Students from Southern Cross Catholic School will mark the International Day for Biodiversity by undertaking environmental projects on their school grounds to benefit the Great Barrier Reef.

Drains around the school grounds will be stencilled with the words 'This drains to the Great Barrier Reef' in an effort to reduce pollution flowing out to the Reef.

Great Barrier Reef Marine Park Authority Reef Guardian Schools Acting Program Manager Carolyn Luder said the International Day for Biological Diversity was a great opportunity to increase understanding and awareness of biodiversity issues.

"Today's activities will educate students and the school community about the connection between our everyday actions, and protecting the biodiversity of our environment and the Reef," Ms Luder said.

"Reducing the amount of pollution and debris that reaches drains has a significant benefit to the health of the Reef and the plants and animals that call it home."

Southern Cross Catholic School is an active member of the Reef Guardian program that encourages understanding and awareness of the Reef and its connected ecosystems.

"We would love to see more Reef Guardian Schools getting involved in activities to spread the word to communities about protecting stormwater drains from rubbish," Ms Luder said.

"As future custodians of the Reef, students are addressing the challenges facing the Reef, and the Reef Guardian program inspires them to make a positive difference."

The project was made possible through a donation of paint and paint brushes from the local Bunnings Warehouse in Garbutt.

Reef Guardian Schools are participating in many other environmental initiatives to improve waste, water and energy management and increase biodiversity.

This includes tree planting, recycling programs, and solar energy installations.

The Reef Guardian Schools program is an environmental education program run by the Great Barrier Reef Marine Park Authority.