Paper published detailing the mineral characteristics of Holocene lake sediments

Based on a plethora of experiments and advanced geochemical analysis techniques, Hussein Kanbar in the Holmboe group (Department of Chemistry/UMU), in a collaboration with PhD student Fredrik Olajos and Professor Göran Englund from the Department of Ecology and Environmental Sciences/UMU, has published a paper in the Journal of Soils and Sediments, detailing the mineral and geochemical characteristics of Holocene lake sediments from the Hotagen lake in west Sweden (Jämtland). Read more here:

Kanbar, H.J., Tran Le, T., Olajos, F. et al. Tracking mineral and geochemical characteristics of Holocene lake sediments: the case of Hotagen, west-central Sweden. J Soils Sediments (2021). https://doi.org/10.1007/s11368-021-03012-y

CLOSED: The Holmboe group is offering 1 PhD student position and 1 postdoc fellowship!

Our planet has more organic carbon in its fragile soil layers than all the carbon on land and atmosphere combined. The Holmboe group is now hiring a PhD student (4 year minimum) and offering one postdoc fellowship (2 years) for two separate but similar projects focusing on the molecular interactions between natural organic molecules and mineral surfaces.

In order to focus on the molecular scale, the research will utilize various experimental methods and molecular dynamics simulations  (extracting for instance free energy profiles as shown below), and why not also virtual reality!


 

To apply for the PhD position, please visit this link.

To apply for the postdoc fellowship financed by the Kempe Foundations, please visit this link.

 

New paper detailing DNA-hotspots in sediments by H. Kanbar and Holmboe

Hussein Kanbar and Michael Holmboe has collaborated with EMG/UMU Prof. Göran Englund and PhD student Fredrik Olajos, on the faith of (ancient)DNA adsorbed onto minerals in 10,000 y old Swedish lake sediments. Their first publication is now available online at: doi.org/10.1016/j.apgeochem.2020.104728.

Highlights

  1. Lake sediment geochmemistry plays a significant role in the sorption.
  2. Clays were the main sedimentary components to host DNA.
  3. Both clay-mineral and organo-clay complexes govern the sorption of DNA.
  4. A DNA infrared fingerprint was determined in sediments via spectral subtraction.
  5. DNA-hotspots in lake sediments were revealed using geochemical approaches.

New associate professor in inorganic chemistry!

Michael Holmboe which initially joined the Chemistry Dept. at Umeå University in 2015 as an assistant professor, has now been appointed to associate professor (universitetslektor) in inorganic chemistry!

Thanks to recent grants from SSM and VR, his groups research is set to start two new projects regarding radiation-induced redox effects in clay minerals and organic/minerals interactions using molecular simulations!

moleculargeo.chem.umu.se/effects-of-gamma-radiation-on-bentonite-project-funded-by-ssm/
moleculargeo.chem.umu.se/project-grant-from-the-swedish-research-council-awarded-to-michael-holmboe/

Effects of gamma-radiation on Bentonite project funded by SSM

The Swedish Radiation Safety Authority, or SSM in short, are funding a 1-year project in the Holmboe group!

In the context of nuclear waste disposal in Sweden and many other countries, this project will investigate the effects of redox and physicochemical changes induced by gamma (γ) irradiation on compacted Bentonite clay and its main component montmorillonite. This is relevant since in nuclear waste repository concepts such as the Swedish KBS-3, the compacted and water saturated Bentonite clay buffer will unavoidably be exposed to significant doses (40-200kGy) of ionizing 137-Cs radiation, which may induce redox-changes in the structural Fe(II)/Fe(III) sites in the clay mineral lattice.

Paper on smectite hydration accepted by ACS Earth and Space Chemistry

Deconvolution of Smectite Hydration Isotherms

Authors: Jerry Lindholm, Jean-Francois Boily and Michael Holmboe.
Link: doi.org/10.1021/acsearthspacechem.9b00178
Synopsis:
Sorption isotherm models have traditionally served as an invaluable tool to characterize synthesized and natural mineral particles, but often fail to describe the behavior of swelling materials. This research presents a novel composite isotherm model that describes water uptake by adsorption, step-wise intercalation, and condensation.

Clays, New Perspectives, Challenges & Opportunities workshop at MIT

Michae Holmboe gave an invited talk on the characterization of clay microstructure and molecular dynamics simulations – at the workshop “Clays, New Perspectives, Challenges & Opportunities”, May 2-3 2019, hosted by Prof Andrew Whittle and his postdoc Ali Seiphoori at the Massachusetts Institute of Technology (MIT). Read more here: clays.mit.edu