Evidence of bacterioplankton community adaptation in response to long-term mariculture disturbance.

Jinbo Xiong,Changju Hu,Heping Chen,Xiansen Ye,Dingjiang Kong,Demin Zhang

doi:10.1038/srep15274

Abstract

Understanding the underlying mechanisms that shape the temporal dynamics of a microbial community has important implications for predicting the trajectory of an ecosystem’s response to anthropogenic disturbances. Here, we evaluated the seasonal dynamics of bacterioplankton community composition (BCC) following more than three decades of mariculture disturbance in Xiangshan Bay. Clear seasonal succession and site (fish farm and control site) separation of the BCC were observed, which were primarily shaped by temperature, dissolved oxygen and sampling time. However, the sensitive bacterial families consistently changed in relative abundance in response to mariculture disturbance, regardless of the season. Temporal changes in the BCC followed the time-decay for similarity relationship at both sites. Notably, mariculture disturbance significantly (P < 0.001) flattened the temporal turnover but intensified bacterial species-to-species interactions. The decrease in bacterial temporal turnover under long-term mariculture disturbance was coupled with a consistent increase in the percentage of deterministic processes that constrained bacterial assembly based on a null model analysis. The results demonstrate that the BCC is sensitive to mariculture disturbance; however, a bacterioplankton community could adapt to a long-term disturbance via attenuating temporal turnover and intensifying species-species interactions. These findings expand our current understanding of microbial assembly in response to long-term anthropogenic disturbances.

Highlights

Understanding the underlying mechanisms that shape the temporal dynamics of a microbial community has important implications for predicting the trajectory of an ecosystem’s response to anthropogenic disturbances
For a given water variable, the temporal change was similar between the two sites; for example, the level of chemical oxygen demand (COD) peaked in autumn, whereas total phosphate (TP) consistently increased over the seasons at both sites (Fig. S1)
The bacterioplankton communities dramatically changed across the three seasons and between sites (Fig. 1), and such variations are closely associated with temperature and geochemical variables (Table 2), matching the notion that temperature and nutrient levels cause pronounced changes in the bacterioplankton community composition (BCC) in coastal waters[4,12,19]

Summary

Introduction

Understanding the underlying mechanisms that shape the temporal dynamics of a microbial community has important implications for predicting the trajectory of an ecosystem’s response to anthropogenic disturbances. We know little on how, and to what extent, disturbances, i.e., coastal aquaculture, affect temporal dynamics in a microbial assembly, even though this information is central to predicting the trajectory of microbial responses to anthropogenic disturbances[4,17,21,23] To acquire this knowledge, we collected seawater samples seasonally from a coastal fish farm and its adjacent control site (1) to explore the temporal pattern of a bacterioplankton community and the surrounding water chemistry and to ascertain their relationship; (2) to evaluate to what extent the bacterial temporal turnover, species-species interactions, and relative importance of deterministic processes are altered by mariculture disturbance; and (3) to screen sensitive bacterial assemblages for characterizing such disturbance

Methods

Results

Conclusion