Short-Term Exposure to High-Temperature Water Causes a Shift in the Microbiome of the Common Aquarium Sponge Lendenfeldia chondrodes

Sergio Vargas,Laura Leiva,Gert Wörheide

doi:10.1007/s00248-020-01556-z

Abstract

Marine sponges harbor diverse microbiomes that contribute to their energetic and metabolic needs. Although numerous studies on sponge microbial diversity exist, relatively few focused on sponge microbial community changes under different sources of environmental stress. In this study, we assess the impact of elevated seawater temperature on the microbiome of cultured Lendenfeldia chondrodes, a coral reef sponge commonly found in marine aquaria. Lendenfeldia chondrodes exhibits high thermal tolerance showing no evidence of tissue damage or bleaching at 5 °C above control water temperature (26 °C). High-throughput sequencing of the bacterial 16S rRNA V4 region revealed a response of the microbiome of L. chondrodes to short-term exposure to elevated seawater temperature. Shifts in abundance and richness of the dominant bacterial phyla found in the microbiome of this species, namely Proteobacteria, Cyanobacteria, Planctomycetes, and Bacteroidetes, characterized this response. The observed resilience of L. chondrodes and the responsiveness of its microbiome to short-term increases in seawater temperature suggest that this holobiont may be capable of acclimating to anthropogenic-driven sublethal environmental stress via a re-accommodation of its associated bacterial community. This sheds a new light on the potential for resilience of some sponges to increasing surface seawater temperatures and associated projected regime shifts in coral reefs.

Highlights

IntroductionThe reef sponge Rhopaloeides odorabile, for instance, showed signs of necrosis after 24 h of exposure to seawater temperatures of 33 °C, only about two to four degrees above the mean highest summer temperature at the site of collection [4]
By the end of this century, moderate climate change scenarios predict the surface temperature of the globe to be over 1.5 °CElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.An increase in seawater temperature of one to two degrees over maximum summer temperatures approaches the upper tolerance level of important coastal ecosystem engineers, like corals [3] and some sponges tested to date [4,5,6,7,8,9]
We found 1343 operational taxonomic unit (OTU) affiliated to 22 bacterial phyla associated with L. chondrodes

Summary

Introduction

The reef sponge Rhopaloeides odorabile, for instance, showed signs of necrosis after 24 h of exposure to seawater temperatures of 33 °C, only about two to four degrees above the mean highest summer temperature at the site of collection [4] At this temperature, the bacterial community associated with R. odorabile suffers irreversible compositional shifts likely caused by a “breakdown” of the sponge symbiotic functions and the colonization of the sponge by opportunistic, potentially pathogenic bacteria [4]. Simister et al [10] reported similar results These authors found a shift in the bacterial community associated with R. odorabile after exposing this sponge to a seawater temperature of 32 °C. The authors reported a highly stable microbiome at temperatures below that upper limit [4, 10]

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Conclusion