Journal of Tropical Oceanography ›› 2026, Vol. 45 ›› Issue (4): 2-14.doi: 10.11978/2025171CSTR: 32234.14.2025171

• Marine Ecology • Previous Articles     Next Articles

Characteristics of bacterioplankton communities and their environmental driving factors in coastal areas of the Pinglu Canal*

JI Jinjie1,2(), WANG Ting1, WEI Dongqun1,3, LI Jialin1,4(), QIN Song1,2   

  1. 1 State Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
    3 School of Pharmacy, Binzhou Medical University, Yantai 264003, China
    4 College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China
  • Received:2025-09-22 Revised:2025-10-14 Online:2026-07-10 Published:2026-07-31
  • Contact: LI Jialin. email:
  • Supported by:
    National Key Research and Development Program of China(2024YFF0808802); National Natural Science Foundation of China(42576259); National Natural Science Foundation of China(42176131)

Abstract:

As sensitive indicators of environmental change, bacterial communities provide valuable insights into the health status of estuarine ecosystems through their spatial distribution patterns. The Pinglu Canal, a vital infrastructure project designed to play a key role in connecting land and sea, is scheduled to open for navigation in 2026. However, its potential ecological impacts remain uncertain, underscoring the importance of establishing baseline ecological data. In this study, seawater samples were collected in August 2024 along a transect extending from the mouth of the Pinglu Canal to the offshore zone, which was classified into three regions: estuarine, transition, and offshore. Using high-throughput sequencing of the 16S rRNA gene, combined with alpha diversity and bacteria-based index of biotic integrity (Ba-IBI) assessments, co-occurrence network construction, and null model simulation, we investigated the distribution patterns of bacterioplankton communities and explored the relationships between community heterogeneity and environmental constraints. Results revealed that the dominant phyla were Pseudomonadota, Cyanobacteriota, Bacteroidota, and Actinomycetota, accounting for 40.1%, 24.0%, 16.0%, and 10.4% of the total sequences, respectively. Rare taxa were more enriched in the transition and offshore zones. Alpha diversity followed the trend of transition zone > estuarine zone > offshore zone. Significant differences in community structure were observed across the three regions (P<0.01), with $\text{NO}_{2}^{-}$ concentration identified as the key factor driving structural heterogeneity. The Ba-IBI, developed using a random forest model, showed the lowest value in the estuarine zone, indicating reduced stability in both community structure and functional integrity compared to the transitional and offshore zones. Bacterial communities were primarily assembled through stochastic processes, which accounted for a relative contribution of 58.0%, with hydrodynamic interference acting as a primary factor shaping these mechanisms. By establishing a preliminary Ba-IBI and elucidating the distribution patterns of bacterioplankton communities in the coastal zone of the Pinglu Canal, this study provides foundational data and scientific insights to guide future ecological management and conservation efforts.

Key words: bacterioplankton, diversity, index of biotic integrity (IBI), assembly mechanism, Beibu Gulf

CLC Number: 

  • P735