Rinke Maria, Maraun Mark, Scheu Stefan
J.F. Blumenbach Institute of Zoology and Anthropology, Animal Ecology University of Göttingen Göttingen Germany.
Centre of Biodiversity and Sustainable Land Use University of Göttingen Göttingen Germany.
Ecol Evol. 2022 Mar 27;12(3):e8767. doi: 10.1002/ece3.8767. eCollection 2022 Mar.
Salt marshes exist at the interface of the marine and the terrestrial system. Shore height differences and associated variations in inundation frequency result in altered abiotic conditions, plant communities, and resource input into the belowground system. These factors result in three unique zones, the upper salt marsh (USM), the lower salt marsh (LSM), and the pioneer zone (PZ). Marine detritus, such as micro- and macroalgae, is typically flushed into the PZ daily, with storm surges moving both salt marsh detritus and marine detritus into higher salt marsh zones. Microbial assemblages are essential for the decomposition of organic matter and have been shown to sensitively respond to changes in abiotic conditions such as oxygen supply and salinity. However, temporal and spatial dynamics of microbial communities of Wadden Sea salt marshes received little attention. We investigated the dynamics of soil microbial communities across horizontal (USM, LSM, and PZ), vertical (0-5 and 5-10-cm sediment depth), and temporal (spring, summer, and autumn) scales in the Wadden Sea salt marsh of the European North Atlantic coast using phospholipid fatty acid (PLFA) analysis. Our results show strong spatial dynamics both among salt marsh zones and between sediment depths, but temporal dynamics to be only minor. Despite varying in space and time, PLFA markers indicated that bacteria generally were the dominant microbial group across salt marsh zones and seasons, however, their dominance was most pronounced in the USM, whereas fungal biomass peaked in the LSM and algal biomass in the PZ. Only algal markers and the stress marker monounsaturated to saturated fatty acid ratio responded to seasonality. Overall, therefore, the results indicate remarkable temporal stability of salt marsh microbial communities despite strong variability in abiotic factors.
盐沼存在于海洋和陆地系统的交界处。海岸高度差异以及相关的淹没频率变化导致非生物条件、植物群落以及进入地下系统的资源输入发生改变。这些因素形成了三个独特的区域，即上盐沼（USM）、下盐沼（LSM）和先锋区（PZ）。海洋碎屑，如微型和大型藻类，通常每天被冲入先锋区，风暴潮会将盐沼碎屑和海洋碎屑带入更高的盐沼区域。微生物群落对于有机物的分解至关重要，并且已被证明对诸如氧气供应和盐度等非生物条件的变化敏感响应。然而，瓦登海盐沼微生物群落的时空动态很少受到关注。我们使用磷脂脂肪酸（PLFA）分析方法，研究了欧洲北大西洋海岸瓦登海盐沼中土壤微生物群落跨水平（USM、LSM和PZ）、垂直（0 - 5厘米和5 - 10厘米沉积物深度）和时间（春季、夏季和秋季）尺度的动态变化。我们的结果表明，盐沼区域之间以及沉积物深度之间存在强烈的空间动态，但时间动态较小。尽管在空间和时间上存在差异，但PLFA标记表明，细菌通常是盐沼区域和季节中占主导地位的微生物群体，然而，它们的优势在USM中最为明显，而真菌生物量在LSM中达到峰值，藻类生物量在PZ中达到峰值。只有藻类标记和应激标记单不饱和脂肪酸与饱和脂肪酸的比例对季节性有响应。因此，总体而言，结果表明尽管非生物因素存在很大变异性，但盐沼微生物群落具有显著的时间稳定性。
