Secondary production of a dominant oligochaete (Monopylephorus rubroniveus) in the tidal creeks of South Carolina and its relation to ecosystem characteristics

Abstract

Measurements of the annual production of the oligochaete Monopylephorus rubroniveus, microphytobenthos, pore-water ammonia, sediment composition, and water quality were made from January through December 2001 in the upper and lower reaches of two tidal creeks in southeastern South Carolina. Secondary production of M. rubroniveus was greater in the shallow upper reaches of tidal creeks (1.0-10.5 g ash-free dry weight [AFDW] m-2 yr-1) than in the lower reaches (0.05-0.2 g AFDW m-2 yr-1), as were benthic chlorophyll a levels and pore-water ammonia concentration. Production of M. rubroniveus was greater in both reaches of Okatee Creek (0.1-10.5 g AFDW m-2 yr-1) than in Malind Creek (0.05-2.0 g AFDW m-2 yr-1). The only significant difference in environmental characteristics between the two creeks was a greater incidence of hypoxia (dissolved oxygen < 28% air saturation) in Malind Creek than in Okatee Creek, 5% of all records observed versus 0.3%, respectively. The rates of production estimated for M. rubroniveus in these creeks were relatively high compared with similar macrobenthos in other environments. Furthermore, the pattern of production within and between creeks provides a basic understanding of energy and material flows out of these important ecosystems and the processes that influence them. © 2005, by the American Society of Limnology and Oceanography, Inc.