Changes in methanogenic substrate utilization and communities with depth in a salt-marsh, creek sediment in southern England
Changes in methanogenic substrate utilization and communities with depth in a salt-marsh, creek sediment in southern England
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DOI：
10.1016/j.ecss.2011.10.025
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发表时间：
2012-01-01
影响因子：
2.8
通讯作者：
Fry, John C.
中科院分区：
文献类型：
--
作者：
Parkes, R. John;Brock, Fiona;Fry, John C.
对英国多塞特郡阿恩半岛盐沼的小溪沉积物(深至65厘米)进行了生物地球化学和分子遗传学的联合研究，确定了用于产甲烷的底物，以及能够代谢这些底物的常见产甲烷菌、甲烷琥珀酸杆菌和甲烷微生物的分布。甲烷浓度增加了11厘米，尽管孔隙水硫酸盐直到45厘米才被去除。甲烷的向上扩散和甲烷的厌氧氧化在该区域似乎都不重要。在近地表硫酸盐还原带(5-25 cm)，非竞争性产甲烷底物三甲胺转化为甲烷的时间最快(80天)，而乙酸盐(7900天)、甲醇(40,500天)和碳酸氢盐(361,600天)的转化时间要长得多。甲烷产生菌以甲基胺利用菌为主(60%~95%)。在较深的沉积物中，竞争性底物的产甲烷速率显著增加，在50 cm以下，乙酸酯的产甲烷速率接近H-2/CO2产甲烷速率的100倍。此外，产甲烷菌的多样性发生了戏剧性的变化，专性利用醋酸盐，甲烷相关序列占主导地位。在类似深度下，甲醇转化为甲烷的速度达到最快(1700天)。这种活性模式与较深的产甲烷菌群(55厘米)是一致的，以利用醋酸盐的甲烷菌为主，同时也存在利用H-2/CO2的甲烷菌和利用酒精的甲烷微生物。因此，产甲烷底物利用的深度分布与能够利用这些化合物的特定产甲烷菌之间存在密切的关系。在沿海沉积物中，乙酸盐是主要的产甲烷底物是不寻常的，而三角洲C-13-CH4值(-74~-71 ppm)对于乙酸盐产甲烷来说是不典型的，这表明普通的稳定同位素替代模型可能不适用于这种具有多个产甲烷底物的动态缺氧沉积物。(C)2011爱思唯尔有限公司。保留所有权利。
A combined biogeochemical and molecular genetic study of creek sediments (down to 65 cm depth) from Arne Peninsula salt-marsh (Dorset, UK) determined the substrates used for methanogenesis and the distribution of the common methanogens, Methanosarcinales and Methanomicrobiales capable of metabolising these substrates. Methane concentrations increased by 11 cm, despite pore water sulphate not being removed until 45 cm. Neither upward methane diffusion or anaerobic oxidation of methane seemed to be important in this zone. In the near-surface sulphate-reduction zone (5-25 cm) turnover time to methane for the non-competitive methanogenic substrate trimethylamine was most rapid (80 days), and were much longer for acetate (7900 days), methanol (40,500 days) and bicarbonate (361,600 days). Methylamine-utilizing Methanosarcinales were the dominant (60-95%) methanogens in this zone. In deeper sediments rates of methanogenesis from competitive substrates increased substantially, with acetate methanogenic rates becoming similar to 100 times greater than H-2/CO2 methanogenesis below 50 cm. In addition, there was a dramatic change in methanogen diversity with obligate acetate-utilizing, Methanosaeta related sequences being dominant. At a similar depth methanol turnover to methane increased to its most rapid (1700 days). This activity pattern is consistent with deeper methanogen populations (55 cm) being dominated by acetate-utilizing Methanosaeta with H-2/CO2 and alcohol-utilizing Methanomicrobiales also present. Hence, there is close relationship between the depth distribution of methanogenic substrate utilization and specific methanogens that can utilize these compounds. It is unusual for acetate to be the dominant methanogenic substrate in coastal sediments and delta C-13-CH4 values (-74 to -71 parts per thousand) were atypical for acetate methanogenesis, suggesting that common stable isotope proxy models may not apply well in this type of dynamic anoxic sediment, with multiple methanogenic substrates. (C) 2011 Elsevier Ltd. All rights reserved.