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Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)

Bull kelp (Nereocystis luetkeana), the only canopy-forming kelp in the Salish Sea, provides primary production in the nearshore subtidal environment and serves as an important habitat for economically and ecologically important species. An annual species, each year juvenile bull kelp sporophytes mus...

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Autores principales: Dobkowski, Katie A, Crofts, Stephanie B
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8363980/
https://www.ncbi.nlm.nih.gov/pubmed/34409261
http://dx.doi.org/10.1093/iob/obab022
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author Dobkowski, Katie A
Crofts, Stephanie B
author_facet Dobkowski, Katie A
Crofts, Stephanie B
author_sort Dobkowski, Katie A
collection PubMed
description Bull kelp (Nereocystis luetkeana), the only canopy-forming kelp in the Salish Sea, provides primary production in the nearshore subtidal environment and serves as an important habitat for economically and ecologically important species. An annual species, each year juvenile bull kelp sporophytes must grow from the hydrodynamically more benign benthos to the water column, where they experience substantial drag at the surface. Because of the differences in morphology and ecology across life stages, and the fact that previous work has focused mainly on adult bull kelp, we tested whether morphology and structural properties change with stipe length, investigating scaling of both juvenile (stipe length < 40 cm) and mature (stipe length > 40 cm) kelp, and testing how juvenile stipes fail. Juvenile bull kelp grow proportionally (isometric growth) when young, but lengthen more quickly than would be predicted by bulb size (negative allometry) at maturity. Based on our data, the predicted breakpoint between isometric and allometric growth occurred at about 33 cm, likely approximately one to two weeks of growth. Cross-sectional area of the stipe, force to failure, work to failure, and stiffness (Young's modulus) all grow more slowly than would be predicted based on length, while maximum stress and toughness increase more quickly than predicted. There is no change in extensibility over the size range we tested, suggesting that this material property does not change with stipe length. The differences in biomechanics between juvenile and adult kelp are likely a response to the varied hydrodynamic environments experienced during the annual life cycle, which highlights the importance of studying organisms across life stages.
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spelling pubmed-83639802021-08-17 Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana) Dobkowski, Katie A Crofts, Stephanie B Integr Org Biol Article Bull kelp (Nereocystis luetkeana), the only canopy-forming kelp in the Salish Sea, provides primary production in the nearshore subtidal environment and serves as an important habitat for economically and ecologically important species. An annual species, each year juvenile bull kelp sporophytes must grow from the hydrodynamically more benign benthos to the water column, where they experience substantial drag at the surface. Because of the differences in morphology and ecology across life stages, and the fact that previous work has focused mainly on adult bull kelp, we tested whether morphology and structural properties change with stipe length, investigating scaling of both juvenile (stipe length < 40 cm) and mature (stipe length > 40 cm) kelp, and testing how juvenile stipes fail. Juvenile bull kelp grow proportionally (isometric growth) when young, but lengthen more quickly than would be predicted by bulb size (negative allometry) at maturity. Based on our data, the predicted breakpoint between isometric and allometric growth occurred at about 33 cm, likely approximately one to two weeks of growth. Cross-sectional area of the stipe, force to failure, work to failure, and stiffness (Young's modulus) all grow more slowly than would be predicted based on length, while maximum stress and toughness increase more quickly than predicted. There is no change in extensibility over the size range we tested, suggesting that this material property does not change with stipe length. The differences in biomechanics between juvenile and adult kelp are likely a response to the varied hydrodynamic environments experienced during the annual life cycle, which highlights the importance of studying organisms across life stages. Oxford University Press 2021-08-14 /pmc/articles/PMC8363980/ /pubmed/34409261 http://dx.doi.org/10.1093/iob/obab022 Text en © The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Article
Dobkowski, Katie A
Crofts, Stephanie B
Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title_full Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title_fullStr Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title_full_unstemmed Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title_short Scaling and Structural Properties of Juvenile Bull Kelp (Nereocystis luetkeana)
title_sort scaling and structural properties of juvenile bull kelp (nereocystis luetkeana)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8363980/
https://www.ncbi.nlm.nih.gov/pubmed/34409261
http://dx.doi.org/10.1093/iob/obab022
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