London’s famous River Thames has come back to life. After the river was declared biologically dead about 60 years ago, cleanup crews have worked to reduce levels of chemicals such as phosphorus, and volunteers have conserved salt marshes for various species of birds and fish.
Now, the Washington Post reports, the River Thames teems with biodiversity — including sharks, sea horses, eels, and seals. The report, conducted by the Zoological Society of London, measured the successes of conservation efforts but also points toward what remains to be addressed, including rising water temperatures, a high concentration of microplastics, and elevated nitrate concentrations that threaten water quality.