A few months ago, readers sent a second round of Santa Cruz-related science questions for students from UCSC’s Science Communication Program to investigate—here are their answers
Where will sea-level rise from climate change hit the hardest in Santa Cruz County, and how soon will we see the impacts?
It may be decades or centuries before tourists will be able to snorkel the Boardwalk. But long before then, we’ll see the effects of rising sea levels, when low-lying coastal areas temporarily flood during major storms.
Locally, Capitola is “ground zero for climate impacts,” says coastal geologist Patrick Barnard of the U.S. Geological Survey. The city has endured significant storm flooding three times since 1978, but rising tides will make it even more vulnerable. Other at-risk areas include downtown Santa Cruz and Twin Lakes. Some of these stretches may face permanent inundation if climate change worsens.
The cliffs and bluffs that line much of our coastline are slowly wearing away, too. “The higher the sea level is, the more waves will hit those cliffs, and the more rapidly they’ll erode,” says geologist Gary Griggs of UCSC. Riprap armoring on the bases of coastal cliffs cannot stave off the Pacific’s relentless pounding. Already, Santa Cruz officials are considering a plan to relocate portions of West Cliff Drive and its pedestrian path further inland.
When will the ocean invade? “No one’s going to be threatened tomorrow,” says Griggs. “But it could be 10, 20, 30 years before the water is in your living room, or the cliff edge is 5 feet away.” By 2050 or so, 7-13 inches of sea level rise—the current likeliest forecast—may double the frequency of flooding along California’s coast.
Such forecasts are imperfect, and perhaps we’ll reduce or even reverse carbon emissions. But there’s little chance the dangers of sea-level rise are being overstated, says Bernard. In fact, he says, “I think we’re going to find it’ll be quite a bit worse.”
— Jesse Kathan
Are there species of birds in Santa Cruz County specially adapted to live only in redwood forests?
Our redwoods host a variety of birds, from little Oregon juncos to great horned owls. But one species in particular—the marbled murrelet—seeks out the upper canopy of old-growth forests to raise its young.
Marbled murrelets, robin-sized seabirds, live along the Pacific Coast from here to Alaska. They spend most days feeding on small fish close to shore. But in the summer, when their plumage changes from black and white to a speckled, “marbled” brown, they venture inland to mate and lay a single jade-green egg.
No one knew where these murrelets nested until 1974, when a tree trimmer in Big Basin Redwoods State Park found a single chick atop a wide branch 150 feet above the ground. The parents take turns watching the nest and flying back to sea for food. Their elusive habits pose a challenge to ecologists. “It’s a bird that’s really hard to know much about,” says Portia Halbert, senior environmental scientist for California State Parks.
By some estimates, only about 600 secretive individuals now live in the Santa Cruz area—earning the bird endangered status in 1992. Logging has destroyed much of the old forests they need for their nests, and their fishy meals could be harder to find at sea.
But park visitors create one of the greatest threats to marbled murrelets. Sloppy tourists leave food waste that attracts aggressive crows and Steller’s jays. Too often, these hungry scavengers turn their hunting eyes to murrelet eggs and chicks. In response, state park officials started a “Crumb Clean” campaign to educate visitors about storing food in lockers and disposing waste in secure bins.
To see our local marbled murrelets, says Halbert, go to Big Basin’s Redwood Meadow for spring and summer sunrises, especially in July. You might spot them circling high above for their morning “social hour,” or hear their piercing, keer-like call.
— Ariana Remmel
With bees in decline, how much impact would there be if 100 Santa Cruz households installed new hive boxes with honeybee colonies in them?
If homeowners managed all of their hives properly, this could be a good move. But planting flowers in your yard is a simpler, more surefire way to support local bees.
Honeybees and other pollinators help produce one-third of our food. Busy bees can’t perform this feat on an empty stomach. They feed on pollen and nectar from flowers, trees and crops to get the protein and carbohydrates they need.
Urbanization in Santa Cruz County—and nationwide—has replaced flowery meadows with acres of pavement, while single-crop farms laced with pesticides can stress bees. Hungry, stressed bees are susceptible to parasites, such as the blood-sucking Varroa mite. As a result, U.S. beekeepers lost two out of every five hives last year, according to a startling survey by the Bee Informed Partnership.
Given this decline, starting your own honeybee hive may seem a noble hobby. Another sweet perk: A single hive can produce up to 100 pounds of honey a year.
But bee conservation researcher Hamutahl Cohen thinks the buzz around honeybees misses the larger point. “We actually have dozens of species of bees in Santa Cruz,” says Cohen, who earned her doctorate in environmental studies at UCSC and is now a postdoctoral scholar at UC Riverside. Beekeepers can always make more honeybees by inseminating the queen, Cohen says, but wild bees are key pollinators that can’t be replaced. Common wild bee species on the Central Coast include the yellow-faced bee, green sweat bee and valley carpenter bee.
Cohen’s research shows that, without proper cleaning, beehives can spread infections to wild species. Instead of starting a hive, she recommends planting clumps of flowers—including sunflowers, cosmos and daisies—to ensure that bees are well fed year-round. UC Berkeley’s Urban Bee Lab (helpabee.org) has online resources if you’re eager to get started.
— Jonathan Wosen
Why does Santa Cruz have such good air quality? Is it luck and geography, or does it result from smart environmental policy and our culture of environmental awareness?
Let’s clear the air: Santa Cruz does boast some of the best air quality in the state. “We’re lucky that way,” says William Chevalier, supervising air monitoring specialist at the Monterey Bay Air Resources District. Ocean winds and a lack of heavy industry provide a breath of fresh air along our shores.
So why does the American Lung Association frequently give Santa Cruz County a failing grade for air quality? Chevalier calls it “a patchy situation.” While the coast enjoys the sea breeze effect, the San Lorenzo Valley is, as the district’s air pollution control officer Richard Stedman puts it, “cursed by geography.” Surrounding hills trap tiny particles from vehicle emissions and wood-burning stoves at ground level.
The district offers an incentive program to encourage the valley’s residents to change out their old stoves for cleaner options. Locals also support other clean initiatives, like forest conservation and recycling, but they tend to resist proposals that could reduce pollution from cars and trucks, says Adam Millard-Ball, an urban planning expert at UCSC.
“Where our environmental awareness falls apart is housing and transportation,” he says.
Replacing some parking spaces with protected bicycle lanes and bus lanes would cut down on emissions. Increasing affordable housing options downtown would also help, notes Millard-Ball. Opposition to new housing construction forces people to live farther out and spend more time driving.
Most of the time, though, poor air-quality days in Santa Cruz result from winds that carry smoke and smog from hundreds of miles away. For instance, the Camp Fire that destroyed Paradise in November 2018 shrouded all of northern California in smoke, including the Monterey Bay area.
In general, Santa Cruz residents can breathe easier knowing that our beautiful geography also protects our air quality.
How does the county handle scheduled burns, and is there a better way to reduce wildfire risk?
Our landscape craves regular fires. Without them, pent-up combustible materials threaten to burst into catastrophic wildfires with a single spark. Prescribed burning is an attempt to negotiate with nature. They consume fuels, but only when it’s safe.
“The majority of California is probably pretty outside of its natural fire regime,” says Andy Hubbs, a forester for Cal Fire’s San Mateo-Santa Cruz unit. To counter this, fire crews try to reduce fuels with chainsaws, wood chippers and heavy machinery to grind up undergrowth. But these labor-intensive methods only mimic what a prescribed burn often does better.
In Santa Cruz County, either Cal Fire or California State Parks manage a handful of burns each year. The agencies require specific conditions: some humidity, low winds and fuels that are damp but still combustible. Controlled burns also require a perimeter: a road, trail or strip of land devoid of fuels to separate it from grasses or trees. Burn crews monitor changes in wind that could cause flare ups, and are ready to mobilize if fire threatens to escape.
These closely watched burns are “highly unlikely” to turn into wildfires, Hubbs says. But even the safest ones produce smoke, another hazard of burning that ignites debate.
David Frisbey, the monitoring manager at Monterey Bay Air Resources District, says smoke gets residents “pretty unglued.” The county’s cities and towns are close to areas that agencies might wish to burn. That means smaller prescribed fires.
“The largest burn we’ll see in Santa Cruz County is about 300 acres up in Big Basin [Redwoods State Park],” Frisbey says. For comparison, a recent burn in a remote part of San Benito County spanned 6,000 acres.
The biggest challenge to prescribed burning, says Hubbs, is getting people used to smoke being “part of life again” in our flammable state.
— Jerimiah Oetting
Are there any negative environmental consequences from flying drones in Santa Cruz’s natural spaces?
Drones are rapidly rising in popularity. But birds and other animals may be less than wild about their artificial associates.
“Most people aren’t necessarily aware of what wildlife is doing when they fly a drone,” says Lisa Sheridan, president of the Santa Cruz Bird Club. Several years ago, club members were monitoring a nest at Anna Jean Cummings Park in Soquel with three baby white-tailed kites when a drone whirred onto the scene. The parents darted away to attack it, abandoning their young. “We were afraid a collision with a bladed helicopter would kill one of them,” she says. “We did our best to inform people, since they weren’t aware of the birth being there.”
Sheridan has also seen terns, willets, plovers, and other migratory birds scatter when drones appear. The birds waste energy fleeing instead of resting and feeding, she says.
Rules written to prevent such clashes mean you can’t fly a drone wherever you wish. Within the California State Parks system, each district sets its own guidelines for drone operation. In Santa Cruz County, for example, only one state park permits visitors to fly drones near its parking lot. County parks forbid them. You also can’t pilot your drone over specific coastlines that are part of the Monterey Bay National Marine Sanctuary. Violators can be fined.
Drones aren’t necessarily all bad, though. This past summer, UCSC researchers flew drones—with permission—to capture aerial photographs of Año Nuevo Island. Citizen scientists counted animals in these photos to tally elephant seals, sea lions and birds, providing a valuable census for ecologists.
“Some of these drones, in the right hands, can be very helpful for research,” Sheridan says. As long as their operators respect the environment, drones and wildlife may be able to coexist after all.
— Jack J. Lee
Why do rip tides happen, and are they dangerous in the Monterey Bay?
Daily tidal ebbs and flows at the narrow mouth of a bay like San Francisco’s can create strong surges called “rip tides,” which funnel out to sea. But in less restricted waters, like those of the Monterey Bay, the hazards actually come from “rip currents”—narrow channels of water in the surf zone that can sweep beach-goers far offshore.
As waves break against an uneven shoreline, seawater flows back out at different speeds. Energetic waves can scour away enough sand to focus outgoing water into rapid rip currents often hidden from plain sight.
There are always rip currents at local beaches, says Eddie Rhee-Pizano, lifeguard supervisor for state parks in Santa Cruz County. Surfers even ride the rips like conveyor belts to get beyond wave breaks.
Many such currents are small and pose no threat to a perfectly planned beach day. But when the currents intensify, these flows can tow swimmers into perilously deep waters.
The main danger stems from panic. Instinctively, most people try to swim straight back to the beach when suddenly dragged out. “But that’s the last thing you want to do,” says Rhee-Pizano. “It’s basically swimming up-river.”
Instead, it’s best to stay calm and ride the rip until it weakens. Moving parallel to shore also allows swimmers to escape the strongest pull and swim back farther down the beach. This is especially important for those without a wetsuit, as the frigid Pacific quickly saps a body’s strength.
Every year, county lifeguards stop hundreds of swimmers teetering close to rip currents. Though the numbers vary, California Sea Grant estimates rip currents lead to about 80% of all beach rescues in the state. To stay safe, pick a beach with lifeguards, ask them about the conditions, and swim alongside a buddy.
— Lara Streiff
Local levels of recycling organic material (i.e. composting) are terrible. How big of a difference would it make if we improved?
If everyone in Santa Cruz County composted their food and organic waste, our landfills would have roughly 40% more space overall. We’d also reduce the county’s greenhouse gas emissions—and get fantastic fertilizer in return. All of this is easy to do.
The U.S. Environmental Protection Agency estimates that more food gets dumped or burned every day than any other kind of trash. Each person who composts diverts more than three pounds of waste from the dump each week.
That impact really adds up, says J. Elliott Campbell, an expert in food sustainability at UCSC. “By composting, you can help to extend the life of the landfills, so we don’t have to build another one,” Campbell says. Indeed, at our current rate of dumping, Santa Cruz County has about 10 years to find a new landfill site.
Composting at home also cuts down the harmful greenhouse gases we release. When food ends up in a landfill, trash is piled on top—just like putting food inside a plastic bag and letting it rot. With no oxygen, the decay produces methane, a gas that traps heat in our atmosphere 25 times more powerfully than carbon dioxide. In a composting bin, oxygen infiltrates the breakdown process and eliminates methane, along with that awful rotten trash smell. Statewide, California residents could release 20% less methane gas if everyone composted.
You can do all of this as a comfortable family project at home. As a bonus, you’ll create soil so rich in nutrients that composters call it “black gold”—good for you and your garden, and great for the planet. To get started, visit dpw.co.santa-cruz.ca.us.
— Ashleigh Papp
What will global warming do to our summer fog bank? And if there’s less fog, would that change our coastal ecosystems?
About one-third of the fog along California’s coast has disappeared over the past century as the planet has heated up, scientists estimate. Losing this cool, moist blanket may put some plant species at risk, but solutions to this clearing of the air are not so clear.
Fog spreads moisture through coastal ecosystems, especially redwood forests, while helping to rinse pollution from the air. Without the higher humidity, water and nutrients carried in fog droplets, like nitrogen and phosphorus, plants may suffer from more heat stress. When it’s cool, plants create sugars they need from photosynthesis more easily than in a blazing-hot sun.
“In the Santa Cruz and Monterey Bay area, the fog provides moisture for a lot of species that are dependent on that moisture when there isn’t any rain,” says Daniel Fernandez, an environmental scientist at California State University, Monterey Bay.
Fog forms when water vapor changes to water droplets at high levels of humidity. When the air is cooled, the water vapor contained in it can condenses into particles, creating the calming mist of fog.
But if climate change erodes more of our fog banks, “it can have an adverse effect on ecosystems during the otherwise-dry summer season,” Fernandez says. Most research he has seen predicts that fog levels will continue to decrease as seawater in the Monterey Bay warms up, creating less of a contrast with the air temperature above the water. That contrast is what makes fog droplets condense, Fernandez says.
Researchers have struggled to make models and projections for coastal fog because its presence depends on so many factors, both local and global. “There will be variability, and not all locations will respond in the same fashion within the same time period,” says Fernandez.
— S. Hussain Ather
Why are male elephant seals so much larger than females?
Among elephant seals, massive males top the breeding hierarchy. The more they mate, the more their genes get passed on to ensure the next generation of giants.
When one sex is larger or flashier than the other, scientists call it sexual dimorphism. We see it in many animals, including gorillas, peacocks and—oddly enough—stick insects. Often, the dimorphism reflects mating style.
The drive to mate creates spectacular displays at Año Nuevo, the nearest breeding ground for northern elephant seals. In early January, females arrive en masse to give birth to their pups. After nursing them for only 28 days, the females mate again before returning to sea.
This tight window creates intense competition among males. Larger seals can weigh more than 4,000 pounds, so fighting is risky. A bellow from their inflated nose sack—think gravel in a garbage disposal—sends smaller males scuttling, but evenly matched pairs come to blows. Colliding violently, they rake each other’s chest, neck and head. The winner gains control of a harem of females, which top out at a slimmer 1,500 pounds. Losers may miss out on mating altogether.
During breeding season, adult seals stop eating and drinking. Their thick layers of fat sustain the males. Still, it’s an amazing physiological feat for such a large mammal, says Patrick Robinson, director of the Año Nuevo Reserve. “They stick it out to the bitter end,” Robinson says. “If there’s one female that it’s possible to mate with, they will be there.”
Hunted down to about 100 seals in 1900, the species has rebounded. However, Robinson says, the animals now suffer from a “genetic bottleneck,” a lack of diversity that occurs when a population expands from just a few sets of parents. This leaves them at risk in a changing ocean. But don’t worry: these seals are fighters.
— Amanda Heidt