Nietzsche was wrong: what doesn’t kill you doesn’t necessarily make you stronger. Sublethal doses of toxic copper can reduce a salmon’s chances of survival, but new research suggests impacts may be different in saltier water.
Juvenile coho in freshwater phase, pre-smolting. Photo: NOAA Fisheries.
A decade of research by David Baldwin of NOAA’s North west Fisheries Science Center and other biologists has shown that in some situations, very low levels of dissolved copper interfere with a salmon’s ability to detect smells. This can be a matter of life or death: salmon rely on their olfac tory sense to avoid predators, locate prey, and home in on their natal streams when they return from the ocean to spawn. Earlier studies involved juvenile fish in freshwater settings. Baldwin’s latest project, funded by the Regional Monitoring Program for Water Quality in San Francisco Bay and the Copper Development Association, suggests things are different in brackish and salt water. At salinities that a young salmon is likely to encounter in San Francisco Bay, even copper concentrations well above the current water quality objective had no effect on test subjects’ olfactory function.
“As freshwater fish move into the estuary they become, in effect, protected from copper,” says Baldwin.
Copper enters the watershed via wastewater discharges, as well as urban and agricultural runoff (some pesticides contain copper), and automobile brake pads. The use of copper in brake pads is now being phased out thanks to state legislation and the efforts of the Brake Pad Partnership (parallel efforts are also in the national pipeline).
To protect all the beneficial uses of Bay, the state’s site-specific water quality objectives are 6.9 micrograms per liter (μg/L) for the South Bay and 6.0 μg/L for the Central Bay and San Pablo and Suisun Bays.
Recent RMP measurements indicate that dissolved copper levels in the Bay are under 4 μg/L, close to what studies in the 1970s found. However, concentrations as low as 3 μg/L have been implicated in behavioral impairment in juvenile salmon in freshwater. They can’t detect the chemicals released when another fish is attacked by a predator, and don’t take evasive action.
To tease out effects on fish, Baldwin has worked with juveniles — smolts — of both Chinook salmon, a species that travels through the Bay and Delta, and coho, a coastal-stream spawner. Smoltification is a complex process, changing the young fish’s appearance and physiology from a freshwater phase to a seawater phase to adapt it for life at sea. Baldwin used electrodes to measure how a smolt’s olfactory system responded to a mix of amino acids after exposure to a strong solution of dissolved copper, 50 μg/L, at a salinity of 10 parts per thousand (ppt.) That salinity was chosen because it matches the salinity of the fish’s internal fluids and tissues, but it’s within the estuarine spectrum.
A seabound Chinook would encounter salinities of 2 ppt where the Sacramento River passes Rio Vista, 7 ppt in San Pablo Bay, and 30 ppt at the Golden Gate.
In Baldwin’s lab, while pre-smolted salmon tested in freshwater show a reduced olfac tory response due to copper exposure, when tested in 10 ppt there’s no reduction. Likewise, in their saltwater phase, copper exposures in 10 ppt appear to have no impact.
Previous freshwater work demonstrated copper olfactory toxicity in a salmon relative, the steelhead, the anadromous form of the rainbow trout. “I don’t see why the results of the estuarine/seawater work in coho and Chinook couldn’t be generalized to steelhead,” Baldwin adds. “It’s unlikely that the steelhead olfactory system is radically different.”
What’s not clear is whether salinity levels below 10 ppt would still be protective. And what about the returning adult salmon, seeking out water that smells like home? That research has yet to be done. But adults have less prolonged exposure to estuarine contaminants than smolts. “Smolts use the estuary as an arena to feed and rear, trying to decide ‘Am I really ready to go out in the ocean?’” Baldwin explains. Adults, however, don’t dither around on their way to the spawning grounds.
Joe Eaton writes about endangered and invasive species, climate and ecosystem science, environmental history, and water issues for ESTUARY. He is also "a semi-obsessive birder" whose pursuit of rarities has taken him to many of California's shores, wetlands, and sewage plants.
Our magazine’s media motto for many years has been “Where there’s an estuary, there’s a crowd.” The San Francisco Estuary is a place where people, wildlife, and commerce congregate, and where watersheds, rivers and the ocean meet and mix, creating a place of unusual diversity. In choosing to tell the...
Ever since the state and federal water projects were built in the 1930s and 1940s, California has captured snowmelt in foothill reservoirs, and moved the fresh water from dam releases and river outflows to parched parts of the state via aqueducts hundreds of miles long. A convoluted system of ancient...
Though the Clean Water Act did an amazing job of reducing wastewater and stormwater pollution of the San Francisco Estuary, some contaminants remain thorny problems. Legacy pollutants like mercury washed into the watershed from upstream gold mining, PCBs from old industrial sites, and selenium from agricultural drainage in the San...
Hothouse Earth
By Ariel Rubissow Okamoto
Photo by Megan Nguyen
Nothing could be stranger than sitting in the dark with thousands of suits and heels, watching a parade of promises to decarbonize from companies and countries large and small, reeling from the beauties of big screen rainforests and indigenous necklaces, and getting all choked up.
It was day two of the September 2018 Global Climate Action Summit in San Francisco when I felt it.
At first I wondered if I was simply starstruck. Most of us labor away trying to fix one small corner of the planet or another without seeing the likes of Harrison Ford, Al Gore, Michael Bloomberg, Van Jones, Jerry Brown – or the ministers or mayors of dozens of cities and countries – in person, on stage and at times angry enough to spit. And between these luminaries a steady stream of CEOs, corporate sustainability officers, and pension fund managers promising percentages of renewables and profits in their portfolios dedicated to the climate cause by 2020-2050.
I tried to give every speaker my full attention: the young man of Vuntut Gwichin heritage from the edge of the Yukon’s Arctic National Wildlife Refuge who pleaded with us not to enter his sacred lands with our drills and dependencies; all the women – swathed in bright patterns and head-scarfs – who kept punching their hearts. “My uncle in Uganda would take 129 years to emit the same amount of carbon as an American would in one year,” said Oxfam’s Winnie Byanyima.
“Our janitors are shutting off the lights you leave on,” said Aida Cardenas, speaking about the frontline workers she trains, mostly immigrants, who are excited to be part of climate change solutions in their new country.
The men on the stage, strutting about in feathers and pinstripes, spoke of hopes and dreams, money and power. “The notion that you can either do good or do well is a myth we have to collectively bust,” said New Jersey Governor Phil Murphy whose state is investing heavily in offshore wind farms.
“Climate change isn’t just about risks, it’s about opportunities,” said Blackrock sustainable investment manager Brian Deese.
But it wasn’t all these fine speeches that started the butterflies. Halfway through the second day of testimonials, it was a slight white-haired woman wrapped in an azure pashmina that pricked my tears. One minute she was on the silver screen with Alec Baldwin and the next she taking a seat on stage. She talked about trees. How trees can solve 30% of our carbon reduction problem. How we have to stop whacking them back in the Amazon and start planting them everywhere else. I couldn’t help thinking of Dr. Seuss and his truffala trees. Jane Goodall, over 80, is as fierce as my Lorax. Or my daughter’s Avatar.
Analyzing my take home feeling from the event I realized it wasn’t the usual fear – killer storms, tidal waves, no food for my kids to eat on a half-baked planet – nor a newfound sense of hope – I’ve always thought nature will get along just fine without us. What I felt was relief. People were actually doing something. Doing a lot. And there was so much more we could do.
As we all pumped fists in the dark, as the presentations went on and on and on because so many people and businesses and countries wanted to STEP UP, I realized how swayed I had let myself be by the doomsday news mill.
“We must be like the river, “ said a boy from Bangladesh named Risalat Khan, who had noticed our Sierra watersheds from the plane. “We must cut through the mountain of obstacles. Let’s be the river!”
Or as Harrison Ford less poetically put it: “Let’s turn off our phones and roll up our sleeves and kick this monster’s ass.”
4th California Climate Change Assessment Blues
by Isaac Pearlman
Since California’s last state-led climate change assessment in 2012, the Golden State has experienced a litany of natural disasters. This includes four years of severe drought from 2012 to 2016, an almost non-existent Sierra Nevada snowpack in 2014-2015 costing $2.1 billion in economic losses, widespread Bay Area flooding from winter 2017 storms, and extremely large and damaging wildfires culminating with this year’s Mendocino Complex fire achieving the dubious distinction of the largest in state history. California’s most recent climate assessment, released August 27th, predicts that for the state and the Bay Area, we can expect even more in the future.
The California state government first began assessing climate impacts formally in 2006, due to an executive order by Governor Schwarzenegger. California’s latest iteration and its fourth overall, includes a dizzying array of 44 technical reports; three topical studies on climate justice, tribal and indigenous communities, and the coast and ocean; as well as nine region-specific analyses.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.
For the first time, California’s latest assessment dives into climate consequences on a regional level. Academics representing nine California regions spearheaded research and summarized the best available science on the variable heat, rain, flooding and extreme event consequences for their areas. For example, the highest local rate of sea level rise in the state is at the rapidly subsiding Humboldt Bay. In San Diego county, the most biodiverse in all of California, preserving its many fragile and endangered species is an urgent priority. Francesca Hopkins from UC Riverside found that the highest rate of childhood asthma in the state isn’t an urban smog-filled city but in the Imperial Valley, where toxic dust from Salton Sea disaster chokes communities – and will only become worse as higher temperatures and less water due to climate change dry and brittle the area.
According to the Bay Area Regional Report, since 1950 the Bay Area has already increased in temperature by 1.7 degrees Fahrenheit and local sea level is eight inches higher than it was one hundred years ago. Future climate will render the Bay Area less suitable for our evergreen redwood and fir forests, and more favorable for tolerant chaparral shrub land. The region’s seven million people and $750 billion economy (almost one-third of California’s total) is predicted to be increasingly beset by more “boom and bust” irregular wet and very dry years, punctuated by increasingly intense and damaging storms.
Unsurprisingly, according to the report the Bay Area’s intensifying housing and equity problems have a multiplier affect with climate change. As Bay Area housing spreads further north, south, and inland the result is higher transportation and energy needs for those with the fewest resources available to afford them; and acute disparity in climate vulnerability across Bay Area communities and populations.
“All Californians will likely endure more illness and be at greater risk of early death because of climate change,” bluntly states the statewide summary brochure for California’s climate assessment. “[However] vulnerable populations that already experience the greatest adverse health impacts will be disproportionately affected.”
“We’re much better at being reactive to a disaster than planning ahead,” said UC Berkeley professor and contributing author David Ackerly at a California Adaptation Forum panel in Sacramento on August 27th. “And it is vulnerable communities that suffer from those disasters. How much human suffering has to happen before it triggers the next round of activity?”
The assessment’s data is publicly available online at “Cal-adapt,” where Californians can explore projected impacts for their neighborhoods, towns, and regions.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.