It might surprise you to hear that there are forests underwater.
In temperate oceans near the shore, kelp grows. It’s technically not a plant, but algae–specifically, a brown macroalgae.
And macro it is. The largest species of kelp can reach 130 feet.
They stretch from the dark ocean floor, where they anchor to rocks. A long stem grows upward to where the kelp can reach light. There, it produces long leaf-life blades that conduct photosynthesis.
The stalk and fronds are held upright by gas-filled buoys that the kelp produces, called pneumatocysts.
Kelp are extraordinary growers, able to leap nearly 2 feet in a single day. As they grow, they take in carbon dioxide, nitrogen, and phosphorus from seawater, de-acidifying it, and they return oxygen, enriching their environment for other lifeforms.
And like terrestrial forests, kelp shelters great biodiversity: fish, shellfish and other invertebrates, and mammals like sea otters and sea lions.
Kelp is often harvested for algin, a gel-like substance used as a thickener in cosmetics, shampoos, toothpastes, and foods like pudding and ice cream.
On top of that, kelp is nutritious, rich in potassium, iron, and other minerals and vitamins. It’s already a staple in many Asian cuisines and is gaining popularity in others.
These qualities make kelp and other large seaweeds ideal candidates for ocean farming, which we’ll talk about in another EarthDate.