College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China,; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.
Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.
Sci Total Environ. 2022 Mar 25;814:152862. doi: 10.1016/j.scitotenv.2021.152862. Epub 2022 Jan 8.
Picoeukaryotic communities respond rapidly to global climate change and play an important role in marine biological food webs and ecosystems. The formation of oxygen minimum zones (OMZ) is facilitated by the stratification of seawater and higher primary production in the surface layer, and the marine picoeukaryotic community this low-oxygen environment is topic of interest. To better understand the picoeukaryotic community assembly mechanisms in an OMZ, we collected samples from the Bay of Bengal (BOB) in October and November 2020 and used 18S rDNA to study the picoeukaryotic communities and their community assembly mechanisms that they are controlled by in deep-sea and hypoxic zones. The results show that deterministic and stochastic processes combine to shape picoeukaryotic communities in the BOB. We divided the water column into three vertical layers: the upper oxycline (UO), the OMZ, and the lower oxycline (LO), based on dissolved oxygen concentrations (dissolved oxygen: UO > LO > OMZ) at vertical depths (from 5 m to 2000 m). Deterministic processes controlled the picoeukaryotic community in the UO, while the picoeukaryotic communities in the OMZ and LO were dominated by stochastic processes. The OMZ had a stronger diffusional limitation and the habitat niche breadth in the UO was wider than that in OMZ and LO. We classified the picoeukaryotic community into three functional composition types (phototrophic, mixotrophic, and heterotrophic); heterotrophs were most abundant in the surveyed area, and the proportion of decreased significantly with increasing depth and decreasing dissolved oxygen. The picoeukaryotes in the investigated area also correlated with temperature, salinity, and nutrients (phosphate, silicate, nitrate, nitrite, and ammonium). These findings contribute to a better understanding of picoeukaryotic communities in deep-sea and low-oxygen environments, their functional structuring, as well as the effects of environmental changes on their community structure.
微微型真核生物群落对全球气候变化响应迅速，在海洋生物食物网和生态系统中发挥着重要作用。海洋微微型真核生物群落受海水分层和表层更高的初级生产力的影响，形成了低氧区（OMZ）。为了更好地了解 OMZ 中微微型真核生物群落的组装机制，我们于 2020 年 10 月和 11 月在孟加拉湾（BOB）采集了样本，并使用 18S rDNA 研究了深海和低氧区中控制微微型真核生物群落及其组装机制的群落。结果表明，确定性和随机性过程共同塑造了 BOB 中的微微型真核生物群落。我们根据溶解氧浓度（溶解氧：UO > LO > OMZ）将水柱分为三个垂直层：上氧跃层（UO）、OMZ 和下氧跃层（LO），垂直深度从 5 米到 2000 米。确定性过程控制了 UO 中的微微型真核生物群落，而 OMZ 和 LO 中的微微型真核生物群落则主要受随机过程控制。OMZ 具有更强的扩散限制，UO 中的栖息地生态位宽度比 OMZ 和 LO 中的更宽。我们将微微型真核生物群落分为三种功能组成类型（光养型、混养型和异养型）；在调查区域中，异养生物最为丰富，随着深度的增加和溶解氧的减少，其比例显著下降。调查区域内的微微型真核生物与温度、盐度和营养物质（磷酸盐、硅酸盐、硝酸盐、亚硝酸盐和铵盐）也存在相关性。这些发现有助于更好地理解深海和低氧环境中的微微型真核生物群落、它们的功能结构以及环境变化对其群落结构的影响。
