Agricultural and sewage pollution can cause low-oxygen conditions and fish kills in rivers. A new study published in Nature Communications reports that hippo waste can have a similar effect in Africa’s Mara River, which passes through the world renowned Maasai Mara National Reserve of Kenya and is home to more than 4,000 hippos.
When we think of global climate change, what comes to mind? Rising seas? Melting glaciers? Shrinking sea ice? How about diminishing ocean oxygen levels?
Beavers are one of nature’s most industrious engineers. Using branches and mud, the intrepid animals create dams that slow moving water. In New York’s Hudson Valley, their constructions are a common sight on streams and in wetlands.