Continued
Staying the course
Though
large areas of coastal waters are still drained of oxygen, Mark Tedesco,
director of the Long Island Sound Study, said he has begun seeing
improvements in areas most affected by hypoxia - though he cautioned
that he doesn't expect to see a "linear response" to nitrogen
reduction.
"Do
we see less nitrogen getting into the Sound? Based on the monitoring
program, we are seeing lower concentrations in the Sound," Tedesco
said. "Are we seeing less plant production as a result of reduced
nutrient levels? Yes, we are. There's evidence that nitrogen is decreasing
in some of the hot spot areas - waters off of Stamford, and moving
west from there."
Tedesco
pointed to two potential culprits for the Sound's still-decreased
dissolved oxygen levels: Nitrogen pollution stored in the Sound's
sediments and the region's increasingly warmer weather.
As
the Sound warms, it separates into two layers: Cooler water remains
at the bottom, while warmer water rises to the surface. The warmer
the water gets, the less oxygen it holds. But that top layer also
seals off the cooler water, preventing oxygen from reaching the bottom.Ê
"We've
had some of the hottest years on record," Tedesco said. "That
can exacerbate hypoxia."
Since
1994, 39 of the 104 sewage treatment plants that empty into the Sound
have been retrofitted with nitrogen removal technology, according
to the Long Island Sound Study report. Had those treatment plants
not been upgraded, hypoxia in the Sound today could be far worse,
Tedesco said.
Terry
Backer, head of the nonprofit Soundkeeper group, agreed that sewage
treatment and nitrogen reduction has been good for the Sound.
He
cited recent research by Ellen Thomas, a scientist at Yale University,
that shows that nitrogen pollution - and possibly warmer water - is
fundamentally changing the Sound's food chain.
Diatoms
- a single-celled, microscopic algae that has, for thousands of years,
been at the base of that food chain - are made of nitrogen and silica.
But the excess nitrogen has made the Sound unfit for diatoms, causing
a surge in blue-green algae - which thrive on nitrogen, but don't
need silica. Jellyfish feed on the latter, but the shellfish and fin
fish that have traditionally populated the Sound don't.
Another
critical piece of the sewage treatment equation, according to Tom
Andersen, author of "This Fine Piece of Water: An Environmental
History of Long Island Sound," is getting New York City to begin
removing nitrogen from wastewater plants that dump sewage into the
East River, much of which flows into the Sound.
In
1998, the city agreed to reduce its nitrogen levels - the same year
as New York state and Connecticut - but shortly after backed away
from its agreement. It wasn't until early 2006 that, after years of
litigation with New York state, the city agreed to lower its nitrogen
releases.
The
city was given until 2017 to fix its nitrogen problem, while the rest
of New York state and Connecticut still have until 2014.
In
a statement, the New York City Department of Environmental Protection
said it is "spending millions to upgrade its plants." Despite
repeated requests, the agency did not provide specifics on those upgrades.
An
alternative?
Art
Glowka, a shellfish commissioner in Stamford and a longtime advocate
for the Sound, is perhaps the fiercest critic of the nitrogen reduction
plan.
"Chemically
clean water is not biologically productive water," he's fond
of saying. "You can't grow fish in a bathtub."
Looking
at an old tidal map of New York Harbor, he points to a line that curves
across the East River.
"The
river flows to the Sound about one hour, then it goes back out,"
he said. "There's a squiggle line where Throgs Neck Bridge is.
. . . That's where the tides meet."
His
hypothesis that New York City's nitrogen doesn't flow to the Sound
isn't his only beef with the restoration plan. Unlike the diatom research,
Glowka said it's a lack of nitrogen that is hurting the Sound - not
an excess of it.
"If
you're only scenario is reducing nitrogen, you starve plankton. You
starve the ecosystem," he said. Starving the plankton reduces
its size and drives out the fish that have traditionally fed on it,
he said.
"Since
they're obsessed with clean, clean, clean, this is where we are now,"
he said. "All our native populations have decreased dramatically,
like winter flounder and blackfish. Until the last couple of weeks,
you didn't even see any birds out there."
Yet
Gary Wikfors, a fish biologist with the Milford branch of the federal
National Oceanic and Atmospheric Administration and a member of the
Long Island Sound Study management committee, said he has not seen
any evidence of shrinking plankton, nor has he seen the blue-green
algae mentioned by Backer.
"The
cast of characters has not changed very much. The same things come
in the spring that came in 1955. It tends to be the same flora,"
he said. "That's one of the issues with any discussion of nitrogen.
Is it going to change what phytoplankton is there? There's no strong
evidence that it's changed."
Wikfors,
however, has his own problems with the restoration plan.
He
said the bulk of nitrogen reduction funds shouldn't be spent only
on sewage treatment upgrades. Fish farms are an equally plausible
solution and have been used in areas facing similar nitrogen problems,
he said. Shellfish would soak up the nitrogen. And once harvested,
the nitrogen would be removed along with the shellfish.
These
shellfish would not be harmful for consumption because "protein
is 16 percent nitrogen by weight," he said.
"It's
not only safe, it's necessary," he said. Ê
Wikfors
is skeptical of another central pillar of the Long Island Sound Study
restoration plan: that excessive nitrogen has spawned algae blooms
in the Sound, which has in turn fueled hypoxia.
"That
hasn't happened. It's not supported by scientific data," he said.
"I study algae blooms. I have to go to the Chesapeake Bay to
study them. I can't find them in the Sound."
Asked
whether or not he thought spending millions on sewage plant upgrades
is money well spent, he said: "I think nitrogen reduction is
not the only step to restoring the Long Island Sound."
Few
dispute that.
Backer
compared restoring the Sound to both peeling an onion and putting
together a giant jigsaw puzzle. As it's repaired, each piece of the
restoration plan - such as stormwater management and sprawl control
- needs to be plugged in correctly, he said.
Robin
Kreisberg of Save the Sound said that sewage treatment is like the
low-hanging fruit of a tree.
"It's
not even clear we have been making progress because there's been so
much development," she said. "It has to be a more holistic
approach."
Although
Tedesco said upgrading sewage treatment plants is still a top priority
in repairing the Sound, he said a "holistic" strategy is
what the Long Island Sound Study has been working on.
"I
think everyone recognizes that restoring and protecting habitats is
key," he said. "We need to improve how we're managing land
use and development, so that we reduce runoff that gets into the Sound.
That is all certainly very important."
