View progress on Phase 2 opening in 2023 

The Underline’s Climate Champs is a citizen science program designed to educate Miami’s future environmental stewards. With The Underline as a platform, children and adults will learn more about the 30,000 native plant and tree species in The Underline’s first phase, Brickell Backyard and the green infrastructure initiatives positively impacting Miami’s resiliency and sustainability. Launched Fall 2022, students and visitors will learn about the long-term and short-term benefits of the park and why protecting nature in our community is vital to our future.

Oolite Room

between SW 13th St and Brickell Metromover

The Oolite Room, © 2022 Sam Orberter

What is Oolite?

In Miami, we see limestone everywhere. Look around and you will see the cream colored, porous monumental rocks in The Underline’s Oolite Room. How did these boulders get here? How did they get their name?

Miami limestone, formerly called Miami oolite, consists of the coastal ridge of southeastern Florida, from Palm Beach to Broward to Miami-Dade to the Everglades to Big Pine Key and Marquesas Keys. Oolite is one of the most common sedimentary rock, formed from ooids, which are spherical grains composed of concentric layers. Sedimentary rocks form over time on the surface of the Earth through the process of erosion, precipitation, and natural weathering.

Underline Oolite Boulder seating © 2021 Robin Hill

Oolite actually dates back to the Sangamon Interglacial Stage, between 125,000 and 75,000 years ago. The Sangamon Interglacial Stage was a period of time in between glacial periods and left behind deposits of what would become Miami limestone. About 75,000 years ago, the Wisconsin Glacial Stage began. It was the last time that glaciers were on top of North America. Decreasing sea levels during the Wisconsin Glacial Stage left Miami limestone exposed, where we see it today.

Oolite also contains fossils of corals, sea urchins, and mollusks. Most oolite is formed of calcium carbonate (calcite or aragonite) but can be composed of phosphate, clays, chert, dolomite or iron minerals.

The mechanism of formation starts with a small fragment of sediment acting as a seed. Strong currents wash the seeds where they accumulate layers of calcite from the water. The Atlantic Coastal Ridge of southeastern Florida, the islands of the Lower Florida Keys, and much of the Everglades, are underlain by Miami Oolite.

© 2020 Rafael Delceggio and Raygun Agency

The Miami Rock Ridge and Biscayne Aquifer

The Miami Rock Ridge is a continuous limestone outcrop which surrounds a large piece of South Florida. It extends from Miami Beach to the upper Florida Keys and southwest into Everglades National Park.

The Rock Ridge was part of the South Florida Pine Rocklands ecosytem, covering about 800 square miles with thin soil and sedimentary rock. It supports numerous unique plants and animals; 20% of the endemic (local) plant species on the Ridge occur nowhere else in the world!

The Biscayne Aquifer stores almost 9 billion gallons of water, which is enough water to fill more than 13,600 Olympic-sized swimming pools! It is about 4,000 square miles, starting in south Palm Beach County and ending in south Miami-Dade County. It is made up of permeable limestone that can quickly clean water and recharge the aquifer.

Hello! I’m over here, I’m the butterfly, bee or small insect that buzzed by. I’m a pollinator, which means that I am responsible for spreading the future seeds of 75% of the world’s flowering plants. Seeing more of me means that your environment is healthy! Seeing less of me means that you may be witnessing the effects of climate change. When areas heat up too much, butterflies must find a new habitat. Butterflies are very sensitive to the climate of an environment.

Pollinators have been around for over 50 million years and are made up of 250,000 species. A pollinator such as a butterfly, helps flowering plants to reproduce. Pollinators will land on a flower to drink its nectar. Then it gathers pollen, a powdery substance, typically yellow, that has microscopic grains that fertilize a flower, on its long, thin legs as it walks around flower clusters. When the pollinator lands on a different flower, the grains of pollen fall off the butterfly’s legs into the flower’s stigma, the plant is then pollinated.

Catch me down the trail in the Fern Room, where you’ll see me as the atala butterfly and the coontie plant, and in the Urban Gym, where you’ll see me as the monarch butterfly and the milkweed plant, and the sulphur butterfly and the senna plant!

Butterflies on The Underline

© 2022 Robin Hill Photography