"It is not just at sea that North America’s smallest marine mammals with a huge appetite are benefitting the ecosystem"
"When Brent Hughes started studying the seagrass beds of Elkhorn Slough, an estuary in Monterey Bay on California’s central coast, he was surprised by what he found. In this highly polluted estuary, excessive nutrients from agricultural runoff spur the growth of algae on seagrass leaves, which kills the plants. Yet in 2010, Hughes noticed that the seagrass beds were thriving. It did not make sense.
“This is the highest nutrient concentration that I had ever seen on the planet,” says Hughes, a biologist at Sonoma State University. “Any model would suggest there should be no seagrass there and yet it was expanding.”
Hughes set out to solve the mystery. He examined every possible factor, including water quality, temperature and changes in seagrass coverage over time, going back 50 years. He was not making any progress until he was approached by a boat captain named Yohn Gideon who had been running wildlife tours in the slough since 1995. Over the years, the captain had handed clickers to his passengers, asking them to count the sea otters they saw."