Panama Pacific upwelling fails for first time on record, threatening marine life and fisheries

Scientists have documented the first recorded failure of the Panama Pacific upwelling — a seasonal rise of cold, nutrient-rich deep water to the surface that historically fuels the region’s marine food webs and cools coastal reefs. Researchers warn the breakdown of the upwelling, observed in satellite and sea‑surface temperature records, could have severe ecological and economic consequences for Panama and adjacent coastal ecosystems.

The upwelling normally occurs between December and April and peaks from January through April. In a typical year the event begins as early as Jan. 20 and lasts about 66 days, driving sea-surface temperatures down to around 19°C (66.2°F) and occasionally as low as 14.9°C (58.8°F). This year, researchers found surface temperatures did not fall below 25°C (77°F) until March 4, more than six weeks later than typical, and the cool period lasted only 12 days — roughly 82 percent shorter than average — with a minimum observed temperature of 23.3°C (73.9°F).

Analysis of wind records and satellite chlorophyll measurements by researchers working with the Smithsonian Tropical Research Institute and other institutions indicates a dramatic reduction in northerly winds that normally drive the upwelling. The team reported 74 percent fewer northerly wind events and that when such winds did occur they were shorter in duration. Satellite imagery showed the customary surge in chlorophyll — a proxy for phytoplankton blooms that support higher trophic levels — was essentially absent this season.

"Over 95 percent of Panama's marine biomass comes from the Pacific side thanks to upwelling," said Dr. Aaron O'Dea of the Smithsonian Tropical Research Institute. He told reporters the upwelling is the foundation of a valuable marine export industry that generates nearly $200 million annually, and that its loss could lead to collapsed food webs, declines in fisheries and increased thermal stress on coral reefs.

Without the regular influx of cold, nutrient-laden water, coastal ecosystems risk losing the base productivity that supports small plankton, forage fish and larger predators. The absence of cooling also increases the likelihood of coral bleaching, a stress response in which corals expel the symbiotic algae that provide energy and color and can lead to coral death if high temperatures persist.

Researchers cautioned that it remains uncertain whether the failure represents a one‑off anomaly driven by interannual climate variability or an emergent, longer-term shift in ocean‑atmosphere patterns. The team noted that this year’s conditions included a La Niña episode, a phase of the El Niño–Southern Oscillation (ENSO) associated with altered wind and sea-surface temperature patterns across the tropical Pacific, and said La Niña could have contributed to the weakened northerly winds.

But investigators also raised the possibility that broader climate change–related disruptions could be altering the predictability of coastal wind patterns that for millennia have sustained regional upwelling. The upwelling’s ecological imprint can be traced in paleorecords back at least 11,000 years, researchers said, underscoring the system’s long-standing importance to coastal communities.

The fallout from the upwelling failure is already visible in remote sensing data and coastal observations. The missing seasonal plankton bloom reduces food availability for fish larvae and small pelagic species that form the basis of coastal fisheries. Scientists warned that fisheries catches could decline if upwelling does not resume, affecting local livelihoods and exports.

"When winds formed, they were as strong as ever, but there simply weren't enough of them to drive the upwelling process," Dr. O'Dea said. He added that the critical unknown is whether the event is an isolated departure linked to this year’s La Niña or the beginning of a new normal in which climate disruption alters formerly reliable seasonal processes.

Scientists called for expanded monitoring and focused studies to determine the drivers of the failure and to assess ecological and socioeconomic impacts. Enhanced observations of winds, currents, subsurface temperatures and nutrient fluxes, combined with ecosystem and fisheries assessments, will be needed to distinguish short-term ENSO effects from longer-term trends related to global warming.

The Panama upwelling supports a complex coastal food web and underpins fisheries and tourism linked to coral reefs. A persistent loss of the upwelling would raise risks for widespread coral bleaching, reduced fish recruitment and diminished commercial catches, with cascading effects on coastal communities and economies. Researchers said timely investigation is essential to inform adaptation strategies if the pattern proves to be more than a transient disruption.

For now, scientists continue to analyze satellite and in situ data to track whether the upwelling resumes in coming seasons and to model possible future scenarios. "Climate disruption can upend seemingly predictable processes that coastal communities have relied upon for millennia," Dr. O'Dea said, summarizing the stakes if the seasonal upwelling ceases to behave as it has for decades.