Skip to main content
WCS
Menu
Library
Library Catalog
eJournals & eBooks
WCS Research
Archives
Research Use
Finding Aids
Digital Collections
WCS History
WCS Research
Research Publications
Science Data
Services for WCS Researchers
Archives Shop
Bronx Zoo
Department of Tropical Research
Browse By Product
About Us
FAQs
Intern or Volunteer
Staff
Donate
Search WCS.org
Search
search
Popular Search Terms
WCS History
Library and Archives
Library and Archives Menu
Library
Archives
WCS Research
Archives Shop
About Us
Donate
en
fr
Title
Photosynthetic responses of subtidal seagrasses to a daily light cycle in Torres Strait: A comparative study
Author(s)
Campbell, S.J.; Kerville, S.P.; Coles, R.G.; Short, F.
Published
2008
Publisher
Continental Shelf Research
Published Version DOI
https://doi.org/10.1016/j.csr.2008.03.038
Abstract
In this study, we examined the photosynthetic responses of five common seagrass species from a typical mixed meadow in Torres Strait at a depth of 5-7 m using pulse amplitude modulated (PAM) fluorometry. The photosynthetic response of each species was measured every 2 h throughout a single daily light cycle from dawn (6 am) to dusk (6 pm). PAM fluorometry was used to generate rapid light curves from which measures of electron transport rate (ETRmax), photosynthetic efficiency (alpha), saturating irradiance (E-k) and light-adapted quantum yield (Delta F/F-m) were derived for each species. The amount of light absorbed by leaves (absorption factor) was also determined for each species. Similar diurnal patterns were recorded among species with 3-4 fold increases in maximal electron rate from dawn to midday and a maintenance of ETRmax in the afternoon that would allow an optimal use of low light by all species. Differences in photosynthetic responses to changes in the daily light regime were also evident with Syringodium isoetifolium showing the highest photosynthetic rates and saturating irradiances suggesting a competitive advantage over other species under conditions of high light. In contrast Halophila ovalis, Halophila decipiens and Halophila spinulosa were characterised by comparatively low photosynthetic rates and minimum light requirements (i.e. low E-k) typical of shade adaptation. The structural makeup of each species may explain the observed differences with large, structurally complex species such as Syringodium isoetifolium and Cymodocea serrulata showing high photosynthetic effciciencies (alpha) and therefore high-light-adapted traits (e.g. high ETRmax and E-k) compared with the smaller Halophila species positioned lower in the canopy. For the smaller Halophila species these shade-adapted traits are features that optimise their survival during low-light conditions. Knowledge of these characteristics and responses improves our understanding of the underlying causes of changes in seagrass biomass, growth and survival that occur when modifications in light quantity and quality arise from anthropogenic and climatic disturbances that commonly occur in Torres Strait. (c) 2008 Elsevier Ltd. All rights reserved.
Keywords
CHLOROPHYLL FLUORESCENCE; HALOPHILA-OVALIS; WATER-QUALITY; PATTERNS; GRADIENT; RECOVERY; DEPTH; DEPRIVATION; DISTURBANCE; AUSTRALIA
Access Full Text
A full-text copy of this article may be available. Please email the
WCS Library
to request.
Back
PUB10503