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Ecophysiology of photosynthesis in macroalgae
Citation
Raven, JA and Hurd, CL, Ecophysiology of photosynthesis in macroalgae, Photosynthesis Research: An International Journal, 113, (1-3) pp. 105-235. ISSN 0166-8595 (2012) [Substantial Review]
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DOI: doi:10.1007/s11120-012-9768-z
Abstract
Macroalgae occur in the marine benthos from
the upper intertidal to depths of more than 200 m, contributing
up to 1 Pg C per year to global primary productivity.
Freshwater macroalgae are mainly green (Chlorophyta) with
some red (Rhodophyta) and a small contribution of brown
(Phaeophyceae) algae, while in the ocean all three higher
taxa are important. Attempts to relate the depth distribution
of three higher taxa of marine macroalgae to their photosynthetic
light use through their pigmentation in relation to
variations in spectral quality of photosynthetically active
radiation (PAR) with depth (complementary chromatic
adaptation) and optical thickness (package effect) have been
relatively unsuccessful. The presence (Chlorophyta, Phaeophyceae)
or absence (Rhodophyta) of a xanthophyll cycle is
also not well correlated with depth distribution of marine
algae. The relative absence of freshwater brown algae does
not seem to be related to their photosynthetic light use.
Photosynthetic inorganic carbon acquisition in some red and
a few green macroalgae involves entry of CO2 by diffusion.
Other red and green macroalgae, and brown macroalgae,
have CO2 concentrating mechanisms; these frequently
involve acid and alkaline zones on the surface of the alga
with CO2 (produced from HCO3
-) entering in the acid
zones, while some macroalgae have CCMs based on active
influx of HCO3
-. These various mechanisms of carbon
acquisition have different responses to the thickness of the
diffusion boundary layer, which is determined by macroalgal
morphology and water velocity. Energetic predictions
that macroalgae growing at or near the lower limit of PAR
for growth should rely on diffusive CO2 entry without acid
and alkaline zones, and on NH4
? rather than NO3
- as
nitrogen source, are only partially borne out by observation.
The impact of global environmental change on marine
macroalgae mainly relates to ocean acidification and
warming with shoaling of the thermocline and decreased
nutrient flux to the upper mixed layer. Predictions of the
impact on macroalgae requires further experiments on
interactions among increased inorganic carbon, increased
temperature and decreased nitrogen and phosphorus supply,
and, when possible, studies of genetic adaptation to environmental
change.
Item Details
Item Type: | Substantial Review |
---|---|
Keywords: | physiological ecology, photosyntheis, carbon aquisition, ocean acidification, algae, seaweed |
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: | 91464 |
Year Published: | 2012 |
Web of Science® Times Cited: | 99 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2014-05-20 |
Last Modified: | 2014-06-10 |
Downloads: | 0 |
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