A new report looks at the effects of increased ocean acidity on how sound travels in seawater, which scientists have long suspected to be influenced by pH. The report found that drops in pH affect the ocean's chemical balance and consequently lower its sound absorption, especially to frequencies below 10 kilohertz (kHz). The researchers say that by the 1990s, the oceans absorbed 15% less sound than during the previous century, which will likely affect the communications of ocean wildlife as well as military operations, by making sound travel farther and increasing the ocean's ambient noise level. Already, scientists have discovered that blue whales, which normally communicate below1 kHz, have started calling at lower frequencies. Learn more about climate change at http://oceana.org/climate.