El Niño a key factor, but global warming to increase marine heatwaves
A disruptive ocean heatwave in the northeastern Pacific Ocean in 2014 and 2015 was probably a manifestation of El Niño, says a new study by scientists with the Georgia Institute of Technology and the National Oceanic and Atmospheric Administration (NOAA).
New research offers clues on global pollution pathways
Polluted dust from Asia is cutting oxygen levels in the tropical Pacific Ocean, researchers said this week, releasing a new study that traces a chain reaction that starts with land-based industrial pollution in China and other Asian countries.
“There’s a growing awareness that oxygen levels in the ocean may be changing over time,” said Taka Ito, an associate professor at Georgia Tech’s School of Earth and Atmospheric Sciences. “One reason for that is the warming environment – warm water holds less gas. But in the tropical Pacific, the oxygen level has been falling at a much faster rate than the temperature change can explain,” Ito said.
Warm ocean temperatures in the Pacific led to what researchers now are calling an unprecedented bloom of toxic algae along the west coast of North America in 2015. The algal toxin domoic acid was found in samples from a wide range of marine organisms — and for the first time, in the muscle tissue of several commercial fish species.
Scientists from the University of California, Santa Cruz led the investigations into the spread of the toxin through the marine food web, finding that it persisted in Dungeness crab months after the algal bloom disappeared from coastal waters.
Domoic acid is a potent neurotoxin produced by a type of microscopic algae called Pseudo-nitzschia that occurs naturally in coastal waters. Blooms of the toxic algae along the California coast typically occur in the spring and fall and last just a few weeks. This year, however, unusual oceanographic conditions (unrelated to El Niño) led to the largest and longest-lasting bloom ever recorded. Continue reading “Algae toxin found in West Coast fish for first time”→
Climate change will likely subject many low-lying Pacific island nations to more extreme fluctuations in sea level from year to year, in synch with more intense El Niño cycles. Some years, high sea level will lead to bigger floods, while in other years, big drops in sea level will leave coral reefs exposed, according to researchers based in Hawaii and Australia. Continue reading “Pacific islands face extreme sea level changes”→
Study pinpoints impacts to island communities & ecosystems
FRISCO — Scientists with the U.S. Geological Survey have developed climate models that help show how global warming will change wind and wave patterns, potentially affecting island communities, especially as sea level rises.
Archaeologists, ocean scientists team upon detailed study of historic climate cycles in Pacific Ocean
FRISCO — Today’s climate models may not do a very good job of predicting changes in the Pacific Ocean El Niño-La Niña cycle, an international team of scientists said after studying old seashells that display a distinct history of climate variations.
Understanding how El Niño responds to global warming is significant because the undulating rhythm of warming and cooling waters in the equatorial Pacific is a key driver of weather patterns around the world. Some modeling studies have suggested that ancient El Niños may have been weaker than today’s but the new research suggests they were as strong and as frequent as they are now, at least going back about 10,000 years. Continue reading “Study: Ancient El Niño just as strong as today’s”→