Spatial and temporal dynamics of microbial communities under environmental perturbation

微型植物底栖生物（MPB）及其相关的原核生物提供了浅海岸海洋沉积物中的底栖食物网的基础。这些微生物群落在时间和空间尺度上的生物量和组成变化很大。特别是在沿海地区，潮汐和热浪或暴雨洪水等频繁扰动引起的环境条件迅速变化。基于其巨大的性状变异，微生物群落使用各种策略来科普这种多变的环境，包括在沉积物中的垂直迁移。然而，对于物种间的相互作用如何影响动态景观中空间结构群落的特征分布，我们仍然缺乏足够的了解，这阻碍了我们对这些群落将如何应对环境变化的预测能力。因此，在DynaCom的第二阶段，我们的项目追求两个主要目标：1）评估自然环境波动和随机干扰对时间和空间特征的影响-基于Spiekeroog后障潮滩底栖海洋食物网中微生物群落的分布和功能，以及2）具体了解MPB基于特征的相互作用，原核生物和大型底栖动物消费者（MZB，SP 5）在应对热浪，考虑到在全球变化下的瓦登海生态系统中微生物食物网的大功能相关性。我们将在项目第一年的春季和夏季在Spiekeroog的潮滩进行实地采样活动，以确定高度可变的真滨海和更稳定的亚滨海区微生物群落和MZB（与SP 5合作）的空间（沉积物中的垂直）和时间（昼夜和潮汐周期）周转。然后，围隔实验将用于调查原核生物，MPB和MZB之间的相互作用的变化，在不同的放牧制度下的热浪（食草动物不同的流动性和压力适应）。将进行伴随的实验室生物测定，以获得生物体的特定特征（例如温度耐受性，可食性），以促进我们对围隔实验和实地观察到的相互作用动态的理解。此外，我们将确定在Spiekeroog实验岛屿上微生物群落的稳定性，以应对冬季风暴和潮汐力引起的物理干扰，在该项目的最后阶段，破波器拆除后。

Microphytobenthos (MPB) and their associated prokaryotes provide the basis of the benthic food web in shallow coastal marine sediments. These microbial communities are highly variable in biomass and composition on temporal and spatial scales. Especially the eulittoral is characterized by rapidly changing environmental conditions induced by the tides and frequent disturbances such as heatwaves or storm floods. Based on their large trait variation, microbial communities use various strategies to cope with this variable environment, including vertical migration in the sediment. However, there is still a substantial lack of understanding of how species interactions relate to trait distribution of spatially structured communities in such dynamic landscapes, hampering our predictive capacity of how these communities will respond to environmental change.In the second phase of DynaCom, our project therefore pursues two major goals: 1) to evaluate the effect of natural environmental fluctuations and stochastic disturbances on the temporal and spatial trait-based distribution and functioning of microbial communities in a benthic marine food web of the backbarrier tidal flat on Spiekeroog, and 2) to specifically understand the trait-based interactions of MPB, prokaryotes and macrozoobenthos consumers (MZB, SP 5) in response to a heatwave, given the large functional relevance of microbial food webs in the Wadden Sea ecosystem under global change. We will conduct field sampling campaigns in the tidal flat on Spiekeroog in spring and summer of the first year of the project to determine spatial (vertical in the sediment) and temporal (over diurnal and tidal cycles) turnover of microbial communities and MZB (in collaboration with SP 5) in the highly variable eulittoral and the more stable sublittoral zone. Mesocosm experiments will then serve to investigate changes in the interactions between prokaryotes, MPB and MZB in response to a heatwave under different grazing regimes (grazers differing in mobility and stress-adaptation). Accompanying laboratory bioassays will be conducted to derive specific traits of the organisms (e.g. temperature tolerance, edibility) to foster our understanding of the interactive dynamics observed in the mesocosm experiments and in the field. Furthermore, we will determine the stability of microbial communities at the experimental islands on Spiekeroog in response to physical disturbances induced by winter storms and tidal forcing after the deconstruction of the wave breakers in the last phase of the project.