Currents and topography drive assemblage distribution on an active hydrothermal edifice: associated data

the deep sea is characterized by a wide range of landscapes, including complex features where topography and currents interact to form highly heterogeneous habitats. in addition to a complex topography, hydrothermal vent environments are characterized by strong environmental gradients that structure the spatial distribution of biological communities. the role of vent fluid temperature and chemical composition on species distribution is now well understood, but investigations on the effects of the complex sulfide edifice topography are scarce. here, we used a novel approach combining 3d photogrammetric reconstruction, in situ environmental measurements and modeling to characterize assemblage distribution on the active edifice eiffel tower (lucky strike, mid-atlantic ridge). through the analysis of a high-resolution 3d model of the edifice, we show that assemblage distribution along with hydrothermal activity vary with their position on the edifice. although physical terrain variables had a minor effect on assemblage distribution, the distance from fluid exits explained the distribution of most assemblages. however, these particular variables did not significantly explain the distribution of medium-sized bathymodiolus azoricus mussels, the dominant assemblage on the edifice. similarly, proximity to fluid exits only partially accounted for the distribution of microbial mats throughout the edifice. by modeling the current-driven dispersion of hydrothermal plumes around the edifice, we demonstrated that differences in mussel sizes may be due to differences in exposure time to currents bringing plume material. for the first time, we provide evidence that hydrothermal plumes can affect faunal assemblages meters away from fluid exits and that this relatively long-distance effect of vent plumes can fully account for microbial mat distribution throughout the edifice. our findings extend the area of influence of hydrothermal plumes on vent communities considerably beyond previous estimations and suggest that the interactions between bottom currents, topography and smoker locations should be further investigated and considered as important structuring factors at vents. this novel approach, allowing to cover large areas of the seafloor, is particularly well suited for deep environments where topography and currents interact to form complex oceanographic patterns (e.g. canyons, seamounts). its application to larger areas and various ecosystems can significantly enhance our understanding of benthic communities’ distribution at large.

深海以其丰富的景观特征著称，包括地形与洋流相互作用形成的复杂地貌，进而构筑出高度异质化的栖息地。除了复杂的地形，海底热液喷口环境以其强烈的生态环境梯度而闻名，这种梯度结构了生物群落的空間分布。目前对于喷口流体温度和化学组成对物种分布的影响已有深入研究，但对于复杂硫化物地质构造地形影响的研究却相对匮乏。在本研究中，我们采用了一种新颖的方法，结合三维摄影测量重建、现场环境测量和建模，以表征活跃地质构造埃菲尔铁塔（幸运打击，中大西洋脊）上的群集分布。通过对地质构造高分辨率三维模型的解析，我们发现群集分布及其水文活动随其在地质构造上的位置而变化。尽管地形变量对群集分布的影响微乎其微，但流体出口距离解释了大多数群集的分布。然而，这些特定变量并不能显著解释中型底栖贝类阿佐里科斯（Bathymodiolus azoricus）的分布，它是地质构造上的主要群集。同样，流体出口的邻近性只能部分解释微生物膜在整个地质构造上的分布。通过模拟流体出口周围由洋流驱动的热液羽流扩散，我们证明了贻贝大小差异可能源于对携带羽流物质的洋流暴露时间的差异。首次，我们提供了证据，表明热液羽流可以影响距离流体出口数米之外的动物群集，并且这种相对长距离的影响可以完全解释地质构造上微生物膜的分布。我们的研究结果将热液羽流对喷口群落的影响范围扩展至以往估计之外，并表明底流、地形和烟囱位置之间的相互作用应进一步研究和考虑，作为喷口结构的重要因素。这种新颖的方法，能够覆盖海底大片区域，特别适用于地形与洋流相互作用形成复杂海洋模式的深海环境（例如峡谷、海山）。将其应用于更大区域和多种生态系统，可以显著增强我们对底栖群落分布的理解。