Physical and biological effects of experimental crude oil spills on Low Arctic tundra in the vicinity of Tuktoyaktuk, N.W.T., Canada

Abstract

Data are presented on the effects of simulated crude oil spills on two Low Arctic terrestrial tundra plant communities near Tuktoyaktuk, Northwest Territories. Spills of fresh, unweathered crude oil had a general herbicidal effect, resulting in rapid damage to, and subsequent death of, all aboveground actively growing foliage coming in contact with the oil. Most species were defoliated. Mosses and lichens were especially susceptible and killed. However, within several weeks of the summer oil spillages, a limited number of relatively tolerant vascular plant species began to develop regrowth shoots.Summer spills were markedly more damaging than were equivalent spills made in winter. No increases were seen in active layer depth from spills made in summer. However, winter spills on one of the two sites did show consistent and statistically significant (P > 0.01) increases in depth of thaw. Examination of several key energy budget parameters at these field sites indicated consistently lower albedos and evapotranspiration and consistently higher soil surface temperatures and soil heat flux at all oil spill sites, relative to their controls. However, except for a winter spill on one site, the recorded differences were not sufficiently large in magnitude to produce significant increases in active layer thaw depths.