Phylum: Heterokontophyta
Class: Phaeophyceae
Order: Laminariales
Family: Laminariaceae

Genus/species: Macrocystis pyrifera

GENERAL CHARACTERISTICS: Stout holdfast attaches to solid substrate to anchor its long, limber stipes (central stalks) and deeply incised blades. Held upright by gas-filled bladders at the base of blades, kelp fronds grow straight up to the surface,

Giant Kelp5055944979_13b2c8c620_b

DISTRIBUTION/ HABITAT: North Atlantic and northern Pacific;
also the Mediterranean Sea and off Brazil. Kelp Forest in general to 100 ft to 175 ft. The water depth zone is often known as the Laminaria zone.

They can grow at a rate of 0.6 metres (2 ft) a day to reach over 45 metres (148 ft) long in one growing season.

REPRODUCTION; Drifting M. pyrifera sporophytes (kelp rafts) are created following sporophyte detachment from benthic substrates. Kept afloat by numerous pneumatocysts (gas-filled bladders), M. pyrifera sporophytes may remain alive and adrift for more than 100 days. the reproductive longevity of drifting M. pyrifera sporophytes is long enough to support effective long-distance dispersal of over 1000 km (620 miles).

LIFESPAN: Five years.

REMARKS: Giant kelp forests are home to many marine species who depend upon the kelp directly for food and shelter, or indirectly as a hunting ground for prey. Invertebrates graze on the blades, fish seek shelter in the fronds and thousands of invertebrates such as brittle stars, sea stars, anemones, sponges and tunicates live in the holdfast. In addition sea otters wrap up in a kelp frond to keep from drifting away when sleeping.



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