The stable microbiome of inter and sub-tidal anemone species under increasing pCO2.

Erinn M Muller,Kim B Ritchie,Maoz Fine

doi:10.1038/srep37387

Abstract

Increasing levels of pCO2 within the oceans will select for resistant organisms such as anemones, which may thrive under ocean acidification conditions. However, increasing pCO2 may alter the bacterial community of marine organisms, significantly affecting the health status of the host. A pH gradient associated with a natural volcanic vent system within Levante Bay, Vulcano Island, Italy, was used to test the effects of ocean acidification on the bacterial community of two anemone species in situ, Anemonia viridis and Actinia equina using 16 S rDNA pyrosequencing. Results showed the bacterial community of the two anemone species differed significantly from each other primarily because of differences in the Gammaproteobacteria and Epsilonproteobacteria abundances. The bacterial communities did not differ within species among sites with decreasing pH except for A. viridis at the vent site (pH = 6.05). In addition to low pH, the vent site contains trace metals and sulfide that may have influenced the bacteria community of A. viridis. The stability of the bacterial community from pH 8.1 to pH 7.4, coupled with previous experiments showing the lack of, or beneficial changes within anemones living under low pH conditions indicates that A. viridis and A. equina will be winners under future ocean acidification scenarios.

Highlights

In concordance with changes in the physiological state of A. viridis, ocean acidification conditions may alter the microbial communities of this anemone
The objectives of the present study were to i) characterize and compare the microbial communities of two anemone species with different life history strategies found along a natural pH gradient within the sublittoral zone of Levante Bay, Vulcano Island, Italy (A. viridis, a subtidal species with an endosymbiont, and A. equina, an intertidal species with no endosymbiont), and ii) to determine whether the bacterial assemblages of these two species differed with decreasing levels of pH
The bacterial composition of the two anemone species, A. viridis and A. equina, was significantly different from each other, which may have been driven by variations in interspecific traits between host genera or because of differences in the tissues sampled between A. viridis and A. equina

Summary

Introduction

In concordance with changes in the physiological state of A. viridis, ocean acidification conditions may alter the microbial communities of this anemone. Webster et al.[16] documented differences in microbial communities associated with the coral species Acropora millipora, the foraminifera Marginopora vertebralis, the crustose coralline algae Hydrolithon onkodes, and reef biofilms between treatments of pH 8.1 and 7.9 conditions. The objectives of the present study were to i) characterize and compare the microbial communities of two anemone species with different life history strategies found along a natural pH gradient within the sublittoral zone of Levante Bay, Vulcano Island, Italy (A. viridis, a subtidal species with an endosymbiont, and A. equina, an intertidal species with no endosymbiont), and ii) to determine whether the bacterial assemblages of these two species differed with decreasing levels of pH

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Conclusion