Physical influences on microbialite morphological variation and distribution in Pavilion Lake, British Columbia, Canada

Microbialite structures at Pavilion Lake, BC, Canada (50°51' N, 121°44' W) are found throughout the lake, spanning the full depth range (max. depth of 61 m), and hence covering a large range of light and temperature regimes. Both the macro- and micro-scale microbialite morphologies vary throughout the lake, with representative morphologies from bulbous to turbinate-shaped components, chimneys, and finger-like structures. Initial exploration suggested that a given morphology is confined to a specific depth range; however, subsequent investigation has shown the morphology distribution to be more complex with both lateral and vertical variations. With the recent extensive exploration of the lake using the single-person-operated DeepWorker submersibles in the 2008 and 2009 field seasons, we have generated morphology maps for much of the lake (e.g. fig. 1). We have also collected a multi-year record of light and temperature measurements throughout the lake and at a weather station on the shore of the lake. Using the light and temperature data from moored stations, together with casts of a Conductivity-Temperature-Depth (CTD) profiler with an attached Photosynthetically Active Radiation (PAR) sensor, we are modeling the light and temperature regimes in the lake as a function of location and depth. Using the microbialite morphology maps together with light and temperature models, and bathymetry and sonar maps, we will present the relationship, and possible control, of light and temperature on microbialite morphology, growth, and distribution. Partial mapping of the Pavilion Lake central basin, overlying the bathymetry.