Yazdani Foshtomi Maryam, Leliaert Frederik, Derycke Sofie, Willems Anne, Vincx Magda, Vanaverbeke Jan
Marine Biology Research Group, Biology Department, Ghent University, Ghent, Belgium.
CeMoFE, Ghent University, Ghent, Belgium.
PLoS One. 2018 Feb 6;13(2):e0192391. doi: 10.1371/journal.pone.0192391. eCollection 2018.
The presence of large densities of the piston-pumping polychaete Lanice conchilega can have important consequences for the functioning of marine sediments. It is considered both an allogenic and an autogenic ecosystem engineer, affecting spatial and temporal biogeochemical gradients (oxygen concentrations, oxygen penetration depth and nutrient concentrations) and physical properties (grain size) of marine sediments, which could affect functional properties of sediment-inhabiting microbial communities. Here we investigated whether density-dependent effects of L. conchilega affected horizontal (m-scale) and vertical (cm-scale) patterns in the distribution, diversity and composition of the typical nosZ gene in the active denitrifying organisms. This gene plays a major role in N2O reduction in coastal ecosystems as the last step completing the denitrification pathway. We showed that both vertical and horizontal composition and richness of nosZ gene were indeed significantly affected when large densities of the bio-irrigator were present. This could be directly related to allogenic ecosystem engineering effects on the environment, reflected in increased oxygen penetration depth and oxygen concentrations in the upper cm of the sediment in high densities of L. conchilega. A higher diversity (Shannon diversity and inverse Simpson) of nosZ observed in patches with high L. conchilega densities (3,185-3,440 ind. m-2) at deeper sediment layers could suggest a downward transport of NO3- to deeper layers resulting from bio-irrigation as well. Hence, our results show the effect of L. conchilega bio-irrigation activity on denitrifying organisms in L. conchilega reefs.
大量活塞式泵动多毛类动物兰氏蛰龙介的存在会对海洋沉积物的功能产生重要影响。它被认为既是一种异源生态系统工程师，也是一种自源生态系统工程师，会影响海洋沉积物的时空生物地球化学梯度（氧气浓度、氧气穿透深度和营养物质浓度）以及物理性质（粒度），而这些可能会影响栖息在沉积物中的微生物群落的功能特性。在这里，我们研究了兰氏蛰龙介的密度依赖性效应是否会影响活跃反硝化生物中典型nosZ基因的水平（米尺度）和垂直（厘米尺度）分布、多样性及组成模式。该基因作为反硝化途径的最后一步，在沿海生态系统的N2O还原中起主要作用。我们发现，当存在大量这种生物扰动者时，nosZ基因的垂直和水平组成及丰富度确实受到了显著影响。这可能直接与异源生态系统对环境的工程效应有关，在高密度兰氏蛰龙介存在的情况下，这表现为沉积物上部厘米层的氧气穿透深度和氧气浓度增加。在更深沉积层中，兰氏蛰龙介高密度斑块（3185 - 3440个个体/平方米）中观察到的nosZ多样性更高（香农多样性和反辛普森指数），这也可能表明生物扰动导致NO3-向下层运输。因此，我们的结果显示了兰氏蛰龙介的生物扰动活动对兰氏蛰龙介礁中反硝化生物的影响。
