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Giant kelp

Macrocystis pyrifera


M. pyrifera is the largest of all algae. The blades grow at irregular intervals along the stipe, with a single gas bladder at the base of each blade. The blades have a corrugated surface (pic 3) and 'spillers' (tooth-like structures on edges of blades) that increase water turbulence to enhance nutrient uptake.


Washed ashore on the beach at the Dungeness National Wildlife Refuge. A narrow spit that extends into the Strait Of Juan de fuca. Giant kelp is common along the coast of the eastern Pacific Ocean, from Baja California north to southeast Alaska, and is also found in the southern oceans near South America, South Africa, Australia, and New Zealand.


The primary commercial product obtained from giant kelp is alginate, but humans also harvest this species on a limited basis for use directly as food, as it is rich in iodine, potassium, and other minerals. It can be used in cooking in many of the ways other sea vegetables are used, and particularly serves to add flavor to bean dishes.

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Spotted by

Washington, USA

Lat: 48.16, Long: -123.17

Spotted on Dec 25, 2018
Submitted on Jan 1, 2019

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