On the Charles River near the Longfellow Bridge, something unusual is floating. At first glance it looks like a small island, but this patch of green is actually a science experiment with big ambitions.

The Charles River Conservancy installed the floating wetland in 2020. It measures about 700 square feet and is planted with 3,000 native species. The goal is to restore some of the biodiversity that disappeared when the river's natural marshlands were replaced by seawalls and development.

"It used to be a marsh," said Laura Jasinski, Executive Director of the Charles River Conservancy. "Artificial wetlands bring back some of that function and biodiversity that has been lost."

Impact of artificial wetland

While the plants look like a garden above the water, the real action happens below.

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