[3] In pre-history, there was a paleolake here complete with overland drainage (deltaic sediments laid down by a paleodrainage system have been found).

The paleolake was much greater in size and depth, as evidenced by strand lines that ring the outer edges of the basin.

[3] The basin is shallow resulting in dramatic variation in the surface area of the lake with even small changes in water level.

Lake Tsimanampetsotsa is in an area with a semi-arid climate; daytime temperatures are high and precipitation low.

[3] Emergent plant species able to grow in the sodic water include southern cattail (Typha domingensis) and flat-sedge (Cyperus spp.).

[5] Other salt-tolerant species move onto the flats as the water levels recede including Salsola littoralis, Atripex perrieri, as well as some grasses (Sporobolus virginicus, Paspalum vaginatum) and the golden leather fern (Acrostichum aureum).

[3] The introduced species beach sheoak (Casuarina equisetifolia) can be found in small stands along the east shore.

High phosphate concentrations, originating from erosion, are thought to be the main factor limiting the diversity of aquatic fauna.