Population biology and secondary production of the suspension feeding polychaete Chaetopterus cf. variopedatus: Implications for benthic-pelagic coupling in lower Chesapeake Bay

Thompson, Michelle L., Linda C. Schaffner

Limnol. Oceanogr., 46(8), 2001, 1899-1907 | DOI: 10.4319/lo.2001.46.8.1899

ABSTRACT: Benthic suspension feeders are functionally important components of many shallow estuarine and coastal ecosystems. Their relative importance in material and energy cycling depends on physical and biological factors, of which population dynamics of individual species are a key feature. We studied the demographics and secondary production of a population of the tubicolous, suspension feeding polychaete, Chaetopterus cf. variopedatus, of southern Chesapeake Bay, Virginia, to better understand its functional role in an estuarine ecosystem. Average worm densities in the study region ranged from 30 to >1000 individuals m-2 and were greatest after the summer recruitment period. Recruitment success varied threefold between 1994 and 1995. A two-cohort model (juveniles and adults) with seasonality best described the data. High secondary production (18 g C m-2 yr-1 in 1994, 34 g C m-2 yr-1 in 1995) was mainly due to rapid growth and maturation of new recruits during summer and tube production. An interannual difference in production was associated with the interannual difference in recruitment success. General temporal trends of primary production and worm production were similar, and the worm population required 35%-100% of the estimated annual net water column community production per m2 for this region of the estuary. Chaetopterus cf. variopedatus is an important component of the lower bay ecosystem and should be considered when modeling carbon, nutrient, and energy flow. Our results further demonstrate that temporal variations in population dynamics lead to significant temporal variability in the relative importance of benthic suspension feeder effects for ecosystem function.

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