User: | Open Learning Faculty Member:
January 26, 2018
12:30 – 13:15
Weather: 5°C and overcast; rain earlier in the day
I have chosen Cultus Lake as my research site. It is 6.3 km2 with a maximum depth of 44 m. The lake basin is bound by International Ridge to the east, Vedder Mountain to the west, the agricultural lands of the Columbia Valley to the south, and a heavily used recreational beach to the north. The mountains around Cultus Lake are forested with mostly coniferous trees and patches of regenerating deciduous trees. The vegetation at the north end of the lake is maintained with almost no understory and only select mature coniferous trees remaining. Portions of Cultus Lake are within a Provincial Park. The park areas are largely occupied by campgrounds. The lake attracts between 1 and 3 million tourist visits per year. The lake is subject to anthropogenic nutrient loading from agricultural activities and septic leaching. It is home to two species at risk, the Cultus Pygmy Sculpin (Cottus aleuticus, Cultus population) and the Cultus population of sockeye salmon (Oncorhynchus nerka). The littoral areas of the lake have been invaded by invasive Eurasian milfoil (an aquatic plant). My questions are as follows:
- Is eutrophication of the lake leading to deep water oxygen depletion?
- Do fish, specifically the Cultus Pygmy Sculpin, favour portions of the lake that have higher concentrations of dissolved oxygen?
- If oxygen depletion does occur, does the lake fully recover during winter overturn?
