Contrasting relationships between biogeochemistry and prokaryotic diversity depth profiles along an estuarine sediment gradient.
Contrasting relationships between biogeochemistry and prokaryotic diversity depth profiles along an estuarine sediment gradient.
复制标题
DOI：
10.1111/1574-6941.12106
复制
发表时间：
2013-07
影响因子：
4.2
通讯作者：
Louise A. O’Sullivan;A. Sass;G. Webster;J. Fry;R. Parkes;A. Weightman
中科院分区：
文献类型：
--
作者：
Louise A. O’Sullivan;A. Sass;G. Webster;J. Fry;R. Parkes;A. Weightman
在英国科尔尼河口的三个地点，沿着从咸淡水到海洋的河口梯度，获得了沉积物地球化学、原核生物多样性和活性（硫酸盐还原和甲烷生成）的详细深度剖面。在两个海洋地点，尽管硫酸盐和甲烷剖面变化有限，但原核生物种群[古生菌、细菌、硫酸盐还原菌（SRB）和产甲烷古生菌（MA）]随深度发生了明显变化。相比之下，半咸水遗址显示出明显的地球化学带（硫化物和甲烷），但原核深度剖面大致相同。尽管硫酸盐浓度不受限制，但在海洋地点，硫酸盐还原率随深度而下降，而氢营养化产甲烷率在地下达到峰值。在半咸淡水中，硫酸盐随着深度的增加而减少，从而促进了乙营养化甲烷生成。令人惊讶的是，在微咸地下，硫酸盐还原也受到了刺激；可能反映了以前的地下海水入侵，厌氧硫化物氧化和/或甲烷厌氧氧化耦合硫酸盐还原。脱硫菌科、脱硫菌科、甲烷球菌科和甲烷微生物科成员是SRB和MA的优势菌。甲基营养型甲烷球虫通常与SRB共存，可能利用非竞争性c1底物。在河口沿岸，SRB和MA的种型分布差异明显，只有SRB2-a （Desulfobulbus）普遍存在。结果表明，河口环境具有高度的动态性，原核生物多样性与沉积物地球化学之间的关系比以前认为的更为复杂。
Detailed depth profiles of sediment geochemistry, prokaryotic diversity and activity (sulphate reduction and methanogenesis) were obtained along an estuarine gradient from brackish to marine, at three sites on the Colne estuary (UK). Distinct changes in prokaryotic populations [Archaea, Bacteria, sulphate-reducing bacteria (SRB) and methanogenic archaea (MA)] occurred with depth at the two marine sites, despite limited changes in sulphate and methane profiles. In contrast, the brackish site exhibited distinct geochemical zones (sulphidic and methanic) yet prokaryotic depth profiles were broadly homogenous. Sulphate reduction rates decreased with depth at the marine sites, despite nonlimiting sulphate concentrations, and hydrogenotrophic methanogenic rates peaked in the subsurface. Sulphate was depleted with depth at the brackish site, and acetotrophic methanogenesis was stimulated. Surprisingly, sulphate reduction was also stimulated in the brackish subsurface; potentially reflecting previous subsurface seawater incursions, anaerobic sulphide oxidation and/or anaerobic oxidation of methane coupled to sulphate reduction. Desulfobulbaceae, Desulfobacteraceae, Methanococcoides and members of the Methanomicrobiales were the dominant SRB and MA. Methylotrophic Methanococcoides often co-existed with SRB, likely utilising noncompetitive C1-substrates. Clear differences were found in SRB and MA phylotype distribution along the estuary, with only SRB2-a (Desulfobulbus) being ubiquitous. Results indicate a highly dynamic estuarine environment with a more complex relationship between prokaryotic diversity and sediment geochemistry, than previously suggested.