Shallow hydrothermal vent meso-zooplankton: A systematic review of species composition and community structure

This systematic review demonstrates that meso-zooplankton communities are significantly influenced by gas-hydrothermal activity within the water columns of shallow hydrothermal vent systems. Elevated concentrations of micronutrients (e.g., Fe, Mn, Zn, Cu, SiO₃, PO₄, NO₃, NH₃), dissolved gases (e.g., CO₂, CH₄, H₂, H₂S), and various chemical compounds (e.g., hydrocarbons, SO, S₂O₃, NH₄) contribute to enhanced meso-zooplankton biomass and abundance in peripheral vent zones. These physicochemical conditions support two primary energy pathways: photosynthetic production by phytoplankton and chemosynthetic production by sulfur and methane-oxidizing bacteria near vent discharges. The availability of these energy sources appears to attract diverse meso-zooplankton taxa to the vicinity of vent effluents. Despite growing interest in hydrothermal vent ecology, the structural and functional dynamics of meso-zooplankton in shallow-vent environments remain poorly understood. Few studies have comprehensively assessed community composition, abundance, and species diversity in these regions. Even fewer have addressed the molecular and physiological mechanisms underlying biomass enhancement, such as metabolic activity, growth rates, mortality, and diapause induction among vent-associated taxa. Overall, shallow hydrothermal vents represent biologically unique and nutrient-enriched habitats that support elevated meso-zooplankton biomass and taxonomic diversity. These systems contribute substantially to local biodiversity and pelagic productivity, particularly in peripheral zones where vent-derived chemical gradients intersect with surface-driven ecological processes.