Jelly-like Microbial Mats over Subsurface Fields of Gas Hydrates at the St. Petersburg Methane Seep (Central Baikal)

The paper presents the results of the study of communities of macroinvertebrates and cottoid fish inhabiting methane seeps of Lake Baikal. For the analysis, we used video surveillance and collection of animals carried out with the help of "Mir" deep-water submersible, as well as NIOZ-type box-corer samplers from the board of a research vessel. Posolskaya Bank and Saint Petersburg methane seeps are located in different basins (southern and middle) and at different depths (300–500 m and ~ 1400 m), characterized by the different underwater landscapes (slope of underwater upland and hills formed by gas hydrates), by the structure of gas hydrates and their depth location in sediments, as well as the composition of microbial mats and communities of microorganisms of bottom sediments. Both seeps are characterized by bubble discharge of methane gas and the formation of highly productive communities of large invertebrates and cottoid fish on seep habitats. Seep animal communities consisted of species-depleted invertebrates and fish of the surrounding deep-water benthal of the Lake. We showed the similarities and differences in the composition of the faunas of two seeps, as well as the quantitative characteristics of taxonomic groups of macroinvertebrates and cottoid fishes. Obligate species have not been revealed on the methane seep Posolskaya Bank. For the methane seep Saint Petersburg, the gastropod species Kobeltocochlea tamarae Sitnikova, Teterina et Maximova, 2021 (Caenogastropoda: Benedictiidae) was designated as an obligate species; among bottom cottoid fishes, Neocottus werestschagini (Taliev, 1953) (Cottoidei: Abyssocottidae) had possible a transitional state to obligate. We presented the data on the assimilation by seep animals of mixed photo- and chemosynthetic food with different proportions of methane-derived carbon. A hypothesis has been substantiated that deep-water seep areas could serve as refugium for the preservation of endemic fauna during the Pliocene-Pleistocene glaciations of Lake Baikal.

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Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

Journal of Geological Research ◽

10.1155/2011/592703 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Daidai Wu ◽

Nengyou Wu ◽

Ying Ye ◽

Mei Zhang ◽

Lihua Liu ◽

...

Keyword(s):

South China Sea ◽

Pore Water ◽

South China ◽

Gas Hydrates ◽

Cold Seep ◽

Methane Seep ◽

Gas Reservoirs ◽

China Sea ◽

Water Composition ◽

Geochemical Properties

Several authigenic minerals were identified by XRD and SEM analyses in shallow sediments from the Southeast Hainan Basin, on the northern slope of South China Sea. These minerals include miscellaneous carbonates, sulphates, and framboidal pyrite, and this mineral assemblage indicates the existence of gas hydrates and a methane seep. The assemblage and fabric features of the minerals are similar to those identified in cold-seep sediments, which are thought to be related to microorganisms fostered by dissolved methane. Chemical composition of pore water shows that the concentrations of SO42-, Ca2+, Mg2+, and Sr2+ decrease clearly, and the ratios of Mg2+ to Ca2+ and Sr2+ to Ca2+ increase sharply with depth. These geochemical properties are similar to those where gas hydrates occur in the world. All results seem to indicate clearly the presence of gas hydrates or deep water oil (gas) reservoirs underneath the seafloor.

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A Permian methane seep system as a paleoenvironmental analogue for the pre-metazoan carbonate platforms

Brazilian Journal of Geology ◽

10.1590/2317-4889201720170125 ◽

2017 ◽

Vol 47 (4) ◽

pp. 722-733 ◽

Cited By ~ 1

Author(s):

Lucas Veríssimo Warren ◽

Fernanda Quaglio ◽

Marcello Guimarães Simões ◽

Mario Luis Assine ◽

Luciano Alessandretti ◽

...

Keyword(s):

Microbial Mats ◽

High Salinity ◽

Oxygen Depletion ◽

Cold Seep ◽

Mass Extinctions ◽

Methane Seep ◽

Carbonate Platforms ◽

Carbonate Production ◽

Microbial Carbonate ◽

Geologic Record

ABSTRACT: Following the rise of metazoans, the beginning of bioclasticity and substrate competition, the saga of microbial mats was in a fluctuating decline in the end of the Neoproterozoic era. Increases in diversity during the Phanerozoic and punctual upturns in the microbial carbonate production occured after the events of global mass extinctions. Gradually along the Phanerozoic, the microbial colonies occupied isolated niches and grazers-free environments, characterized by physically and/or geochemically stressful conditions, such as those found in saline bays, alkaline lakes and hydrothermal or cold seep vents. Here we report one of the oldest occurrences of a vent camp coupled with cold seepage of methane in the geologic record, associated with well-preserved microbialites and elephant skin structures. During the seep activity, oxygen depletion and high salinity conditions are prohibitive for complex animal life, clearing the way to microbial colonies to flourish. Due to the co-occurrence of high adaptability and low competitiveness of microbial forms, they became highly specialized in stressful conditions. We argue that the sporadic microbial mat upturns in Earth’s history are not restricted to geological periods, following massive death of metazoan species; they also may occur in response to punctual paleoenvironmental conditions that enable microbial colonies to growth. Indeed, the Phanerozoic geological record is punctuated of these examples, in a kind of hide-and-seek game of Precambrian times.

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Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

Biogeosciences ◽

10.5194/bg-13-4491-2016 ◽

2016 ◽

Vol 13 (15) ◽

pp. 4491-4512 ◽

Cited By ~ 24

Author(s):

Heiko Sahling ◽

Christian Borowski ◽

Elva Escobar-Briones ◽

Adriana Gaytán-Caballero ◽

Chieh-Wei Hsu ◽

...

Keyword(s):

Gulf Of Mexico ◽

Gas Hydrates ◽

Microbial Mats ◽

Continental Margins ◽

Associated Gas ◽

Carbon Isotopic ◽

Tube Worms ◽

Southern Gulf Of Mexico ◽

Gaseous Hydrocarbons ◽

Multibeam Mapping

Abstract. Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1–2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

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Biodiversity in soft-sediments of mud volcanoes in the eastern Mediterranean Sea

10.7287/peerj.preprints.26955 ◽

2018 ◽

Author(s):

Patricia A Ramey-Balci ◽

Nicole Raineault ◽

Derya Ürkmez

Keyword(s):

Mediterranean Sea ◽

Spatial Scale ◽

Deep Sea ◽

Microbial Mats ◽

Eastern Mediterranean ◽

Sediment Cores ◽

Methane Seep ◽

Mud Volcanoes ◽

Soft Sediments ◽

History Of

Biodiversity in coastal ecosystems of the Mediterranean Sea have a long history of intense studies but investigations in deep-sea habitats are scarce. In collaboration with the (E/V) Nautilus, we examined the Anaximander Seamounts, located in the south of Turkey, at the junction of the Hellenic and Cyprus arcs. Five mud volcanoes (Amsterdam, Kula, Thessaloniki, Kazan, Athina; depths 1250−2300 m) and a non-seep site (Anaximenes Ridge, 818-m depth) were sampled in July/August 2012 and quantitative, soft-sediment cores (6-cm diameter, 10-cm deep) were collected for community analyses and DNA barcoding of organisms. Actively seeping fluid (14°C) containing methane was present at several volcanoes. The seabed was heterogeneous, consisting of soft-sediments interspersed with carbonate crusts harboring mussels and tubeworms. Varying colors of patchy, superficial microbial mats were the most common methane seep habitat. We characterized the distribution and community structure of macro- and meiobenthos in these reduced sediments. Specific questions addressed include: Do community composition and diversity differ: A. from one mud volcano to another (spatial scale of km), B. from communities in non-seep sediments, and C. at different locations/depths on mud volcanoes (spatial scale <1 m to km)? How unique and diverse are these communities compared to those in similar habitats elsewhere?

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Biodiversity in soft-sediments of mud volcanoes in the eastern Mediterranean Sea

10.7287/peerj.preprints.26955v1 ◽

2018 ◽

Author(s):

Patricia A Ramey-Balci ◽

Nicole Raineault ◽

Derya Ürkmez

Keyword(s):

Mediterranean Sea ◽

Spatial Scale ◽

Deep Sea ◽

Microbial Mats ◽

Eastern Mediterranean ◽

Sediment Cores ◽

Methane Seep ◽

Mud Volcanoes ◽

Soft Sediments ◽

History Of

Biodiversity in coastal ecosystems of the Mediterranean Sea have a long history of intense studies but investigations in deep-sea habitats are scarce. In collaboration with the (E/V) Nautilus, we examined the Anaximander Seamounts, located in the south of Turkey, at the junction of the Hellenic and Cyprus arcs. Five mud volcanoes (Amsterdam, Kula, Thessaloniki, Kazan, Athina; depths 1250−2300 m) and a non-seep site (Anaximenes Ridge, 818-m depth) were sampled in July/August 2012 and quantitative, soft-sediment cores (6-cm diameter, 10-cm deep) were collected for community analyses and DNA barcoding of organisms. Actively seeping fluid (14°C) containing methane was present at several volcanoes. The seabed was heterogeneous, consisting of soft-sediments interspersed with carbonate crusts harboring mussels and tubeworms. Varying colors of patchy, superficial microbial mats were the most common methane seep habitat. We characterized the distribution and community structure of macro- and meiobenthos in these reduced sediments. Specific questions addressed include: Do community composition and diversity differ: A. from one mud volcano to another (spatial scale of km), B. from communities in non-seep sediments, and C. at different locations/depths on mud volcanoes (spatial scale <1 m to km)? How unique and diverse are these communities compared to those in similar habitats elsewhere?

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