4.3 Bacteria Adaptation during marine heatwaves
The Microbiome Flexibility Hypothesis of Metaorganism Adaptation suggests that changes in microbial communities contribute to the response and adaptation of organisms to environmental fluctuations (Voolstra and Ziegler, 2020). Our results demonstrate that following the second marine heatwave, there was a significant increase in the abundance of certain bacteria.
Specifically, there was an increase in the abundance of u. Coxiella, u. Flavobacteriaceae, Achromobacter arsenitoxydans , andHalomonas desiderata . Coxiella has been shown to cause diseases in invertebrates and is closely associated with coral health and disease (Antonio et al., 2000; Casas et al., 2004). u. Flavobacteriaceae, as a core community from the first to the second recovery phase, indicates its importance for coral health. Additionally, previous studies have demonstrated that Achromobacter arsenitoxydans andHalomonas desiderata enhance coral’s resistance to environmental stress as stress-tolerant bacteria (Abrego et al., 2008; Rosado et al., 2019).
These findings highlight the complex dynamics of the microbial community during the recovery phases. Although repeated heatwaves can lead to the emergence of pathogenic bacteria, the abundance of beneficial bacterial communities also increased. At the end of the second recovery phase, there was a significant increase in the abundance of u. Dadabacteriales, u. Woeseia, Rubritalea tangerine , uncultured delta proteobacterium , and other beneficial microorganisms. These bacteria have important roles in coral health and growth status (Roder et al., 2014; Radecker et al., 2015; Röthig et al., 2016; Jiang et al., 2019).
These strategic changes in the microbial community might represent corals adaptive responses to the stress, where the microbial community undergoes adjustments to thrive within the marine heatwave environment (van Oppen and Blackall, 2019). This adaptability of the microbial community is crucial for supporting coral health and resilience in the face of stressful events like marine heatwaves.