These are not the product of photoshopping, pharmaceutical chemical run-off or man made dyes. These are naturally occurring lakes.
Lake Hillier in Western Australia is teeming with salmon pink water.
Likewise, Lake Retba in Senegal is so milkshake pink that its water looks good enough to drink.
To find out why these bodies of water look so bubblegummy, researchers from the University of Bath (for real, no watery pun intended) in the UK examined pink lake H20 under their microscopes and found that:
The lakes are saltier than the sea
Almost ten times saltier than the regular ocean in fact. This high salinity (up to 40% salt in solution) makes the lake just like the Dead Sea where swimmers are so buoyant that they float around due to its high density compared to their body mass.
The lakes are full of algae and bacteria
Samples of the H20 when examined under the microscope reveal large quantities of the salt loving micro-algae Dunaliella salina and halophilic bacteria. The law of osmosis tells us that water moves from regions of high concentration to regions of low concentration in the presence of a semi-permeable membrane. Most cellular organism therefore would shrivel up and die when placed in the high saline environment of these lakes because all of their water would move out of their cells into the surrounding lake across their semi-permeable plasma membranes by osmosis. D. salina, however, can survive in these conditions. It does so by synthesizing large volumes of glycerol in the cytoplasm of its cells to counter-balance the effects of osmosis resulting in no net move of water across its membranes (Oren, 2005). This makes them highly suited to life in a salty lake but it doesn’t explain the pink hue to the lake.