Geothermal heating a total capacity of 15 GW extracted 88 PJ of heat energy for space heating. Global ground-source heat pump capacity is growing by 10% annually. Hot springs have been used for bathing at least since Paleolithic times. The oldest known spa is a stone pool on China's Mount Li built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. Geothermal energy supplied channeled district heating for baths and houses in Pompeii around 0 AD. In the first century AD, Romans conquered Aquae Sulis in England and used the
Aphanizomenon flos-aquae (dietary supplement) This linked article is about a single strain of AFA labeled as toxic that has been reclassified. Colony-forming morphology is one of the characteristics of the species "Aphanizomenon flos-aquae"; conversely "Aphanizomenon" are not known to form colonies. Algologists Li and Carmichael noted colony formation, or lack thereof, and other morphologic distinctions when comparing "Aphanizomenon flos-aquae" with "Aphanizomenon". Their genetic comparison of "Aphanizomenon flos-aquae" to other species in the genus "Aphanizomenon" indicates dissimilarity between "Aphanizomenon flos-aquae" and "Aphanizomenon" species. Cyanobacteria have been a staple in the diets of many cultures and have been used for both food and commerce by indigenous