Meiofauna enhances organic matter mineralization in soft sediment ecosystems

We investigated the influence of meiofauna on the benthic decomposition of a radiolabeled diatom bloom by measuring the production of 14CO₂ in a laboratory microcosm. Mineralization of the diatom bloom material in the sediment was significantly enhanced in the treatment with high meiofauna abundance, with cumulative mineralization values, on average, 50% greater in the treatment with high meiofaunal abundance after 17 d, compared to sediments with low meiofauna abundance. In addition, bacteria species composition in the treatment with high meiofauna abundance was significantly different from the treatment with low meiofauna abundance, indicating that the activities of meiofauna in the sediments had an effect on the bacterial community composition. Meiofauna can enhance the mineralization of organic matter, probably by stimulating the activity of sediment bacterial community, indicating that positive biological interactions such as facilitation from meiofauna are important for ecosystem processes in soft sediments.