, 1100-1115.
| doi:10.2138/am-2021-7832 |

Albers E, Shervais JW, Hansen CT, Ichiyama Y, Fryer P (2022): Shallow depth, substantial change: fluid-metasomatism causes major compositional modifications of subducted volcanics (Mariana forearc). Frontiers in Earth Science - Petrology10:826312.
| doi:10.3389/feart.2022.826312 |

Dede B, Hansen CT, Neuholz R, Schnetger B, Kleint C, Walke S, Bach W, Amann R, Meyerdierks A (2022): Niche differentiation of sulfur-oxidizing bacteria (SUP05) in submarine hydrothermal plumes. ISME Journal.
| doi:10.1038/s41396-022-01195-x |

Song M, Schubotz F, Kellermann MY, Hansen CT, Bach W, Teske AP, Hinrichs K-U (2021): Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments. PNAS118(47), e2005219118.
| doi:10.1073/pnas.2005219118 |

Geilert S, Albers E, Frick DA, Hansen CT, von Blankenburg F (2021): Systematic changes in serpentine Si isotope signatures across the Mariana forearc – a new proxy for slab dehydration processes. Earth and Planetary Science Letters575, 117193.
| doi:10.1016/j.epsl.2021.117193 |

Noowong, A., Gomez-Saez, G. V., Hansen, C.T., Schwarz-Schampera, U., Koschinsky, A., and Dittmar, T. (2021): Imprint of Kairei and Pelagia deep-sea hydrothermal systems (Indian Ocean) on marine dissolved organic matter. Organic Geochemistry, 152, 104141.
| doi: 10.1016/j.orggeochem.2020.104141  |

Merder, J., Freund, J.A., Feudel, U., Hansen, C.T., Hawkes, J.A., Jacob, B., Klaproth, K., Niggemann, J., Noriega-Ortega, B.E., Osterholz, H., and others (2020): ICBM-OCEAN: Processing Ultrahigh-Resolution Mass Spectrometry Data of Complex Molecular Mixtures. Analytical Chemistry, 92, 6832–6838.
| doi: 10.1021/acs.analchem.9b05659  |

Hansen CT, Niggemann J, Simon M, Bach W, Dittmar T (2019): The biodegradability of hydrothermally altered deep-sea dissolved organic matter. Marine Chemistry, 217.
| doi: 10.1016/j.marchem.2019.103706 |

Hansen CT, Meixner A, Kasemann SA, Bach W (2017): New insight on Li and B isotope fractionation during serpentinization derived from batch reaction investigations, Geochimica et Cosmochimica Acta, 217, 51-79.
| doi:10.1016/j.gca.2017.08.014 |

Kahl W.-A., Hansen C, Bach W (2016): A new X-ray-transparent flow-through reaction cell for a µ-CT-based concomitant surveillance of the reaction progress of hydrothermal mineral-fluid interactions, Solid Earth, 7, 651-658.
| doi: 10.1016/j.gca.2015.11.025 |

Hawkes JA, Hansen CT, Goldhammer T, Bach W, Dittmar T (2016): Molecular alteration of marine dissolved organic matter under experimental hydrothermal conditions, Geochimica et Cosmochimica Acta, 175, 68-85.
| doi: 10.1016/j.gca.2015.11.025 |

Hawkes JA, Rossel PE, Stubbins A, Butterfield D, Connely DP, Achterberg EP, Koschinsky A, Chavagnac V, Hansen CT, Bach W, Dittmer T (2015): Efficient removal of recalcitrant deep-ocean dissolved organic matter during hydrothermal circulation. Nature Geoscience, 8, 856-860.
| doi:10.1038/ngeo2543 |

Kiel S, Hansen C, Nitzsche KN, Hansen BT (2014): Using ⁸⁷Sr/⁸⁶Sr ratios to date fossil methane seep deposits: Methodological requirements and an example from the Great Valley Group, California. J. Geol., 122(4), 353-366.
| doi:10.1086/676594 |

Brandmeier M, Erasmi S, Hansen C, Höweling A, Nitzsche K, Ohlendorf T, Mamani M, Wörner G (2013): Mapping patterns of mineral alteration in volcanic terrains using ASTER data and field spectrometry in Southern Peru. J. South Am. Earth Sci., 48, 296-314.
| doi:10.1016/j.jsames.2013.09.011 |

Conference contributions

Hansen CT, Kleint C, Böhnke S, Klose L, Adam N, Sass K, Perner M, Dittmar T and Koschinsky A (2021): The impact of variable Fe concentrations on Fe-binding ligands, dissolved organics and microbial communities in hydrothermal plumes – an experimental study. GeoKarlsruhe 2021, Karlsruhe.

Hansen CT, Schlicht LEM, Reeves EP, Meixner A, Kasemann SA, Bach W (2019): Boron isotope behavior in ultramafic hosted hydrothermal systems: Nature vs. Experiment. Goldschmidt-Conference 2019, Barcelona, Spain.

Hansen CT, Noriega-Ortega BE, Niggemann J, Simon M, Bach W, Dittmar T (2018): The biodegradability of hydrothermally altered deep-sea dissolved organic matter. Ocean Science Meeting 2018, Portland, Oregon.

Hansen C, Meixner A, Kasemann S, Bach W (2015): New insight on lithium and boron isotope fractionation during serpentinization derived from batch reaction investigations. Goldschmidt-Conference 2015, Prague, Czech Republic.

Hansen C, Meixner A, Kasemann S, Bach W (2014): New insight on lithium and boron isotope fractionation during serpentinization derived from batch reaction investigations. DMG-Meeting 2014, Jena, Deutschland.