BoatU.S. - December 2011

PACIFIC SALMON should get a big break in a few years when the coun- try’s biggest dam-removal project begins to pay off on Washington’s Elwha River. Once a major spawning stream for six salmon species plus steelhead, two dams built for power generation, in 1913 and 1927, have blocked all but the final five miles of the river, which flows into the Strait of Juan de Fuca.

Neither dam had fish-passage channels built in, cutting off the interior 40 miles of river, and another 30 miles of tributary streams to spawning coho, pink, sockeye, and chum salmon, as well as Chinook, which could weigh in at 100 pounds or more. An estimated 400,000 fish once returned to the Elwha annually to spawn. Now, only about 4,000 fish spawn in the lower river that remains open to the sea. Dam removal began in the summer of 2010 with shutting off the hydroelectric generators and draining the two lakes behind the Elwha and Glines Canyon Dams. Actual demolition of the dams began this past September and is expected to

Grinding to a halt: The Elwha River dam will be completely demolished in three years.

take about three years. Nearly the entire Elwha watershed is within Olympic National Park, so the spawning habitat has remained largely pristine.

The nation’s largest dam-removal project has been a long time coming. The Lower Elwha Klallam Tribe, which occupies land at the river mouth, has pressed for dam removal since at least 1968. The tribe led restoration efforts on the lower river and has operated a salmon hatchery there since 1976. Congress passed legislation to study how to remove the dam and restore the Elwha in 1992. The decade-long wait and pent-up demand to open the river again spawned Celebrate Elwha, on September

14, in nearby Port Angeles. Events marking the start of demolition included a music and arts festival on City Pier, a concert, poetry readings, and a science fair. — R.L.

During JUNE 2010, Ben Van Mooy and researchers from the Woods Hole Oceanographic Institution went to the Gulf of Mexico to learn what part microbes played in the rapid breakdown of the oil slick left by the Deepwater Horizon spill.

“The question was: Is this oil food in their eyes?” Van Mooy says. “And if it was, were they going to be able to eat it?” They found microbes feeding on the oil, but that wasn’t the surprising part; they’re known to be able to degrade oil under the right circumstances. But the area of the Gulf where the spill occurred seemed a poor environment for that, making it difficult for microbes to break down the oil.

“We tried to make a calculation to figure out if the microbial banquet was big enough that it might play a role in getting rid of the slick,” Van Mooy says. “We found out it was probably a huge component. We think the microbial degradation was probably one of the bigger processes that contributed to the natural disappearance of the slick.” Respiration — the process of converting food or, in this case, oil into energy — was happening inside the slick at five times the rate it was happening outside the slick, he reports.

What the microbes did with all
that extra energy remains a mystery.
Ordinarily, microbes with a supply of nutri-
ents would multiply and when the Woods Hole team
added nutrients to their samples, that’s exactly
what happened. In the Gulf, though, the oil worked
more like junk food.
“It seems like they ate the oil, but didn’t have
the nutrients to grow,” he says. “So they were
faced with the question ‘What do we do with the
energy we’ve just gained from this oil?’ When we
humans gorge ourselves, we get fat. Microbes
have the ability to make fat molecules, and
they use those to store energy, and we think
that’s probably what they did — they just
gained weight.”
Van Mooy cautions against see-
ing microbes as a garbage disposal
for oil spills. They didn’t work fast
enough, he said, “Even though the
microbes may have played a role
in degrading it, they couldn’t
prevent it. “The slick still hap-
pened.” The long-term conse-
quences remain to be seen.
“Oil has thousands of differ-
ent kinds of molecules in it.
Research suggests that they
probably ate the less toxic mol-
ecules, and left the toxic mol-
ecules behind. They degraded a
lot of the oil, but at this point we
don’t know what role they played
in the long-term toxic effects of the
oil.” — C.L