Decade-scale stability and change in a marine bivalve microbiome

Area of Science:

• Ecology
• Microbiology
• Marine Biology

Background:

• Predicting organismal responses to anthropogenic change is crucial.
• Microbial community predictions are limited by data availability, especially for host-associated microbes.
• Long-term data on marine host-associated microbial communities is scarce.

Purpose of the Study:

• To quantify the decadal diversity and composition of the microbiome in the marine bivalve Donax gouldii.
• To assess the impact of seasonal temperature and phytoplankton blooms on the host microbiome.
• To evaluate the utility of ethanol-preserved tissues for long-term microbiome analysis.

Main Methods:

• Collected fresh and ethanol-preserved Donax gouldii soft tissue samples over a decadal timescale.
• Quantified microbiome diversity and composition using amplicon sequencing.
• Correlated microbiome data with site-level measurements of temperature, salinity, and chlorophyll a.

Main Results:

• Microbiome richness (ASV richness) remained stable over the decade despite environmental fluctuations.
• Phylogenetic composition varied significantly across collection years, indicating substantial microbial turnover.
• Ethanol-preserved tissues provided high-resolution temporal data on microbiome composition.

Conclusions:

• The diversity of the Donax gouldii microbiome is stable over decadal timescales and in response to seasonal environmental changes.
• Despite stable diversity, the microbiome composition undergoes significant annual turnover.
• Ethanol-preserved samples are a viable method for long-term studies of host-associated microbial communities.