"A floating robot has been deployed to track great white sharks in the Pacific as part of efforts to understand the giant predators."

"OKLAHOMA CITY (AP) — High temperatures and an ongoing drought are having an impact on more than just crops and livestock. State health officials say they are also creating ideal conditions for the growth of a tiny, single-cell organism that lives in Oklahoma's rivers, lakes and ponds and can cause a disease that is almost always fatal."

"ABOARD THE DREDGE POTTER, on the Mississippi River — This ship is making sure that the Big River, shrinking under one of the worst droughts in modern history, stays deep enough."

"Beside Seattle’s notoriously polluted Duwamish River, an excavator scoops up small pieces of waste metal and slings them onto a rusty mountain at Seattle Iron & Metals Corp. A pile of flattened cars and trucks squats nearby amid vast sheets of scrap metal. For at least the last four years, this auto-shredder and metal recycler has dumped more pollutants into the river than allowed under the federal Clean Water Act, government records show. The levels have ranged higher than 250 times above what’s known to harm salmon that migrate through the river."