They’re undeniably adorable and certainly play key roles in ecosystems—but are sea otters more important than we give them credit for? It seems that way according to two recent studies that have found sea otters vital to the restoration of carbon-fighting water plants.
In an estuary on the central Californian coast, sea grass was deemed nearly extinct as rapid urbanization and increased agricultural activity has led to high levels of nutrient pollution in coastal waters. Sea grass all over the world is now in a state of decline because of pollution.
This decline may not seem so significant at first (it’s just grass, right?), but in reality sea grass absorbs and uses carbon dioxide in our water and atmosphere, potentially helping to reduce the effects of climate change. Moreover, sea grass “acts as a nursery habitat for many species of fish,” reports the BBC, and also aids in the protection of a shoreline’s overall stability.
According to new research published in the scientific journal, PNAS, the reintroduction of sea otters to the Elkhorn Slough in Monterey Bay (the otters were hunted to near-extinction in the area during the late 19th and 20th centuries) have had very positive effects on sea grass populations, even with the nutrient-rich water.
Brent Hughes, the study’s lead author, said, “This estuary is part of one of the most polluted systems in the entire world, but you can still get this healthy thriving habitat, and it’s all because of the sea otters. So it’s almost like these sea otters are fighting the effects of poor water quality.”
The sea otters do this by reducing the number of crabs in the water which feed on the sea grass. This allows sea grass population levels to bounce back and helps support an overall healthy, balanced water ecosystem.
Sea otters are also playing an important role in reviving kelp forests, one of the planet’s great carbon sinks.
According to another study out of the University of California in Santa Cruz, a vibrant population of sea otters allows kelp forests to thrive which then results in a significant decrease of carbon in the atmosphere.
Sea otters are able to have such a great influence on kelp levels as they manage sea urchin populations, which when left unchecked can decimate entire kelp forests. The study notes too that when sea otters are removed from the ecosystem, kelp then disappears, highlighting the crucial part sea otters really play in the wild.
Chris Wilmers, one of the study’s main authors, told Public Radio International that their research shows that “sea otters are, indirectly, responsible for removing between $205 and $400 million worth of atmospheric carbon.” These numbers are based on the current costs of carbon on European markets.
The study’s focus areas included the Aleutian Islands and much of the North American coast from the south all the way to the north, where overall sea otter populations are declining.
Much like the previous study mentioned, the decrease in sea otter populations and the subsequent reduction in important carbon-fighting water plants is due to a domino effect initiated by human activity.
In the case of the University of California study’s sea otters, their population is coming under increasing threat as killer whales have been targeting them instead of baleen whales, their usual food source.
It is theorized that heavy whaling activities after World War II depleted most of the baleen whale population, forcing killer whales to search for food elsewhere. This led to them preying on harbor seals, whose populations they drastically reduced, then to fur seals, which were also depleted, and after to Stellar sea lions, whose population took a hit as well. Now the whales have moved on to sea otters to survive.
While the two sea otter studies featured here highlight the great importance and benefit of reintroducing these vital species back into their native habitats, our impact as humans on ecosystems should not be ignored. We are as much a part of the solution as other species and in order for animals to work their magic, we must be present, active participants too, doing what we can to reduce environmental hazards and protect the planet.
Image source: Wikipedia Commons