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Nitrogen ecophysiology of intertidal seaweeds from New Zealand: N uptake, storage and utilisation in relation to shore position and season

Citation

Phillips, JC and Hurd, CL, Nitrogen ecophysiology of intertidal seaweeds from New Zealand: N uptake, storage and utilisation in relation to shore position and season, Marine Ecology Progress Series, 264 pp. 31-48. ISSN 0171-8630 (2003) [Refereed Article]


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Licenced under Creative Commons Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/

DOI: doi:10.3354/meps264031

Abstract

The nitrogen ecophysiology of 4 intertidal seaweeds (Stictosiphonia arbuscula, Apophlaea lyallii, Scytothamnus australis, Xiphophora gladiata) from southeastern New Zealand is described in terms of N status, N uptake rates and N utilisation. The species growing in the highest shore position had large internal NO3- and NH4+ pools. For all species, tissue NH4+ pools were greater than tissue NO3- pools. Total tissue N was directly related to shore position with high intertidal species having highest tissue N, while the opposite trend was observed for C:N ratios. The ability to take up inorganic (NO3-, NH4+) and organic (urea) N when one or all N forms were present in the culture medium was measured using time-course uptake experiments at initial concentrations of 5 and 30 然. Nitrate uptake did not vary over time for any of the species. S. arbuscula and S. australis exhibited a surge phase of NH4+ uptake at both concentrations. Urea uptake at 5 然 was generally low and consistent over time; uptake at 30 然 was highly variable. All species were capable of simultaneous uptake of all N forms. The relative importance of each N form to overall N nutrition indicated that NH4+ was an important N source in winter for all species. Urea was an important N source in summer, contributing 27 to 33% to the total N acquisition for most species. A relative preference index indicated that in winter N sources were utilised in the order NH4+ > NO3- > urea, while in summer the order was NH4+ = NO3- > urea. Estimates of the amount of N that each species could acquire during a tidal cycle indicated that the high intertidal S. arbuscula had the greatest capacity for N acquisition, regardless of season.

Item Details

Item Type:Refereed Article
Keywords:intertidal zonation, seaweed, nitrogen uptake, macroalgae, intertidal seaweed, nitrogen uptake, ammonium, urea, season, New Zealand
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Ecological Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Biological Sciences
Author:Hurd, CL (Associate Professor Catriona Hurd)
ID Code:93132
Year Published:2003
Web of Science® Times Cited:33
Deposited By:IMAS Research and Education Centre
Deposited On:2014-07-14
Last Modified:2014-08-05
Downloads:162 View Download Statistics

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