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Conditional mutualism between the giant kelp Macrocystis pyrifera and colonial epifauna


Hepburn, CD and Hurd, CL, Conditional mutualism between the giant kelp Macrocystis pyrifera and colonial epifauna, Marine Ecology Progress Series, 302 pp. 37-48. ISSN 0171-8630 (2005) [Refereed Article]


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Licenced under Creative Commons Attribution 3.0 Unported (CC BY 3.0)

DOI: doi:10.3354/meps302037


It is generally considered that colonial invertebrates living on the surfaces of macroalgae have a negative influence on the growth rates and survivorship of their substratum. To date no evidence has been provided from natural macroalgal/epifaunal associations to support this view. We investigated the influence of colonial bryozoans and hydrozoans on the growth rate and nitrogen physiology of their substratum, the giant kelp Macrocystis pyrifera, and the impact of seasonal changes of light and the seawater nitrogen concentration on this relationship. Throughout this study there was no evidence of any negative impact of colonization by either epifaunal group on the growth of M. pyrifera. During a period of low concentrations of inorganic nitrogen in seawater, the growth of M. pyrifera fronds heavily colonized by hydroid colonies was higher than less heavily colonized individuals. During this time hydroids could provide on average between 71 and 122% of the nitrogen required for uptake by tagged M. pyrifera fronds at ambient seawater nitrogen concentrations. Evidence suggests that enhanced growth was caused by the provision of ammonium excreted by the hydroid colonies. Evolutionary pressure to limit the impact of colonization by sessile animals on macroalgae is likely to be exerted on both the algal substratum and the attached animal. We suggest that due to their close relationship this pressure may ultimately result in the development of mutualistic partnerships between algae and specialized sessile seaweed-dwelling fauna in natural associations.

Item Details

Item Type:Refereed Article
Keywords:kelp, Macrocystic, mutualism, bryozoa, hydrozoa, invertebrate, nitrogen, light
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 agricultural, food and veterinary sciences
UTAS Author:Hurd, CL (Professor Catriona Hurd)
ID Code:93128
Year Published:2005
Web of Science® Times Cited:51
Deposited By:IMAS Research and Education Centre
Deposited On:2014-07-14
Last Modified:2014-08-05
Downloads:633 View Download Statistics

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