Alaskan Volcanic Rebirth
A secluded island in the Aleutian chain is revealing secrets of how land and marine ecosystems react to and recover from a catastrophic volcanic eruption that at first wiped life off the island. Kasatochi, an island in the Alaska Maritime National Wildlife Refuge rarely studied by scientists before its Aug. 7, 2008, volcanic eruption, is showing signs of recovery.
Kasatochi Island also known as Kasatochi volcano is an active stratovolcano and one of the Andreanof Islands subgroup of the Aleutian Islands of southwestern Alaska. It lies at the Atka Pass northwest of the western tip of Atka Island and east of Great Sitkin Island. Kasatochi Island has a land area of 1.9503 square miles and is unpopulated.
On August 7, 2008, Kasatochi began erupting explosively with an ash plume maintaining an altitude of 35,000 feet and reaching 45,000 feet.
In the summer of 2009, scientists with the U.S. Geological Survey, U.S. Fish and Wildlife Service, and the University of Alaska Museum of the North returned to the island to begin long term studies to better understand the effects of the eruption and how quickly the island’s ecosystems recover.
Despite the frequency of volcanic eruptions in Alaska, this is one of the first studies of its kind in the remote Aleutian Islands. Their findings are detailed in a series of 10 reports published in the August 2010 issue of the journal Arctic, Antarctic, and Alpine Research.
Prior to the eruption, Kasatochi was one of the most picturesque of the Aleutian Islands. Its steep slopes were covered with low-growing grasses and wildflowers, and in the center of the island there was a steep-walled crater filled at the bottom with a small turquoise lake.
Kasatochi Island hosted a colony of about 250,000 least and crested auklets, making it one of the major seabird breeding colonies in the Aleutian Islands. In turn, the numerous seabirds attracted avian predators such as bald eagles, peregrine falcons and ravens.
Immediately after the eruption, other than sea lions loafing on a newly formed beach, the island appeared to be completely devoid of life. The entire island and neighboring seafloor were covered with thick layers of volcanic ash and deposits from the eruption.
That first summer after the eruption, A baseline survey was made. The team also set up sampling plots and equipment such as seismometers, time lapse cameras and bird song recorders.
“When we first landed on the island, we were unsure of what we would find. The formerly lush, green island was uniformly gray and in the 10 months since the eruption, considerable erosion of volcanic ash had occurred." said project manager Tony DeGange of the USGS.
By late summer, the team found several kinds of green plants scattered around the island bravely poling green leaves above the ground.
USGS research geneticist Sandra Talbot stated: “Most of the plants likely originated from underground root systems, rhizomes or seed banks that survived the eruption, particularly in areas that were protected from the hot volcanic flows and where the ash eroded off quickly to expose the pre-eruption soils."
Entomologist Derek Sikes from the University of Alaska Museum of the North also discovered that terrestrial arthropods had survived the eruption. He found wingless carrion beetles, a centipede and a spider, as well as kelp flies and a blowfly that were eating bird carcasses and kelp that had washed up on the island.
Thousands of seabirds returned to the island that first summer, although none nested successfully, according to Jeff Williams of the U.S. Fish and Wildlife Service’s Alaska Maritime National Wildlife Refuge.
"The auklet colony was buried under volcanic debris and ash. They were unable to locate suitable nesting crevices and laid eggs on the ground or in the water instead. It will be interesting to see if erosion eventually exposes the rock crevices that these birds need for nesting or if they eventually abandon the island." said Wlliama
Similar to what the research team found onshore, near shore habitats were blanketed with sediments and were largely devoid of life. Most of the kelp forests in the ocean around the island had been covered with volcanic debris.
“We are now in the midst of our second year of research at Kasatochi Island, and our intent is to continue this work for many years,:" said DeGange.
For further information: http://en.wikipedia.org/wiki/Kasatochi_Island