Brownish discoloration of the summit crater lake of Mt. Shinmoe-dake, Kirishima Volcano, Japan: volcanic–microbial coupled origin

Chemistry, Growth, and Fate of the Unique, Short‐Lived (2019–2020) Water Lake at the Summit of Kīlauea Volcano, Hawaii

“…There, a change in color from blue‐green to brown was attributed to the presence of schwertmannite. A cultivation test from the Shinmoe‐dake lake revealed that the lake hosts iron‐oxidizing bacteria, which likely mediated schwertmannite formation (Ohsawa et al., 2014).…”

2015 Atomic Spectrometry Update – a review of advances in X-ray fluorescence spectrometry and their applications

“…Alternative materials for the removal of uoride from ground water were characterised by a range of techniques, including EDXRF spectrometry by Mohan et al 154 These materials were corn stover biochar and magnetic corn stover biochar (corn stover is the leaves and stalks of maize, le in the elds aer harvest) and both were considered to be an effective substitute for expensive commercial absorbents. Turning to another geochemical application, Ohsawa et al 157 studied the brownish colouration that occurred in the summit crater of Mount Shinoe-dake, Kirishima Volcano, Japan using the XRF and FTIR techniques to show the presence of schwertmannite (Fe 8 O 8 (OH) 6 SO 4 ), probably formed by ironoxidising bacteria that use pyrite (FeS 2 ) as an energy source. The authors considered that the attachment of microorganisms could be ascribed to the presence of muscovite, which facilitated adhesion.…”

“…In a similar vein, As and Fe speciation and distribution in organic ocks from the streambed of an area of arsenic-enriched peat land at Gola di Lago, Switzerland were studied by ThomasArrigo et al 156 Mössbauer and SR (m-XRF, AS, XRD) techniques were used to characterise the species present and the authors concluded that the oc bioorganics primarily served as nucleation sites for the precipitation of nanocrystalline Fe III -(oxyhydr)oxides, rendering these ocks as effective absorbents for metals and metalloids. Turning to another geochemical application, Ohsawa et al 157 studied the brownish colouration that occurred in the summit crater of Mount Shinoe-dake, Kirishima Volcano, Japan using the XRF and FTIR techniques to show the presence of schwertmannite (Fe 8 O 8 (OH) 6 SO 4 ), probably formed by ironoxidising bacteria that use pyrite (FeS 2 ) as an energy source. Geothermal energy is oen generated in volcanic regions and XRF, XRD and SEM instrumentation were used by Demir et al 158 to characterise the type of scaling formed during the extraction of geothermal brine at 173 C in the Tuzla area, north western Turkey.…”