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Nereocystis luetkeana

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Domain Eukarya
Kingdom Protoctista
Phylum Phaeophyta
Class Phaeophyceae
Order Laminariales
Family Lessoniaceae
Genus Nereocystis
Species luetkeana
Common Name: Bull kelp
Nereocystis, Bull Kelp
Kohei Noda, a Pearson College Diver of year 32, took this photo representing the typical underwater appearance of bull kelp at Race Rocks as the current starts to increase.
This linked file shows the role of kelp in rafting other organisms to shore kelp on beach Nereocystis growth after winter deployment of the tidal current turbine kelp on turbine
nereocystis video Kelp and color Ben blows canopy regrowth
A video set to the music of Holly Arntzen:. by Jean Olivier Dalphond
(PC yr26)
The "Color of Kelp" from an underwater point of view Ben plays the Nereocystis trumpet! A diver under the canopy of the Nereocystis forest regeneration: A Nereocystis growing as an epiphyte on the stype of Pterophyga
nereocystis nereocystis nereocystis
Bull Kelp growing on the North side of Race Rocks.. The direction of the stipe indicates the current flow Viewed from underwater, the canopy is a analogous to a forest canopy.
nereocystis nereocystis nereocystis
Pneumatocysts on thesurface viewed from above. Baby Nereocystis grow as epiphytes on the perennial Pterophyga algae. Photos by Ryan Murphy June 2002
Bull Kelp Pneumatocyst
At slack tide north of the docks. Young Nereocystis reaching for the surface They live in up to 12 meters of water. Portrait of a pneumatocyst .

Nereocystis (greek= mermaid's bladder) has only one species, N. luetkeana. Plants consist of a long stipe (up to 36 m/118') attached to the ocean floor by a holdfast composed of numerous haptera (finger-like projections) and terminated above, on the ocean surface, by a single float from which a cluster of tightly branched smooth blades arise. The blades are long (up to 4 m/13') and narrow (usually less than 20 cm/8" wide). Overall, this species reminds us of a very large gothic brown onion of extraterrestrial origin. This form, commonly referred to as bull kelp, is attached subtidally but forms surface canopies throughout its distribution from Alaska to central California.

At Race Rocks, all the islands are fringed by this species during the summer months. Several features make this species unique. It grows as an annual although some members persist into a second year. Most palnts gets torn off by winter storms, landing on beaches to be decomposed, releasing the nutrients back into the ocean through a saprophytic food web. The following pictures illustrate the tangled masses which end up on beaches near the reserve.

bull kelp beached kelp beached kelp beached kelp
Intact plants end up on the shoreline when they become detached in the fall storms. Often the twisted masses collect a variety of other algae This mass which has started to decompose shows the holdfasts. Holdfasts often carry up rocks or attached invertebrates to the beach. See file linked above--G.Fletcher photos

This means that the plant achieves its significant length in one growing season (most growth occurs between March and September). To reach the maximum stipe lenght of 36 m (118'), the plant must grow an average of 17 cm per day over the approximate 210 day period. Nereocystis has a logistic problem in completing its life cycle. The spores are produced on the blades at the ocean surface, often several metres above the ocean floor, but a critical concentration of spores is required near where the parent plant is successfully established to assure re-occupation of this optimal space once the annual plant is lost. So the sorus (spore patch) drops from the blade and delivers its concentrated spores to the bottom before releasing the spores. This is the only kelp to release spore patches.

Ronald E. Foreman in pursuit of his PhD discovered that the float, which may have a volume of up to 3 liters, has carbon monoxide, an infamous poison as one of his buoyancy gases. Foreman has studied the commercial cultivation of red seaweeds.

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The Race Rocks Taxonomy
This file is provided as part of a collaborative effort by the students of Lester B. Pearson College 08/12/2002 Susanna B. (PC yr 28)
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Garry Fletcher