Symbioses from Cold Seeps

Abstract

Establishing symbiosis between bacteria and invertebrates can significantly enhance energy transfer efficiency between them, which may aid in shaping the flourishing community in deep-sea chemosynthetic ecosystems, including cold seeps, hydrothermal vents, and organic falls. The symbionts utilize the chemical energy from reductive materials to fix carbon, and the hosts absorb the nutrients for growth through farming, milking, or both. Moreover, symbiosis can enhance the sustainability of both participants to survive in harsh conditions. However, the exact process and the regulatory network of symbiosis are still unknown. The cold seeps in the South China Sea offer natural laboratories to study the composition, ecological functions, and regulatory mechanisms of deep-sea symbioses. In this chapter, we focused on two dominant species, a deep-sea mussel Gigantidas platifrons and a squat lobster Shinkaia crosnieri, which represent endosymbiosis and episymbiosis, respectively, at Site F to summarize our understanding of deep-sea chemosymbiosis. We also discussed some promising avenues for future studies, such as deep-sea in situ experiments to show the exact responses of deep-sea organisms, culture-dependent experiments with genetic operations to validate the functions of critical genes, and microscale omics to elucidate the possible interactions at subcellular levels.