Posts Tagged water temperatures

Jun 13 2016

Why the ocean water along the Central Coast turned cold

As most beachgoers will tell you, the seawater temperatures along the Central Coast have turned downright cold.

In fact, the harbor seals and sea lions seem to want to spend more time on the rocks and beaches. My children, Chloe and Sean, are using thicker wetsuits.

So why is the seawater so cold?

Strong to gale-force northwesterly winds have produced greater amounts of upwelling along the coastline.

As the northwesterly winds blow parallel to our coastline, the friction of the wind causes ocean surface water to move. Because of the Coriolis effect, the surface water flows to the right, or offshore.

This, in turn, causes upwelling along the coast as cold, clear and nutrient-rich water rises to the surface along the immediate shoreline.

Farther away, another factor may help to keep seawater temperatures at normal or below normal: It’s called El Niño-Southern Oscillation (ENSO). The latest surface seawater temperature (SST) data from the central equatorial region of the Pacific Ocean called Niño 3.4 indicates this past “Godzilla” El Niño has died. Region 3.4 is the standard for classifying El Niño (warmer-than-normal SST) and La Niña (cooler-than-normal SST) events. The fortunetelling SST cycles in Niño 3.4 are categorized by the amount they deviate from the average SST. In other words, an anomaly.

A weak El Niño is classified as an SST anomaly between 0.5 and 0.9 degrees Celsius, a moderate El Niño is an anomaly of 1.0 to 1.4 degrees Celsius and a strong El Niño ranges from 1.5 to 1.9 degrees Celsius. A very strong El Niño anomaly is anything above 2.0 degrees Celsius (or 3.6 degrees Fahrenheit), a very rare event indeed.

Last winter’s temperatures reached a little over 3 degrees Celsius, one of the strongest on record.

William Patzert, a respected climatologist with Caltech’s NASA Jet Propulsion Laboratory in Pasadena, said, “Unfortunately, its effects weren’t as great as the 1997-98 El Niño. That cycle produced huge amounts of rain and snow. This year’s El Niño was no Godzilla, more of a gecko as far as impacts were concerned along the Central Coast.”

For reasons we really don’t understand, pressure areas change places at irregular intervals over the equatorial Pacific. This is part of the broader El Niño-Southern Oscillation climate pattern.

During a La Niña phase, high pressure builds in the eastern equatorial Pacific, while low pressure develops to the west, producing a stronger equatorial pressure gradient. Almost like a car rolling downhill, the easterly trade winds strengthen, causing upwelling off the coastlines of Peru and Ecuador and lowering sea surface temperatures throughout the eastern Pacific Ocean.

The latest model runs from NOAA’s Climate Prediction Service indicate that we will go into a La Niña cycle by July and remain in this cycle through early 2017.

The good news is that upwelling brings nutrients to the surface waters off the coast, allowing fish populations living in these waters to thrive. The bad news is this condition often shifts the storm track farther north into the Pacific Northwest, leaving the Central Coast high and dry with below-average rainfall.

However, there have been periods of heavy rain during neutral conditions (“El Nothing”) and La Niña cycles. An atmospheric river (Pineapple Express) could develop over the Central Coast during winter and produce copious amounts of rain along the Central Coast, regardless of ENSO.

Otherwise, chances are, we will probably see another year of below-average rainfall. Only time will tell the story.

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Sep 23 2015

‘The Blob’ Fueling Drastic Changes Under The Sea Ahead Of El Niño

It’s the crack of dawn on a recent morning at Fisherman’s Landing in Point Loma, and the docks are bustling.

Dozens of enthusiastic anglers have just returned with a boatload of bluefin tuna, dorado and yellowtail.

It’s been a banner season, said Andrew Dalo, who books reservations for Point Loma Sportfishing.

“I’ve got overnight and day-and-a-half boats that are catching 100- to almost 200-pound bluefin tuna up off our coast here, out west and up north,” Dalo said. “And that’s stuff that we don’t even normally see up here, let alone go after.”

A group of anglers on a Point Loma Sportfishing expedition pose with their bluefin tuna catches, weighing 100 to 200 pounds each, July 29, 2015.

Point Loma Sportfishing – A group of anglers on a Point Loma Sportfishing expedition pose with their bluefin tuna catches, weighing 100 to 200 pounds each, July 29, 2015.

The tropical fish are typically reeled in off Mexico and far off-shore, Dalo said. Now they’re being hooked as close as 10-20 miles off of San Diego, where water temperatures are exceptionally warm.

“Right now we’re 4 to 5 degrees above normal, which to you and me doesn’t seem like much, but if you’re an animal living in the sea and you live at that temperature — that’s a huge change,” said Toby Garfield, director of the Environmental Research Division at Southwest Fisheries Science Center in La Jolla.

The warm water, which scientists have named “the blob,” formed two years ago near Alaska and has spread down the West Coast. Garfield said the warm conditions have sent mother nature into disarray.

“In fact, having this additional warm water has changed the winds a little bit,” Garfield explained. “The upwelling winds really drive the productivity along the California coast. So if you reduce that productivity, you start changing a lot of different parts of the whole ecosystem.”

Much of the fishery population has shifted north, and El Niño hasn’t even arrived yet, said Garfield, who analyzes ocean conditions and reports his findings to the Pacific Fishery Management Council.

“If you go out and do an assessment and you’re not sure where that population is from, you can get some erroneous results in terms of how you’re going to divide up the fisheries,” Garfield said. “And remember, the fish don’t know there’s a Mexican border or Canadian border.”

“We really do have a front row seat on a fascinating change,” Garfield added. “We haven’t seen it this anomalously warm in the record, and at the same time, we’re having a developing El Niño.”

Garfield said he sees two possible scenarios playing out this winter: El Niño’s storm energy will stir up the water, causing the cool water from the ocean depths to mix with and cool the water at the surface.

“That’s one scenario — that it may disappear and will go back to more normal temperatures,” Garfield explained. “The other scenario is that the two will reinforce each other and we’ll have even warmer conditions, and the weather patterns will be different than we expect with a normal El Niño.”

Garfield says additional heat from El Niño could produce storms with higher energy and moisture.

Meanwhile, the telltale signs of current ocean water temperatures from “the blob” have appeared in recent months along San Diego’s shores. The unusual visitors range from hammerhead sharks to tropical fish to millions of red tuna crabs.

“We’ve also seen ‘by the wind sailors’ that have occurred en masse on the shores here on La Jolla and elsewhere,” said David Checkley, a professor of marine biology at Scripps Institution of Oceanography.

Checkley said the reduction in upwelling of cold water nutrients from the ocean floor has drastically altered the food web.

“At the base of the food chain it’s been observed that the amount of chlorophyll or phytoplankton is lower than normal because we have fewer nutrients brought up into the surface waters,” Checkley said.

Phytoplankton provide food for a wide range of sea creatures including whales, shrimp, snails, and jellyfish, according to the National Oceanic Atmospheric Administration.

“The continued poor health of the California sea lion population is likely due to a lack of forage — anchovy, sardines… perhaps squid,” Checkley said.

An algal bloom occurring along the West Coast from California up to Alaska is also a growing concern.

“Those harmful algal blooms sometimes come with toxins — demoic acid that can poison marine mammals that eat fish that consume those algae,” he said.

Checkley said water temperatures will likely eventually return to normal, but he can’t help but look at the conditions as a harbinger of the future.

“What perhaps is worrisome is if you think of things such as this and a long-term trend in a rise in temperatures associated with the climate warming or climate change,” Checkley said.

He predicts some sea creatures will suffer through El Niño.

“The winners are the recreational fishermen,” Checkley said.

San Diego’s sportfishing season usually wraps up in September, but not this year.

“We’re hoping this stuff stays around,” Dalo said. “If it stays up here, we can fish in U.S. waters. You bet. We’ll fish into October. We’ll fish into November.”


This map of the West Coast shows sea surface temperature anomalies in the Pacific Ocean in March 2015. They show how much above (red) or below (blue) water temperatures were compared to the long-term average from 2003 to 2012.

NASA – This map of the West Coast shows sea surface temperature anomalies in the Pacific Ocean in March 2015. They show how much above (red) or below (blue) water temperatures were compared to the long-term average from 2003 to 2012.

Tuna crabs blanket the shoreline at Ocean Beach in San Diego, June 12, 2015. By Susan Murphy – Tuna crabs blanket the shoreline at Ocean Beach in San Diego, June 12, 2015.

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Jan 27 2015

Atlantic, Pacific Fish Face Mixing as Arctic Warms


The gradual warming of the Arctic Ocean over the next century will weaken a natural barrier that has separated fish from the Atlantic and Pacific Oceans for millions of years, leading to a mixing of species that could make life difficult in fishing communities from Alaska to Norway.

A new study by scientists in Denmark combined current models of climate change, and the biological water temperature and food requirements for 520 fish species native to the two oceans. The report forecast changes in the range of these fish in five-year increments from now until 2100, when the world’s oceans are expected to heat up globally by an average 4 degrees Celsius (7 degrees Fahrenheit).

“There will be an interchange of the fish communities between those two seas,” beginning as soon as 2050, said Mary Wisz, lead author on the report in Nature Climate Change and a senior ecosystem scientist at Aarhaus University in Denmark. “We know from historical examples that this kind of interchange, when biotas have been separated over long evolutionary time scales, can have huge consequences.”

In this warmer future, fishermen based in Kodiak, Alaska, could be pulling up Atlantic cod, a prized species normally caught off New England and Northern Europe. A similar change has already started off the coast of Greenland, where fishermen in the last five years have been catching larger numbers of Atlantic mackerel, which prefers more temperate water.

Wisz and colleagues say that by 2100, up to 41 species could enter the Pacific and 44 species could enter the Atlantic, through Arctic water passages over Canada or Russia. This interchange will have ecological and economic consequences to ecosystems that at present contribute 39 percent to global marine fish landings.

While some fishermen may benefit from the new catches, scientists warn that it’s hard to predict exactly what kind of fish will take over, and which will be driven away by the newcomers. It’s also possible that several kinds of fish could compete for the same food source – smaller fish, marine shrimp or larvae, for example, leading to a big reshuffling of the existing marine food chain.

“Some species when they come together they get along,” said Peter Moller, curator of fishes at the Natural History Museum of Denmark and another author on the new report. “But of course the Atlantic cod has the potential to become extremely numerous and dominating if it has the right conditions. There is speculation if it gets to a new place, it can be a real game-changer.”

Moller said the cod is an especially voracious predator of smaller fish, and could impact commercial landings of Alaska Pollock, for example. Around 3 million tons of Alaska pollock are caught each year in the North Pacific from Alaska to northern Japan. Alaska pollock is the world’s second most important fish species in terms of total catch.

Jason Link, senior scientist for ecosystem management at the National Oceanic and Atmospheric Administration, agreed that the mixing of species will cause changes in the food web in both oceans, but it’s hard to predict exactly how it will shake out.

“Another issue not noted in this paper is what happens in the ecosystem that these fish move out of, do they remain there or do other species replace them from the south?” Link said via e-mail.

Another thorny issue is how to manage fishing boats who will likely be plying the rugged Arctic Ocean once commercial harvests become feasible.

“This work raises important ramifications for fishes in response to changes in sea ice,” Link said.

Wisz and Moller say their next task is to look at realistic scenarios of predators and prey in the new warmer Arctic ecosystem.

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