K-systems analysis for determining the factors influencing benthic microfloral productivity in a Louisiana estuary, USA

Abstract

About 3000 sediment cores from Baratana Estuary, Louisiana, USA, were incubated between 26 Jul and 25 Aug 1983. For the month, benthic microfloral production measured at a subtidal site consisting of muddy sand was almost twice that measured at a sandy intertidal site (27 g C m-' vs 14 g C m-'). However, maximum productivity rates (230 mg C m-' h') were greatest at the sandy site; these rates occurred under periods of subaerial exposure which were limited to late afternoons on 11 d of the study, yet accounted for 43 % of the total monthly production at the sand site. Other variables monitored were chlorophyll a, light intensity, water temperature, salinity, benthic community respiration, productivity of the water column, biological activity (muddy sand site), wave height (sand site), meteorological tides (wind-induced water levels), tide height, and initial dissolved oxygen. Multichannel information analysis indicated that the information accounted for in productivity by these variables peaked at slightly less than 7 and 3 d periods for the sand site and weak peaks occurred at about 10 and 3 d periods for the muddy sand site. K-systems analysis indicated that the environmental variables acted in combination to influence productivity, and that the combinations changed through time. Physical processes (meteorologic, astronomic, and anthropogenic) largely controlled productivity at the sand site. Productivity at the muddy sand site was influenced by a combination of physical and biological activities.