1 OCN621: Biological Oceanography- Sediment Microbiology Guangyi Wang POST 103B [email protected]Three Domains of Life Slide material courtesy: Craig Smith 1) Unrooted phylogenetic tree constructed based on small-subunit rRNA genes; 2) Members of all the three domains of (microbial) life are found in Marine sediments; 3) Fungi and protists are commonly present in all types of marine sediment. 4) Bacteria and archaea were collectively called prokaryote that is still commonly used in literature now.
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OCN621: Biological Oceanography- Sediment Microbiology · OCN621: Biological Oceanography-Sediment Microbiology Guangyi Wang POST 103B [email protected] Three Domains of Life Slide
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– Important in plant derived organic matter decomposition.– A few of fungi and protozoans are capable of anaerobic metabolism.
Stratification of fungi and radiolarians in the deep-sea sediment core taken at a depth of 5904m from a trench at the southern extension in the in the Indian Ocean (Raghukumara et al. 2004)
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Bacterial Distribution in Marine Sediments
• Vertical distribution
Why do bacterial populations fluctuate as depth changes?
Bacterial populations were determined using the acridine orange direct count (AODA) techniques (Teske, 2006, Geobiol. J.)
800 m
• Vertical distribution (cont.)
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Microbial Activities in Deep-sea Sediments
a) Sulfate reducing prokaryotes dominates in the sulfate containing upper sediment layer (Bale et al, 1997; Barnes et al. 1998)
b) Methanogenic archaea dominates in the methane-enriched deeper sediment layer (Marchesi et al. 2001)
c) Sulfate-dependent methanotrophic consortia dominate the sulfate-methane transition zone (Boetius et al. 2000; Mechaelis et al. 2002); Teske et al, 2002, 2003) (see anaerobic methane oxidation)
• General distribution patterns of dominant prokaryotic microbes in deep-sea sediments
DeLong, 2000Abundance of archaea/SRB in a sediment core from a Beggiatoa mat. Boetius et al. (2000).
In situ identfication of archaea/SRB aggregates with fluorescently labledrRNA-targetted oligonucliotideprobes; Archaea = red, SRB = green, white images are DAPI (DNA) stained. Boetius et a. (2000).
Anaerobic Oxydation of Methane by Microbial Consortium
CH4 + H2O → CO2+ H2 (red cells)
H2 + SO4-2 → HCO3
-+ HS- + H20 (green cells)
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Sediment Microbial Growth and Biomass
Linkage between bacterial biomass and carbon production??
Linkage between bioenergetics and microbial growth??
Sediment microbes are a very active, but mostly non-growing community (Novitsky, 1987 AEM; modified from Craig Smith’s lecture)
Main Points1.Classification of sediment microbes;2.Significance of marine sediment microbial
communities, particularly, prokaryotes;3.Distribution and metabolic activities;4.Abundance of major marine sediment microbial
communities in different type of sediment;5.Relationship between sediment microbial