Morphological, growth and meadow characteristics of the seagrass Posidonia sinuosa along a depth-related gradient of light availability

Collier, CJ; Lavery, PS; Masini, RJ; Ralph, PJ

Morphological, growth and meadow characteristics of the seagrass Posidonia sinuosa along a depth-related gradient of light availability

Collier, CJ Lavery, PS Masini, RJ Ralph, PJ

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Publication Type:: Journal Article
Citation:: Marine Ecology Progress Series, 2007, 337 pp. 103 - 115
Issue Date:: 2007-05-14

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Field	Value	Language
dc.contributor.author	Collier, CJ	en_US
dc.contributor.author	Lavery, PS	en_US
dc.contributor.author	Masini, RJ	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2007-05-14	en_US
dc.identifier.citation	Marine Ecology Progress Series, 2007, 337 pp. 103 - 115	en_US
dc.identifier.issn	0171-8630	en_US
dc.identifier.uri	http://hdl.handle.net/10453/3854
dc.description.abstract	Morphological and growth characteristics of the meadow-forming seagrass Posidonia sinuosa (Cambridge et Kuo), were measured along a depth-related gradient of light to infer its response to long-term differences in light availability. Morphometric measurements were carried out at 6 depths between 1.6 and 9.0 m in summer and winter at Cockburn Sound and summer only at Warnbro Sound in south-western Australia. The minimum light requirement for P. sinuosa of 8.5 % sub-surface light was among the lower range reported for seagrasses. Its slow growth rate (0.5-1.5 mgdry shoot-1 d -1), relative to similarly sized species, may contribute to the low light requirements of this species. Shoot density, leaf area index and biomass showed pronounced and consistent differences among depths (up to 88-fold reduction of above-ground biomass from shallow to deep sites). At the deeper sites, the reduced shoot density probably reduces respiratory demand and alleviates self-shading. Morphological differences (leaf length, width and thickness and number of leaves per shoot) did not follow a clear and consistent trend with depth. Despite a 70 % reduction in light availability at the canopy level between the shallowest and deepest sites, leaf growth rate was unaffected by depth during summer, and in winter differed between only a few depths. We propose that the reduction in shoot density partially alleviates the effects of self-shading and permits comparable leaf growth rates across the depth range. These results suggest that for interpreting long-term responses to light availability, shoot density is the most sensitive of the morphological characteristics measured here. © Inter-Research 2007.	en_US
dc.relation.ispartof	Marine Ecology Progress Series	en_US
dc.relation.isbasedon	10.3354/meps337103	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Morphological, growth and meadow characteristics of the seagrass Posidonia sinuosa along a depth-related gradient of light availability	en_US
dc.type	Journal Article
utslib.citation.volume	337	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0405 Oceanography	en_US
utslib.for	0608 Zoology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	closed_access
pubs.publication-status	Published	en_US
pubs.volume	337	en_US

Abstract:

Morphological and growth characteristics of the meadow-forming seagrass Posidonia sinuosa (Cambridge et Kuo), were measured along a depth-related gradient of light to infer its response to long-term differences in light availability. Morphometric measurements were carried out at 6 depths between 1.6 and 9.0 m in summer and winter at Cockburn Sound and summer only at Warnbro Sound in south-western Australia. The minimum light requirement for P. sinuosa of 8.5 % sub-surface light was among the lower range reported for seagrasses. Its slow growth rate (0.5-1.5 mgdry shoot-1 d -1), relative to similarly sized species, may contribute to the low light requirements of this species. Shoot density, leaf area index and biomass showed pronounced and consistent differences among depths (up to 88-fold reduction of above-ground biomass from shallow to deep sites). At the deeper sites, the reduced shoot density probably reduces respiratory demand and alleviates self-shading. Morphological differences (leaf length, width and thickness and number of leaves per shoot) did not follow a clear and consistent trend with depth. Despite a 70 % reduction in light availability at the canopy level between the shallowest and deepest sites, leaf growth rate was unaffected by depth during summer, and in winter differed between only a few depths. We propose that the reduction in shoot density partially alleviates the effects of self-shading and permits comparable leaf growth rates across the depth range. These results suggest that for interpreting long-term responses to light availability, shoot density is the most sensitive of the morphological characteristics measured here. © Inter-Research 2007.

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http://hdl.handle.net/10453/3854