China
Africa
Explore chapters and articles related to this topic
Enrichment of ANME-2 Dominated Anaerobic Oxidation of Methane Coupled to Sulfate Reduction Consortia from Cold Seep Sediment (Ginsburg Mud Volcano, Gulf of Cadiz) in a Membrane Bioreactor
Published in Susma Bhattarai Gautam, Performance Assessment and Enrichment of Anaerobic Methane Oxidising Microbial Communities from Marine Sediments in Bioreactors, 2018
S. Bhattarai, C. Cassarini, E.R. Rene, S. Kümmel, G. Esposito
The AOM activity and rate in the MBR is in the range of seep and mud volcano samples (Knittel & Boetius, 2009). However, it was lower than the so far reported rates for high pressure incubations and bioreactor systems (Deusner et al., 2009; Timmers et al., 2015; Zhang et al., 2010). As methane is poorly soluble in marine water at ambient pressure (Thauer & Shima, 2008; Yamamoto et al., 1976), the AOM reaction is highly influenced by the methane partial pressure in both natural environments and bioreactor systems. An effective and continuous methane supply to anaerobic methanotrophs is an important factor for the enrichment of ANME. Similar to a previously reported MBR, the methane was continuously bubbled in the MBR to ensure the continuous methane availability to the AOM enrichments (Meulepas et al. 2009). However the AOM rate achieved in this MBR was almost 100 times lower than the AOM rate achieved in that MBR operated by Meulepas et al. (2009). The inoculum used in the previous MBR study was from Eckernförde Bay with a water depth of 28 m (Meulepas et al. 2009), so maybe AOM activity was favored in the ambient condition. However, MBR operated in this study was inoculated by cold seep sediment from Ginsburg mud volcano obtained from 910 m water depth, so the in situ pressure of biomass origin was 90 times of atmospheric pressure. On a positive note, the AOM rate obtained in this study is comparable to the results achieved in a hanging sponge bioreactor that was fed with high sulfate loads (30 mmol L−1 day−1) and operated at 10°C for 2,013 days (Aoki et al., 2014).
Physiology and Distribution of Anaerobic Oxidation of Methane by Archaeal Methanotrophs
Published in Chiara Cassarini, Anaerobic Oxidation of Methane Coupled to the Reduction of Different Sulfur Compounds as Electron Acceptors in Bioreactors, 2019
Other cold seep sediments were also extensively studied as ANME habitats. The Gulf of Mexico, a cold seep with bottom water temperature of 6°C to 8°C, is known for its gas seepage and associated hydrates. These CH4 hydrates located at around 500 m seawater depth in the Gulf of Mexico are inhabited by diverse microbial communities: Beggiatoa mats with active AOM are common bottom microbial biota in the sulfidic sediments (Joye et al., 2004; Lloyd et al., 2006; Orcutt et al., 2005; Orcutt et al., 2008). ANME-1 dominates the sediment of the Gulf of Mexico, particularly in the hypersaline part as a monospecific clade, whereas ANME-2 (a and b) are present together with DSS groups in the less saline hydrates (Lloyd et al., 2006; Orcutt et al., 2005). Similarly, different mud volcanoes of the Gulf of Cadiz cold seep harbor ANME-2 with the majority being ANME-2a (Niemann et al., 2006a), whereas the hypersaline Mercator Mud Volcano of the Gulf of Cadiz hosts ANME-1 (Maignien et al., 2013). Retrieval of ANME-1 in the hypersaline environment suggests the ANME-1 adaptability to wider salinity ranges compared to other ANME phylotypes. Mud volcanoes from the Eastern Mediterranean (Kazan and Anaximander mountains) are inhabited by all three ANME phylotypes, whereas Kazan Mud Volcano hosts the distinct ANME-2c clade (Heijs et al., 2007; Kormas et al., 2008; Pachiadaki et al., 2010; Pachiadaki et al., 2011). Likewise, Haakon Mosby Mud Volcano (HMMV) in the Barents Sea is the firstly described habitat for ANME-3 with almost 80 % of the microbial cells being ANME-3 and DBB (Figures 2.6B and 2.2D) (Losekann et al., 2007; Niemann et al., 2006b).
Genetic link between Miocene seafloor methane seep limestones and underlying carbonate conduit concretions at Rocky Knob, Gisborne, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2019
Campbell S. Nelson, Kathleen A. Campbell, Stephanie L. Nyman, Jens Greinert, David A. Francis, Steven D. Hood
Rocky Knob, the largest of the Bexhaven Limestone bodies in East Coast Basin, is broadly lenticular, up to 60 m thick and at least 200 m across (Figure 2A), with an inferred maximum burial depth of some 1500–2500 m (Francis unpublished). It is located c. 40 km north of Gisborne in Moonlight Forest on Moonlight Station (Figure 1B, C), from whence the earlier informal name ‘Moonlight limestone’ was coined by Kamp and Nelson (1988) for this ‘unusual’ carbonate unit. Mazengarb et al. (1991) showed it to be middle Miocene in age (upper Lillburnian New Zealand stage, or Langhian-Serravallian international stage) based on diagnostic microfossils from the enclosing deep-water mudstone. Collins (1999) was the first to systematically document the chemosymbiotic bathymodioline mussel fossils at Rocky Knob, which implied a methane seep connection. Recognition of the body as a cold seep carbonate complex by Campbell et al. (2008) was accomplished utilising reconnaissance stratigraphic, lithologic, paleontologic, stable isotopic and petrologic information. Detailed paleontological study of the Miocene East Coast Basin seep carbonates followed, including the fossil-rich Rocky Knob locality (Saether, Little, Campbell, Marshall, et al. 2010; Saether, Little, Campbell 2010; Saether et al. 2012, 2016; Amano et al. 2014, 2015). A special feature of the Rocky Knob occurrence is the presence of tubular conduit concretions in the host mudstone stratigraphically just beneath the fossiliferous seep limestone deposit which we have previously inferred mark parts of the focussed plumbing pathways of methane ascent to the paleo-seabed (Figure 2B; Campbell et al. 2008). This relationship is otherwise unstudied until this contribution.
Aluminium-normalised trace-element paleoredox proxies and their application to the study of the conditions of Burgess Shale-type preservation
Published in Australian Journal of Earth Sciences, 2023
K. C. Meehan, W. G. Powell, D. M. McKirdy, P. A. Hall, C. Nedin, P. A. Johnston, C. J. Collom
Recent studies of Mesozoic ichnofossil assemblages and modern polychaetes have shown that some burrowing organisms are more tolerant of osmotic stress and other environmental perturbations than previously recognised (Fraiser & Bottjer, 2009; Jaglarz & Uchman, 2010; Lamptey & Armah, 2008). Priapulids, abundant by the end of the Neoproterozoic (Vannier et al., 2010), were joined by polychaetes in the early Cambrian (Vinther et al., 2011). Such fauna may have filled hypersaline and hypoxic niches, as they and some oligochaetes and hirudineans do today (Dávila-Jiménez et al., 2019; Kornijów et al., 2010; Reynoldson, 1987). Moreover, unknown only a few decades ago, methane cold-seep systems (modern and ancient) preserve abundant infaunal organisms inhabiting sediments enriched in methane, hydrogen sulfide and sulfates (Campbell, 2006; Levin, 2005). Methanogenic epi- and endosymbionts have allowed countless organisms, motile and sessile, to thrive under conditions commonly considered inhospitable but now understood to offer oases in a multitude of less optimal environments. These include ancient and modern basins, shallow lagoons, metal-rich brine seeps and deep-sea abyssal plains (Åström et al., 2018; Brankovits et al., 2017; Feng et al., 2018; Landman et al., 2012; Little et al., 2015; Meehan & Landman, 2016; Rowe et al., 2020). Modern severe hypoxia is known to decimate some populations, whereas other opportunistic organisms rapidly inhabit these areas and flourish (Blasnig, 2012; Hernández-Miranda et al., 2012, 2017; Labra et al., 2020; Por, 2012). Like that of ichnofossil assemblages, our understanding of epifaunal inhabitants of non-traditional or extreme environments is in its nascency. Accordingly, the redox conditions associated with BST preservation require re-examination with consideration given to geochemical proxies, and not inferred from paleontology alone.