The Los Angeles River in 2013. Engineers turned it into a narrow concrete channel in the 1940s, after a flood destroyed homes and left 100 people dead in 1938. Steve Lyon/Flickr hide caption

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A worker installs solar panels atop a government building in Lakewood, Colo. The industry has added more than 80,000 jobs since 2010, according to The Solar Foundation. John Moore/Getty Images hide caption

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Cruden ranks the Gulf oil spill as one of the most significant environmental disasters of our time. It "deserves ... all of our energy to make sure nothing like this ever happens again," he says. Gerald Herbert/AP hide caption

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The city of Des Moines, Iowa, sits on the Raccoon and Des Moines rivers. The city's water works says it will sue three neighboring counties for high nitrate levels in these waterways. iStockphoto hide caption

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The elusive Kraken wasn't seen in its natural habitat until Dr. Edith Widder came up with some innovative technology. Kraken Attack by Ben Wooten/Used with permission of Paizo Publishing hide caption

itoggle caption Kraken Attack by Ben Wooten/Used with permission of Paizo Publishing

An excavator loads a truck with oil sands at the Suncor mine near the town of Fort McMurray in Alberta, Canada in 2009. Environmental groups that oppose oil sands mining have pointed to delayed and canceled projects as a sign of recent success. Mark Ralston/AFP/Getty Images hide caption

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The IUCN says the Atlantic bluefin tuna is endangered. Its stocks have declined globally between 29 percent and 51 percent over the past 21 to 39 years, according to the conservation group. Tono Balaguer/iStockphoto hide caption

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Darlene Arviso is known as the water lady in Smith Lake, N.M., on the Navajo Nation. She delivers water to 250 people each month. Here, she fills buckets from her water truck. Laurel Morales/KJZZ hide caption

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Barotrauma can cause a fish's eyes to pop out of its head and its stomach to be pushed out of its mouth, according to Chris Lowe, a marine scientist at California State, Long Beach. Jon Hamilton/NPR hide caption

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