Characterizing the Gut Microbial Communities of Native and Invasive Freshwater Bivalves after Long-Term Sample...

Area of Science:

• Ecology
• Microbiology
• Conservation Science

Background:

• Freshwater mussels are vital environmental health indicators but face population declines due to habitat loss, climate change, and pollution.
• Declining mussel biodiversity poses risks to freshwater ecosystems, highlighting the need to understand their gut microbiomes for conservation.
• Museum collections offer a potential resource for historical ecological data, but the suitability of preserved specimens for microbiome analysis is unclear.

Purpose of the Study:

• To determine if ethanol-preserved freshwater mussel specimens provide representative gut microbiome data for historical ecological studies.
• To validate ethanol as a preservation method for bivalve microbiome analysis using the invasive clam *Corbicula fluminea*.
• To assess the gut microbiomes of nine native mussel species preserved in ethanol for 2-9 years.

Main Methods:

• A preservation experiment was conducted using *Corbicula fluminea* to test ethanol's efficacy for microbiome preservation.
• Gut microbiomes of nine native mussel species stored in ethanol for 2-9 years were analyzed using sequencing.
• Bacterial assemblages and sequencing depth were compared between fresh and preserved specimens.

Main Results:

• Ethanol preservation effectively maintains sequencing depth and bacterial richness in bivalve gut samples.
• The study provides insights into the gut microbiomes of *C. fluminea* and nine native mussel species.
• A core bacterial genus, *Romboutsia*, was identified as potentially common across freshwater bivalve species.

Conclusions:

• Ethanol is a suitable method for preserving freshwater mussel specimens for gut microbiome research.
• Museum collections of ethanol-preserved mussels can be utilized to study long-term changes in their gut microbiomes.
• Identifying core bacterial genera like *Romboutsia* aids in understanding mussel health and ecological roles.