Sodium molybdate does not inhibit sulfate-reducing bacteria but increases shell growth in the Pacific oyster Magallana gigas

Abstract

Recent work on microbe-host interactions has revealed an important nexus between the environment, microbiome, and host fitness. Marine invertebrates that build carbonate skeletons are of particular interest in this regard because of predicted effects of ocean acidification on calcified organisms, and the potential of microbes to buffer these impacts. Here we investigate the role of sulfate-reducing bacteria, a group well known to affect carbonate chemistry, in Pacific oyster (Magallana gigas) shell formation. We reared oyster larvae to 51 days post fertilization and exposed organisms to control and sodium molybdate conditions, the latter of which is thought to inhibit bacterial sulfate reduction. Contrary to expectations, we found that sodium molybdate did not uniformly inhibit sulfate-reducing bacteria in oysters, and oysters exposed to molybdate grew larger shells over the experimental period. Additionally, we show that microbiome composition, host gene expression, and shell size were distinct between treatments earlier in ontogeny, but became more similar by the end of the experiment. Although additional testing is required to fully elucidate the mechanisms, our work provides preliminary evidence that M. gigas is capable of regulating microbiome dysbiosis caused by environmental perturbations, which is reflected in shell development.

Prokaryotic communities of the French Polynesian sponge Dactylospongia metachromia display a site-specific and stable diversity during an aquaculture trial

“…The core taxa of D. metachromia within the phylum Acidobacteriota, were assigned to Vicinamibacterale, Thermoanaerobaculales and the uncultured group PAUC26f. Marine Thermoanaerobaculales are not strictly sponge-related, as they have also been extracted from molluscs (Neu et al 2021b ; Banker et al 2022 ). Likewise, a core ASV was affiliated to the class bacteriap25 (Myxococcales; Proteobacteria), which is found in soils and terrestrial plants such as some non-indigenous Asteraceae that have been introduced in French Polynesia (Landwehr et al 2016 ; Monteiro 2020 ).…”

Sulfur cycling likely obscures dynamic biologically‐driven iron redox cycling in contemporary methane seep environments

“…Sulfate-depleted media may inadvertently select for organisms that are specially adapted to sulfate-limitation, in which case we suggest parallel enrichment efforts where sodium molybdate is added to gradient tubes containing the conventional (28 mM) sulfate concentration. Sodium molybdate is an inhibitor of metabolic sulfate reduction, but as it has been shown to have variable efficacy for different species of sulfate-reducing bacteria (Banker et al, 2022;Biswas et al, 2009;Nunoura et al, 2012) we suggest running sodium molybdateamended enrichments in parallel with sulfate-depleted enrichments.…”

Deep resilience: An evolutionary perspective on calcification in an age of ocean acidification

“…We have performed experimental work on the chalky deposits of oysters, which offers another example of remote calcification, but so far have been unable to demonstrate a bacterial contribution (Banker and Vermeij, 2018;Banker and Coil, 2020;Banker and Sumner, 2020). However, chemical manipulation of the microbial community in juvenile oysters does cause a significant change in shell size, and a return to normal shell growth correlates with a reestablishment of the wildtype microbiome, which appears to be mediated by the oyster (Banker et al, 2022). Other scientists are also exploring microbiomes in marine calcifiers, although most of the work is similarly nascent, and focused on determining the taxonomy and distribution of microbes residing in calcifying fluids or skeletons (Li et al, 2014;Garate et al, 2017;Prazeres et al, 2017;Marcelino et al, 2018;Sakowski et al, 2020).…”