School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, People's Republic of China.
Appl Microbiol Biotechnol. 2011 Feb;89(4):1243-54. doi: 10.1007/s00253-010-2929-0. Epub 2010 Oct 16.
We investigated the diversity, spatial distribution, and abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in sediment samples of different depths collected from a transect with different distances to mangrove forest in the territories of Hong Kong. Both the archaeal and bacterial amoA genes (encoding ammonia monooxygenase subunit A) from all samples supported distinct phylogenetic groups, indicating the presences of niche-specific AOA and AOB in mangrove sediments. The higher AOB abundances than AOA in mangrove sediments, especially in the vicinity of the mangrove trees, might indicate the more important role of AOB on nitrification. The spatial distribution showed that AOA had higher diversity and abundance in the surface layer sediments near the mangrove trees (0 and 10 m) but lower away from the mangrove trees (1,000 m), and communities of AOA could be clustered into surface and bottom sediment layer groups. In contrast, AOB showed a reverse distributed pattern, and its communities were grouped by the distances between sites and mangrove trees, indicating mangrove trees might have different influences on AOA and AOB community structures. Furthermore, the strong correlations among archaeal and bacterial amoA gene abundances and their ratio with NH (4) (+) , salinity, and pH of sediments indicated that these environmental factors have strong influences on AOA and AOB distributions in mangrove sediments. In addition, AOA diversity and abundances were significantly correlated with hzo gene abundances, which encodes the key enzyme for transformation of hydrazine into N(2) in anaerobic ammonium-oxidizing (anammox) bacteria, indicating AOA and anammox bacteria may interact with each other or they are influenced by the same controlling factors, such as NH (4) (+) . The results provide a better understanding on using mangrove wetlands as biological treatment systems for removal of nutrients.
我们调查了香港不同距离红树林区域的不同深度沉积物样本中氨氧化古菌（AOA）和氨氧化细菌（AOB）的多样性、空间分布和丰度。所有样本中的古菌和细菌 amoA 基因（编码氨单加氧酶亚单位 A）都支持独特的系统发育群，表明红树林沉积物中存在具有特定生态位的 AOA 和 AOB。与 AOA 相比，AOB 在红树林沉积物中的丰度更高，尤其是在靠近红树林树的地方，这可能表明 AOB 在硝化作用中起着更重要的作用。空间分布表明，AOA 在靠近红树林树（0 和 10 m）的表层沉积物中具有更高的多样性和丰度，但远离红树林树（1000 m）时则较低，AOA 群落可以聚类为表层和底层沉积物层群。相比之下，AOB 呈现出相反的分布模式，其群落由站点与红树林树之间的距离分组，表明红树林树可能对 AOA 和 AOB 群落结构有不同的影响。此外，古菌和细菌 amoA 基因丰度及其与 NH（4）（+）、盐度和沉积物 pH 的强烈相关性表明，这些环境因素对红树林沉积物中 AOA 和 AOB 的分布有很强的影响。此外，AOA 多样性和丰度与 hzo 基因丰度显著相关，hzo 基因编码将肼转化为厌氧氨氧化（anammox）细菌中的 N（2）的关键酶，表明 AOA 和 anammox 细菌可能相互作用，或者它们受到相同的控制因素的影响，例如 NH（4）（+）。这些结果为利用红树林湿地作为去除营养物质的生物处理系统提供了更好的理解。
