Effect of sediment load on the microbenthic community of a shallow-water sandy sediment
Wulff, A.; Sundbäck, K.; Nilsson, C.; Carlson, L.; Jonsson, B. (1997). Effect of sediment load on the microbenthic community of a shallow-water sandy sediment. Estuaries 20(3): 547-558
www.jstor.org/stable/1352613
In: Estuaries. The Estuarine Research Federation, Chesapeake Biological Laboratory: Columbia, S.C., etc.,. ISSN 0160-8347; e-ISSN 1559-2758, more
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| Authors | | Top |
- Wulff, A.
- Sundbäck, K.
- Nilsson, C.
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| Abstract |
Anthropogenic activities, such as construction work, dredging, and different kinds of recreation activities, can alter sediment loading in shallow coastal areas. The effect of increased load of fine sediment on the microbenthos (benthic microalgae, bacteria, and meiofauna) was studied in two experiments using undisturbed cores of a sandy sediment from a microtidal bay on the Swedish west coast. In each experiment, a total of 24 cores were incubated in an outdoor flow-through set-up. Twelve cores were treated with a 2.5-mm thick layer of autoclaved fine-grained, (silt) carbonrich surface sediment. In the first experiment, estimates of the impact were based on measurements of chlorophyll a, biomass of microalgae, bacteria, and meiofauna, and bacterial production. The main purpose of the second experiment was to study the effect on sediment oxygen profiles using microsensors. Within a week, after being covered by fine sediment, benthic microalgae (particularly diatoms) had migrated upward and the oxygen profiles were restored at the sediment surface by photosynthesis. However, the oxygen-producing layer became thinner and the algal composition changed. Bacterial biomass was restored to the same level as in the sandy sediment. Meiofauna also appeared to move upward and the meiofaunal composition was re-established. The results suggest that the microbenthic community of sandy sediment has an inherent capacity to recover after a moderate deposition of fine-particle sediment. Active upward migration of benthic diatoms appears to be a key mechanism for restoring the oxygenation of the sediment surface. The altered sediment type also implies changed species composition, and hence altered benthic trophic interactions, which may affect, for example, flatfish recruitment. |
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