E-Flora BC: Electronic Atlas of the Flora of British Columbia

Porphyra nereocystis Anderson
red alga (Bull-kelp Laver)

Introduction to the Algae
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Distribution of Porphyra nereocystis
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Ocean Biogeography Information System (global distribution)

Species Information

Family Description:
The members of this family and order are among the most primitive of the red algae and lack the complex structures that appear in most other reds. The conspicuous individual is the haploid gametophyte, and the alternate phase is a microscopic filamentous "conchocelis" phase that grows within the shells of marine mollusks and barnacles. Egg cells form on the macroscopic gametophyte, and they are fertilized by spermatia from the same or a different plant. Following fertilization, the zygote divides directly into a packet of spores called zygotospores (to differentiate them from carpospores formed in higher red algae). These diploid spores germinate into the diploid filamentous (and presumably perennial) conchocelis. In some species, gametophytic and conchocelis phases produce asexual spores that germinate to give rise to another individual of the same phase. Therefore, despite being structurally simple, many species of Porphyra rival other reds in the complexity of their life cycles. Botanists have suggested that the boring conchocelis phase is an adaptation to resist grazing by such herbivores as limpets. However, fossils of boring conchocelis have been dated to more than 500 million years ago, long before the first limpet appeared.
Porphyra is a difficult genus of red algae, and you cannot expect to identify every specimen you find. Species in addition to those listed below are also found in our area.
Species description:
Bull-kelp Laver lives epiphytically on the stipes and sometimes on the floats of Bull Kelp (Nereocystis luetkeana), or rarely on other laminarians, and its distribution almost precisely matches the distribution of its main host. Bull-kelp Laver forms blades that are rose to purplish red in color and up to 50 cm (20 in) wide by 1.7 m (5.5 ft) long. The blade is not as ruffled as those of other species of Porphyra and is one cell layer thick. It is considered to be very delicious and has a relatively high caloric value (4.09 Calories per gram of dry weight). Because it is large, delicious, and easy to recognize thanks to its specific substratum, this widespread species should be more heavily utilized.

Light colored spots on the blade are male areas, while zygotospores are more darkly pigmented and are produced near the blade margins. The holdfast is small and discoidal. Some workers have suggested that Bull-kelp Laver might have a subtidal conchocelis phase.

In Puget Sound, a fungus (Pythium marinum) infects this species of Porphyra, causing lesions in the blades, and we've seen similarly afflicted Bull-kelp Laver in the Sitka, Alaska, area.

Source: North Pacific Seaweeds

Habitat / Range

Bathymetry: shallow subtidal
World Distribution: Umnak Island (Aleutian Islands), Alaska, to San Luis Obispo County, California

Source: North Pacific Seaweeds

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