Ocean acidification alters the diversity and structure of oyster associated microbial communities

Abstract

Understanding microbial responses to environmental disturbances is critical. However, in host-associated microbial communities, it is unclear whether microbial response to disturbance is linked to the environment, or if it is mediated via host response. We used Eastern oysters as a model to demonstrate that both environment-and host-linked factors influence the composition and structure of gill microbial communities exposed to ocean acidification. Remarkably, members of the microbiome linked directly to elevated pCO 2 were different from those linked to the host's physiological response. Disentangling the microbial community's response to environmental disturbance from its response to the host's reaction to that disturbance is essential to understand and predict the effect of global change drivers on host-associated microbial communities.

The Prokaryotic and Eukaryotic Microbiome of Pacific Oyster Spat is Shaped by Ocean Warming but not Acidification

“…S6a-c), even though a pCO2 level of 2800 μatm equates to a pH drop of ~0.55 (e.g., the 18°C treatment), which is greater than the predicted pH drop of 0.29 in the ocean by the year 2100 (Bindoff et al 2019). In contrast to our observations, challenge experiments with adult eastern oysters (Crassostrea virginica, pH drop ~0.7; Unzueta-Martínez et al 2021) and Sydney rock oysters (Saccostrea glomerata, pH drop ~0.34; Scanes et al 2021a;Scanes et al 2021b;Scanes et al 2021c) showed that pCO2-mediated acidification affected the microbiome. Possibly, the lack of an observable effect of acidification on the spat microbiome could be attributed to resilience to changes in pCO2 and pH, as has been reported in terms of survival across multiple oyster species (Ginger et al 2013;Lawlor and Arellano 2020).…”

“…We grew Pacific oyster spat at pCO2 levels of 800, 1600, and 2800 μatm (e.g., resulting in pH mean ± SD in tank water at the 18°C treatment: 7.79 ± 0.09 [n = 30], 7.50 ± 0.04 [n = 30] and 7.24 ± 0.04 [n = 30], respectively; further details are in Table S1) to assess the effect of acidification on the spat microbiome. Previous studies have shown that changes in pH as a result of pCO2, influence the physiology of marine organisms such as corals and oysters (Alma et al 2020;van Hooidonk et al 2014;Waldbusser et al 2015), and also play a role in shifting the composition of the microbiome (Scanes et al 2021a;Scanes et al 2021b;Scanes et al 2021c;Unzueta-Martínez et al 2021). Therefore, we expected pCO2 to affect the biology of the spat, and thus influence the microbiome.…”

“…Consequently, short-term excursions of low pH waters are becoming increasingly common under a scenario of climate change. In turn, increasing acidity and temperature can profoundly affect marine ecosystems (Hoegh-Guldberg and Bruno 2010), including influencing the microbiome of oysters (Fernandez-Piquer et al 2012;Lim et al 2021a;Lokmer and Mathias Wegner 2015;Scanes et al 2021a;Scanes et al 2021b;Scanes et al 2021c;Unzueta-Martínez et al 2021) and the interaction of the oyster immune system with the microbiome (Dang et al 2023). Despite the potential influence of the microbiome on oyster health, and the frailty of spat to environmental change, the impact of temperature and pCO2 on oyster spat remains unexplored, as does effects on the eukaryotic microbiome of oysters, in general.…”

Taking steps to address inequities in open‐access publishing through an early career publication honor

“…They found that predicted poleward extensions of species' ranges are reduced by as much as 60% when topography is considered, highlighting the need for incorporating static topography into predictions of future species' distributions. In another marine‐focused study, Unzueta‐Martínez et al (2021) sampled oyster microbial communities to test host‐associated microbial stability under rising levels of atmospheric CO 2 and ocean acidification. They reported that some taxa within the oyster microbiome responded directly to ocean acidification, while others were more sensitive to host response, thereby identifying which members of the microbiome may contribute to the health and resistance of their host and which are most vulnerable to acidification.…”

Impact of lowered pH on the morphological, physiological, and microbial community composition of the temperate calcareous sponge, Grantia sp.

“…Whose functional roles are still not completely understood but likely range from providing symbiotic relationships with the host, to being pathogenic to the host (Katharios et al, 2015). Previous studies have found mixed results in marine species, Unzueta-MartÍnez et al, (2021) found an initial increase in the abundance of Oceanospirillales in oysters after 24hr of exposure to low pH conditions, however they decreased when recorded again on day 9. In biofilm communities, Oceanospirillales have also been found to decrease in low pH and high nutrient environments compared to their controls and have been found to grow best in alkaline conditions (Wang et al, 2015).…”