Anaerobic ammonium oxidation (Anammox) in Chesapeake Bay sediments
Anaerobic ammonium oxidation (Anammox) in Chesapeake Bay sediments
复制标题
DOI：
10.1007/s00248-007-9277-3
复制
发表时间：
2008-02-01
影响因子：
3.6
通讯作者：
Ward, Bess B.
中科院分区：
文献类型：
--
作者：
Rich, Jeremy J.;Dale, Olivia R.;Ward, Bess B.
厌氧氨氧化（anammox）最近被认为是从水生生态系统中去除固定氮的途径。然而，河口沉积物中厌氧氨氧化的定量意义是可变的，并且测量仅限于少数河口。我们测量了切萨皮克湾及其两个子河口（乔普坦克河和帕图森特河）沿盐度梯度的沉积物中的厌氧氨氧化和常规反硝化活性。将均质沉积物与 NH4+、NO3- 和 NO2- 的 N-14/15 改良剂一起孵育，以确定厌氧氨氧化和反硝化的相对活性。在切萨皮克系统中，厌氧氨氧化产生的 N-2 百分比 (ra%) 在 0 到 22% 之间，其中切萨皮克湾上游主干的淡水部分的 ra% 最高，那里的水柱 NO3- 浓度始终很高。在 Choptank 河的潮汐淡水和中盐位置对应的位置检测到相对厌氧氨氧化的中等水平（10%），而在 Patuxent 河的潮汐淡水位置未检测到厌氧氨氧化。在切萨皮克湾的临海端也没有检测到厌氧氨氧化活动，那里的水柱 NO3- 浓度一直很低。 ra%与缺氧沉积物培养中NH4+积累率无关，但ra%与水体NO3-浓度和盐度相关。还通过使用对厌氧氨氧化生物体 16S rRNA 基因特异的聚合酶链反应 (PCR) 引物扩增从切萨皮克湾上游沉积物中提取的 DNA 来检查厌氧氨氧化细菌群落。总共检测到 35 个厌氧氨氧化样序列，系统发育分析将这些序列分为属于 Candidatus“Scalindua”属的两个不同簇。
Anaerobic ammonium oxidation (anammox) has recently been recognized as a pathway for the removal of fixed N from aquatic ecosystems. However, the quantitative significance of anammox in estuarine sediments is variable, and measurements have been limited to a few estuaries. We measured anammox and conventional denitrification activities in sediments along salinity gradients in the Chesapeake Bay and two of its sub-estuaries, the Choptank River and Patuxent River. Homogenized sediments were incubated with N-14/15 amendments of NH4+, NO3-, and NO2- to determine relative activities of anammox and denitrification. The percent of N-2 production due to anammox (ra%) ranged from 0 to 22% in the Chesapeake system, with the highest ra% in the freshwater portion of the main stem of upper Chesapeake Bay, where water column NO3- concentrations are consistently high. Intermediate levels of relative anammox (10%) were detected at locations corresponding to tidal freshwater and mesohaline locations in the Choptank River, whereas anammox was not detected in the tidal freshwater location in the Patuxent River. Anammox activity was also not detected in the seaward end of Chesapeake Bay, where water column NO3- concentrations are consistently low. The ra% did not correlate with NH4+ accumulation rate in anoxic sediment incubations, but ra% was related to water column NO3- concentrations and salinity. Anammox bacterial communities were also examined by amplifying DNA extracted from the upper Chesapeake Bay sediment with polymerase chain reaction (PCR) primers that are specific for 16S rRNA genes of anammox organisms. A total of 35 anammox-like sequences were detected, and phylogenetic analysis grouped the sequences in two distinct clusters belonging to the Candidatus "Scalindua" genus.