Rising global temperatures are fueling not just extreme weather events but also changes in ocean temperatures and phytoplankton populations.
What’s Happening? Every year, a plume of cold water rises to the surface in the Gulf of Panama, bringing with it a colossal surge of life – from phytoplankton to migratory sharks and whales. This annual upwelling, where deeper, colder, and nutrient-rich water replaces the warmer, nutrient-depleted surface water, has been a remarkably predictable phenomenon for at least the last 40 years. It always began by January 20, lasted around 66 days, and dropped the surface temperature to 19°C or below.
Except this year, it didn't. The temperature in the Gulf of Panama didn't start to change until March 4, and the drop, which only reached 23.3°C, lasted just 12 days. STRI researchers found that this "unprecedented suppression" of the upwelling was linked to "anomalous wind patterns" that could have been affected by La Niña conditions.
Why is Panama’s Ocean Upwelling Important? This process is vital for marine ecosystems, modern fisheries, and even pre-Columbian societies that relied on it. It fuels the production of phytoplankton, which form the foundation of aquatic food webs and produce approximately half of the Earth's oxygen. A weakened upwelling threatens coastal communities that depend on stable fisheries for income and food security.
"What we actually said was that we only have 40 years' worth of high-quality data and that, within those 40 years, we've never seen this happen," said Aaron O'Dea, a staff scientist at the Smithsonian Tropical Research Institute. It's unknown whether this was an isolated incident or the start of a new trend. Scientists plan to start monitoring Panama’s ocean in January 2026 when the upwelling is expected to begin to help them assess the impact of such disruptions on marine ecosystems.
"We did go back and change the press release," O'Dea adds, "but by then it was too late."
Based on anecdotal evidence, the failed upwelling has already affected small pelagic fish, like anchovies and herring, whose populations are strongly correlated to the strength of the upwelling. 'We're hearing that the catch for this year has already dropped quite significantly.'
