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Restricted use of nitrate and a strong preference for ammonium reflects the nitrogen ecophysiology of a light-limited red alga


Pritchard, DW and Hurd, CL and Beardall, J and Hepburn, CD, Restricted use of nitrate and a strong preference for ammonium reflects the nitrogen ecophysiology of a light-limited red alga, Journal of Phycology, 51, (2) pp. 277-287. ISSN 0022-3646 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 Phycological Society of America

DOI: doi:10.1111/jpy.12272


Ammonium and nitrate are important sources of inorganic nitrogen for coastal primary producers. Nitrate has higher energy requirement for uptake and assimilation, compared with ammonium, suggesting that it might be a more efficient nitrogen source for slow-growing, light-limited macroalgae. To address this hypothesis, we examined the nitrogen ecophysiology of Anotrichium crinitum, a rhodophyte macroalgae common in low-light habitats in New Zealand. We measured seasonal changes in seawater nitrate and ammonium concentrations and the concentration of nitrate and ammonium stored internally by A. crinitum. We determined the maximal uptake rates of nitrate and ammonium seasonally and grew A. crinitum in the laboratory with these nitrogen sources under two ecologically relevant saturating light levels. Our results show that field-harvested A. crinitum has a high affinity for ammonium and although it will grow when supplied exclusively with nitrate, internal nitrate pools are low and it is unable to take up nitrate without several days of acclimation to saturating light. Our data predict that A. crinitum would be able to sustain growth with ammonium as the sole source of nitrogen, a strategy that would help it survive under low-light conditions that prevail in the field.

Item Details

Item Type:Refereed Article
Keywords:nutrients, nitrogen, seaweed, growth, physiological ecology
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:100175
Year Published:2015
Web of Science® Times Cited:17
Deposited By:IMAS Research and Education Centre
Deposited On:2015-05-06
Last Modified:2017-10-31

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