Substrate-driven body size variation in marine nematodes: a comparative study of mangrove sediments and leaf litter

Body size is closely related to environmental factors. In June 2021, to investigate substrate-driven body size variation in marine nematodes between mangrove sediment and leaf litter, sampling was conducted at a subtropical mangrove in China. The results showed significant differences in body size attributes, biomass size composition, species composition, and diversity of marine nematodes between sediment and leaf litter substrates. The body size attributes of marine nematodes between sediment and leaf litter substrates varied depending on food resources, environmental stability, and oxygen content. Substrate-driven species differentiation was an intrinsic reason for the morphological adaptation of marine nematodes to specific substrate conditions. Habitat heterogeneity caused by different mangrove vegetation types was a prominent factor leading to variations in body size attributes of nematodes in both substrates. The body size attributes varied due to differences in variables related to different tree species, such as mangrove density, underground root biomass, hydrodynamic stress, and leaf area. The findings of this study showed that nematodes employed morphological specialization to adapt to specific environmental conditions, and body size-based approaches can provide valuable information about the responses of marine nematode communities to environmental variations.