Area of Expertise:
Dr. Johannessen is a geochemical oceanographer at the DFO Institute of Ocean Sciences in Sidney, B.C. She studies climate change and carbon cycling, from photochemical processes at the top of the ocean to the burial and reworking of organic matter and other tracers at the bottom. Recent and ongoing projects include: (1) the effects of climate change on the Strait of Georgia; (2) effects of short-term variability on productivity and carbon cycling in coastal water; (3) hypoxia and acidification in the Strait of Georgia; and (4) the effect of photochemical oxidation (burning of organic matter in seawater by sunlight) on the ability of natural or artificially-induced phytoplankton blooms to draw down carbon dioxide from the atmosphere. Dr. Johannessen uses marine geochemical tools, including sediment cores, sediment traps and a photochemical laboratory that simulates chemical reactions driven by sunlight at the surface of the ocean. She has worked in the Mid-Atlantic Bight, the Bering Sea, the Arctic Ocean and, most recently, the Strait of Georgia.
Select Presentation(s) / Publication(s):
Johannessen, Sophia, “Has primary productivity declined in the Strait of Georgia since the 1970s?” (2018). Salish Sea Ecosystem Conference. 173.
S. C. Johannessen, R. W. Macdonald, C. W. Wright, D. J. Spear 2017. Short-term variability in particle flux: storms, blooms and river discharge in a coastal sea. Continental Shelf Research143: 29-42. Paper summary, Pdf
Loos, E.A., Costa, M., and Johannessen, S. C. 2017. The underwater optical environment of the coastal waters of British Columbia.FACETS 2: 872-891, .doi: 10.1139/facets-2017-0074. Paper summary
R. Pawlowicz, R. Di Costanzo, M. Halverson, E. Devred and S. Johannessen 2017. Advection, surface area, and sediment load of the Fraser River plume under variable wind and river forcing. Atmosphere-Ocean 55(4-5): 293-313.Paper summary
Johannessen, Sophia, “Sewage in the Strait of Georgia: how big is the problem and what can we achieve by treatment?” (2018). Salish Sea Ecosystem Conference. 19.
Ianson, D., Allen, S. E., Moore-Maley, B.L., Johannessen, S. C. and Macdonald, R. W. 2016. Vulnerability of a semienclosed estuarine sea to ocean acidification in contrast with hypoxia. Geophysical Research Lettersdoi 10.1002/2016GL068996. Paper summary
Johannessen, S.C., Macdonald, R.W., Burd, B., van Roodselaar, A. and Bertold, S. 2015. Local environmental conditions determine the footprint of municipal effluent in coastal waters: A case study in the Strait of Georgia, British Columbia. Science of the Total Environment508: 228-239. Paper summary
Yunker, M.B., Macdonald, R.W., Ross, P.S., Johannessen, S.C. and Dangerfield, N. 2015. Assessment of alkane and PAH provenance and potential bioavailability in coastal marine sediments subject to a north to south gradient of increasing anthropogenic sources in British Columbia, Canada. Organic Geochemistry 89-90: 80-116. Paper summary
Johannessen, S.C., Masson, D. and Macdonald, R.W. 2014. Oxygen in the deep Strait of Georgia, 1951-2009: The roles of mixing, deep-water renewal, and remineralization of organic carbon. Limnology and Oceanography59(1): 211-222. Paper summary
Riche, O., Johannessen, S.C. and Macdonald, R.W. 2014. Why timing matters in a coastal sea: trends, variability and tipping points in the Strait of Georgia, Canada. Journal of Marine Systems131: 36-53.
Sutton, J.N., Johannessen, S.C. and Macdonald, R.W. 2013. A nitrogen budget for the Strait of Georgia, British Columbia. Biogeosciences10: 7179-7194.