Kelp Forest Ecosystems

What Is a Kelp Forest Ecosystem?

Word of the Week

Algae

Algae are plant-like organisms that are typically found in water. Like plants, they use energy from the sun to produce sugar (energy) for themselves.

Kelp, sea grass, and zooxanthellae (found in corals) are all types of algae.

Species Spotlight

Purple Urchin

Strongylocentrotus purpuratus

Purple urchins live in cool waters off the west coast of North America. Like all sea urchins, purple urchins are benthic, meaning they live on the ocean floor. They use long suction cups called tube feet to move around. They also use tube feet to breathe and taste.

Purple urchins are found in tidepools and kelp forests where they feed on algae. They use five sharp teeth to scrape algae off rocks and chew through kelp. Purple urchins are protected from predators by sharp spines. They have also been observed covering themselves in shells and seaweed. Scientists hypothesize they may be hiding from predators.

While they have a good defense, purple urchins are still eaten by predators like sunflower stars, California sheepheads, and sea otters. These predators have an important job - to keep the population size of purple urchins in check.

Without these predators, the population of purple urchins would grow quickly. They would destroy the entire kelp forest as they ate more and more kelp. The other animals that rely on the kelp forest for food and shelter would have nowhere to live. The entire ecosystem would collapse if the purple urchin's predators disappeared.

Purple urchins represent the importance of balance in nature. If we disrupt nature's balance, it could fall apart.

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Conservation Corner

Helping Hand of Urchin Hunting

Is hunting animals good or bad?

Oftentimes, it is bad. Hunting is one of the main reasons animals like rhinos and elephants are endangered. We often call this illegal hunting “poaching.” Poaching can cause a habitat to fall out of balance.

However, hunting is not always bad. Hunting can help protect an ecosystem or even other species. It is especially helpful when the ecosystem is already out of balance. Let’s look at an example.

Kelp forests are an important ocean ecosystem. They provide food and shelter for hundreds of animals. Each animal here depends on kelp for survival and the kelp depends on them. There needs to be a balance of animals that eat kelp (like sea urchins) and predators that eat them (like sea otters).

Unfortunately, many kelp forests have fallen out of balance. There are too many sea urchins eating kelp and not enough sea otters to keep their urchin population in check. Luckily, people can help because we eat sea urchins, too. Sea urchin is often called uni when being eaten by people. Uni is considered a delicacy in some cultures! We can help keep kelp forests in balance by hunting and eating sea urchins.

*Please note: It is important to follow all local laws and regulations when hunting.*

BRAIN BLAST

Research restaurants and markets in your area to see if any of them sell uni. If so, reach out to them to see where they get their sea urchins from.

Quiz

Quiz Printable

Kelp Components

Label the kelp forest diagram below.

Kelp Components Printable

Coral Reef Vs. Kelp Forest Challenge

Comparing & Contrasting

*To complete this challenge, you will also need to complete the Coral Reef Adventure*

Beginner

Compare and contrast coral reefs and kelp forests using art. Discuss the similarities and differences between them.
Beginner
Expert

Create a poster to compare and contrast kelp forests and coral reefs. Use the prompts on the packet to guide your poster design.
Expert