Scientists in an international team said they have recorded the most intense algae bloom ever—and it was under the polar ice caps in the Arctic last summer. The findings have stunned researchers. "The water was completely green," Stanford University's Kevin Arrigo, leader of the international team that reported Thursday, said. "It was like pea soup." It turns out that first-year polar ice, which were long considered impenetrable to sunlight, can create ideal conditions for growing phytoplankton, the single-celled plants crucial to the Arctic food chain.