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EFFECTS OF SEDIMENT TYPE ON BENTHIC MACROINFAUNAL COLONIZATION OF LABORATORY MICROCOSMS
Citation:
Flemer, D A., B. F. Ruth, AND C. M. Bundrick. EFFECTS OF SEDIMENT TYPE ON BENTHIC MACROINFAUNAL COLONIZATION OF LABORATORY MICROCOSMS. HYDROBIOLOGIA 485(1-3):83-96, (2002).
Description:
We tested the effects of four different sediment types on macroinfaunal colonization and community development in our laboratory flow-thru microcosm system (all microcosms were 20 cm side-1 and sediment depth was 5 cm) over a period of 41 days. Sediments included Santa Rosa Island, FL beach sand, a fine-grained mud from lower Perdido Bay, AL/FL, a 50:50 mixture of Perdido mud and Santa Rosa beach sand, and Western Santa Rosa Sound silty mud. A total of 49 taxa were collected from the four sediments. The phyla Annelida, Mollusca, and Arthropoda dominated taxa richness in all four sediment types. Unidentified Actiniaria (sea anemones) numerically dominated densities among all four sediments with relative densities ranging between 46.5 to 60.5%. Average taxa richness per microcosm (N:10 replicates per treatment, respectively) ranged from 10.4 in the Perdido mud to 14.9 taxa in Santa Rosa sand. These were the only significant differences (p u 0.05) in taxa richness. We detected no significant effects of sediment type on animal densities. In vertically sectioned microcosms, taxa richness averaged 8.9 (N:15 for each sediment type - -5 replicates and 3 depths) in Santa Rosa sand and this mean was significantly greater than that of the other three sediment types. A non-parametric multivariate analysis (Primer) revealed that community structure differed between Santa Rosa sand and Perdido mud in vertically sectioned microcosms. Mean taxa richness of top sections differed significantly from mid- and bottom sections (top mean equals 11.1; mid-depth mean equals 5.6 and bottom mean equals 5.6). We detected significantly higher animal densities and taxa richness in vertically sectioned vs non-sectioned microcosms. However, these differences were inexplicable based on experimental protocols. Differences in community metrics, although statistically significant, were generally of relatively small magnitude.