Structure of biocenoses formed on bitumen mounds in the abyssal zone of Lake Baikal

Abstract

For the first time, a study has been performed on specific small biocenoses of bitumen mounds formed in the region of natural oil seeps in the abyssal zone of Lake Baikal. These biocenoses consist of dia tom detritus populated by archaea, bacteria, aquatic fungi, nematodes, and ostracods. Fungi and bacteria decompose petroleum hydrocarbons, thereby contributing to biodegradation of crude oil. Microorganisms together with planktonic diatoms settling onto bitumen form a substrate for invertebrates. It is hypothesized that the cohabitation of three distinctive nematode species (Eutobrilus mirandus, Monhystera naphthera, and Eumonhystera abyssalis) in the same bitumen biocenosis is possible due to their different feeding strategies and the presence of bacterial symbionts.

The First Data on Harpacticoid Copepod Diversity of the Deep-Water Zone of Lake Baikal (Siberia, Russia)

“…A brief description of sampling areas and main habitat characteristics is given according to published data [5,6,9,[14][15][16][17] and the results of viewing videos received by stationary cameras installed on the staffed submersible Mir.…”

“…The factors that determine the increase in the abundance of harpacticoids in such communities include the total organic carbon concentration or/and the food amount [7,29,30], whereas the decrease in their abundance is determined by toxicity of environmental conditions (hypoxia and the presence of hydrogen sulfide) [8]. Similar to other benthic nonpredatory invertebrate [9,16], in the deep-water zone of LB, harpacticoids likely prefer the rich food resources provided by microbial mats concentrated in the so-called "oases of life" of vent and seep areas.…”

Anaerobic oxidation of petroleum hydrocarbons in enrichment cultures from sediments of the Gorevoy Utes natural oil seep under methanogenic and sulfate-reducing conditions

“…In places where oil accumulated on a at area and near the structures, hydrocarbon gases discharged, which contained 99% of methane and approximately 1% of its homologues [19]. There were dense populations of benthic animals on asphalt structures, whose density was an order of magnitude higher than that at the reference sites of the bottom [20] (Fig. 1b).…”