Other names: kelp, kombu, tashima, haidai Japan sea tangle is a large sea brown algae, the blade of which consists of a ribbon-like smooth or wrinkled laminae 10—35 cm wide, 1—13 m long in the lower part, turning into a cylindrical or squeezed cylindrical stipe 50—100 cm long. Its blade (thallus) is attached to the rocky ground by strongly developed root-like projections — holdfast. The edges of the laminae are smooth or wavy. The whole plant is permeated with mucus passages and lacunae. The lamina is destroyed annually, and a new lamina grows from the remaining stipe. The life span of sea tangle varies from 2 (in the Sea of Japan) to 3—4 years (in northern seas), depending on climatic conditions. Sporocarps (sporangia) mature from July to October. Microscopic female or male prothalli develop from the spores, forming gametal cells. Japan sea tangle is common in the southern regions of the Sea of Japan and the Sea of Okhotsk Sea tangles grow, forming dense thickets in places with a constant current, making the so-called "laminaria belt" at a certain depth along the shores. Large underwater "algae forests" are usually formed at a depth of 4—10 m. On stony ground, sea tangle in some areas can be found up to a depth of 35 m. To get the daily dose of iodine (in regions with iodine deficiency in water), it is enough for human to take about 30—40 grams of fresh sea tangle daily. Sea tangle is ill-advised for people with hypersensitivity to iodine.