Laney battles Merritt Channel pollution
Garbage from students hurting rare Oakland nature preserve
Published: Friday, April 20, 2012
Updated: Saturday, May 19, 2012 20:05
Just east of the Laney parking lot lies the last stretch of the Merritt Channel before it empties into the Oakland Estuary. At the water's edge, a snowy egret stalks a small frog that will become its next meal. Noise from the 880 freeway is muffled. In a cacophony of flapping and honking, a flock of Canada geese rises into the air.
In their wake, an empty Doritos bag floats languidly on the water. It will be gone in a few hours, taken out to the Bay on the tide that flows through the channel. It's a small sign of a much larger problem for the small, often overlooked marine habitat.
The habitat does have its champions, including David Kammerer, a local fisheries and aquatic biologist. "Because the channel area, and waterways in general, are a 'sink' for trash, it all ends up in the ocean," said David Kammerer, He recently worked observing the freeway construction's impact on local wildlife. That's when he noticed the trash accumulating in the channel.
"I've noticed that there's been a lot of backsliding. That people are accepting it as a degraded area, when it is an extremely valuable habitat," he said.
The channel and nearby Lake Merritt (which isn't really a lake, but a salt water lagoon) are both part of a highly tidal estuary where salty marine water mixes with fresh water that drains from nearby creeks. The lake and the channel are subject to the same twice-daily tides as the rest of the San Francisco Bay.
The area was originally a tidal slough (or marsh). Businessman and Oakland Mayor Samuel Merritt built a dam in 1869 at the lake's inlet near today's 12th Street to control the water levels. Over the decades, the land surrounding the Merritt Channel (also sometimes called the Merritt Estuary) has been filled in as the city around it has been built up. Marshland all around the bay have been filled in and built on over the decades and the channel is one of the few that remains.
The grate around the flood control station underneath the 8th Street overpass is meant to catch debris, but trash sometimes makes it through the 4-inch gap between the bars, according to Gene Mazza, pump station supervisor for Alameda County Public Works Agency. This is despite the efforts of the station's staff to keep the grate clean.
If trash falls into the section of the channel downstream from the flood control station, there are no further barriers to keep it from floating out to the Bay and eventually the Pacific Ocean.
It is home to a surprising number of animals. Elephant seals often swim up to the barrier at the flood control station and the channel is an "anchovy factory" according to Kammerer. Estuaries and bays provide protection from predators until the young anchovies can brave rougher waters.
They are joined by bat ray fish that feed on mussels and other shellfish, as well as sculpins, a small bottom-dwelling fish. Dozens of bird species can be spotted on the water. Besides the easy to identify gulls and ducks, there are also terns, egrets, herons and coots.
Because the marine debris doesn't accumulate like trash does on land, its impact goes unnoticed by many. But elephant seals can swallow plastic bags. Both seals and birds can get tangled up in them.
Small fish that feed on plankton or mussels can ingest toxins that leach from plastic and other debris and settle on the bottom of the channel.
Those small fish are then eaten by larger fish, each step in the food chain increasing the toxin level in the animal. It's a process called bioaccumulation and is the main reason people should limit how many servings they eat of the fish they catch in the Bay.
That's just the local impact. Floating trash is pulled out to the Pacific Ocean with the tide where it is taken up by the California current. Eventually, it reaches the North Pacific Garbage Patch, a huge gyre of marine debris that extends for miles in the middle of the ocean. Currents in the North Pacific bring trash from many countries and that trash ends up floating indefinitely, affecting animals such as leatherback turtles, seals and albatross.
An estimated 80 percent of the plastic debris in this part of the ocean is from land-based sources, or in other words, from people living along waterways, according to Captain Charles Moore of the Algalita Marine Research Foundation who discovered the North Pacific Garbage Patch.
Save the Bay, a local environmental group, notes on their website that Bay Area residents use 3.8 billion plastic bags every year. It is estimated that one million end up in the Bay each year. The Lake Merritt Institute estimates that it pulls up to 6,000 pounds of trash per month from Lake Merritt alone, though that includes other types of trash besides plastic.
Because of strapped resources both for Laney Campus and the City of Oakland, the area depends on volunteers to keep it clean. Every September, the Lake Merritt Institute sponsors a Creek to Bay clean up that includes the channel.
During Earth Week later this month, Sustainable Peralta is holding their annual conference at Laney Bistro on April 26, from 11 a.m. to 3 p.m. Part of the day's activities include an estuary clean-up in the afternoon, led by Mark Rauzon, a Laney geography instructor who is also a wildlife biologist.
Read Part 2 of this article here: http://www.laneytower.com/merritt-channel-part-2-1.2868509