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Macrocystis integrifolia

THE RACE ROCKS TAXONOMY
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Domain Eukarya
Kingdom Plantae
Division Chromophyta
Class Phaeophyceae
Subclass
Order Laminariales
Family Lessoniaceae
Genus Macrocystis
Species integrifolia (Bory)
Common Name: Giant Kelp
macro macro
wind drift
wind drift
The version of the video made for lower bandwidth, 56k.
Macrocystis (Greek=Large bladder), the largest of all seaweeds, is represented by two species along the shoresof British Columbia.
Macrocystis integrifolia is the most common species, distributed from Alaska to Monterrey, where it normally inhabits the lower intertidal and upper subtidal regions in areas subjected to moderate waves. Macrocystis pyifera is distributed from Monterrey to Mexico with suspected populations in northern BC and Alaska. This species is restricted to the relatively deep subtidal region in areas exposed to open ocean conditions, so it is unlikely that it comes ashore here.

Macrocystis integrifolia (Bory)

Description: This species of kelp forms extensive forests and is one of the largest and most complex algae. Floating at or near the sea surface, extensive masses of beds with rich-brown leaf-like blades 25 to 35 cm long by 5 cm wide.The blade or lamina is wrinkled or grooved in an irregular pattern and each is bouyed up at its origin by a small pneumatocyst. The blade edge is lined with toothlike projections.The lamina of this kelp grow throughout the length of the stipe of the algae instead of only at the terminal region near the surface.Thus a dense forest is established which serves as a valuable habitat for many species of fish and invertebrates.

Habitat and Distribution: Macrocystis integrifolia occurs in the very lowest portion of intertidal and in subtidal waters 7 to 10 m deep. It favors areas exposed to the open sea but somewhat sheltered from the full force of heavy wave action. It does not seem to grow in areas with salinity lower than that of the open coastal waters, so it is not found very far into the strait of Juan de Fuca. The closest beds we know of to Race Rocks are to the west at Sooke. After the first large storms in October, Macrocystis will end up in tangled masses with Nereocystis on the beaches at Race Rocks and on other beaches on Southern Vancouver Island.

References:

Link to Macrocystis in Ryan's digital herbarium

See the file on Wind as an Abiotic Factor

Druehl, Louis 2000, Pacific seaweeds.

Common seaweeds of the Pacific Coast by J. Robert Waaland

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Copyright
Lester B. Pearson College
This file is provided as part of a collaborative effort by the students of Lester B. Pearson College Dec. 2002 Matthieu Bakhoun, (PC yr 28)