Violet Lake: Has the mystery been solved?

Susan, Catherine and Jennifer at Environment Yukon have been great about following up on my questions about "Lac Violet".  They suggest that the colouration  might be from a green algae called chlamydomonas nivalis, also known as "Watermelon Snow".

Chris proposed that it might be "Purple Sulphur Bacteria".  Judging by the sulphury smell around the lake, I don't think that suggestion can be ruled out, though I don't know if the environment is as oxygen-deprived as the Wikipedia entry suggests that it needs to be for Purple Sulphur Bacteria.

I guess the only way to really find out is to get ahold of a 400x microscope and go collect a few samples...