Molecular Profiling of Microbial Communities Associated with a Potential Mud Volcano (Düzce, NW-Türkiye)

Abstract

The geographic distribution of mud volcanoes is contingent upon geological processes, with the majority occurring in regions of recent tectonic activity, particularly within compressional zones. The current understanding of microorganisms involved in the anaerobic oxidation of methane in these settings is largely derived from studies of methane seep environments, where high concentrations of methane and sulfate sustain the high activity of syntrophic archaeal and bacterial consortia. This study was designed to investigate the microbial communities within a potential mud volcano observed following the Ml=6.0 earthquake that occurred in Düzce Province, Türkiye, in 2022. In this context, mud and water samples were collected in November 2023 to characterize the initial stage of a potential mud volcano. To determine microbial diversity and abundance, gene regions specific to the BACT, ARC, ANME-1, MCRA, SRB2, DSS, and DBB groups were quantified using Real-Time Quantitative PCR (qPCR). The highest bacterial abundance (1.52 × 10¹⁰ gene copies g⁻¹) was observed in the mud sample. Conversely, the lowest abundance was recorded for the Desulfobulbus group (2.49 × 10² gene copies mL⁻¹) in the water sample. This research represents the first investigation in Türkiye to assess the presence and abundance of archaeal and bacterial groups in a potential mud volcano located in an onshore setting. The mechanisms of formation, structural characteristics, and microbial diversity of terrestrial mud volcanoes may be further elucidated using advanced techniques such as phylogenetic analysis, radioisotope measurements, lipid biomarker analysis, and isotopic investigations.

Keywords

• Archaea
• Bacteria
• Mud volcano
• Düzce
• Microbial abundance

Project Number

FHD-2023-3225

Olası Bir Çamur Volkanı (Düzce, KB-Türkiye) İlişkili Mikrobiyal Toplulukların Moleküler Profili

Abstract

Çamur volkanlarının coğrafi oluşumu jeolojik olaylara bağlıdır ve bunların çoğunluğu yakın zamandaki tektonik aktivite alanlarında, özellikle de sıkışma bölgelerinde meydana gelmektedir. Bu alanlarda anaerobik metan oksidasyonunda rol oynayan mikroorganizmalar hakkındaki mevcut bilgi birikimi, yüksek metan ve sülfat konsantrasyonlarının arke ve bakteri sintrofik ilişkilerinin yüksek aktivitesini desteklediği metan sızdıran ortamların çalışmalarına dayanmaktadır. 2022 yılında Düzce ilinde (Türkiye) gerçekleşen Ml=6.0 büyüklüğündeki depremden sonra gözlenen olası bir çamur volkanında mikrobiyolojik toplulukların araştırılması amacıyla çalışma planlanmıştır. Bu kapsamda, Düzce ilinde olası bir çamur volkanının başlangıç aşamasının araştırılmasına yönelik olarak, 2023 yılı Kasım ayında çamur ve su örnekleri toplanmıştır. Çalışmada mikrobiyal çeşitliliğin ve bolluğun belirlenmesinde; BACT, ARC, ANME-1, MCRA, SRB2, DSS ve DBB gruplarına ait gen bölgeleri Real time quantitative PCR (qPCR) ile belirlenmiştir. En yüksek bakteri bolluğu (1.52x1010 gen kopya sayısı/gr) çamur örneğinde gözlenmiştir. En düşük yoğunluğa sahip grup su örneğinde Desulfobulbus (2.49x102 gen kopya sayısı/mL) olarak saptanmıştır. Düzce ili çamur volkanında yürütülen bu çalışma, arke ve bakteri gruplarının varlığı ve bolluğunun araştırıldığı, ülkemizde karasal bir ortamda varlığı bilinen bir çamur volkanında gerçekleştirilen ilk çalışma olma özelliğini taşımaktadır. Filogenetik analizler, radyoizotop ölçümleri, lipit analizleri ve izotopik araştırmalar gibi ileri düzey analizlerle, karasal çamur volkanlarının oluşumu, yapısı ve mikrobiyal çeşitliliği daha anlaşılır olabilecektir.

Keywords

• Arke
• Bakteri
• Çamur volkanı
• Düzce
• Mikrobiyal bolluk

Supporting Institution

Çalışma Dokuz Eylül Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi FHD-2023-3225 koduyla desteklenmiştir.

Project Number

FHD-2023-3225

Ethical Statement

Çalışma, etik kurul izni veya herhangi bir özel izin gerektirmemektedir.

Thanks

Bu çalışma Dokuz Eylül Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi FHD-2023-3225 koduyla desteklenmiştir. Proje ekibine ayrıca teşekkür ederiz.

References

1. Merkel, A. Y., Chernyh, N. A., Pimenov, N. V., Bonch-Osmolovskaya, E. A., & Slobodkin, A. I. (2021). Diversity and metabolic potential of the terrestrial mud volcano microbial community with a high abundance of Archaea mediating the anaerobic oxidation of methane. Life, 11(9), 953. https://doi.org/10.3390/life11090953
2. Mazzini, A., & Etiope, G. (2017). Mud volcanism: An updated review. Earth-Science Reviews, 168(1), 81–112. https://doi.org/10.1016/j.earscirev.2017.03.001
3. Dimitrov, L. I. (2002). Mud volcanoes – the most important pathway for degassing deeply buried sediments. Earth-Science Reviews, 59(1–4), 49–76. https://doi.org/10.1016/S0012-8252(02)00069-7
4. Kopf, A. J. (2002). Significance of mud volcanism. Reviews of Geophysics, 40(2), 1–52. https://doi.org/10.1029/2000RG000093
5. Planke, S., Svensen, H., Hovland, M., Banks, D. A., & Jamtveit, B. (2003). Mud and fluid migration in active mud volcanoes in Azerbaijan. Geo-Marine Letters, 23, 258–268. https://doi.org/10.1007/s00367-003-0152-z
6. Davies, R. J., Swarbrick, R. E., Evans, R. J., & Huuse, M. (2006). Birth of a mud volcano: East Java, 29 May 2006. Geological Society of America Today, 17(2), 4–9. https://doi.org/10.1130/GSAT01702A.1
7. Manga, M., Brumm, M., & Rudolph, M. L. (2009). Earthquake triggering of mud volcanoes. Marine and Petroleum Geology, 26(9), 1785–1798. https://doi.org/10.1016/j.marpetgeo.2009.01.019
8. Milkov, A. V., Sassen, R., Apanasovich, T. V., & Dadashev, F. G. (2003). Global gas flux from mud volcanoes: a significant source of fossil methane in the atmosphere and the ocean. Geophysical Research Letters, 3, 1037–1040. https://doi.org/10.1029/2002GL016358

9. Etiope, G., & Milkov, A. V. (2004). A new estimate of global methane flux from onshore and shallow submarine mud volcanoes to the atmosphere. Environmental Geology, 46(8), 997–1002. https://doi.org/10.1007/s00254-004-1085-1
10. Alain, K., Holler, T., Musat, F., Elvert, M., Treude, T., & Kruger, M. (2006). Microbiological investigation of methane- and hydrocarbon-discharging mud volcanoes in the Carpathian Mountains, Romania. Environmental Microbiology, 8(4), 574–590. https://doi.org/10.1111/j.1462-2920.2005.00922.x
11. Istadi, B. P., Pramono, G. H., Sumintadireja, P., & Alam, S. (2009). Modeling study of growth and potential geohazard for LUSI mud volcano: East Java, Indonesia. Marine and Petroleum Geology, 26(9), 1724–1739. https://doi.org/10.1016/j.marpetgeo.2009.03.006
12. Tahlatli, N. E., Bakdamirova, G. İ., & Yusifova, T. C. (2023, 23–26 Mayıs). 2010–2020 yılları arasında Azerbaycan'da çamur volkanları etrafında gerginlik vaziyetinin değerlendirilmesi [Konferans bildirisi]. The International Scientific and Practical Conference, Haydar Aliyev and Azerbaijan Oil Strategy: Advances in Oil and Gas Geology and Geotechnologies, Bakü, Azerbaycan.
13. Niemann, H., Lösekann, T., De Beer, D., Elvert, M., Nadalig, T., Knittel, K., Amann, R., Sauter, E. J., Schlüter, M., Klages, M., Foucher, J. P., & Boetius, A. (2006). Novel microbial communities of the Haakon Mosby mud volcano and their role as a methane sink. Nature, 443, 854–858. https://doi.org/10.1038/nature05227
14. Lösekann, T., Knittel, K., Nadalig, T., Fuchs, B., Niemann, H., Boetius, A., & Amann, R. (2007). Diversity and abundance of aerobic and anaerobic methane oxidizers at the Haakon Mosby Mud Volcano, Barents Sea. Applied and Environmental Microbiology, 73(10), 3348–3362. https://doi.org/10.1128/AEM.00016-07
15. Omoregie, E. O., Mastalerz, V., De Lange, G., Straub, K. L., Kappler, A., Røy, H., Stadnitskaia, A., Foucher, J. P., & Boetius, A. (2008). Biogeochemistry and community composition of iron- and sulphur-precipitating microbial mats at the Chefren mud volcano (Nile Deep Sea Fan, Eastern Mediterranean). Applied and Environmental Microbiology, 74, 3198–3215. https://doi.org/10.1128/AEM.01751-07
16. Pachiadaki, M. G., Lykousis, V., Stefanou, E. G., & Kormas, K. A. (2010). Prokaryotic community structure and diversity in the sediments of an active submarine mud volcano (Kazan mud volcano, East Mediterranean Sea). FEMS Microbiology Ecology, 72, 429–444. https://doi.org/10.1111/j.1574-6941.2010.00857.x
17. Pachiadaki, M. G., Kallionaki, A., Dahlmann, A., De Lange, G. J., & Kormas, K. A. (2011). Diversity and spatial distribution of prokaryotic communities along a sediment vertical profile of a deep-sea mud volcano. Microbial Ecology, 62, 655–668. https://doi.org/10.1007/s00248-011-9855-2
18. Lazar, C. S., Parkes, R. J., Cragg, B. A., L’Haridon, S., & Toffin, L. (2011). Methanogenic diversity and activity in hypersaline sediments of the centre of the Napoli mud volcano, Eastern Mediterranean Sea. Environmental Microbiology, 13(8), 2078–2091. https://doi.org/10.1111/j.1462-2920.2011.02425.x
19. Lazar, C. S., Parkes, J. R., Cragg, B. A., L’Haridon, S., & Toffin, L. (2012). Methanogenic activity and diversity in the centre of the Amsterdam Mud Volcano, Eastern Mediterranean Sea. FEMS Microbiology Ecology, 81(2), 243–254. https://doi.org/10.1111/j.1574-6941.2012.01375.x
20. Ruff, S. E., Biddle, J. F., Teske, A. P., Knittel, K., Boetius, A., & Ramette, A. (2015). Global dispersion and local diversification of the methane seep microbiome. Proceedings of the National Academy of Sciences of the United States of America, 112, 4015–4020. https://doi.org/10.1073/pnas.1421865112
21. Coelho, F. J., Louvado, A., Domingues, P. M., Cleary, D. F., Ferreira, M., Almeida, A., Cunha, M. R., Cunha, Â., & Gomes, N. C. (2016). Integrated analysis of bacterial and microeukaryotic communities from differentially active mud volcanoes in the Gulf of Cadiz. Scientific Reports, 6(1), 35272. https://doi.org/10.1038/srep35272
22. Hoshino, T., Toki, T., Ijiri, A., Morono, Y., Machiyama, H., Ashi, J., Okamura, K., & Inagaki, F. (2017). Atribacteria from the subseafloor sedimentary biosphere disperse to the hydrosphere through submarine mud volcanoes. Frontiers in Microbiology, 8(1), 1135. https://doi.org/10.3389/fmicb.2017.01135
23. Slobodkina, G. B., Merkel, A. Y., Novikov, A. A., Bonch-Osmolovskaya, E. A., & Slobodkin, A. I. (2020). Pelomicrobium methylotrophicum gen. nov., sp. nov. A moderately thermophilic, facultatively anaerobic, lithoautotrophic and methylotrophic bacterium isolated from a terrestrial mud volcano. Extremophiles, 24, 177–185. https://doi.org/10.1007/s00792-019-01145-0
24. Wrede, C., Brady, S., Rockstroh, S., Dreier, A., Kokoschka, S., Heinzelmann, S.M., Heller, C., Reitner, J., Taviani, M., Daniel, R., & Hoppert, M. (2012). Aerobic and anaerobic methane oxidation in terrestrial mud volcanoes in the Northern Apennines. Sedimentary Geology, 263, 210–219. https://doi.org/10.1016/j.sedgeo.2011.06.004
25. Green-Saxena, A., Feyzullayev, A., Hubert, R. J., Kallmeyer, J., Krueger, M., Sauer, P., Schulz, H. M., & Orphan, V. J. (2012). Active sulphur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan. Environmental Microbiology, 14(12), 3271–3286. https://doi.org/10.1111/1462-2920.12015
26. Cheng, T. W., Chang, Y. H., Tang, S. L., Tseng, C. H., Chiang, P. W., Chang, K. T., Sun, C. H., Chen, Y. G., Kuo, H. C., Wang, C. H., Chu, P. H., Song, S. R., Wang, P. L., & Lin, H. H. (2012). Metabolic stratification driven by surface and subsurface interactions in a terrestrial mud volcano. The ISME Journal, 6(12), 2280–2290. https://doi.org/10.1038/ismej.2012.61
27. Wang, P. L., Chiu, Y. P., Cheng, T. W., Chang, Y. H., Tu, W. X., & Lin, L. H. (2014). Spatial variations of community structures and methane cycling across a transect of Lei-Gong-Hou mud volcanoes in eastern Taiwan. Frontiers in Microbiology, 5, 121. https://doi.org/10.3389/fmicb.2014.00121
28. Yang, H. M., Lou, K., Sun, J., Zhang, T., & Ma, X. L. (2012). Prokaryotic diversity of an active mud volcano in the Usu City of Xinjiang, China. Journal of Basic Microbiology, 52, 79–85. https://doi.org/10.1002/jobm.201100074
29. Lin, Y. T., Tu, T. H., Wei, C. L., Rumble, D., Lin, L. H., & Wang, P. L. (2018). Steep redox gradient and biogeochemical cycling driven by deeply sourced fluids and gases in a terrestrial mud volcano. FEMS Microbiology Ecology, 94(12), fiy171. https://doi.org/10.1093/femsec/fiy171
30. Ren, G., Ma, A., Zhang, Y., Deng, Y., Zheng, G., Zhuang, X., Zhuang, G., & Fortin, D. (2018). Electron acceptors for anaerobic oxidation of methane drive microbial community structure and diversity in mud volcanoes. Environmental Microbiology, 20, 2370–2385. https://doi.org/10.1111/1462-2920.14128
31. Schulze-Makuch, D., Haque, S., Beckles, D., Schmitt-Kopplin, P., Harir, M., Schneider, B., Stumpp, C., & Wagner, D. A. (2020). A chemical and microbial characterization of selected mud volcanoes in Trinidad reveals pathogens introduced by surface water and rain water. Science of the Total Environment, 707, 136087. https://doi.org/10.1016/j.scitotenv.2019.136087
32. Tu, T. H., Wu, L. W., Lin, Y. S., Imachi, H., Lin, L. H., & Wang, P. L. (2017). Microbial community composition and functional capacity in a terrestrial ferruginous, sulfate-depleted mud volcano. Frontiers in Microbiology, 8, 2137. https://doi.org/10.3389/fmicb.2017.02137
33. Mardanov, A. V., Kadnikov, V. V., Beletsky, A. V., & Ravin, N. V. (2020). Sulfur and methane-oxidizing microbial community in a terrestrial mud volcano revealed by metagenomics. Microorganisms, 8(9), 1333. https://doi.org/10.3390/microorganisms809133
34. Chang, Y. H., Cheng, T. W., Lai, W. J., Tsai, W. Y., Sun, C. H., Lin, L. H., & Wang, P. L. (2012). Microbial methane cycling in a terrestrial mud volcano in eastern Taiwan. Environmental Microbiology, 14(4), 895–908. https://doi.org/10.1111/j.1462-2920.2011.02658.x
35. Kokoschka, S., Dreier, A., Romoth, K., Taviani, M., Schafer, N., Reitner, J., & Hoppert, M. (2015). Isolation of anaerobic bacteria from terrestrial mud volcanoes (Salse di Nirano, Northern Apennines, Italy). Geomicrobiology Journal, 32(4), 355–364. https://doi.org/10.1080/01490451.2014.940632
36. Rinke, C., Chuvochina, M., Mussig, A. J., Chaumeil, P. A., Davín, A. A., Waite, D. W., Whitman, W. B., Parks, D. H., & Hugenholtz, P. (2021). A standardized archaeal taxonomy for the Genome Taxonomy Database. Nature Microbiology, 6, 946–959. https://doi.org/10.1038/s41564-021-00918-8
37. Knittel, K., & Boetius, A. (2009). Anaerobic oxidation of methane: Progress with an unknown process. Annual Review of Microbiology, 63(1), 311–334. https://doi.org/10.1146/annurev.micro.61.080706.093130
38. Adam, P., Borrel, G., Brochier-Armanet, C., & Gribaldo, S. (2017). The growing tree of Archaea: New perspectives on their diversity, evolution and ecology. The ISME Journal, 11(11), 2407–2425. https://doi.org/10.1038/ismej.2017.122
39. Bhattarai, S., Cassarini, C., & Lens, P. N. L. (2019). Physiology and distribution of archaeal methanotrophs that couple anaerobic oxidation of methane with sulfate reduction. Microbiology and Molecular Biology Reviews, 83(1), e00074-18.
40. Raghoebarsing, A. A., Pol, A., Van de Pas-Schoonen, K. T., Smolders, A. J., Ettwig, K. F., Rijpstra, W. I., Schouten, S., Damsté, J. S., den Camp, H. J., Jetten, M. S., & Strous, M. (2006). A microbial consortium couples anaerobic methane oxidation to denitrification. Nature, 440, 918–921. https://doi.org/10.1038/nature04617
41. Beal, E. J., House, C. H., & Orphan, V. J. (2009). Manganese-and iron-dependent marine methane oxidation. Science, 325(5937), 184–187.
42. Cai, C., Leu, A. O., Xie, G. J., Guo, J., Feng, Y., Zhao, J. X., Tyson, G. W., Yuan, Z., & Hu, S. (2018). A methanotrophic archaeon couples anaerobic oxidation of methane to Fe(III) reduction. The ISME Journal, 12(8), 1929–1939.
43. Leu, A. O., Cai, C., McIlroy, S. J., Southam, G., Orphan, V. J., Yuan, Z., Hu, S., & Tyson, G. W. (2020). Anaerobic methane oxidation coupled to manganese reduction by members of the Methanoperedenaceae. The ISME Journal, 14(5), 1030–1041. https://doi.org/10.1038/s41396-020-0590-x
44. Joye, S. B., Boetius, A., Orcutt, B. N., Montoya, J. P., Schulz, H. N., Erickson, M. J., & Lugo, S. K., (2004). The anaerobic oxidation of methane and sulfate reduction in sediments from Gulf of Mexico cold seeps. Chemical Geology, 205(3–4), 219–238. https://doi.org/10.1016/j.chemgeo.2003.12.019
45. Biddle, J. F., House, C. H., & Brenchley, J. E. (2005). Microbial stratification in deeply buried marine sediment reflects changes in sulfate/methane profiles. Geobiology, 3(4), 287–295.
46. Bulut Üstün, A., Özata, A., Özerk, O. C., Osmançelebioğlu, R., Esirtgen, T., Kazancı, N., & Gürbüz, A. (2019). 1/250.000 ölçekli Türkiye sıvılaşmaya yatkınlık haritaları Adapazarı (NK 36-13), Ereğli (NK 36-9), Zonguldak (NK 36-10) ve Bolu (NK 36-14) paftaları. (Türkiye Sıvılaşmaya Yatkınlık Haritaları Serisi No. 1). Maden Tetkik ve Arama Genel Müdürlüğü.
47. Emre, Ö., Duman, T. Y., Awata, Y., Doğan, A., & Özalp, S. (2000, Eylül 10-15). Surface ruptures of November 12, 1999 Düzce Earthquake, NW Turkey. In XXVII General Assembly of the European Seismological Commission (ESC–2000): Book of Abstracts and Papers (pp. 247-252). Lisbon, Portugal.
48. Tokcaer, M. (2024). 23 Kasım 2022 Düzce depremi sonrasında gelişen gazlı su çıkışının kökensel açıdan değerlendirilmesine yönelik ön çalışma (Proje No: FHD-2023-3225). Dokuz Eylül Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi.
49. Emre, Ö., Duman, T. Y., & Özalp, S. (2021). 1:250.000 ölçekli Türkiye diri fay haritası serisi: Adapazarı (NK 36-13) paftası (Türkiye Diri Fay Haritası Serisi No. 14). Maden Tetkik ve Arama Genel Müdürlüğü.
50. Steinberg, L. M., & Regan, J. M. (2009). mcrA-targeted real-time quantitative PCR method to examine methanogen communities. Applied and Environmental Microbiology, 75, 4435–4442. https://doi.org/10.1128/AEM.02858-08
51. Vigneron, A., Cruaud, P., Pignet, P., Caprais, J. C., Cambon-Bonavita, M. A., Godfroy, A., & Laurent, T. (2013). Archaeal and anaerobic methane oxidizer communities in the Sonora Margin cold seeps, Guaymas Basin (Gulf of California). ISME Journal, 7, 1595–1608. https://doi.org/10.1038/ismej.2013.18
52. Vigneron, A., Cruaud, P., Pignet, P., Caprais, J. C., Gayet, N., Cambon-Bonavita, M. A., Godfroy, A., & Toffin, L. (2014). Bacterial communities and syntrophic associations involved in anaerobic oxidation of methane process of the Sonora Margin cold seeps, Guaymas Basin. Environmental Microbiology, 16, 2777–2790. https://doi.org/10.1111/1462-2920.12324
53. Timmers, P. H. A., Gieteling, J., Widjaja-Greefkes, H. C. A., Plugge, C. M., Stams, A. J. M., Lens, P. N. L., & Meulepas, R. J. W. (2015). Growth of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a high-pressure membrane capsule bioreactor. Applied and Environmental Microbiology, 82, 1286–1296. https://doi.org/10.1128/AEM.03255-14
54. Timmers, H. A., Welte, C. U., Koehorst, J. J., Plugge, C. M., Jetten, M. S. M., & Stams, A. J. M. (2017). Reverse methanogenesis and respiration in methanotrophic archaea. Archaea, 2017, 1654237. https://doi.org/10.1155/2017/1654237
55. Ma, K., Ma, A., Zheng, G., Ren, G., Xie, F., Zhou, H., Yin, J., Liang, Y., Zhuang, X., & Zhuang, G. (2021). Mineralosphere microbiome leading to changed geochemical properties of sedimentary rocks from Aiqigou mud volcano, Northwest China. Microorganisms, 9(3), 560. https://doi.org/10.3390/microorganisms9030560
56. Zhong, S., Zhang, J., Luo, J., Yuan, Y., & Su, P. (2021). Geological characteristics of mud volcanoes and diapirs in the Northern Continental Margin of the South China Sea: implications for the mechanisms controlling the genesis of fluid leakage structures. Geofluids, 2021, 5519264. https://doi.org/10.1155/2021/5519264
57. Farhan Ul-Haque, M., Crombie, A. T., Ensminger, S. A., Baciu, C., & Murrell, J. C. (2018). Facultative methanotrophs are abundant at terrestrial natural gas seeps. Microbiome, 6(1), 118. https://doi.org/10.1186/s40168-018-0500-x
58. Webster, G., Cragg, B. A., Rinna, J., Watkins, A. J., Sass, H., Weightman, A. J., & Parkes, R. J. (2023). Methanogen activity and microbial diversity in Gulf of Cadiz mud volcano sediments. Frontiers in Microbiology, 14, 1157337. https://doi.org/10.3389/fmicb.2023.1157337
59. United States Environmental Protection Agency. (2010). Methane and nitrous oxide emissions from natural sources (EPA 430-R-10-001). U.S. Environmental Protection Agency.
60. Miyake, N., Ishimaru, R., Komatsu, G., & Matsui, T. (2022). Characterization of archaeal and bacterial communities thriving in methane-seeping on-land mud volcanoes, Niigata, Japan. International Microbiology, 26, 191–204. https://doi.org/10.1007/s10123-022-00288-z
61. Kumar, R., Merugu, R., Mohapatra, S., Sharma, S., & Hemlata. (2022). Extremophiles: Life of microorganisms in extreme environments. In Extremophiles (pp. 43–66). CRC Press. https://doi.org/10.1201/9781003014188-3
62. Huang, Z., Xu, S., Han, Y., Gao, Y., Wang, Y., & Song, C. (2016). Comparative study of Dushanzi and Baiyanggou mud volcano microbial communities in Junggar Basin in Xinjiang. International Research Journal of Public and Environmental Health, 11(3), 244–256. https://doi.org/10.15739/irjpeh.16.031
63. Asif, A., Koner, S., Chen, J. S., Hussain, A., Huang, S. W., Hussain, B., & Hsu, B. M. (2024). Uncovering the microbial community structure and physiological profiles of terrestrial mud volcanoes: A comprehensive metagenomic insight towards their trichloroethylene biodegradation potentiality. Environmental Research, 258(1), 119457. https://doi.org/10.1016/j.envres.2024.119457
64. Liu, C. C., Maitya, J. P., Jean, J. S., Sracek, O., Kar, S., & Li, Z. (2011). Biogeochemical interactions among the arsenic, iron, humic substances, and microbes in mud volcanoes in southern Taiwan. Journal of Environmental Science and Health, Part A, 46(11), 1218–1230. https://doi.org/10.1080/10934529.2011.598793
65. Yakimov, M., Giuliano, L., Crisafi, E., Chernikova, T., Timmis, K., & Golyshin, P. (2002). Microbial community of a saline mud volcano at San Biagio-Belpasso, Mt. Etna (Italy). Environmental Microbiology, 4, 249–256. https://doi.org/10.1046/j.1462-2920.2002.00293.x
66. Martinez, R. J., Mills, H. J., Story, S., & Sobecky, P. A. (2006). Prokaryotic diversity and metabolically active microbial populations in sediments from an active mud volcano in the Gulf of Mexico. Environmental Microbiology, 8(10), 1783–1796. https://doi.org/10.1111/j.1462-2920.2006.01063.x
67. Chen, J. N., Chiu, Y. P., Tu, T. H., Italiano, F., Wang, P. L., & Lin, L. H. (2024). Variations in microbial community compositions and processes imposed under contrast geochemical contexts in Sicilian mud volcanoes, Italy. Frontiers in Microbiology, 15, 1461252. https://doi.org/10.3389/fmicb.2024.1461252
68. Remizovschi, A., Carpa, R. (2021). Biologically-oriented mud volcano database: muddy_db. PeerJ, 9, e12463. http://doi.org/10.7717/peerj.12463