Halfar, Jochen

Ph.D. | Associate Professor & Associate Chair | Earth SciencePaleoclimate and Paleontology

Contact Information

905 828 5419
905 828 5425
Mailing Address: 
3359 Mississauga Road
Postal Code: 
L5L 1C6
Halfar Picture

Research Areas:

Coralline Algal Paleoclimatology, Carbonate Sedimentology

Research Profile:

Halfar‘s paleoclimate laboratory focuses on deciphering paleoclimates on different time scales ranging from the past Halfar Researchcenturies to 55 million years ago using sclerochronological, geochemical, and sedimentological multi-proxy approaches. Our highly interdisciplinary research is conducted in close collaboration with biologists, oceanographers, and climate physicists.

Currently, the group focuses on three main directions of research. First, we study crusty Arctic seafloor algae that can live up to 650 years while depositing annual tree-ring like layers. Using geochemical techniques we interpret past ocean climates and even sea-ice conditions from these layers. Another aspect of our current research focuses on modern shallow water marine carbonate environments in the tropics where we evaluate their adaptation to nutrient enrichment and the ongoing acidification of the ocean. Back on land we are studying exceptionally well-preserved fossil wood in volcanoclastic deposits associated with early Paleogene kimberlite pipes (55.1 million years) in the Northwest Territories, Canada, to explore terrestrial climate variability during a period of extreme  warmth.

Courses Taught:

ERS315H5 and ERS321H5 (undergraduate); ESS2303H5 (graduate)



Hook, B.A., Halfar, J., Gedalof, Z., Bollmann, J., Rahman, Md.A., Reyes, J., Schulze, D. (2015) Extraction of α-cellulose from mummified wood for stable isotopic analysis, v. 405, 19-27, Chemical Geology

Fietzke, J., Ragazzola, F., Halfar, J., Dietze, H., Foster, L., Hansteen, T., Eisenhauer, A., Steneck, R.S. (2015) Boron isotope images reveal seasonal cycle and long-term trend in sea water pH, Proceedings National Academy of Sciences, www.pnas.org/cgi/doi/10.1073/pnas.1419216112

Rahman, A., Halfar, J. (2014) First evidence of chitin in calcified coralline algae: new insights into the algal calcification process, Scientific Reports (Nature), 4: 6162 | DOI: 10.1038/srep06162.

Halfar, J., Adey, W.H., Kronz, A., Hetzinger, S., Edinger, E., Fitzhugh, W., 2013, Arctic sea-ice decline archived by multicentury annual-resolution record from crustose coralline algal proxy, Proceedings National Academy of Sciences, www.pnas.org/cgi/doi/10.1073/pnas.1313775110.

Hetzinger S., Halfar J., Zack T., Mecking J., Kunz, B., Jacob D., Adey, W.H., 2013, Coralline algal Barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability, Scientific Reports (Nature), 3, 1761, 33. ]

Hetzinger, S., Halfar J., Mecking, J. V., Keenlyside N. S., Kronz A., Steneck R. S., Adey W. H., Lebednik, P. A., 2012, First proxy evidence linking decadal North Pacific and Atlantic climate, Climate Dynamics, 39 (6), 1447-1455.

Halfar, J., Williams, B, Hetzinger, S., Steneck, R.S., Lebednik, P., Winsborough, C., Omar, A., Chan, P., Wanamaker, A., 2011, 225 years of Bering Sea climate and ecosystem dynamics archived by coralline algae, Geology, v. 39, 6, 579-582, doi:10.1130/G31996.

Chan, P., Halfar, J., Hetzinger, S., Williams, B., Steneck, R.S., Zack, T., Kunz, B., Jacob, D., 2011, Freshening of the Alaska Coastal Current recorded by coralline algal Ba/Ca ratios, Journal of Geophysical Research – Biogeosciences 116, G01032, doi:10.1029/2010JG001548.