Detection of methane in the water column at gas and oil seep sites in central and southern Lake Baikal

Abstract

Microbiological and biogeochemical investigation of the water column of oligotrophic Lake Baikal at the sites of the K2 and Bolshoi mud volcanoes and the Gorevoy Utes oil seep was carried out in July 2013. Total microbial numbers (TMN), cell numbers of type I and type II methanotrophs, and methane con centrations were measured; the rate of methane oxidation was determined. Methane concentrations in Lake Baikal water column varied from 0.09 to 1 µL/L, while methane oxidation rates varied from 0.007 to 0.9 nL/(L day). The highest rates of methane oxidation were revealed in the near bottom water horizons at the sites of the Bolshoy mud volcano and the Gorevoy Utes oil seep. These were the sites where the most pro nounced anomalies in methane concentration were also detected. TMN varied from 0.123 × 10 6 to 1.64 × 10 6 cells/mL. Methanotrophic bacteria were revealed in the water column at all sites, their abundance did not always correlate with methane concentrations and the rates of methane oxidation. Methanotrophs consti tuted not more than 1.63% of the total microbial number, with their highest abundance in the upper 200 m of the water column.

Methane release from sediment seeps to the atmosphere is counteracted by highly active Methylococcaceae in the water column of deep oligotrophic Lake Constance

“…Our data confirm earlier results derived from depth profiles of methane isotopic carbon signatures, which indicated that around 90% of the pockmark-derived methane is oxidized within the deep hypolimnion (Bussmann et al 2013). Thus, methane availability appears to largely determine the activity of methanotrophic bacteria, as has been repeatedly observed in studies on lake water columns and on marine pelagic environments adjacent to methane seeps or methane gas hydrates (Valentine et al 2001;Durisch-Kaiser et al 2005;Sundh, Bastviken and Tranvik 2005;Kankaala et al 2006;Zakharenko et al 2015). The positive correlation between methane concentrations and MOX should be typically double-checked since activity calculations depend linearly on methane concentrations (see Material and Methods).…”

Microbiome of the deep Lake Baikal, a unique oxic bathypelagic habitat

“…The large amounts of methane hydrates found in Lake Baikal sediment (Khlystov et al 2013) attests to the high methane concentrations contained there. High concentrations of methane and oxidation rates were previously recorded in the deep layers of the water column of Lake Baikal (Zakharenko et al 2015). Along the same lines, the methanotroph Methyloglobulus was one of the most abundant microbes in dLB recruiting > 1% of the reads.…”

Evolución fisicoquímica y de las bacterias del azufre en microcosmos de diferentes sistemas acuáticos de la Región Amazonas

“…Las muestras de sedimento se recolectaron en recipientes de plástico tipo "tupperware" de un litro. Para la toma de muestras de sedimentos se siguieron las recomendaciones de Karlov et al (2017) y Zakharenko et al (2015). Una vez establecidas las columnas de Winogradsky, se tomaron muestras de agua de la parte superior e inferior de cada una, una vez al mes, durante la duración del estudio.…”