Fig 7. Frequency maps of lake water temperature and dissolved oxygen.

Empirical frequency maps of (a) water temperature-depth and (b) oxygen as a function of water depth for Lake Kariba calculated by using the aggregated database of this study [34]. Frequency is quantified as the average number of days per year (colour-coded) in which observed temperatures and oxygen concentrations fall within a bin of 0.5°C for temperature and 0.5 mg L^-1 for oxygen. The box plots show the statistical distributions (medians, 25^th and 75^th percentiles) of water temperature and dissolved oxygen at five different depths. The whiskers extend to the most extreme data points not considered outliers, and the outliers are plotted individually using the '+' symbol.