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Flow-induced morphological variations affect diffusion boundary-layer thickness of macrocystis pyrifera (Heterokontophyta, Laminariales)
Citation
Hurd, CL and Pilditch, C, Flow-induced morphological variations affect diffusion boundary-layer thickness of macrocystis pyrifera (Heterokontophyta, Laminariales), Journal of Phycology, 47, (2) pp. 341-351. ISSN 0022-3646 (2011) [Refereed Article]
Copyright Statement
Copyright 2011 Phycological Society of America
DOI: doi:10.1111/j.1529-8817.2011.00958.x
Abstract
In slow mainstream flows (<46 cm Ζ s)1), the
transport of dissolved nutrients to seaweed blade
surfaces is reduced due to the formation of thicker
diffusion boundary layers (DBLs). The blade morphology
of Macrocystis pyrifera (L.) C. Agardh varies
with the hydrodynamic environment in which it
grows; wave-exposed blades are narrow and thick
with small surface corrugations (1 mm tall), whereas
wave-sheltered blades are wider and thinner with
large (25 cm) edge undulations. Within the surface
corrugations of wave-exposed blades, the DBL thickness,
measured using an O2 micro-optode, ranged
from 0.67 to 0.80 mm and did not vary with mainstream
velocities between 0.8 and 4.5 cm Ζ s)1. At
the corrugation apex, DBL thickness decreased with
increasing seawater velocity, from 0.4 mm at
0.8 cm Ζ s)1 to being undetectable at 4.5 cm Ζ s)1.
Results show how the wave-exposed blades trap fluid
within the corrugations at their surface. For wavesheltered
blades at 0.8 cm Ζ s)1, a DBL thickness of
0.73 ± 0.31 mm within the edge undulation was 10-
fold greater than at the undulation apex, while at
2.1 cm Ζ s)1, DBL thicknesses were similar at
<0.07 mm. Relative turbulence intensity was measured
using an acoustic Doppler velocimeter (ADV),
and overall, there was little evidence to support our
hypothesis that the edge undulations of wave-sheltered
blades increased turbulence intensity compared
to wave-exposed blades. We discuss the
positive and negative effects of thick DBLs at seaweed
surfaces.
Key index words: blade morphology; diffusion
boundary layer; kelp; Macrocystis pyrifera; microoptode;
oxygen profiles; turbulence intensity
Abbreviations: ADV, acoustic Doppler velocimeter;
DBL, diffusion boundary layer
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | seaweed, kelp, macrocystis, boundary layers, photosynthesis, morphology |
Research Division: | Biological Sciences |
Research Group: | Plant biology |
Research Field: | Phycology (incl. marine grasses) |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Adaptation to climate change |
Objective Field: | Ecosystem adaptation to climate change |
UTAS Author: | Hurd, CL (Professor Catriona Hurd) |
ID Code: | 91476 |
Year Published: | 2011 |
Web of Science® Times Cited: | 39 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2014-05-20 |
Last Modified: | 2017-11-03 |
Downloads: | 0 |
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