Scientists monitoring the waters off California have recorded an unprecedented rise in ocean temperatures beneath Monterey Bay, with readings reaching 64.72 degrees Fahrenheit (18.18 degrees Celsius) at a depth of approximately 200 feet on October 26, 2026.
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readings → monitor → October
The measurement surpassed the previous record set during the powerful 1997 El Niño event, marking the highest temperature recorded at that depth in nearly four decades of monitoring.
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measurement → surpass → monitoring
The Monterey Bay Aquarium Research Institute (MBARI) announced the findings on October 29, while Phys dot org and Ocean News also reported on the unusual warming and its emerging effects on marine life.
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org → announce → life
The temperature increase is among the clearest indications that the developing 2026-27 El Niño has reached Central California.
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Niño → develop → California
Researchers have also begun spotting marine creatures normally associated with tropical and warmer southern waters, suggesting that the changing ocean conditions are already influencing the region’s underwater ecosystem.
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conditions → begin → ecosystem
A nearly 40-year record broken underwater
The measurements come from MBARI’s M1 mooring, a scientific monitoring station positioned in the middle of Monterey Bay, near the underwater Monterey Canyon.
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measurements → break → Canyon
Its instruments have collected oceanographic and meteorological information since 1989, providing researchers with a long-running record of changes in the Pacific.
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instruments → collect → Pacific
The monitoring system includes instruments attached to a buoy and along a cable extending hundreds of metres beneath the surface.
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system → monitor → surface
They measure several environmental indicators, including temperature, salinity, oxygen levels, chlorophyll and ocean currents.
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They → measure → temperature
On October 26, the temperature recorded at 60 metres, or approximately 200 feet, reached 18.18 degrees Celsius.
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temperature → record → degrees
This exceeded the previous high recorded on November 19, 1997, during another major El Niño event.
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This → exceed → event
According to MBARI senior scientist Francisco Chavez, the latest readings were more than seven degrees Celsius above the long-term average at that depth.
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readings → accord → depth
The warming has also contributed to a rise in sea level of approximately 16 centimetres, or 6.25 inches, in the region.
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warming → contribute → region
Researchers are continuing to examine daily measurements to determine whether temperatures will climb further.
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temperatures → continue → measurements
What is driving the unusual warming?
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What → drive → warming
El Niño is a naturally occurring climate phenomenon involving changes in ocean temperatures and atmospheric conditions across the tropical Pacific.
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Niño → occur → Pacific
It develops when trade winds weaken, allowing warm surface water that normally accumulates in the western Pacific to shift eastwards towards the Americas.
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that → develop → Americas
This movement alters ocean circulation, atmospheric patterns and weather systems across different parts of the world.
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movement → alter → world
Its effects can include warmer ocean temperatures, changes in rainfall, coastal sea-level fluctuations and disruptions to marine ecosystems.
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effects → include → ecosystems
Scientists have been tracking the developing event using a global network of autonomous ocean-monitoring floats through the Global Ocean Biogeochemistry Array (GO-BGC), a programme led by MBARI researchers and supported by the US National Science Foundation.
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Scientists → track → Foundation
In late September, measurements from the equatorial Pacific showed rising water temperatures alongside declining nitrate and dissolved carbon dioxide concentrations.
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measurements → show → concentrations
Researchers also recorded falling chlorophyll levels, indicating a reduction in phytoplankton biomass.
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Researchers → record → biomass
These changes suggest that the normal process of nutrient-rich deep water rising towards the surface is weakening, potentially reducing the productivity of marine ecosystems.
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process → suggest → ecosystems
Tropical marine creatures appear in California waters
The changing conditions are also becoming visible through unusual wildlife sightings.
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conditions → appear → sightings
During a recent research expedition west of Davidson Seamount, MBARI scientists encountered a winged comb jelly belonging to the Ocyropsis genus and a rose siphonophore, both typically associated with tropical waters.
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scientists → encounter → waters
Researchers also spotted schools of halfmoon fish near the M1 monitoring station.
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Researchers → spot → station
The species is more commonly encountered in Southern California.
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species → encounter → California
Further underwater surveys revealed juvenile pelagic red crabs, which are known to move northwards during El Niño events.
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which → reveal → events
Although adult specimens have previously been observed in Monterey Bay, researchers had not recorded juveniles this far north.
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researchers → observe → juveniles
The team also briefly encountered Humboldt squid, a large predator whose range can expand along the American coastline during particularly strong El Niño conditions.
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range → encounter → conditions
These arrivals could signal broader changes in the composition of Monterey Bay’s marine communities.
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arrivals → signal → communities
Warmer-water species moving north can alter existing food webs, while animals adapted to colder conditions may retreat towards higher latitudes.
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animals → move → latitudes
Effects could reach the deep ocean
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Effects → reach → ocean
The consequences of El Niño are not restricted to the upper layers of the ocean.
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consequences → restrict → ocean
MBARI researchers have been studying the midwater ecosystem and deep-sea habitats of Monterey Bay for more than three decades.
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researchers → study → decades
Changes in surface productivity can eventually affect organisms living thousands of metres below.
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Changes → affect → metres
One important source of food for deep-sea communities is marine snow, consisting of sinking organic material such as dead plankton and other biological matter.
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source → consist → plankton
When El Niño reduces phytoplankton production near the surface, less organic material may reach deeper ecosystems, potentially affecting the animals that depend on it.
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that → reduce → it
Researchers expect some of the strongest biological consequences of the current event to become apparent during spring 2027.
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some → expect → spring
MBARI is continuing to monitor the developing conditions through its underwater instruments, research expeditions and autonomous technology.
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MBARI → continue → instruments
…and 2 more, not listed.
The Aporia
