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 Aphanizomenon flos-aquae Aphanizomenon flos-aquae is a brackish and freshwater species of cyanobacteria found around the world, including the Baltic Sea and the Great Lakes. "Aphanizomenon flos-aquae" can form dense surface aggregations in freshwater (known as "cyanobacterial blooms"). These blooms occur in areas of high nutrient loading, historical or current. "Aphanizomenon flos-aquae" has both toxic and nontoxic forms. Most sources worldwide are toxic, containing both hepatic and neuroendotoxins. Most cyanobacteria (including "Aphanizomenon") produce BMAA, a neurotoxin amino acid implicated in ALS/Parkinsonism. Toxicity of "A. flos-aquae" has been reported in Canada, Germany and China. "Aphanizomenon flos-aquae" is known to produce endotoxins, the