Scheme of a stratified marine lake transect. (1) Ocean level (tidal amplitude). (2) Tidal amplitude inside the stratified lake. (3) Rain that decreases the salinity of shallower layers of water. Some of the rain evaporates with the typical high temperatures. (4) Seawater column showing the mixolimnion layer, rarely mixed by the wind (8); the chemocline gradient, where the oxygen concentration declines to 0 ppm; and the pycnocline, where there is a sudden change in the vertical gradient of water density. In the chemocline gradient, there is also a pink layer that represents the presence of anoxic bacteria responsible for this color; the monimolimnion layer, under the chemocline, where there is little or no sunlight and no seawater mixing. The layer thickness can be different across lakes. (5) Seawater mixing inside tunnels and channels is represented by the blue cycle icon. (6) Colder water (denser water) comes from the ocean to the bottom of the lake. (7) Depending on the input of seawater, the chemocline can be mixed, expanding or shrinking the bacterial plate. (8) Effects of wind are lacking in stratified marine lakes due to the structure of the limestone around them (modified from Blanchette et al., 2020).

This project was titled:

Dichotomy or gradient? How marine lake states are distributed in Palau.