Press "Enter" to skip to content

CRITTER: Pipeline reef is made up of fossilized coral

I was recently watching an old surf movie about the Pipe Masters surf contest held at Pipeline on the North Shore of O‘ahu and got a kick out of the prio surfers talking about the reef at Pipeline.

We all know that more surfers get hurt at Pipeline than any other break in the world and that is because the waves break over an uneven reef that is only a few feet deep below the giant surf!

The surfers in the movie were talking about the sharp corals and jagged lava reef below the waves that will give you serious cuts if you fall off the wave and hit the bottom. They were correct that it is easy to get injured at Pipeline, if not killed but there is no live coral or jagged lava reef at Pipeline.

When we surf at Hanalei Bay, we ride over a shallow reef that is covered with live coral. Antler corals, cauliflower corals and mound corals grow upward a few feet from the lava reef and when you fall off your surfboard at Hanalei you may get cut up by all the live coral.

Pipeline is a completely different type of reef than the Hanalei reef and live coral cannot grow on the Pipe reef because during the summer months sand covers much of the reef. The reef at Pipeline runs parallel to the beach and depending on the time of the year, size of the surf and direction of the swell, sand flows on and off of the reef at Pipeline.

Corals are slow growing and need constant sunlight to live and stay healthy. The average foot tall coral on the Hanalei reef is from two to four years old and that coral would die if it gets covered up by sand. The Pipeline reef has so much sand on it during the summer when the waves are small that you can walk down the beach in the same spot that people are surfing over during the winter.

The reef at Pipeline formed over a very long time and a series of events happened to create this unique surf spot. Originally the reef at Pipe was a lava reef way back when the island of O‘ahu had active volcanoes.

Thousands of years later the sea levels rose and the lava reef at Pipeline was covered in a thick layer of live coral. Then about 10 thousand years ago during the ice age, the sea levels lowered by over 100 feet.

This left the live corals at Pipeline high and dry, and they all died but the corals left behind their hard calcium carbonate skeletons. This layer of dead coral hardened over time into a fossil coral bed over 20 feet thick.

After the ice age the sea levels rose back to the current level we see today. The large waves at Pipeline carved all kinds of odd shapes in the fossil coral bed and this is what we see today under the big waves.

The fossilized coral bed is relatively soft, so the waves that contained a lot of sand in them basically sanded the reef into rounded mounds and pinnacles that stick up off of the seafloor right under where people surf. When you fall off on a big wave and hit your head on the bottom you are running into dead fossilized coral that is over 5,000 years old.

Each of our famous Hawaiian surf breaks was formed in a different way due to the geology of the area, active rivers or old rivers that no longer exist and wave size, shape and direction. The surf shapes the reef and the reef shapes the surf. Each surf spot took thousands of years to form and the process of developing a world class wave to surf on is quite complex.

I have a new series of movies to be used in our school classes called Surf and Reef Science Class. The series will show the reef and marine life below each famous surf spot and talk about the current changes to the reef, waves, beaches and marine life that will eventually change how the waves break at each reef.

You can see my Pipeline Surf and Reef Documentary Movie at


Terry Lilley is a marine biologist living in Hanalei Kaua‘i and co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to
Source: The Garden Island

Be First to Comment

    Leave a Reply