Kim Yumi, Kang Sung-Min, Jo Kyoung-Nam, Roh Yul
Department of Geological and Environmental Sciences, Chonnam National University, 77 Yongbong-Ro, Buk-Gu, Gwangju, 61186, Republic of Korea.
Department of Geology, Kangwon National University, Chuncheon, 24341, Republic of Korea.
Sci Rep. 2025 Feb 28;15(1):7182. doi: 10.1038/s41598-025-91585-w.
Cave microorganisms associated with calcareous speleothems have been reported to facilitate calcium carbonate precipitation through crystal nucleation and mineral growth. In this study, we used carbonate-forming microorganisms enriched from cave water droplets and stalactite biofilm samples to induce precipitation of Mg or Sr-coprecipitated carbonate minerals and explored their mineralogical properties. The samples for these analyses were collected from Yongcheon Cave, a lime-decorated lava tube located on Jeju Island in South Korea. They included five soil and sediment samples from outside the cave, seven drip water samples from inside the cave, and nine biofilm samples swiped using sterilized cotton swabs from inside the cave. The microorganisms enriched from the drip water samples comprised bacterial genera, including Pseudomonas, Bacillus, Stenotrophomonas, Acinetobacter, and Morganella. which are known to contribute to carbonate formation. In contrast, the microorganisms enriched from the biofilms were dominated by Pseudomonas. When only Ca was present in the growth medium (Ca:Sr = 3:0), these microorganisms precipitated calcite and vaterite. Conversely, when Ca and Sr were present at varying ratios (Ca:Sr = 2:1, 1:1, and 1:2), calcian-strontianite was precipitated. Furthermore, when only Sr was present (Ca:Sr = 0:3), strontianite was formed. Adding Ca and Mg at varying ratios (Ca:Mg = 2:1, 1:1, and 1:2) led to the precipitation of magnesian-calcite and monohydrocalcite. When only Mg was added to the medium (Ca:Mg = 0:3), nesquehonite and struvite precipitated. These findings suggest that microorganisms enriched from the lava tube cave induce calcium carbonate precipitation through ureolysis and that Sr/Cr and Mg/Ca ratios influence the type of precipitated carbonate or phosphate minerals.
据报道，与钙质洞穴沉积物相关的洞穴微生物可通过晶体成核和矿物生长促进碳酸钙沉淀。在本研究中，我们使用从洞穴水滴和钟乳石生物膜样品中富集的碳酸盐形成微生物来诱导镁或锶共沉淀碳酸盐矿物的沉淀，并探索其矿物学性质。这些分析的样品采自韩国济州岛一个石灰装饰的熔岩管——龙川洞。它们包括五个洞穴外的土壤和沉积物样品、七个洞穴内的滴水样品，以及九个用无菌棉签从洞穴内擦拭的生物膜样品。从滴水样品中富集的微生物包括假单胞菌属、芽孢杆菌属、嗜麦芽窄食单胞菌属、不动杆菌属和摩根氏菌属等细菌属，已知这些细菌有助于碳酸盐的形成。相比之下，从生物膜中富集的微生物以假单胞菌属为主。当生长培养基中仅存在钙（钙：锶 = 3：0）时，这些微生物沉淀出方解石和球霰石。相反，当钙和锶以不同比例存在（钙：锶 = 2：1、1：1和1：2）时，沉淀出钙锶菱锶矿。此外，当仅存在锶（钙：锶 = 0：3）时，形成菱锶矿。以不同比例添加钙和镁（钙：镁 = 2：1、1：1和1：2）导致沉淀出镁方解石和一水碳钙石。当仅向培养基中添加镁（钙：镁 = 0：3）时，沉淀出三水碳酸镁石和鸟粪石。这些发现表明，从熔岩管洞穴中富集的微生物通过尿素分解诱导碳酸钙沉淀，并且锶/铬和镁/钙的比例会影响沉淀的碳酸盐或磷酸盐矿物的类型。
