Extreme temperatures destroy kelp, seagrass and corals – with alarming impacts for humanity
The number of heatwaves affecting the planet’s oceans has increased sharply, scientists have revealed, killing swathes of sea-life like “wildfires that take out huge areas of forest”.
The damage caused in these hotspots is also harmful for humanity, which relies on the oceans for oxygen, food, storm protection and the removal of climate-warming carbon dioxide the atmosphere, they say.
Global warming is gradually increasing the average temperature of the oceans, but the new research is the first systematic global analysis of ocean heatwaves, when temperatures reach extremes for five days or more.
The research found heatwaves are becoming more frequent, prolonged and severe, with the number of heatwave days tripling in the last couple of years studied. In the longer term, the number of heatwave days jumped by more than 50% in the 30 years to 2016, compared with the period of 1925 to 1954.
As heatwaves have increased, kelp forests, seagrass meadows and coral reefs have been lost. These foundation species are critical to life in the ocean. They provide shelter and food to many others, but have been hit on coasts from California to Australia to Spain.
The average temperature in the United States has risen rapidly and drastically since 1980, and recent decades have been the warmest of the past 1,500 years, according to a sweeping federal climate change report awaiting approval by the Trump administration.
The draft report by scientists from 13 federal agencies, which has not yet been made public, concludes that Americans are feeling the effects of climate change right now. It directly contradicts claims by President Trump and members of his cabinet who say that the human contribution to climate change is uncertain, and that the ability to predict the effects is limited.
“Evidence for a changing climate abounds, from the top of the atmosphere to the depths of the oceans,” a draft of the report states. A copy of it was obtained by The New York Times.
The authors note that thousands of studies, conducted by tens of thousands of scientists, have documented climate changes on land and in the air. “Many lines of evidence demonstrate that human activities, especially emissions of greenhouse (heat-trapping) gases, are primarily responsible for recent observed climate change,” they wrote.
The report was completed this year and is a special science section of the National Climate Assessment, which is congressionally mandated every four years. The National Academy of Sciences has signed off on the draft report, and the authors are awaiting permission from the Trump administration to release it.
Mary Callahan, THE PRESS DEMOCRAT
Aerial surveys conducted each year to gauge abundance in the iconic kelp forests off the North Coast showed a slight improvement last fall, offering a glimmer of hope for the recovery of the coastal marine habitat, the California Department of Fish and Wildlife has reported.
But conditions for the “bull kelp,” an annual type of seaweed — especially off Sonoma County — have become so bleak in recent years that even a reported doubling of the forest canopy during last year’s growing season has done little to bring the underwater habitat back to full strength, scientists said.
Despite patches that resemble the historic ecosystem in some ways, large swaths of ocean floor off the North Coast remain devoid of bull kelp and other fleshy algal species, prompting continued starvation among common marine herbivores like red abalone and urchins, they said.
Even with growth in the overall canopy last year, data indicates the kelp off Sonoma and Mendocino counties covered at least 95 percent less surface area in 2016 than it did in the banner year of 2008, said Cynthia Catton, an environmental scientist with the state wildlife agency.
The apparent expansion of the kelp canopy “is deceptive,” said Sonke Mastrup, environmental program manager for the agency’s invertebrate program, “because 2016 is still way below anything we would consider normal.”
Read more at: Along the North Coast, mixed news about the health of the undersea kelp forest | The Press Democrat
HALF MOON BAY REVIEW
California Department of Fish and Wildlife Director Charlton H. Bonham is extending the emergency commercial rock crab fishery closure for areas north of Bodega Bay, which was due to expire May 16. Meanwhile, all crab — Dungeness and rock — is deemed safe to eat south of the North Bay.
State health agencies determined last fall that rock crabs north of Pigeon Point to the Oregon border had unhealthy levels of domoic acid and recommended a commercial fishery closure. Subsequently, Bonham submitted an emergency rule to close the commercial rock crab fishery north of Pigeon Point. That authority is new to the director this year.
Following new recommendations of state health agencies, the CDFW director announced on Feb. 10 that the open area of the commercial rock crab fishery had been extended northward to Bodega Bay in Sonoma County. CDFW is continuing to work closely with state health agencies to monitor levels of domoic acid in rock crabs and other species not affected by this closure.
This closure shall remain in effect until the director of the Office of Environmental Health Hazard Assessment, in consultation with the Department of Public Health, determines that domoic acid levels no longer pose a significant risk to public health and recommends the fishery be open.
The recreational fishery for rock crab remained open statewide, but the California Department of Public Health issued a warning to avoid consuming the viscera of rock crab caught in the closure area. As a precaution, state authorities recommend avoiding the viscera in Dungeness crab as well.
State officials continue to test domoic acid levels in crab along the coast to determine when the fishery can safely be opened.Domoic acid is a potent neurotoxin produced by a naturally occurring marine alga. Those levels can be increased under certain ocean conditions.
Source: State monitors domoic acid on coast | Local News Stories | hmbreview.com
Earth Sciences, PHYS.ORG
A reduction in the amount of oxygen dissolved in the oceans due to climate change is already discernible in some parts of the world and should be evident across large regions of the oceans between 2030 and 2040, according to a new study led by the National Center for Atmospheric Research (NCAR).
Scientists know that a warming climate can be expected to gradually sap oceans of oxygen, leaving fish, crabs, squid, sea stars, and other marine life struggling to breathe. But it’s been difficult to determine whether this anticipated oxygen drain is already having a noticeable impact.
“Loss of oxygen in the ocean is one of the serious side effects of a warming atmosphere, and a major threat to marine life,” said NCAR scientist Matthew Long, lead author of the study. “Since oxygen concentrations in the ocean naturally vary depending on variations in winds and temperature at the surface, it’s been challenging to attribute any deoxygenation to climate change. This new study tells us when we can expect the impact from climate change to overwhelm the natural variability.”
The study is published in the journal Global Biogeochemical Cycles, a publication of the American Geophysical Union. The research was funded by the National Science Foundation, NCAR’s sponsor.
Read more at: Widespread loss of ocean oxygen to become noticeable in 2030s
Mary Callahan, THE PRESS DEMOCRAT
Scientists at the UC Davis Bodega Marine Laboratory say a new study shows that the response by certain aquatic animals to warming ocean temperatures may make them more vulnerable to growing acidification, a secondary effect of climate change already measurable off the Sonoma Coast.
The research showed that organisms called bryozoan changed the composition of their skeletons in warm water to ones that quickly dissolved when exposed to water of higher acidity, causing the animals to shut down, lead author Dan Swezey said. He said the study mimicked condititions expected to be widespread by the end of the century.
The findings suggest that some marine life faced with adapting to a shifting ocean environment may be in a double bind when confronted with the “one-two punch” of global warming, a university representative said, with implications for sea stars, sea urchins, coralline algae and other ecologically significant marine life that depend on mineralized skeletons containing magnesium.
UC Davis spokeswoman Kat Kerlin likened the bryozoan to a “canary in a coal mine.”
“Our results add to this growing body of evidence that ocean acidification is a threat for lots of marine animals that are producing hard shells and skeletons,” said the study’s co-author, Eric Sanford, a professor of evolution and ecology. “But that might be increasingly true if the trend of acidification is combined with this trend of warming oceans.”
Read more at: UC Davis study: North Coast water changes affecting marine life | The Press Democrat
Henry Fountain, THE NEW YORK TIMES
Less than a year after one of the strongest El Niños on record, forecasters see an increasing possibility that another will begin later this year.
There is no word yet on how strong a new El Niño might be, but even a mild one could affect weather patterns around the world. Among the potential effects are wetter conditions across the southern United States, including Southern California; a drier Midwest; and drought in parts of Africa, Asia and South America.
An El Niño can also influence global temperatures that are already rising because of greenhouse gas emissions. The strong El Niño of 2015-16 contributed to those years’ being the two warmest on record.
An El Niño occurs when warm water in the equatorial Pacific shifts, creating an immense warm zone in the central and eastern Pacific. This adds heat and moisture to the air, releasing energy that affects the high-altitude winds known as jet streams that circle the planet.
Wildlife managers hope lessening pressure on the imperiled mollusks will help the fishery rebound from a catastrophic mix of ocean conditions that have prompted extensive starvation in abalone stocks.
In a normal year, veteran diver Matt Mattison would likely have started this weekend clad in neoprene, plying the waves off the Sonoma Coast, eager to bag his first red abalone of the season.
Instead, the Monte Rio resident was among a group of volunteers who fanned out Saturday along the North Coast’s most popular abalone hunting grounds to head off any divers or rock pickers who mistakenly turned up and to inform them the traditional season start has been delayed.
A jubilant occasion that typically draws hundreds, perhaps thousands, of restless abalone hunters to coastal waters each year, the April 1 opener is a little like Christmas for those who pursue the succulent sea snails. It’s a rite of spring.
But after four decades of time-honored ritual — cause for reunions of family and friends on the Sonoma and Mendocino coast every year — the California Fish and Game Commission has taken emergency action curtailing this year’s season, axing both April and November from the calendar and sharply reducing the allowable annual catch, from 18 abalones to 12.
It will be the first April since 1921 — a time when the season began in mid-March — that red abalone cannot legally be harvested, according to Jerry Kashiwada, an environmental scientist with the state Department of Fish and Wildlife.
Read more at: Unprecedented delay in California abalone season shuts down North Coast in April | The Press Democrat
Mary Callahan, THE PRESS DEMOCRAT
California fishermen are bracing for the worst salmon season in eight years, one so grim that many will likely sit the season out completely.
Years of drought and unfavorably warm ocean conditions that existed when this year’s potential crop of king salmon was young have reduced the adult population to the lowest level forecast since 2009, when projections were so pathetic both sport and commercial salmon seasons were canceled.
Some hope that abundant winter rainfall and last year’s welcome spring rains will help restore next year’s salmon fishery to something approximating full strength. But until then, “we have one more bad drought hangover year to work through,” said John McManus, executive director of the Golden Gate Salmon Association.
“It looks horrible,” said Bodega Bay fisherman Lorne Edwards, who may skip what would be his third season in a row.
The recreational salmon fishery opens to California sport fisherman on April 1 every year and would normally open to the commercial fleet May 1.
But it will be several weeks yet before the season schedule is set, based on complex modeling and statistical projections aimed at estimating the number of adult salmon waiting in the ocean for the signal to swim upstream and spawn throughout the intensively managed West Coast fishery off California, Oregon and Washington states.
Analysts weigh a host of factors, including the previous year’s landings, the number of adult salmon found dead after spawning and the number of fish set aside for Native American tribes to catch. State and federal biologists consider each distinct natural and hatchery salmon population and their historic distribution in the ocean to determine where and when sport fishers and trollers are allowed to drop their lines in a given year.
Read more at: Worst salmon season in eight years projected in California | The Press Democrat
A small bunch of tiny red crustaceans that ought to be hanging out a thousand miles south of here came ashore on Salmon Creek Beach last week, the final remnants, it seems, of a wave of southern species brought north by unusually warm ocean conditions over the past few years.
The 18 pelagic red crabs now living at the UC Davis Bodega Marine Lab are the first ones reported this far north since 1985, when an isolated sighting was recorded in Fort Bragg, according to Eric Sanford, a UC Davis professor of evolution and ecology.
But those who follow life along the Pacific Coast may recall seeing images of the spidery, vermilion-colored creatures as they came ashore by the thousands last year in Monterey and a year prior, when beaches on both the Central Coast and in and around Orange County were covered in blankets of bright red crabs.
At the time, ocean waters were atypically high, a result initially of a phenomenon called “The Warm Blob” and then an ensuing El Niño ocean warming phase of record strength.
The surprise in finding the rare crabs off the Sonoma Coast at this point in time is that the ocean waters have cooled significantly over the past nine months or so, when the latest El Niño dissipated, Sanford said.
“They’re more often found in southern and central Baja, off of Mexico, and it’s very rare to see them even in the state of California,” Sanford said.
Seeing them now “is just another indicator of how strong that El Niño was,” he said.