This document presents advances in process-based models for benthic ecosystems developed under NECCTON Work Package 6, focusing on sea-bottom flora and fauna (Task 6.2.4). Benthic ecosystems – the communities living on and in the seafloor – play crucial roles in marine food webs, support fisheries, and regulate biogeochemical cycles. However, predicting their dynamics remains challenging due to limited availability of observational data and incomplete understanding of key processes. The work addresses critical gaps in benthic ecosystem modelling by delivering three new products: benthic macrofaunal biomass by functional type (deposit feeders, suspension feeders, and newly introduced predators), filter-feeding bivalve (Mytilus) growth and biomass, and red seaweed (Phyllophora) biomass.