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Effect of bryozoan colonization on inorganic nitrogen acquisition by the kelps Agarum fimbriatum and Macrocystis integrifolia


Hurd, CL and Durante, KM and Chia, F-S and Harrison, PJ, Effect of bryozoan colonization on inorganic nitrogen acquisition by the kelps Agarum fimbriatum and Macrocystis integrifolia, Marine Biology, 121, (1) pp. 167-173. ISSN 0025-3162 (1994) [Refereed Article]

Copyright Statement

Copyright 1994 Springer-Verlag

DOI: doi:10.1007/BF00349486


The effect of bryozoan colonization on inorganic nitrogen acquisition by Agarum fimbriatum Harv. and Macrocystis integrifolia Bory., collected from the west coast of Vancouver Island, British Columbia, Canada, was examined in laboratory experiments during June and July 1992. Pieces of kelp blades that were completely covered on one side by the bryozoans Lichenopora novae-zelandiae Busk or Membranipora membranacea, L., or uncolonized (clean treatment), were used to estimate the rate at which nitrate and ammonium were removed from the surrounding seawater. In addition, the rate of ammonium excretion by bryozoans isolated from their associated kelp was measured and also estimated from the results of the uptake experiments. Values obtained were used to estimate the contribution of ammonium excreted by bryozoans to the total amount of inorganic nitrogen available to the associated kelp. Both bryozoan species reduced the ability of the associated kelp to remove nitrate and ammonium from seawater but provided a source of ammonium to the kelp through excretion. The nitrogen status of colonized and clean kelp disks was determined from the ratio of total particulate carbon to total particulate nitrogen (C:N ratio). The C:N ratios for A. fimbriatum colonized with either L. novae-zelandiae or M. membranacea were similar (C:N=12 to 14), and differences between colonized and clean treatments were not significant. For A. fimbriatum, therefore, the C:N ratio indicates that this species was not nitrogen limited at the time of the present study. In contrast, both colonized and clean disks of M. integrifolia were nitrogen limited, but colonized disks (C:N=19) were significantly less limited by nitrogen than clean disks (C:N=29). Results are discussed in relation to the different environments inhabited by both kelp species and are consistent with the hypothesis that ammonium excreted by bryozoans was an important source of inorganic nitrogen to M. integrifolia, but not to A. fimbriatum, at the time of the study.

Item Details

Item Type:Refereed Article
Keywords:seaweed, Agarum, bryozoan, nitrogen, species interactions
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Phycology (incl. marine grasses)
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Hurd, CL (Professor Catriona Hurd)
ID Code:93164
Year Published:1994
Web of Science® Times Cited:40
Deposited By:IMAS Research and Education Centre
Deposited On:2014-07-14
Last Modified:2014-08-01

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