Population dynamics and production of the spionid polychaete
Marenzelleria viridiswere studied at Great Sippewissett salt marsh (Massachusetts, USA) for two years. Marenzelleria viridiswas the main contributor in biomass and production to the macroinfaunal assemblages of the sandy organic sediments of the marsh. Marenzelleria viridisspawned during the cold part of the year and the appearance of settled larvae on sediments was observed from January to May. The density of M. viridisrose sharply from winter to late spring followed by a striking drop through summer. The estimated mean annual production of M. viridiswas 60.0 g dry weight m2 during the first year and 26.3 g dry weight m2 during the second year. The population of M. viridisis affected by different processes during the year. The number of initial recruits seems to be largely governed by meteorological conditions. The numbers of recruits are then affected by competition for resources, and later, as predators become active, predation pressure determines the abundance of the population of M. viridis.