Tadlac Lake

About

Tadlac Lake, also colloquially known as Crocodile Lake, is a freshwater volcanic maar lake located in Barangay Tadlac, in the municipality of Los Baños, Laguna. The lake-filled maar is located along the southern shore of Laguna de Bay, the largest lake in the Philippines, with Tadlac Lake protruding out of the shore of the larger lake. If not for its slightly-elevated crater rim, Tadlac Lake would be wholly engulfed by Laguna de Bay. The volcanic lake is one of many maars in the Laguna Volcanic Field. It is listed as one of the inactive volcanos in the Philippines by the Philippine Institute of Volcanology and Seismology (PHIVOLCS). Tadlac Lake is also notable for its history of annual lake overturns, locally called langal. This phenomenon, rare elsewhere but common in Tadlac Lake during the cold season (December-February), is the result of trapped carbon dioxide (CO2) erupting from the deep layers of the lake towards the surface, leading to fish kills from low levels of dissolved oxygen. This was greatly heightened by the introduction of aquaculture to the lake in the mid-1980s, eventually leading to a massive and costly fish kill in 1999, which in turn led to the cessation of aquaculture there. Prior to the introduction of aquaculture, Tadlac Lake was considered as an oligotrophic lake, having low nutrient content and low algal production, resulting in very clear water with h

Adapted from Wikipedia (CC BY-SA). Photography via Wikimedia Commons.