Beaches provide the spaces to connect to our ocean. I am one of many people whose first trip to the water’s edge as a child fueled a lifelong fascination with all the incredible creatures that lie beneath the waves. I’m still that curious child at heart. While some people might go to beaches to relax and read a book, I often find myself exploring. I’ll dive under waves to look at fish, poke weird holes in the sand and gaze closely at seashells. I always have questions when I’m at the beach, and in case you have someone like me in your life, I’m here with the answers so you can quickly get back to your book and sunbathing.  

How are beaches formed? 

Most beaches are the result of thousands of years of weather and erosion. Where ocean meets land, wind and water pound down cliffs and coastlines into your favorite summer vacation spots. Tides and currents can deposit sediment like sand from places that may be hundreds of miles away. Each beach is a beautiful reflection of the marriage of forces on land with the forces in the ocean. For instance, sand dunes are made of sediment both from ocean and inland rivers, created by wind that blows in from the ocean toward the land and often stabilized by vegetation onshore. It’s the interactions between ocean and land that make beaches an ever-changing environment and makes a beach one of the primary places where we land-dwelling humans can experience the wonder of the ocean. 

How is sand made?

Have you ever taken a close look at sand? While it might seem all golden tan or white from afar, up close you can see small spots of black or glittery white. That’s because sand is actually made of many different substances. Some of this sand is rock that has been eroded over thousands or millions of years by the ocean and rivers. The most common of these rocks is quartz which is used to make glass. You’ll also find a lot of minerals that have either made their way down from glaciers or waterways or have been pushed up from ocean depths in heavy storms. 

Ocean animals also help form beaches. For instance, beaches can contain crushed bones or byproducts from ocean inhabitants that lived many years ago. You might be looking at what once was a sea urchin spine or a shell. On some beaches, for instance the white sand beaches of Hawaii, you can find yourself standing on (and I hate to tell you this) parrotfish poop. Parrotfish live in, and also eat, coral reefs. When that (I assume delicious?) coral comes out, we get beautiful smooth sand. A large Hawaiian parrotfish can defecate up to 800 pounds of sand each year. Sorry, did I just ruin beaches for you? 

Why are some beaches black?

The composition of every beach is different, which can lend itself to different hues. Generally, you find black sand beaches on volcanic islands (like Hawaii, Iceland and Greece). There the sand forms from lava which will shatter into many smaller pieces when it hits the water. In fact, lava from a volcanic eruption has the power to create new black sand beaches overnight. It may be obvious, but you have to be cautious since black sand absorbs more heat from the sun. Just like that black t-shirt worn on a sunny day, it can burn your feet if you’re not wearing your flippy floppies. 

There are other colors of vibrantly hued beaches. For instance, in a few places in the world like Norway and Ecuador you can find green sand beaches. They get their color from olivine, a green glassy mineral that is denser than most sand. This density gives olivine staying power when other sand washes away. You can find pink beaches in Bermuda, the Bahamas, Indonesia and a few other beautiful locations. They get their color due to the deaths of small plankton called foraminfera. When these red organisms die, their bodies get mixed with crushed coral and seashells to give that pleasantly pink hue. 

Why do some beaches have pebbles? 

My dad is from San Francisco, and when we would return to visit in summers my sister and I would always beg to go to the pebble beaches and rocky coasts. There my sister would hunt for beautiful rocks while I would enjoy tide-pooling in the rocky outcrops. Pebble beaches (also called shingle beaches) are formed in places where the rocks are resistant to erosion so are less likely to be turned into sand. You can find them in England near cliffs made of flint and chalk. In Oregon there is a black pebble beach made of basalt. You’re more likely to find pebble beaches in higher latitudes, either to the far north or far south on our planet. These places were covered in glaciers that left the rocks and pebbles we find on the shorelines. 

Where does driftwood come from? 

If you find driftwood on the beach, it is usually from the remains of trees. These could be branches or parts of trees taken down during storms or high wind. They could also be brought down by human means such as logging or come from man-made objects like building materials or furniture dumped or blown into rivers and shorelines during extreme weather events. Driftwood could also be flotsam and jetsam from the ocean. No, I’m not talking about Ursula’s eels in The Little Mermaid; flotsam and jetsam are nautical terms to describe debris that resulted in shipwrecks from weather-related or other accidents. Jetsam describes lost cargo dropped or lost from ships while flotsam refers to the remains of the shipwrecked boats themselves. 

No matter how it gets there, driftwood has an important role in the lives of humans and animals alike. On beaches, it can be home for all sorts of tiny creatures, a place for seabirds to nest or a protected place for plants to grow. Driftwood can stabilize sand dunes or become an important buffer for tides and waves. Out on the ocean driftwood can become a sort of floating reef providing a landing space, food or a safe space to lay eggs. For people around the world, driftwood has cultural significance, too. Vikings often used driftwood to build their ships and homes. In Norse mythology, the first two humans Askr and Embla were made from driftwood found on the shore. Driftwood is also important to the Inuits; they used it for everything from shelter to tools for collecting food. 

What is sea glass? 

Glass is made from sand, and sometimes it returns to the sand from which it came. Sea glass is simply broken shards of glass that has been weathered by being tumbled in the ocean waves. Sea glass comes from broken bottles or even shipwrecks offshore. Sea glass shards may be beautiful, but they are a reminder of how human contributions, like trash, are changing our beaches in less pretty ways.

It is important that we protect and keep beaches clean not just for humans to enjoy but for all the incredible wildlife that live on our coasts and in  our ocean. That’s why Ocean Conservancy leads the International Coastal Cleanup®, the world’s largest annual beach and waterway cleanup effort. You can join nearly 17 million volunteers who have worked together to collect more than 350 million pounds of trash and counting! Simply download Clean Swell® and go clean up your community, your favorite park or your local beach or waterway.  

Another way we can help our beaches is to stop plastic pollution at the source. In our work, we’ve seen beaches around the world covered in plastic pollution that has washed up from all over the world. Meanwhile, the threat of plastic keeps growing. Did you know that half of the plastics ever manufactured have been made in the last 20 years alone? We need to reduce the sheer volume of plastics produced and used, while holding plastic producers responsible for the harmful waste they have generated and continue to pump into the environment. Luckily, there are policies that can help us tackle plastic pollution at the source. Take action now to fight for policies that keep our ocean trash free.