TABLE 1.

Pattern of occurrence of mcrA clones in different sediment depths and in situ temperature regimes

OrderCultured genus or uncultured phylogenetic lineage or cluster (no. of mcrA clones)No. of redundant clonesa (name of representative clone) at the following sediment depths (temp):Inferred methanogenic substrateb
1 and 3 cm (∼3-10°C)5 and 7 cm (∼15-30°C)9 and 11 cm (∼40-60°C)13 and 15 cm (∼70-95°C)
MethanomicrobialesMethanocorpusculum (15)17 (D08)7H2 + CO2, formate, sometimes alcohols
Methanoculleus (6)3 (C10)3 (H07)H2 + CO2, formate, sometimes alcohols
Methanomicrobium (1)1 (B12)H2 + CO2, formate
Uncultured OS77 (39)17 (C01)11 (B06)83Possibly H2 + CO2, formate
MethanosarcinalesBasal to ANME-2: D06 type (8 total)4 (D06)4Possibly acetate
Basal to Methanosaeta and ANME-2: C05 type (12 total)25 (C05)2 (D11, D07)3Possibly acetate
Methanococcoides (1)1 (B09)Methanol methylamines
Basal to ANME-2 and Methanosaeta (1)1 (A07)Unknown
MethanococcalesMethanocaldococcus jannaschii (1)1 (D03)H2 + CO2
  • a Groups of near-identical clones, represented by selected clones listed here and in Fig. 1.

  • b Based on the general characteristics of the phylogenetically most closely related methanogen genera and orders.