Wikipedia:Reference desk/Archives/Science/2019 March 29

= March 29 =

Pink lakes
This BBC article states that the pink color of the lake in Melbourne's Westgate Park is caused by Dunaliella algae; however, the WP article classifies it as green algae. What causes the bright pink pigmentation? And, are these lakes where Pepto-Bismol comes from? —2606:A000:1126:28D:84A8:1E5E:5535:59A2 (talk) 17:22, 29 March 2019 (UTC)


 * Beta carotene is also present in green algae. Since that's what makes flamingos pink, it seems likely to play a role.  If the other pigments in the algae, chlorophyll a and chlorophyll b (both green) and xanthophylls (yellow) are somehow suppressed, then the color of the beta carotene could be expected to show, much as tree leaves change color when the chlorophyll disappears in autumn.  I'm not sure what would cause this in the lakes, however. SinisterLefty (talk) 20:14, 29 March 2019 (UTC)


 * This covers some of their biology. Note that they can survive in salt concentrations up to the point of saturation.  (They can grow better at lower salinity, but other organisms outcompete them given the chance)  They do have chlorophyll in addition to their pink pigments (beta carotene and canthaxanthin.  It says in the Dead Sea "red beta-carotene rich types" of D. parva are never encountered.  I am sure there is more to this story (strain and environment dependence of beta-carotene and other pigment production) that I don't know; but there are a lot of other papers about it. Wnt (talk) 23:43, 29 March 2019 (UTC)
 * "Green algae" is a taxonomic classification. It doesn't mean that all such organisms are necessarily colored green. Land plants evolved from green algae, and if you want to be strictly monophyletic you could say that all land plants are a subgroup of green algae. Indeed, this grouping of the green algae and land plants together is one increasingly-accepted formal taxonomic definition of the Kingdom Plantae: this group may also be referred to as the "green plants" to be more explicit. --47.146.63.87 (talk) 00:18, 30 March 2019 (UTC)


 * See Pink Lake (Western Australia). Dolphin ( t ) 02:03, 30 March 2019 (UTC)


 * Thanks y'all for the interesting info/links. —2606:A000:1126:28D:84A8:1E5E:5535:59A2 (talk) 06:03, 30 March 2019 (UTC)