Kelp Forests

Photo of a sea lion within a kelp forest taken by Dr. Alex Mustard. To see more of his wonderful images visit his website

When I spoke about sea otters, I briefly touched on kelp forests, which is where a lot of sea otters happen to live, and I just wanted to take the time to expand on these unique habitats. As the name suggests, kelp forests are made up of giant kelp (Macrocystis pyrifera) that can grow up to 30m (~98.5ft) long and as fast as 50cm (~20in) a day! These habitats are found along the coasts were the water is cold and nutrient rich, so from Alaska to California, along the west coast of South America below the tropics, and even near the borders of the poles.

The simplest way to describe a kelp forest is to relate them to forest found on land. Both are made up of plants that use photosynthesis to make food and oxygen, which isn’t a gas that plants use so it ends up being released into the environment. Anyways, both land forests and kelp forests are also considered habitats because they provide food and shelter to all sorts of creatures. Kelp forests are used by various species of fish that only go there to give birth to their young, which then use the kelp as a refuge until they reach maturity.

Cool fact: the fish born in kelp forests are typically a different color than their adult selves, using shades of green and brown to help camouflage them from predators like larger fish! Also, kelp forests are pretty important to coasts not only for the food it provides, but because they can also protect the coastline from severe storms by absorbing the intense wave-energy. Without kelp forests, intense storms can wipe out entire stretches of coastline and greatly change the layout of the coast.

Now, why are sea otters important to kelp forests? Well like many land forests, kelp forests can be wiped out and made barren, but not by man. Sea urchins typically feed on fallen kelp; however, if left unchecked their populations can grow to into frighteningly large numbers and can wipe out a whole bed of kelp. Luckily, sea urchins are a favorite menu item for sea otters, so they keep the sea urchin population down, which also keeps the kelp forests healthy and vibrant!

Kelp forests are pretty cool habitats and I think it would be cool to go diving near one, just to see all those fish and sea otters that call it home! And while sea urchins are interesting, I’ll definitely view those guys from a far because those spikes can seriously hurt.

Sources and cool things to check out:
Ocean: The Definitive Visual Guide (American Museum of Natural History)