Singapore-based photographer Calvin Chow’s project Once Beating Heart focuses on the great Tonlé Sap in Cambodia. As the largest freshwater lake in Southeast Asia, it swells to over five times its usual size during monsoon season as the water from the Mekong river reverses its flow into the lake. “This movement of water pumps the lake like a beating heart, nourishing both people and wildlife in an interconnected web of nature, water and man,” says Chow.

Fish is the lifeblood for those who call the lake their home, but Chow says ever since a series of hydropower dams were constructed up north along the Mekong in Laos and China, the inflow of water into the Tonlé Sap has dwindled and fish supplies have been decimated. “Coupled with the effects of climate change, such as a devastating drought in 2019, the greatest in a century, it has left families with little income, threatening their lives and affecting their access to basic necessities such as clean drinking water and toilets,” the photographer explains.