Long-term variability of estuarine meiobenthos: an 11 year study

Abstract

Eleven years of monthly (or fortnightly) meiofauna abundance and physical variable data at 2 subtidal estuarine sites (sand and mud) in South Carolina, USA suggest that complex interactions control fauna1 abundance. At the mud site abundance peaked in late wintedearly spring, reaching over 1800 meiofauna 10 cm-2; seasonal abundance was correlated with salinity changes. In sand, abundance peaked in mid-summer and was positively correlated with temperature (and negatively with RPD). Variability in abundance at the mud site was appriximately twice that of the sand site, and year to year variability was greater at both sites than the inherent seasonality. There were no long-term cycles in the fauna or temperature/salinity at either site; 12 mo was the period recurrent throughout the data set. The period 1975-1977 had the highest abundances at both sites, but these peaks were not correlated with any of the measured (or obtained) physical variables. Grain size at the sand site decreased in the 1980's and there was a concommitant decrease in the abundance of copepods and in increase in the nematode/copepod ratio.