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Prof. Dr. Nikolaus J. Kuhn

Department of Environmental Sciences
Profiles & Affiliations

From process to planets

Processes, such as wind and water erosion, acting on the surface of Earth and other planets are the agents of environmental change. Human activities often change, at least on Earth, these rates or the processes themselves, causing environmental change. Therefore, understanding both the processes, but also their impact on the local, regional and global environment is essential to assess the relevance of human activities on the environment. My research interests therefore combine the study of processes and their controlling factors, as well as tools to upscale the effect of changing processes and their rates on the environment. For example, the combination of climate and land use change leaves rangelands exposed to an increased risk of erosion. Key questions are whether such erosion destroys soils locally, impacts environmental and human health regionally and affects global cycles, such as nutrients and carbon, globally. Our group has therefore developed a suite of tools, ranging from lab experiments, the use of UAVs to the analysis of satellite data, that connect the different scales. This expertise in the study and connection of processes and landforms has also raised the interest of the planetary science community, leading to a participation in space missions such as the European Space Agency's ExoMars mission.

Selected Publications

Nyathi, Nesisa Analisa, Musakwa, Walter, Delzeit, Ruth, & Kuhn, Nikolaus. (2022). Ecosystem Services in Southern Africa: Current and Emerging Trends-A Bibliometric Review. Diversity, 14(5), 359. https://doi.org/10.3390/d14050359

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Vos, Heleen C., Karst, Isabel G., Eckardt, Frank D., Fister, Wolfgang, & Kuhn, Nikolaus J. (2022). Influence of Crop and Land Management onWind Erosion from Sandy Soils in Dryland Agriculture. Agronomy, 12(2), 457. https://doi.org/10.3390/agronomy12020457

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Bontognali, Tomaso, Meister, Yardena, Kuhn, Brigitte, Josset, Jean-Luc, Hofmann, Beda A., & Kuhn, Nikolaus J. (2021). Identifying optimal working conditions for close-up imagining during the ExoMars rover mission. Planetary and Space Science, 208, 105355. https://doi.org/10.1016/j.pss.2021.105355

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Krenz, Juliane, Greenwood, Philip, & Kuhn, Nikolaus J. (2021). Anthropogenic erosion-induced small-scale soil heterogeneity in South African rangelands. Anthropocene, 34, 100290. https://doi.org/10.1016/j.ancene.2021.100290

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Salawu-Rotimi, Adeola, Lebre, Pedro H., Vos, Heleen Cornelia, Fister, Wolfgang, Kuhn, Nikolaus J., Eckard, Frank D., & Cowan, Don A. (2021). Gone with the Wind: Microbial Communities Associated with Dust from Emissive Farmlands. Microbial Ecology, 82(4), 859–869. https://doi.org/10.1007/s00248-021-01717-8

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Selected Projects & Collaborations

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Contribution to the Swiss science exploitation of the CLose-UP Imager on the ExoMars 2022 rover mission

Research Project  | 2 Project Members

The close-up imager CLUPI is one of the instruments that will be onboard ESA's "Rosalind Franklin" rover, searching for signs of life in the framework of the joint ESA-Roscosmos "ExoMars 2022" mission. CLUPI will acquire high-resolution images essential to investigate the geology of Mars, selecting samples with a high potential to contain biomarkers. This project includes CLUPI- science validation/training activities aimed at optimizing the scientific return of the instrument during the primary mission on Mars (e.g., determining the ideal lighting conditions and positions relative to rock surfaces, developing drive paths and imaging options enabling the identification of rock types and mineralogy,...). These simulations will be mostly carried out in the "Marslabor" of the Uni Basel, a state-of-the-art Marsyard. The project will also include the development of new image analysis approaches (e.g. using software for determining size and shape of rock forming particles or rock structures such as thickness and patterns of laminae). Starting from the third year of the project, the PhD candidate will have the opportunity to participate in the primary mission and contribute to the interpretation of the images that will be acquired on Mars. Interactions with the Space Exploration Institute of Neuchâtel (headed by Dr. Jean-Luc Josset, PI of the CLUPI instrument), the Naturhistorisches Museum Bern (affiliation of the CLUPI Co-PI Prof. Beda Hofmann), plus collaborations with the international CLUPI science team are foreseen in this highly multidisciplinary project.

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South African cropland dust emission risks: physical thresholds, environmental and socio-economic impacts

Research Project  | 6 Project Members

Southern African dust sources have been well documented, feature some of the world's dustiest regions, and disperse dust throughout the subcontinent and beyond. The west coast of South Africa produces dust from coastal pans, river valleys, and deltas in both the Namib and Northern Cape regions. Further East, mine tailings in and around Johannesburg (Gauteng province) are among the most studied dust sources in South Africa due to systematic monitoring efforts and immediate impact on nearby urban air quality. However, few studies have drawn attention to dust originating from South Africa's extensive farmland. These areas appear to be most productive in early summer at the onset of the rainy season as part of cold pool outflows from convective storms over the Free State and Northern Cape. Such ground level events have often been reported by the media, but have gone unmonitored due to their association with cloud and rain events. These associations are different from most other dust events that produce elongated plumes during the clear winter months, particularly in Namibia and Botswana, and disperse throughout the region. Nevertheless, the use of Meteosat MSG clearly suggests that southern African events are not infrequent and not insignificant in extent. Exposed agricultural lands are thus important dust sources in South Africa, and the supply of fine dust material may be even more pronounced during drought cycles. Such events represent a loss of soil mass at the site of origin, but also impact ecosystem services further afield and, potentially, contribute to climate change. Microbial and chemical contaminants transported by dust from cropland add to the public health concerns with dust originating from farms and reaching urban areas. The research questions of this four-year project thus are: (i) what are the environmental thresholds for generation of dust (wind, soil moisture soil crust) in relation to farmland management? and, (ii) to what extent do farmland dust sources impact ecosystem services, public health, and potentially climate? This research aims to fill this knowledge gap by using a holistic and interdisciplinary approach spanning geomorphology, land management, and microbiomics. A Swiss - South African partnership of four institutions (University of Basel, Agricultural Research Council, University of Cape Town, and University of Pretoria), which encompasses the necessary expertise, has been formed to conduct this research. The objectives of the project are (i) to identify the spatial and temporal pattern of dust emissions from agricultural land in South Africa, (ii) to determine the environmental boundary conditions for dust emission on South African cropland identified as dust sources, (iii) to identify the impact of land management practices on dust emission and ecosystem services losses, (iv) to identify microbiomics air contamination due to dust, and (iv) to synthetize the above information and produce holistic knowledge on dispersal, impact of dust and thresholds to inform policy in farming systems. Activities and methods will be divided in five interconnected work packages (one WP per objective), using remote sensing of Meteosat and MODIS satellite imagery to identify and quantify dust sources emitted from farmland (WP1), using a rain and wind tunnel simulator to determine crust formation and dust physical boundaries (WP2), using leaf area index and interviews to identify biophysical and management attributes (WP3), using dust samples to determine microbial population phytogenetics, including impacts of the transport of microorganisms, whether suspended in aqueous aerosols or adsorbed to mineral (dust) particles (WP4), and using the results of WP1-4 for a synthesis leading to publish holistic scientific contributions on South African cropland dust emissions, identify farmland management best practices, and inform policy. Dust emission is a growing issue affecting soil mass losses, ecosystem services, public health, and climate change. Understanding dust emission dynamics originating from farming in drylands is crucial not only to prepare and respond to the aforementioned impacts, but also to secure food production in the best possible conditions using marginal lands, a resource becoming increasingly important for food security of a warming planet.

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Jijiga One Health Initiative

Research Project  | 3 Project Members

The interdisciplinary project aims to improve training for students of human and veterinary medicine, and subsequently to establish an interdisciplinary centre of excellence for health at the local university. Jigjiga University aims to become the health centre for pastoralist communities in the Horn of Africa, and eventually an attractive partner for neighbouring universities in Ethiopia, Somalia and Kenya. Cooperation between the various educational and research institutions will foster long term the activities of the SDC and its partners in addressing health and food security-related issues. The Physical Geography and Environmental Chnage Research Group contributes to the project through graduate student training, PhD supervision, exploration of remote sensing tools for assessing land quality and the development of soil and GIS labs at Jijiga University.