Concentration, distribution, and bacterial colonization of transparent expolymer particles (TEP) among Mackenzie Delta lakes

Concentrations, distributions, and bacterial colonization of transparent exopolymer particles (TEP) were tracked from June through August 2006 among three lakes of varying flooding frequency, in the Mackenzie Delta. Microscopic image analysis showed spectrophotometric methods generally over-estimated TEP concentrations in this system. TEP concentrations were highest immediately after river flooding and declined through August. Contrary to expectation, TEP concentrations were highest in the high flood frequency lake (lowest dissolved organic carbon). TEP accounted for an average of ~83.7% of particulate organic carbon in the lakes during summer, 2006. Total suspended bacterial abundances ranged from ~106 to 107 cells/ml. Microscopic partitioning of this community estimated that free-living cells, TEP-attached, and other-attached bacteria respectively accounted for 13.9, 9.6, and 76.5% of total suspended bacteria. TEP-attached bacterial densities increased over the summer and were higher in low flood frequency lakes. Results suggest TEP-attached bacterial density is related to the abundance of favourable colonization sites.