Collaborative Research: Dimensions: The Macroalgal Microbiome in Space and Time---Maintaining Primary Producers in the Atlantic Rocky Intertidal Zone

潮间带大型藻类（“海藻”）为许多无脊椎动物和幼鱼提供栖息地、庇护所和食物。 人们对潮间带藻类如何应对自然压力知之甚少，但对与这些藻类相关的天然细菌群落知之甚少。实验室过去的研究发现，一些“海藻”在用抗生素去除细菌后会分解，这表明这些细菌对宿主的健康至关重要。这项研究将研究与几种“海藻”相关的细菌生物多样性的遗传，分类和功能方面，这些海藻对海洋生态系统的总体健康特别重要。这项研究将确定这些细菌如何随着季节、潮间带位置和纬度范围而变化。通过研究在不同采样时间存在的特定细菌基因和研究宿主对特定细菌接种的反应，检查与宿主相关的细菌物种的稳定性或变化。这项工作还将研究是否有任何细菌受到潮间带或纬度上的极端环境的抑制，特别是在气候变化可能扰乱宿主细菌群落的宿主范围的南部边界。研究人员将存款分离和凭证标本到公共收藏，并与训练有素的公民科学家合作，将提供数字访问所有藻类材料在缅因州大学植物标本馆。在这项研究中收集的多方面的数据将有助于其他潮间带生态学家的研究。大型藻类微生物群落在空间和时间上的变化知之甚少。是否存在“凉爽、潮湿”与“炎热、干燥”的大型藻类微生物组？如果是，这对宿主功能有何影响？在这里，微生物组将在缅因州海岸的潮间带的垂直梯度的特点在两个突出的属，墨角藻（岩藻）和紫菜（紫菜）内的差异分区物种。与此同时，一项跨大西洋的研究的微生物组的中间区紫菜脐和墨角藻vesiculosus将确定是否组成的变化，发现在潮间带应力梯度反映在纬度范围内的中间区物种。如果是这样，这重要吗？这个问题将通过使用鸟枪宏基因组分析来回答，以比较遗传组成与大型藻类微生物组的特征分类组成。与微生物组收集相关的环境变化将用原位传感器和来自政府气候服务（例如，NOAA）。将使用植物标本馆标本评估检测历史时期变化的潜力。为了研究可能对墨角藻和紫菜的正常结构和功能最关键的细菌，研究人员将专注于从孢子和受精卵中分离细菌，并辅以流式细胞术和单细胞基因组学。为了确定这些关联的关键性，将用这种细菌分离株接种微生物组耗尽的胚胎，并通过用RNA-Seq分析宿主转录组来研究所产生的相互作用。将在实验室实验中确定关键菌种（操作分类单位）的温度耐受性。这项研究将作为大型藻类微生物生物多样性的重要跨大西洋基线。

Intertidal macro algae ('seaweeds') provide habitat, shelter and food to many invertebrates and young fishes. Much is known about how intertidal algae react to natural stresses, but little is known about the natural community of bacteria associated with these algae. Past studies in the laboratory found that some 'seaweeds' disintegrate after removal of their bacteria with antibiotics suggesting these bacteria are essential to the health of their hosts. This research will examine the genetic, taxonomic, and functional aspects of biodiversity of bacteria associated with several 'seaweeds' that are particularly important to the general health of marine ecosystems. The research will determine how these bacteria change with season, position within the intertidal zone and latitudinal range. Stability or change in the bacterial species associated with a host will be examined by studying the particular bacterial genes that are present at different sampling times and by studying host responses to inoculations with particular bacteria. The work will also study whether any bacteria are inhibited by the environmental extremes found across the intertidal zone or over latitude, especially at the southern borders of a host's range where climate change may disturb the bacterial community on the host. Researchers will deposit isolates and voucher specimens into public collections, and, in collaboration with trained citizen scientists, will provide digital access to all algal materials within the University of Maine Herbarium. The multi-faceted data collected during this research will aid studies by other intertidal ecologists. How macroalgal microbiomes change in space and time is poorly known. Is there a 'cool, wet' versus a 'hot, dry' macroalgal microbiome(s)? If so, how does this affect host function? Here, microbiomes will be characterized over the vertical gradient of the intertidal zone on the Maine shore in differentially zoned species within each of two prominent genera, Fucus (rockweed) and Porphyra (laver). Contemporaneously, a trans-Atlantic study of microbiomes of the mid-zone Porphyra umbilicalis and Fucus vesiculosus will determine whether compositional changes found over an intertidal stress gradient are mirrored over the latitudinal range of mid-zoned species. If so, does this matter? This question will be answered by using shotgun metagenomic analyses to compare the genetic composition with the characterized taxonomic composition of the macroalgal microbiomes. Environmental variation associated with microbiome collections will be measured with in situ sensors and from archival and real time data available from government climate services (e.g., NOAA). The potential to detect changes over historic time will be assessed using herbarium specimens. To study bacteria that are likely to be most critical to normal structure and function of Fucus and Porphyra, the researchers will focus on bacterial isolations from spores and fertilized eggs, aided by flow cytometry and single cell genomics. To establish the criticality of these associations, microbiome-depleted embryos will be inoculated with such bacterial isolates, and the resulting interaction will be investigated by analysis of the host transcriptome with RNA-Seq. The temperature tolerance of key bacterial species (operational taxonomic units) will be established in laboratory experiments. This research will serve as an important trans-Atlantic baseline of the biodiversity of macroalgal microbiomes.