From humpbacks breaching by the Santa Cruz Wharf to an algae-slimed Del Monte Beach, Monterey Bay is a strange place these days. What’s driving the warmest-water summer on record.
Published in Hilltromper Santa Cruz | 2014
by L. Clark Tate
Aug. 13, 2014—Relationships are so complex. She’s hot when I thought she’d be cold. She offers up a dazzling parade of schooling anchovies, breaching humpbacks and bombardiering sea birds, then tosses out rotting fish, shiny Velella velellas and sea lettuce. WTF, Monterey Bay? It’s like we don’t even know you anymore.
Why is our beloved Bay suddenly so moody?
Well, like any lasting love affair worth its salt, it’s complicated.
Luckily, we’re talking about the most heavily researched ocean body in the world. And while Andrew DeVogelaere, Research Coordinator for the Monterey Bay National Marine Sanctuary, offers up a disclaimer—“Unfortunately we don’t understand the ocean well enough to be able to tell you with certainty what’s happening as it’s happening”—that doesn’t mean there aren’t a lot of very smart folks taking some very good guesses.
1. The Arrival Of The Anchovies Is Pretty Normal.
Ever hear of the Pacific Decadal Oscillation (PDO)? Yeah, we hadn’t either. But according to Monterey Bay–area scientists, it’s the reason sardines and anchovies trade off in a boom-and-bust cycle every 10 to 20 years. Like a meta–El Nino/La Nina cycle, the PDO shifts average Pacific Ocean temperatures. Positive PDOs equal warmer waters (good for sardines), and negative PDOs cool things off, favoring anchovies.
The Pacific switched to a negative PDO in 2008, according to Raphael Kudela, a Professor of Ocean Sciences at the University of California–Santa Cruz (UCSC). Lagging behind cooling ocean temperatures, the shift from sardines to anchovies began in earnest last year.
Read about the 2013 Monterey Bay anchovy bloom in The Anchovy Vs. The Whale.
The length of delay is the strange part. Francisco Chavez, a senior scientist at the Monterey Bay Aquarium Research Institute (MBARI), notes that the sardines and anchovies switched out much sooner following the PDO shift in Japan and Peru.
“The organisms in the ocean off California have behaved differently than they have in other parts of the world,” says Chavez, “and we don’t know why.” Weird.
2. Blame It On The Wind. It’s Screwing Up Everything In Monterey Bay.
But wait—why is the Monterey Bay so warm this year if the Pacific is cooling down overall? A water temperature of 68 degrees—the highest since recordkeeping started in 1987—was recorded by a Monterey buoy on July 24, according KSBW.
Annual weather patterns, including a fickle El Nino cycle, and their impact on ocean water movements are the likely culprits.
According to William Patzert, an ocean circulation expert at NASA’s Jet Propulsion Laboratory, the early stages of El Nino sent Kelvin waves our way, moving heat energy absorbed in the ocean off the Philippines three to four months ago to the Bay.
Like any wave, Kelvin waves transfer energy, not water. So these uber long-period bumps aren’t currents. As they ripple across the ocean, Kelvin waves thicken the layer of warm surface water, creating a slab of heat that rolls across the cooler waters at depth, forcing them beneath the wave like a ginormous watery rolling pin.
So— according Patzert—the reason surfers are splashing around in board shorts is that they’ve been sitting on the backs of gigantic Kelvin waves. “It’s global to local,” he says.
In addition, say Chavez and National Weather Service Forecaster Steve Anderson, the high-pressure systems that usually bring brisk northwesterly winds to Monterey Bay in the summertime got a little lost, leaving us with windless days and relatively stagnant, warming water in the Bay. According to Anderson the weather just isn’t moving around like usual, and that’s allowing systems to languish.
Feeling extra brainy today? Curious about El Nino? Jump to the El Nino and Monterey Bay Geek Page for all the nerdy details.
So why does the wind matter? Northwest winds generally ramp up in March, moving ocean surface waters away from shore. This pulls cold, nutrient-dense waters up from the ocean floor to replace them. This process, known as upwelling, cools the Bay, feeds phytoplankton (a type of algae) and produces a lot of fog as warming spring and summer air shivers out water droplets when drifting over cool waters. (You noticed that lack of June Gloom too, eh?)
UCSC’s Kudela explains that this year’s upwelling, driven by northwesterly winds, started out strong in March, though somewhat later than usual. Then it turned off for April. We got a few more bumps in May and June, with a pulse occurring every 10 days or so, but overall relatively low levels of nutrients were brought up.
This lack of upwelling typically makes for warmer, less productive waters. This year the Bay has the lowest nitrogen levels (a proxy for overall nutrient levels) recorded since monitoring began in 2002, according to MBARI’s resident nutrient monitor Ken Johnson.
3. All The Bay’s Food, Including The Whale Food, Is Concentrated Near The Shore Because of The Above Climatic Monkey Business. Lucky Us.
So while Monterey Bay nutrient levels were low, the pulses of nutrient-rich waters pulled up by intermittent upwelling then sat in relatively calm, very warm waters with a lot of access to the sun. Boom. Algae.
Phytoplankton (a microalgae, to be specific) found the perfect conditions to grow. And so grow they did, jump-starting a food web reaction that progressed during the spring and summer from phytoplankton to zooplankton to baby fish and krill to anchovies, and then to the more charismatic birds and marine mammals. The lack of moving currents, wind, and waves concentrated all this primary productivity near shore.
And thus, when the riotous herd of anchovies, humpbacks and seabirds began to arrive in mid-July, they were drawn to a very narrow feeding corridor right offshore. Let’s just call it a trough.
It’s not so much that there were more animals than normal, says DeVogelaere, but that they were packed in close by the shoreline for our viewing pleasure.
In fact, during the same period of time, action (i.e. whale sightings) was pretty slow offshore, he states.
Johnson goes further to postulate that there isn’t much food along the Pacific Coast anywhere due to an overall lack of upwelling. The whales and other animals may be here, he says, “because there’s no food anywhere else.”
Johnson believes that another source of upwelling has also contributed to the boom. “The Monterey Canyon is a source of upwelling as well, due to some weird currents, independent of the wind,” Johnson says. “Canyon-induced upwelling is still happening, and maybe that’s why the whales are here. That’s our favorite hypothesis. There’s not much data.”
That may also account for a shift in timing from last year’s early-fall feeding frenzy. According to the Monterey Bay Aquarium’s website, humpbacks can stop by the Bay anytime from April to December. They’ll show up when the food does.
4. Dead Anchovies And Sick Sea Lions Are The Flip Side of The Amazing Monterey Bay Whale Spectacle.
While the show is spectacular, it comes with some pretty gnarly side effects.
Warm waters hold less oxygen than cold, and algal bloom decomposition depletes the oxygen supplies. These underlying conditions set the stage for the Santa Cruz Harbor’s massive anchovy die-off. Scientists postulate that the school sought shelter in the Harbor from the shock and awe of predatory onslaught. They then quickly sucked up all the oxygen in the enclosure, like a handful of goldfish in an old-fashioned fishbowl. (NOTE: If you were unlucky enough to splash around in that oily mess, save your clothes with this recipe.)
Read about the anchovy die-off of 2013 in The Harbor’s Stinky Situation.
Perhaps a more insidious consequence is the heightened presence of domoic acid. Pseudo-nitzschia, a toxin-producing diatom (a type of phytoplankton), has been present in all but one weekly sample since early spring, according to Jason Smith of Moss Landing Marine Laboratories. This is also very weird. Smith isn’t sure exactly why it’s happening, but the cycle nutrient additions to warm, relatively stagnant surface water is likely contributing.
Domoic acid accumulates in fish (mainly sardines and anchovies) and shellfish and, when consumed, induces neurological disorders in marine mammals and people. “California sea lions are the only species demonstrating negative effects [from domoic acid] so far; about 20 have been stranded this year,” reports Frances Gulland of the Marine Mammal Center. (Read more at the Santa Cruz Sentinel.) Due to these elevated levels, the California Department of Public Health warned against consuming sardines or anchovies from the Bay from April 4 to July 11.
5. Blue And Green Beaches: Not As Terrifying As You Might Think.
As visually arresting but surprisingly less bizarre (at least among the scientific community) than the above phenomena are the mass strandings of blue-tinted Velella velella and Del Monte Beach’s green tide.
The southern winds and warm water currents that are rippling through the Bay ecosystem likely blew the Velella velella our way. “We get questions about these funny little beasts every year,” states Rich Mooi, curator of invertebrate zoology at the California Academy of Sciences. According to Mooi, the only thing unusual about this event is that it’s happening a little later in the year than usual. That being said, Mooi notes that, “We know almost nothing about these little guys.”
Born at sea in the middle of the Pacific and built to travel at a 45% angle to the wind, these lovely jellies, commonly called “By-the-wind Sailors,” are at the mercy of prevailing conditions, according to Kudela and DeVogelaere. The SIMoN website explains that strong winds overcome their ability to tack and can push them ashore. The last major events were in the spring of 2002 and summer of 2003.
But according to forecaster Anderson, the Bay hasn’t experienced any strong southerlies this summer, although there have been more frequent and more consistent swells than usual. That consistency might have been responsible for shoving the Velellas onshore.
As of the second weekend in August, a mass of the passive sailors, a beloved Mola mola snack, were still floating just outside the kelp beds off of Wilder Ranch like children’s bubbles blown out to sea. Social media snaps have placed them all over the Bay.
And then Del Monte Beach was green. When mid-July waves washed up a mass of Ulva spp., a seaweed known as sea lettuce, from Sand City to Monterey, folks were a little freaked out.
Mike Graham, an associate professor at Moss Landing Marine Laboratories, has seen similar events, though admittedly slightly smaller ones, four times in the past 12 years. Ulva spp. grows throughout the Bay but en masse on the Del Monte Shale Beds, a reef about a quarter-mile offshore. Graham always notices massive amounts on the reef, which he studies, just before a green tide.
A fast-growing species that responds quickly to light (which penetrates deeper during low-nutrient years) and warm water while requiring minimal amount of nutrients, the sea lettuce was loving it this year.
So why is it suddenly swamping the beach? “This is paper-thin, and it takes pretty much nothing to wash it up there,” Graham notes, adding that it can attach to the ocean floor or grow free-floating. “I think the reason they’re washing up on that beach is just proximity.”
So does this have anything to do with the rest of the weirdness? “There probably is a link, and I’m assuming it has something to do with warming conditions,” Graham states.
In A Nutshell, Then…
So while primary (plankton), secondary (anchovy), and tertiary (whales and such) production has been crammed into the narrow strip of nutrient-rich waters by the shoreline, there isn’t much happening farther out in the bay. This makes for a spectacular (and occasionally stinky) show, it but actually means that there might be less productivity overall in the Bay this year. We’re likely a year out from knowing for sure.
“Things are always changing, and you have to look at multi-year or decadal time frames,” states Smith.
In the meantime, try not to dwell on the seemingly perpetual lack of normality.
“These are kind of strange days in the Monterey Bay right now. It’s not the normal year by any means,” sums up DeVogelaere. “Lots of mysteries to solve. It’s like the CSI of the sea, and putting these puzzles together can be really rewarding when they get figured out.”
Nothing like a little mystery to keep the romance alive.