Abstract
Building man-made structures in coastal seas are often preceded by dredging operations, inducing turbid plumes of suspended sediment. To study the effects of such high-concentration sediment plumes on the suspension-feeding polychaete Lanice conchilega, a laboratory experiment was performed, in which individuals of L. conchilega were exposed to natural seawater with a suspended sediment concentration (SSC) of ?0.3 g l-1 and treatments with elevated SSC of 5 and 1 g l-1, representing concentrations in a dredging plume at the moment of sediment release and after initial dilution, respectively. We measured clearance rates of sediment particles, biogeochemical fluxes, and bio-irrigation. While clearance rates and nitrite efflux significantly increased in both treatments with elevated SSC compared with the control, bio-irrigation increased at 1 g l-1 but was lowest at 5 g l-1. It is suggested that piston pumping is intensified under intermediate concentrations to remove sediment, but ceases under high concentrations are due to sediment ingestion. By transporting oxygen into the sediment, bio-irrigation enhances aerobic microbial processes, among which nitrification. We conclude that short-Term extreme suspended sediment concentrations can have a significant impact on the biogeochemistry of the seabed through changes in behaviour of L. conchilega.
Original language | English |
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Pages (from-to) | 1219-1226 |
Number of pages | 8 |
Journal | ICES Journal of Marine Science |
Volume | 77 |
Issue number | 3 |
DOIs | |
Publication status | Published - May 2020 |
Keywords
- bio-irrigation
- biogeochemistry
- dredging
- Lanice conchilega
- SSC
- suspension feeding