FACTORS RELATED TO THE VARIATION IN MIXING DEPTH AMONG MEROMICTIC LAKES

Although the factors that influence the mixing depth of holomictic lak es have been well investigated, meromictic lakes, which never mix comp letely, have received little attention in this regard. The purpose of the present study was to determine if the geographic variation in mixi ng depth of the mixolimnion is related to the same factors as is the e pilimnion depth. Data on the lake morphometry, elevation, latitude sal inity in the mixo- and monimolimnia, and the depths of the epi- and mi xolimnia were obtained for 56 meromictic lakes worldwide. The depth of the mixolimnion was most closely related to the maximum depth of the lake (r2 = 0.69); no other variables were significant after accounting for depth. In the same data set, epilimnetic depth was also most clos ely related to maximum depth, rather than fetch, as earlier studies ha d found. Our results suggest that wind-induced turbulence has much les s effect on the depth to which both the epilimnion and the mixolimnion circulate in meromictic lakes than does morphometry.