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Deep oceans off Alaska face threats of their own

Doug O'Harra

If deep oceans covered an area only the size of the state of Alaska, then humans have so far explored in detail only about 2,400 square feet -- enough space to park seven or eight cars, according to details contained in a new report about the threats facing the Earth’s watery abyss.

It may be a cliché, but people truly know less about the deep ocean floor than we do about the dark side of the moon. And little wonder.

With an average depth more than 3.8 kilometers, the global ocean could swallow 14 North Americas or 211 Alaskas whole. Of the deep areas, covering about 326 million square kilometers, almost nothing has been touched by human eyes or their robot arms. (Check out this story on deep sea exploration.)

The vast dark region below the waves is the largest and least visited environment on the home planet. It may be the least viewed habitat in the solar system.

“Of this great expanse, only the area equivalent to a few football fields has been sampled biologically,” according to the team conducting the deep sea project for the Census of Marine Life. “The main problem is that we still know very little of what we call the deep sea, making it difficult to evaluate accurately the real impact of industrial activities, litter accumulation and climate change in the deep sea habitats.”

But a new report in the journal PLOS one -- Man and the Last Great Wilderness: Human Impact on the Deep Sea -- warns that humans have begun to change the unknown abyss on a scale never seen before. And without protection and active management, it’s going to grow worse.

Centuries of dumping waste -- sewage, garbage, chemicals, plastics, drugs -- has now morphed into industrial-scale fishing and accelerating resource extraction. Humans have introduced invasive species from one hemisphere to another, and global climate change has begun to alter the basic chemistry of marine life with dramatic increases in the concentrations of dissolved CO2 and overall world temperatures.

“As prospectors increase their efforts to exploit the resources locked up at the bottom of the oceans, scientists and legislators continue to lag behind, a panel of experts has warned,” says a Nature news blog about the report. “From simply throwing waste over the side of ships, humanity has advanced to actively exploiting the deep sea.”

The authors add: “The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present. … We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact  on deep-sea habitats and their fauna.”

The problem? People who want to exploit the ocean -- or don’t want to fully check out how their activities might ultimately cause marine problems -- can often move as quickly as financing and logistics allow. “Lagging behind” are the scientists, managers and officials who must gather data, conduct studies and debate what to do.

“The fastest movers in the deep sea are those who wish to use it as a service provider,” the authors wrote. “Impacts can occur quickly because they often arise through economic imperatives, while understanding by scientists follows a process governed by funding cycles and with slow and long scientific procedures, thereby introducing a time lag to any response to a perceived threat.”

The report touches specifically on Alaska only a few times. The authors point out that the Gulf of Alaska and Bering Seas are some of the few places where deep sea closures have protected sensitive habitats from bottom trawling, adding: “The high seas are still lacking a fully coordinated approach or network of conservation areas.”

It warns that extracting methane hydrates from the seafloor -- something under study for Alaska’s North Slope -- may be more complicated and ecologically sensitive than first thought.

“Most gas hydrates are buried beneath a thick sediment cap on the sea floor below 250 (meters),” the authors wrote. “In places where gas hydrates intercept the sediment surface … methane seep ecosystems are well developed. Should mass extraction of gas hydrates become a reality, many methane seeps might become subject to disturbance more significant than that of oil and gas extraction.”

Finally, the spread of lower-oxygen water in the North Pacific has allowed the jumbo Humboldt squid to substantially expand its range -- including recent sightings in the Gulf of Alaska.

For much more detail about the state of the Earth's deep oceans, and how people should respond, read the report.

Contact Doug O'Harra at doug(at)alaskadispatch.com