Dr. Christian Mohr

Contact

University of  Potsdam,
Institute of Earth and Environmental Science

Dr. Christian Mohr
Building 1, Room 1.20

Karl-Liebknecht-Str. 24-25
14476 Potsdam-Golm
E-mail:
cmohr@uni-potsdam.de
Phone:
+49 331 977 5875
Fax:
+49 331 977 2092
Dr. Christian Mohr

 

  • Biography
  • Research
  • Teaching
  • Publications

Biography

1999 - 2007
Studies of Geography, Soil Scienes and Geology at the Universities of Cologne and Bonn
2008-
PhD-student at the University of Potsdam, Hydrology and Climatology Research Group
2012
Scolar at Department of Earth and Planetary Science at University of California, Berkeley
2013-
Research fellow, Geohazards Research Group

Research

Disturbance Ecogeomorphology and Hydrology

  • Soil Erosion and Forestry
  • Sediment and Organic Carbon Fluxes
  • Earthquake Hydrology
  • Post-eruptive hillslopes

Dendro Seismology (Wood Anatomy, and Stabile Isotopes)

Teaching

Interested in how high magnitude earthquakes modulate the hydrological cycle?

Master Thesis Project: Recovery of hydraulic permeability after large subduction earthquakes

The impressive number of stream gauges in Chile, combined with a suite of past and recent large earthquakes, make Chile an ideal natural laboratory to study streams that recorded responses to multiple seismic events. Recently, we documented changes in discharge in streams in Chile following two or more large earthquakes. In all cases discharge increases. The underlying mechanism, however, are still subject of an ongoing controversial debate. Competing mechanisms comprise static stress, compaction of saturated layers, the release of soil water, or enhanced hydraulic permeability due to seismic shaking. While all hypotheses may hold true under certain conditions, the results are always the same: Stream discharge increases due to enhanced subsurface flow. Our recent results suggest a complete recovery of hydraulic permeability during one seismic cycle, i.e. here ~ 25 years for earthquakes >8M.

This Master theses will explore the time scales in which permeability recovery occurs in one of the seismically most active regions worldwide. We will take advantage of extraordinarily long records (1940-today) of daily streamflow discharge along the steep topographic and climatic gradients of Chile, and in highly differing geologies. These records allow us to estimate recovery of (seismically enhanced?) permeability over time during seismic cycles. This master project comprises time series analysis and model testing using a self-developed 1D ground water flow model. Start is as soon as possible.

 

Interested in how plants respond to volcanic eruptions?

Master thesis project: Disturbance ecology: Plant ecologic response to recent tephra fall

Large explosive eruptions can bury landscapes beneath thick layers of tephra such that rivers subsequently overload with excess pyroclastic sediments. Much less is known about how hillslopes respond to tephra loads. Our recent work points to a distinctly delayed increase in landslide activity following the recent eruption of Chaitén volcano, Chile. Landslides began to denude densely forested hillslopes three to six years after being covered by tephra in the 2008 eruption. This lagged slope instability is consistent with a gradual loss of shear strength of decaying tree roots in areas of high tephra loads known from forestry studies.

In Feb-March 2018, we acquired tephra samples along the Chaitén volcano hillslopes aiming to explore root growth modulated under recent tephra cover. We are going to apply tephra layers of typical grain size distributions and varying thickness in plant experiments while all other hydro-climatic controls are held constant at the same time. To this end we follow a two-step approach. First, we grow lupines and weigh their total root biomass under different applications of tephra (grain size, thickness, time steps). Anticipating positive results, we next grow lupines in rhizotrons and use state-of-the-art non-invasive optical imaging techniques (cooperation with Dr. Nicole Rudolph-Mohr and Prof. Dr. Sascha Oswald).  Oxygen is essential for several important cellular physiological processes and root oxygen uptake is correlated with root growth. Because of the extremely high ratio between gaseous and aqueous O2 diffusion coefficients, the soil O2 diffusion rate is a strong function of the air content, tortuosity, and continuity of the gas phase. Optical imaging using planar optodes is sensitive to oxygen chances and able to measure oxygen concentrations in soil over several weeks. Hence, this setup is promising to investigate plant growth response to tephra stress, which in turn finally allows us to independently test eco-geomorphic hillslope models in volcanically disturbed areas on a small spatial scale.

This master thesis will comprise experimental work in the lab, (statistical) data analysis and state-of-the-art optical imaging. Start is as soon as possible.

Interested? Contact either cmohr@uni-potsdam and/or nrudolph@uni-potsdam.de

 

 

Further Bachelor and Master theses available covering the following topics:

  • Sediment Fluxes in Micro Catchments
  • Dendro Seismology (Wood Anatomy and Stabile Isotopes)
  • Earthquake Hydrology
  • Eco-Geomorphology

Publications

Peer reviewed

Mohr, C.H.,Manga, M., and Wald, D. (accepted): Stronger peak ground motion, beyond the threshold to initiate a response, does not lead to larger stream discharge responses to earthquakes. Geophysical Research Letters.

Mohr, C.H., Korup, O., Ulloa, H., and Iroumé, A. (2017): Pyroclastic eruption boosts organic carbon fluxes into Patagonian fjords. Global Biogeochemical Cycles, 31, doi:10.1002/2017GB005647. 

Mirus, B., Ebel, B., Mohr, C.H., and Zegre, N. (accepted): Disturbance Hydrology: Preparing for an Increasingly Disturbed Future. Water Resources Research, doi:10.1002/2017WR021084.

Mohr, C.H., M. Manga, C.-Y. Wang, and Korup , O. (2016): Regional changes in streamflow after a megathrust earthquake. Earth and Planetary Science Letters, 458, 418-428, doi:10.1016/j.epsl.2016.11.013.

Ulloa, H., A. Iroumé, L. Picco, C.H. Mohr, B. Mazzorana, L. Lenzi, and Mao , L. (2016): Spatial analysis of the impacts of the Chaitén volcano eruption (Chile) in three fluvial systems. Journal of South American Earth Sciences, 69, 213-225, doi:10.1016/j.jsames.2016.04.008.

Mohr, C.H., M. Manga, C.-Y. Wang, J.W. Kirchner, and Bronstert , A. (2015): Shaking water out of soils. Geology, 43, 207-210, doi:10.1130/G36261.1.

Mohr, C.H., A. Zimmermann, O. Korup, A. Iroumé, T. Francke, and Bronstert , A. (2014): Seasonal logging, process response, and geomorphic work. Earth Surface Dynamics, 2, 117-125, doi:10.5194/esurf-2-117-2014.

Mohr, C. H., R. Coppus, A. Iroumé, A., A. Huber and Bronstert, A. (2013): Runoff generation and soil erosion processes after clear cutting, Journal of Geophysical Research – Earth Surface, 118, 1 – 18, doi:10.1002/jgrf.20047.

Mohr, C. H., D.R. Montgomery, A. Huber, A. Bronstert and Iroumé, A. (2012): Streamflow response in small upland catchments in the Chilean Coastal Range to the 8.8MW Maule Earthquake on February 27 2010, Journal of Geophysical Research – Earth Surface, 117, F02032, doi:10.1029/2011JF002138.

Huber, A., Iroumé, A., Mohr, C. H., Frene, C. (2010): The effect of Pinus radiata and Eucalyptus globulus plantations on water resource in the Coastal Range of Bió-Bío region, Chile, Bosque 31 (3):219-230.

 

Other publications

Mohr, C. H., Huber, A. and Bronstert, A. (2010): Einfluss unterschiedlicher forstwirtschaftlicher Praktiken auf die Abflussbildung und die Bodenerosion in experimentellen Einzugsgebieten in Südchile, Hydrologie und Wasserbewirtschaftung, 29 (10): 235-243.

 

Conferences and presentations

Mohr, C. H. , Zimmermann, A., Korup, O., Iroumé, A., Francke, T. and Bronstert, A., (2013): Seasonal Logging, Process Response, and Geomorphic Work. Oral presentation at AGU Fall Meeting 2013, San Francisco.

Mohr, C. H. , Iroumé, A., Bronstert, A. and Huber, A., (2012): Runoff generation and soil erosion processes after clear-cuttings. Oral presentation at AGU Fall Meeting 2012, San Francisco (http://fallmeeting.agu.org/2012/events/ep52c-human-influences-on-hydroecogeomorphic-processes-across-spatial-scales-in-forested-landscapes-ii-video-on-demand).

Mohr, C. H., Manga, M. and Wang, C.Y. (2012): Intensified plant activity following the 2010 M8.8 Maule Earthquake. Poster presentation at AGU Fall Meeting 2012, San Francisco.

Mohr, C. H. (2012): Streamflow response to the Maule M8.8 earthquake in small upland catchments of the Chilean Coastal Range. Invited talk at the USGS, Menlo Park, CA, in Water Resources Discipline Research Seminar (http://wwwrcamnl.wr.usgs.gov/wrdseminar/playwrd.htm?id=06sep2012).

Mohr, C. H. and Wang, C.Y. (2011): Streamflow response to the 2010 M8.8 Maule Earthquake. Poster presentation at AGU Fall Meeting 2011, San Francisco.

Mohr, C. H., Huber, A. and Bronstert, A. (2011): The effect of large scale clear cutting on infiltration conditions in experimental upland catchments in the Chilean Coastal Range, Bío-Bío Region. Poster presentation at EGU Assembly 2011, Vienna.

Mohr, C. H., Huber, A., Bronstert, A and Iroumé, A. (2011): Hydrological Response to the Earthquake of 27 February 2010 in small Upland Catchments in the Chilean Coastal Range, Bío-Bío Region. Poster presentation at EGU Assembly 2011, Vienna.

Mohr, C. H., Huber, A., Bronstert, A. and Iroumé, A. (2010): Hydrological Response to the Earthquake of 27 February 2010 in experimental catchments of the Cordillera de la Costa, Bío-Bío Region, Chile. Poster presentation at AGU Fall Meeting 2010, San Francisco.

Mohr, C. H., Bronstert, A., Huber, A. and Iroumé, A. (2010): Influence of different forest management practices and vegetation cover on runoff generation and sediment flux in the Coastal Range of Southern Chile. Poster presentation at EGU Assembly 2010, Vienna.

Mohr, C. H. and Huber, A. (2010): Design and application of a dript-type rainfall simulator adapted to steep topography and low intensity-rainfall characteristics in the Coastal Range of Southern Chile. Oral presentation at EGU Assembly 2010, Vienna. 

Mohr, C. H., Bronstert, A. and Huber, A. (2010): Einfluss unterschiedlicher forstwirtschaftlicher Praktiken auf die Abflussbildung und die Bodenerosion in Südchile. Oral presentation at Tag der Hydrologie 2010, Braunschweig.


PhD thesis

Mohr, C. H.  (2014): Hydrological and erosion responses to man-made and natural disturbances - Insights from forested catchments in south-central Chile.

 

Media

Earth Magazine   (2015): Soils may supply surging streams after earthquakes (http://www.earthmagazine.org/article/soil-may-supply-surging-streams-after-earthquakes).

Earth Magazine   (2012): Clarifying earthquake-driven hydrologic changes (http://www.earthmagazine.org).

EOS  Trans. AGU, 93(34)  (2012): Research Spotlight - Balcerak, E. (2012), Streamflow changes following the 2010 Chile earchquake. Clarifying earthquake-driven hydrologic changes (http://www.earthmagazine.org).

Biography

1999 - 2007
Studies of Geography, Soil Scienes and Geology at the Universities of Cologne and Bonn
2008-
PhD-student at the University of Potsdam, Hydrology and Climatology Research Group
2012
Scolar at Department of Earth and Planetary Science at University of California, Berkeley
2013-
Research fellow, Geohazards Research Group

Research

Disturbance Ecogeomorphology and Hydrology

  • Soil Erosion and Forestry
  • Sediment and Organic Carbon Fluxes
  • Earthquake Hydrology
  • Post-eruptive hillslopes

Dendro Seismology (Wood Anatomy, and Stabile Isotopes)

Teaching

Interested in how high magnitude earthquakes modulate the hydrological cycle?

Master Thesis Project: Recovery of hydraulic permeability after large subduction earthquakes

The impressive number of stream gauges in Chile, combined with a suite of past and recent large earthquakes, make Chile an ideal natural laboratory to study streams that recorded responses to multiple seismic events. Recently, we documented changes in discharge in streams in Chile following two or more large earthquakes. In all cases discharge increases. The underlying mechanism, however, are still subject of an ongoing controversial debate. Competing mechanisms comprise static stress, compaction of saturated layers, the release of soil water, or enhanced hydraulic permeability due to seismic shaking. While all hypotheses may hold true under certain conditions, the results are always the same: Stream discharge increases due to enhanced subsurface flow. Our recent results suggest a complete recovery of hydraulic permeability during one seismic cycle, i.e. here ~ 25 years for earthquakes >8M.

This Master theses will explore the time scales in which permeability recovery occurs in one of the seismically most active regions worldwide. We will take advantage of extraordinarily long records (1940-today) of daily streamflow discharge along the steep topographic and climatic gradients of Chile, and in highly differing geologies. These records allow us to estimate recovery of (seismically enhanced?) permeability over time during seismic cycles. This master project comprises time series analysis and model testing using a self-developed 1D ground water flow model. Start is as soon as possible.

 

Interested in how plants respond to volcanic eruptions?

Master thesis project: Disturbance ecology: Plant ecologic response to recent tephra fall

Large explosive eruptions can bury landscapes beneath thick layers of tephra such that rivers subsequently overload with excess pyroclastic sediments. Much less is known about how hillslopes respond to tephra loads. Our recent work points to a distinctly delayed increase in landslide activity following the recent eruption of Chaitén volcano, Chile. Landslides began to denude densely forested hillslopes three to six years after being covered by tephra in the 2008 eruption. This lagged slope instability is consistent with a gradual loss of shear strength of decaying tree roots in areas of high tephra loads known from forestry studies.

In Feb-March 2018, we acquired tephra samples along the Chaitén volcano hillslopes aiming to explore root growth modulated under recent tephra cover. We are going to apply tephra layers of typical grain size distributions and varying thickness in plant experiments while all other hydro-climatic controls are held constant at the same time. To this end we follow a two-step approach. First, we grow lupines and weigh their total root biomass under different applications of tephra (grain size, thickness, time steps). Anticipating positive results, we next grow lupines in rhizotrons and use state-of-the-art non-invasive optical imaging techniques (cooperation with Dr. Nicole Rudolph-Mohr and Prof. Dr. Sascha Oswald).  Oxygen is essential for several important cellular physiological processes and root oxygen uptake is correlated with root growth. Because of the extremely high ratio between gaseous and aqueous O2 diffusion coefficients, the soil O2 diffusion rate is a strong function of the air content, tortuosity, and continuity of the gas phase. Optical imaging using planar optodes is sensitive to oxygen chances and able to measure oxygen concentrations in soil over several weeks. Hence, this setup is promising to investigate plant growth response to tephra stress, which in turn finally allows us to independently test eco-geomorphic hillslope models in volcanically disturbed areas on a small spatial scale.

This master thesis will comprise experimental work in the lab, (statistical) data analysis and state-of-the-art optical imaging. Start is as soon as possible.

Interested? Contact either cmohr@uni-potsdam and/or nrudolph@uni-potsdam.de

 

 

Further Bachelor and Master theses available covering the following topics:

  • Sediment Fluxes in Micro Catchments
  • Dendro Seismology (Wood Anatomy and Stabile Isotopes)
  • Earthquake Hydrology
  • Eco-Geomorphology

Publications

Peer reviewed

Mohr, C.H.,Manga, M., and Wald, D. (accepted): Stronger peak ground motion, beyond the threshold to initiate a response, does not lead to larger stream discharge responses to earthquakes. Geophysical Research Letters.

Mohr, C.H., Korup, O., Ulloa, H., and Iroumé, A. (2017): Pyroclastic eruption boosts organic carbon fluxes into Patagonian fjords. Global Biogeochemical Cycles, 31, doi:10.1002/2017GB005647. 

Mirus, B., Ebel, B., Mohr, C.H., and Zegre, N. (accepted): Disturbance Hydrology: Preparing for an Increasingly Disturbed Future. Water Resources Research, doi:10.1002/2017WR021084.

Mohr, C.H., M. Manga, C.-Y. Wang, and Korup , O. (2016): Regional changes in streamflow after a megathrust earthquake. Earth and Planetary Science Letters, 458, 418-428, doi:10.1016/j.epsl.2016.11.013.

Ulloa, H., A. Iroumé, L. Picco, C.H. Mohr, B. Mazzorana, L. Lenzi, and Mao , L. (2016): Spatial analysis of the impacts of the Chaitén volcano eruption (Chile) in three fluvial systems. Journal of South American Earth Sciences, 69, 213-225, doi:10.1016/j.jsames.2016.04.008.

Mohr, C.H., M. Manga, C.-Y. Wang, J.W. Kirchner, and Bronstert , A. (2015): Shaking water out of soils. Geology, 43, 207-210, doi:10.1130/G36261.1.

Mohr, C.H., A. Zimmermann, O. Korup, A. Iroumé, T. Francke, and Bronstert , A. (2014): Seasonal logging, process response, and geomorphic work. Earth Surface Dynamics, 2, 117-125, doi:10.5194/esurf-2-117-2014.

Mohr, C. H., R. Coppus, A. Iroumé, A., A. Huber and Bronstert, A. (2013): Runoff generation and soil erosion processes after clear cutting, Journal of Geophysical Research – Earth Surface, 118, 1 – 18, doi:10.1002/jgrf.20047.

Mohr, C. H., D.R. Montgomery, A. Huber, A. Bronstert and Iroumé, A. (2012): Streamflow response in small upland catchments in the Chilean Coastal Range to the 8.8MW Maule Earthquake on February 27 2010, Journal of Geophysical Research – Earth Surface, 117, F02032, doi:10.1029/2011JF002138.

Huber, A., Iroumé, A., Mohr, C. H., Frene, C. (2010): The effect of Pinus radiata and Eucalyptus globulus plantations on water resource in the Coastal Range of Bió-Bío region, Chile, Bosque 31 (3):219-230.

 

Other publications

Mohr, C. H., Huber, A. and Bronstert, A. (2010): Einfluss unterschiedlicher forstwirtschaftlicher Praktiken auf die Abflussbildung und die Bodenerosion in experimentellen Einzugsgebieten in Südchile, Hydrologie und Wasserbewirtschaftung, 29 (10): 235-243.

 

Conferences and presentations

Mohr, C. H. , Zimmermann, A., Korup, O., Iroumé, A., Francke, T. and Bronstert, A., (2013): Seasonal Logging, Process Response, and Geomorphic Work. Oral presentation at AGU Fall Meeting 2013, San Francisco.

Mohr, C. H. , Iroumé, A., Bronstert, A. and Huber, A., (2012): Runoff generation and soil erosion processes after clear-cuttings. Oral presentation at AGU Fall Meeting 2012, San Francisco (http://fallmeeting.agu.org/2012/events/ep52c-human-influences-on-hydroecogeomorphic-processes-across-spatial-scales-in-forested-landscapes-ii-video-on-demand).

Mohr, C. H., Manga, M. and Wang, C.Y. (2012): Intensified plant activity following the 2010 M8.8 Maule Earthquake. Poster presentation at AGU Fall Meeting 2012, San Francisco.

Mohr, C. H. (2012): Streamflow response to the Maule M8.8 earthquake in small upland catchments of the Chilean Coastal Range. Invited talk at the USGS, Menlo Park, CA, in Water Resources Discipline Research Seminar (http://wwwrcamnl.wr.usgs.gov/wrdseminar/playwrd.htm?id=06sep2012).

Mohr, C. H. and Wang, C.Y. (2011): Streamflow response to the 2010 M8.8 Maule Earthquake. Poster presentation at AGU Fall Meeting 2011, San Francisco.

Mohr, C. H., Huber, A. and Bronstert, A. (2011): The effect of large scale clear cutting on infiltration conditions in experimental upland catchments in the Chilean Coastal Range, Bío-Bío Region. Poster presentation at EGU Assembly 2011, Vienna.

Mohr, C. H., Huber, A., Bronstert, A and Iroumé, A. (2011): Hydrological Response to the Earthquake of 27 February 2010 in small Upland Catchments in the Chilean Coastal Range, Bío-Bío Region. Poster presentation at EGU Assembly 2011, Vienna.

Mohr, C. H., Huber, A., Bronstert, A. and Iroumé, A. (2010): Hydrological Response to the Earthquake of 27 February 2010 in experimental catchments of the Cordillera de la Costa, Bío-Bío Region, Chile. Poster presentation at AGU Fall Meeting 2010, San Francisco.

Mohr, C. H., Bronstert, A., Huber, A. and Iroumé, A. (2010): Influence of different forest management practices and vegetation cover on runoff generation and sediment flux in the Coastal Range of Southern Chile. Poster presentation at EGU Assembly 2010, Vienna.

Mohr, C. H. and Huber, A. (2010): Design and application of a dript-type rainfall simulator adapted to steep topography and low intensity-rainfall characteristics in the Coastal Range of Southern Chile. Oral presentation at EGU Assembly 2010, Vienna. 

Mohr, C. H., Bronstert, A. and Huber, A. (2010): Einfluss unterschiedlicher forstwirtschaftlicher Praktiken auf die Abflussbildung und die Bodenerosion in Südchile. Oral presentation at Tag der Hydrologie 2010, Braunschweig.


PhD thesis

Mohr, C. H.  (2014): Hydrological and erosion responses to man-made and natural disturbances - Insights from forested catchments in south-central Chile.

 

Media

Earth Magazine   (2015): Soils may supply surging streams after earthquakes (http://www.earthmagazine.org/article/soil-may-supply-surging-streams-after-earthquakes).

Earth Magazine   (2012): Clarifying earthquake-driven hydrologic changes (http://www.earthmagazine.org).

EOS  Trans. AGU, 93(34)  (2012): Research Spotlight - Balcerak, E. (2012), Streamflow changes following the 2010 Chile earchquake. Clarifying earthquake-driven hydrologic changes (http://www.earthmagazine.org).