Larvae of Deep-Sea Invertebrates Harbor Low-Diversity Bacterial Communities

Area of Science:

• Marine microbiology
• Deep-sea ecology
• Invertebrate biology

Background:

• Microbial symbionts are common in marine invertebrate development.
• Coastal invertebrate larvae host species-specific bacterial communities of high diversity.
• It is unknown if deep-sea invertebrate larvae associate with similar bacterial communities.

Purpose of the Study:

• To investigate the bacterial communities associated with deep-sea invertebrate larvae.
• To compare the diversity and specificity of bacterial communities between deep-sea and coastal invertebrate larvae.

Main Methods:

• Amplicon sequencing was used to profile bacterial communities.
• Larvae from multiple taxonomic groups (annelids, molluscs, crustaceans) were collected from deep-sea hydrothermal vent regions in the Pacific Ocean.
• Bacterial communities were analyzed for diversity and taxonomic specificity.

Main Results:

• Deep-sea invertebrate larvae associate with low-diversity bacterial communities, averaging around 30 bacterial taxa.
• These bacterial communities lack specificity between different invertebrate taxonomic groups.
• The bacterial diversity associated with deep-sea larvae is significantly lower than that of coastal larvae.

Conclusions:

• Deep-sea invertebrate larvae harbor much simpler bacterial communities than coastal species.
• This suggests deep-sea larvae may have a reduced reliance on microbial symbionts.
• The findings challenge previous assumptions about the universality of complex host-microbe associations in marine invertebrate development.