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Temporal Variation in Resuspension Potential and Associated Nutrient Dynamics in Shallow Coastal Environments

Temporal Variation in Resuspension Potential and Associated Nutrient Dynamics in Shallow Coastal Environments

Authors :
Conrad A. Pilditch
Alf Norkko
Mari Joensuu
Marine Ecosystems Research Group
Tvärminne Benthic Ecology Team
Aquatic Biogeochemistry Research Unit (ABRU)
Environmental Sciences
Ecosystems and Environment Research Programme
Tvärminne Zoological Station
Biological stations
Source :
Estuaries and Coasts. 43:1361-1376
Publication Year :
2020
Publisher :
Springer Science and Business Media LLC, 2020.

Abstract

Sediment resuspension may play a major role in sediment-water exchange of nutrients, matter and energy in coastal areas where waves and currents dominate sediment transport. Biogeochemical sediment properties regulate sediment erodibility, but there is only limited knowledge of how temporal variability in environmental variables is reflected in the resuspension potential, especially for subtidal habitats. Further, the significance of resuspension on nutrient fluxes in coastal environments has remained unclear as contradicting results have been reported. Here we quantified the temporal variation in resuspension potential metrics (erosion threshold (τc; N m−2) and erosion constant (me; g N−1 s−1)) and associated nutrient fluxes from three sites in the Hanko archipelago (Finland) using a core-based erosion device (EROMES). The sites were sampled bi-monthly from April to December. We also quantified the temporal variation in biogeochemical sediment properties at each site. The τc exhibited the clearest temporal pattern in muddy sediment, where the coefficient of variation (= 67) was two to three times higher than the mixed (= 29) and sandy (= 16) sediments. Dry bulk density was the best predictor for sediment erodibility at all sites explaining 26–46% of the temporal variation in τc despite its limited variability at sandier sites. In addition, temporal variations in the macrofaunal community were important predictors of muddy sediment erodibility and therefore community dynamics need to be considered in sediment transport studies. All sites were potential nutrient sources, yet the overall role of sediment resuspension on nutrient release from the sediments was small.

Details

ISSN :
15592731 and 15592723
Volume :
43
Database :
OpenAIRE
Journal :
Estuaries and Coasts
Accession number :
edsair.doi.dedup.....f2179d1d8c0545203cc475ebbfc1313e
Full Text :
https://doi.org/10.1007/s12237-020-00726-z