Al-biomineralization of alunite，variscite，gibbsite and boehmite was observed in white seawater containing high concentrations of Al at Kitabirashita beach，Satsuma．Iwojima Island，Kyushu，Southwest Japan．The white seawater at Kitabirashita beach has been investigated every year since 1997．The color and distribution of this white seawater have been different in each investigation．ICP-MS analysis of the white seawater showed high concentrations of Al（475.0 ppm），Fe（120 ppm）and Si（58 ppm），suggesting that hydrothermal fluids including such elements emanated from the seafloor in this area．XRD amlysis reveals that the first precipitates deposited in a container from extracted white seawater contain halite（NaCl），alunite（KAl_3（SO_4）_2（OH）_6），boehmite（AlO（OH）），and variscite（AlPO_4・2H_2O）．After 10 months，precipitates deposited in the container comprised halite，gibbsite（Al（OH）_3）and boehmite．SEM and TEM observation of
these deposits found that bacilli and cocci type bacteria were covered with fine spherical grains or flakey materials．
Especially，the bacteria inhabiting in the precipitate after 10 months possessed flakey materials covering thin films．EDX analysis of the precipitates showed that the minerals occuring around bacterial cell walls were rich in Al．Electron diffraction patterns ofthe flakey materials identified gibbsite with diffraction rings at 2.5 A（021），2.1 A（312）and 1.5A．
Bacteria tolerant to high Al（Al-resistant bacteria）may be useful for Al-rich polluted soils associated with bioremediation plants．