Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

Mussels are a group of bivalves that includes the dominant species of shallow-sea, freshwater, and deep-sea chemosynthetic ecosystems. Mussels cling to various solid underwater surfaces using a proteinaceous thread, called the byssus, which is central to their ecology, physiology, and evolution. Mussels cluster using their byssi to form mussel beds, thereby increasing their biomass per unit of habitat area, and also creating habitats for other organisms. Clustered mussels actively filter feed to obtain nutrients, but also ingest pollutants and suspended particles; thus, mussels are good subjects for pollution analyses, especially for microplastic pollution. The byssus also facilitates invasiveness, allowing mussels to hitchhike on ships, and to utilize other man-made structures, including quay walls and power plant inlets, which are less attractive to native species. Physiologically, mussels have adapted to environmental stressors associated with a sessile lifestyle. Osmotic adaptation is especially important for life in intertidal zones, and taurine is a major component of that adaptation. Taurine accumulation systems have also been modified to adapt to sulfide-rich environments near deep-sea hydrothermal vents. The byssus may have also enabled access to vent environments, allowing mussels to attach to evolutionary stepping stones and also to vent chimneys.

Automated summary

Mussels are bivalves that play a key role in various ecosystems, forming mussel beds with their proteinaceous threads and serving as good indicators of pollution due to their filter feeding behavior. Their adaptations to different environments, such as osmotic adaptation and taurine accumulation, allow them to thrive in challenging habitats like intertidal zones and sulfide-rich deep-sea environments. Their ability to utilize byssus for attachment also enables them to colonize diverse environments, from ship hulls to deep-sea hydrothermal vents.