kelp

Kelp is a large algae seaweed. It is not a plant (nor an animal or fungus) but a heterokont. They can grow to as much as half a meter a day, ultimately reaching a height of up to 80 meters.

These heterokonts grow in forests - underwater kelp forests - in nutrient-rich waters at temperatures between 6 and 14 °C. They do not have roots; all of the necessary nutrients are obtained directly from the water.

Dense kelp forests provide habitat for thousands of other marine species. Sharks, fish, lobsters, squids, and other marine animals are known to live in or near kelp forests.