A new view of meiofauna biomass turnover rates

D.H. Anderson. Kissimmee Division, South Florida Water Management District, West Palm Beach, Florida 33406

One way to answer the question "Do meiofauna matter?" is to consider their contribution to energy flow as indicated by their secondary production, which depends in part on the biomass turnover rate or annual P/B. An early influential study suggested that meiofauna have a low annual P/B of approximately 10, however this value is inconsistent with more recent laboratory growth studies, which suggest that annual P/B may exceed 20. Partly because of this early conservative value, Banse and Mosher (1980) suggested that if their empirical model of annual P/B, developed for animals ranging in size from macroinvertebrates to mammals, was used for meiofauna that the predicted values be adjusted by dividing by 3 to 5. I estimated annual P/Bs for microcrustaceans for 2 years in a forested floodplain swamp from biomass and growth rates, obtained under conditions of natural food and temperature. For 25 meiobenthic taxa, annual P/B ranged from 6 to 132 with a median of 23. These values suggest that meiofauna can attain high turnover rates. Accurate estimates of meiofaunal growth and annual P/B are essential to assess the contribution of meiofauna to energy flow through aquatic ecosystems.