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Survival in low light: photosynthesis and growth of a red alga in relation to measured in situ irradiance1


Pritchard, DW and Hurd, CL and Beardall, J and Hepburn, CD, Survival in low light: photosynthesis and growth of a red alga in relation to measured in situ irradiance1, Journal of Phycology, 49, (5) pp. 867-879. ISSN 0022-3646 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 Phycological Society of America

DOI: doi:10.1111/jpy.12093


Reduced light availability for benthic primary producers as a result of anthropogenic activities may be an important driver of change in coastal seas. However, our knowledge of the minimum light requirements for benthic macroalgae limits our understanding of how these changes may affect primary productivity and the functioning of coastal ecosystems. This knowledge gap is particularly acute in deeper water, where the impacts of increased light attenuation will be most severe. We examined the minimum light requirements of Anotrichium crinitum, which dominates near the maximum depth limit for macroalgae throughout New Zealand and Southern Australia, and is a functional analog of rhodophyte macroalgae in temperate low-light (deep-water) habitats throughout the world. These data show that A. crinitum is a shade-adapted seaweed with modest light requirements for the initiation of net photosynthesis (1.49–2.25 lmol photons  m 2  s 1) and growth (0.12–0.19 mol photons  m 2  d 1). A. crinitum maintains high photosynthetic efficiency and pigment content and a low C:N ratio throughout the year and can maintain biomass under sub-compensation (critical) light levels for at least 5 d. Nevertheless, in situ photon flux is less than the minimum light requirement for A. crinitum on at least 103 d per annum and is rarely sufficient to saturate growth. These findings reinforce the importance of understanding the physiological response of macroalgae at the extremes of environmental gradients and highlight the need to establish minimum thresholds that modification of the subtidal light environment should not cross.

Item Details

Item Type:Refereed Article
Keywords:seaweed, photosynthesis, productivity
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
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:89046
Year Published:2013
Web of Science® Times Cited:15
Deposited By:IMAS Research and Education Centre
Deposited On:2014-02-24
Last Modified:2014-06-02

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