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Colony structure and seasonal differences in light and nitrogen modify the impact of sessile epifauna on the giant kelp Macrocystis pyrifera (L.) C Agardh

Citation

Hepburn, CD and Hurd, CL and Frew, RD, Colony structure and seasonal differences in light and nitrogen modify the impact of sessile epifauna on the giant kelp Macrocystis pyrifera (L.) C Agardh, Hydrobiologia, 560, (1) pp. 373-384. ISSN 0018-8158 (2006) [Refereed Article]

Copyright Statement

Copyright 2006 Springer

DOI: doi:10.1007/s10750-005-1573-7

Abstract

The presence of the stoloniferous hydroid Obelia geniculata (L.) had no effect on the pigment concentration or nitrogen status of underlying blade tissue of the giant kelp Macrocystis pyrifera (L.) C. Agardh. The sheet-like colonies of the bryozoan Membranipora membranacea (L.) markedly reduced the pigment concentration of colonized blade tissue, but only during winter. Reductions in pigment concentration are most likely a result of damage to underlying tissue due to some factor related to the presence of bryozoan colonies on blade surfaces. Blade tissue colonized by M. membranacea also had higher δ15N signatures than surrounding bryozoan-free tissue, possibly indicating the provision of nitrogen to M. pyrifera by bryozoan colonies. Results show that seasonal changes in nitrogen and colony size can strongly modify the effect of epifauna on macroalgae they colonize. Unlike bryozoans, hydroid colonies provided no barrier to nitrogen uptake by colonized M. pyrifera tissue and enhanced ammonium uptake was observed for tissue colonized by O. geniculata during nitrogen limitation. Epifauna with stoloniferous growth forms such as hydroids are more likely to have benign or even mutualistic relationships with macroalgae they colonize than the sheet-like colonies of bryozoans.

Item Details

Item Type:Refereed Article
Keywords:kelp, Macrocystis, nitrogen, light, photosynthesis, invertebrates, mutualism
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 Mathematical Sciences
Author:Hurd, CL (Associate Professor Catriona Hurd)
ID Code:93126
Year Published:2006
Web of Science® Times Cited:19
Deposited By:IMAS Research and Education Centre
Deposited On:2014-07-14
Last Modified:2014-08-05
Downloads:0

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