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Effects of a small-bladed macroalgal canopy on benthic boundary layer dynamics: implications for nutrient transport
journal contribution
posted on 2023-05-18, 00:50 authored by Kregting, L, Stevens, C, Cornelisen, C, Pilditch, C, Catriona HurdCatriona HurdField and laboratory velocity profiles were used to quantify boundary layer dynamics within communities of a small (< 0.2 m tall), dense canopy-forming seaweed Adamsiella chauvinii (Rhodophyta) in a soft-sediment habitat and to examine the role of hydrodynamics in modulating nutrient supply. At the ‘canopy scale’ there was a mixing layer at the fluid−canopy interface where turbulent kinetic energy was greatest, potentially enhancing nutrient uptake in this region. In the lower half of the canopy, a drag-dominated area of very low water velocity (< 0.01 m s−1) occurred. Spectral analysis revealed a reduction in energy within the canopy of around 1 Hz. The hydrodynamic parameters obtained from flume measurements were in good agreement with those recorded in the field. To understand the implications of the hydrodynamic environment on nutrient uptake, a flushing ratio was developed that compares the time for macroalgae to remove all nutrients from the canopy volume relative to the timescale for flushing. Results suggest that when nutrient demand is low, the canopy is well flushed and not mass-transfer limited. However when nutrient demand is high, the canopy can deplete nutrients more quickly than they can be replenished by ambient flows and are potentially mass-transfer limited.
History
Publication title
Aquatic BiologyVolume
14Pagination
41-56ISSN
1864-7782Department/School
Institute for Marine and Antarctic StudiesPublisher
Inter-ResearchPlace of publication
GermanyRights statement
Copyright 2011 Inter-ResearchRepository Status
- Restricted