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Dr. Mohammed S. Hashim

Postdoctoral Investigator (NSF/OCE postdoctoral fellow)
Marine Chemistry and Geochemistry

Contact Information:
Work: 508-289-3792
Building: McLean 203

266 Woods Hole Road, MS #08
Woods Hole Oceanographic Institution
Woods Hole, MA 02543

Research Interests

I am interested in marine calcium carbonates in the modern ocean and throughout Earth history. My current research focuses on three themes:

  1. Exploring the roles of calcium carbonate in the oceanic carbon cycle.
  2. Quantifying the impact of sub-seafloor processes on ocean chemistry.
  3. Reconstructing aspects of Earth history using the carbonate record.

My current and previous projects focus on fish produced carbonates and bryozoan in the North Atlantic near Bermuda, sub-seafloor carbon cycling in the Baffin Bay near Greenland glaciated margin, and carbonate sediments on the slope of the Great Bahama Bank. I have also cultured coccolithophores in the lab, and conducted experiments to study the formation, alteration, and dissolution of carbonate minerals (aragonite, calcite, and dolomite) to constrain trace element incorporation and isotope fractionation using experiments. So far, I have been focusing on iodine, barium, and sulfur.


I am always excited to chat about science, ocean, and carbonates! Other topics could also be an option, so please don't hesitate to reach out!

Selected Peer-Reviewed Publications

Hashim, M., Rose, K., Cohen, H., and Kaczmarek, S. 2023. Effects of Sodium and Potassium on Dolomite formation rate, Stoichiometry, Crystallographic Characteristics. Sedimentology.

Hashim, M., Burke, J., Hardisty, D., and Kaczmarek, S.E. 2022. Iodine Incorporation into Dolomite: Experimental Constraints and Implications for the Iodine Redox Proxy and Proterozoic Ocean.  Geochimica et Cosmochimica Acta.

Hashim, M. and Kaczmarek, S.E. 2022. Rhombic Calcite Microcrystals as a Textural Proxy for Meteoric Diagenesis. Scientific Reports.

Hashim, M. and Kaczmarek, S.E. 2021. The Transformation of Aragonite to Calcite in the Presence of Magnesium: Implications for Marine Diagenesis. Earth and Planetary Science Letters, v. 574., no. 117166. Doi:

Hashim, M. and Kaczmarek, S.E, 2021. Evolution of Calcite Microcrystal Morphology during Experimental Dissolution. Journal of Sedimentary Research, v. 91 (3), p. 229–242.

Hashim, M. and Kaczmarek, S.E, 2020. Experimental Stabilization of Carbonate Sediments to Calcite: Insights into the Depositional and Diagenetic Controls on Calcite Microcrystal Texture. Earth and Planetary Science Letters. vol. 538, no. 116235.

Selected Awards and Academic Honors

  • 2022: NSF Ocean Sciences Postdoctoral Research Fellowship
  • 2022: NSF Earth Sciences Postdoctoral Research Fellowship (award declined by me due to the acceptance of another award)
  • 2022: Invitation to join Dissertations Symposium in Chemical Oceanography (DISCO) at the University of Hawai'i.
  • 2022: Western Michigan University's institutional nominee for the Council of Graduate School’s Dissertation Award in the Mathematics, Physical Sciences, and Engineering category
  • 2022: Woods Hole Oceanographic Institution Postdoctoral Fellowship
  • 2021: Outstanding Student Presentation Award (OSPA) at the American Geophysical Union (AGU) Fall Meeting
  • 2021: Schlanger Ocean Drilling Fellowship, U.S. Science Support Program (funded by NSF)
  • 2021:  Best Student Talk Award (Ph.D. category), Midwest Geobiology Symposium, Indianapolis, IN
  • 2021: All-University Graduate Research and Creative Scholar Award (Ph.D. category), Western Michigan University
  • 2021: Department-Level Graduate Research and Creative Scholar Award (Ph.D. category), Western Michigan University
  • 2021: Lloyd and Marilyn Schmaltz Professional Activities Award, Department of Geological and Environmental Sciences, Western Michigan University


Ph.D.: Geosciences. 2022. Western Michigan University, Kalamazoo, Michigan, USA.

B.Sc: Geology. 2012. University of Baghdad, Baghdad, Iraq