University of Kansas Field Station: Water temperature profiles at Frank B. Cross Reservoir (Kansas, USA) 1993-2016

These vertical profiles of water temperature data are from Frank B.
Cross Reservoir, a small freshwater impoundment in northeastern Kansas
(USA). Cross Reservoir, located at the University of Kansas Field
Station near Lawrence (KS), has a 3-ha surface area and a maximum
depth of 12 m. Temperature data were collected at discrete depths in a
vertical profile using a Water Quality Checker U-10 (Horiba
Instruments, Kyoto, Japan). These temperature data were collected in
conjunction with ecological studies at Cross Reservoir examining
deep-dwelling, vertically-migrating phytoplankton communities that
form a deep chlorophyll maxima, especially during times of thermal
stratification. Therefore, the most frequent sampling dates occurred
in July, August, September and October during thermal stratification
when vertically migrating deep algae were most common (other months
were sampled less frequently through the years). Cross Reservoir has
high water clarity due to its watershed vegetation and physical
(protected) setting. Thermal stratification begins each year in April,
and complete mixing occurs during November. The bottom of the
epilimnion is typically located at 3 m in July and usually deepens to
approximately 9 m by late November. The bottom of the epilimnion is
defined here as the bottom of the first 1 m depth interval that
exhibited a >1 C temperature decrease per meter. The water column
also consistently exhibits strong chemical stratification during the
summer months. Sporadic ice cover can occur during December–February.