# meta.depths: Calculate the Top and Bottom Depths of the Metalimnion In rLakeAnalyzer: Lake Physics Tools

## Description

Calculates the top and bottom depths of the metalimnion in a stratified lake. The metalimnion is defined as the water stratum in a stratified lake with the steepest thermal gradient and is demarcated by the bottom of the epilimnion and top of the hypolimnion.

## Usage

 `1` ```meta.depths(wtr, depths, slope = 0.1, seasonal = TRUE, mixed.cutoff = 1) ```

## Arguments

 `wtr` a numeric vector of water temperature in degrees C `depths` a numeric vector corresponding to the depths (in m) of the wtr measurements `slope` a numeric vector corresponding to the minimum slope `seasonal` a logical value indicating whether the seasonal thermocline should be returned. This is fed to thermo.depth, which is used as the starting point. The seasonal thermocline is defined as the deepest density gradient found in the profile. If `FALSE`, the depth of the maximum density gradient is used as the starting point. `mixed.cutoff` A cutoff (deg C) where below this threshold, thermo.depth and meta.depths are not calculated (NaN is returned). Defaults to 1 deg C.

## Value

A numeric vector of the top and bottom metalimnion depths in meters. Returns the bottom depth if no distinct metalimion top and bottom found.

## Author(s)

Jennifer Brentrup, Luke Winslow

## References

Wetzel, R. G. 2001. Limnology: Lake and River Ecosystems, 3rd ed. Academic Press.

`ts.meta.depths`, `thermo.depth`
 ```1 2 3 4 5 6 7 8 9``` ```wtr = c(22.51, 22.42, 22.4, 22.4, 22.4, 22.36, 22.3, 22.21, 22.11, 21.23, 16.42, 15.15, 14.24, 13.35, 10.94, 10.43, 10.36, 9.94, 9.45, 9.1, 8.91, 8.58, 8.43) depths = c(0, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20) m.d = meta.depths(wtr, depths, slope=0.1, seasonal=FALSE) cat('The top depth of the metalimnion is:', m.d[1]) cat('The bottom depth of the metalimnion is:', m.d[2]) ```