What happened to Panama’s upwelling in 2025? Causes, science, and what to watch next

The short answer: In early 2025, the Gulf of Panama’s normal winter upwelling failed to kick in. That upwelling—driven by strong seasonal winds—usually draws cool, nutrient-rich water to the surface, supercharging marine life. Instead, winds were too weak, the ocean surface stayed warm, and coastal productivity dropped.

Why it matters: This one-year miss is more than a curiosity. It shows how tightly coastal food webs, fisheries, and even local climates can hinge on wind patterns. When the wind engine stalls, nutrients don’t arrive, the base of the food chain shrinks, and heat builds up—amplifying stress on corals, fish, and people who depend on the sea.

Who this guide is for

• Coastal residents, divers, fishers, and tourism operators around Panama and Central America
• Students and readers who want a plain-English explainer on upwelling and climate
• Policymakers and NGOs planning for climate variability and marine heat risk
• Journalists covering ocean change and fisheries impacts

Key takeaways

• Upwelling 101: Wind-driven upwelling is a seasonal process that brings cold, nutrient-rich water to the surface, boosting phytoplankton and everything that feeds on them.
• What changed in 2025: Seasonal winds over the Gulf of Panama were unusually weak, undercutting the Ekman transport that normally fuels upwelling. Surface waters stayed warmer and clearer.
• Why that matters: Weaker productivity can mean fewer forage fish, poorer larval survival, and heat stress for coral and coastal ecosystems. Fisheries and tourism can feel the effects in weeks to months.
• Bigger picture: The failure underscores how sensitive coastal upwelling systems are to wind shifts associated with climate variability (like El Niño) and long-term warming.
• What to watch: Wind strength, sea-surface temperature (SST), and satellite chlorophyll are practical, public indicators of whether upwelling is healthy or stalled.

Upwelling, explained in plain English

Upwelling is nature’s conveyor belt, lifting deep, cold, nutrient-loaded water to the sunlit surface where microscopic plants (phytoplankton) can bloom. Those microscopic plants feed zooplankton, which feed small fish, which feed larger fish, seabirds, and marine mammals. If upwelling weakens, the nutrient conveyor slows, and the whole food web thins.

In the tropics and subtropics, wind is the key. When winds blow along the coast, Earth’s rotation nudges surface water sideways (a process called Ekman transport). That sideways push pulls surface water away from shore, and deeper water rises to replace it. The result is cooler, greener water near the coast.

Why the Gulf of Panama is special

The Gulf of Panama sits at a crossroads of atmosphere and ocean. Each boreal winter (roughly December–April), strong trade winds accelerate through mountain gaps from the Caribbean side to the Pacific, forming so-called “gap winds” or jets. One of these, often dubbed the Panama Jet, fans over the gulf and nearby waters.

• In a typical winter: Those winds churn the surface, push warm water offshore, and allow cold, nutrient-rich water to well up from below. Sea-surface temperatures drop several degrees, and satellite chlorophyll spikes—classic signs of a productive season.
• In summer: Winds relax, the water stratifies and warms, and productivity ebbs until the next winter reset.

This winter pulse has persisted for decades, anchoring a predictable seasonal rhythm that local fishers, wildlife, and coastal economies rely on.

What broke in 2025

In 2025, scientists reported that the expected wind surge was unusually weak. With less push from the atmosphere:

• Ekman transport faltered, so less surface water was moved away from the coast.
• Upwelling slackened or didn’t materialize, keeping cool, nutrient-rich subsurface water at depth.
• Sea-surface temperatures stayed high; satellite images and local measurements showed warmer, clearer water than normal.
• Lower nutrients meant smaller phytoplankton blooms, echoing up the food chain.

That’s the recipe for a “quiet” season in a system that’s normally loud with life.

Possible drivers of the weak winds

While each event has its own mix of causes, these are usual suspects when winter winds miss a beat:

• El Niño: During El Niño, the tropical Pacific atmosphere often reorganizes. Trade winds can weaken and the Intertropical Convergence Zone (ITCZ) can shift, altering regional wind jets and stability.
• Shifts in the ITCZ: Even a small latitudinal move can change where rain bands and pressure gradients set up, nudging gap winds stronger or weaker.
• Basin-scale patterns: The Pacific Decadal Oscillation (PDO) and Atlantic variability can modulate background conditions and teleconnections to Central America.
• Long-term warming: A warmer ocean stratifies more easily, requiring stronger winds to achieve the same amount of mixing and upwelling. If winds don’t scale up, upwelling efficiency drops.

Researchers pointed first to weak winds in 2025 as the immediate culprit, with climate variability and long-term warming likely shaping the backdrop.

How scientists know upwelling failed

You don’t need to guess—there are clear fingerprints when upwelling is strong or weak:

• Wind metrics: Satellite scatterometers (which measure ocean surface winds) and coastal stations show whether winds met the typical winter thresholds. Indices like the Bakun Upwelling Index convert wind stress into an upwelling “score.”
• Sea-surface temperature (SST): Upwelling usually cools the surface by several degrees. Sustained warmth during the upwelling season is a red flag.
• Chlorophyll-a (satellite): Instruments like MODIS and VIIRS measure ocean “greenness.” If chlorophyll stays low when it should peak, productivity likely suffered.
• Profiles and moorings: Instruments on buoys, gliders, or Argo floats reveal whether the thermocline (the boundary between warm and cool water) rose toward the surface as expected. In a weak year, it stays deeper.
• Sea level: Coastal sea level can dip slightly during strong upwelling due to surface water being pushed offshore. A muted drop suggests weaker upwelling.

Together, these indicators painted a 2025 picture of warm, low-chlorophyll waters and underperforming winds.

What a missed upwelling season does to marine life and people

The consequences tend to arrive fast and cascade widely:

• Phytoplankton: With fewer nutrients, blooms are smaller and shorter-lived. The base of the food web shrinks.
• Zooplankton and forage fish: Less food means reduced growth and lower survival for anchovies, sardines, and other small fish that many predators depend on.
• Fisheries: Catch rates can fall or shift in space and timing. Fish may move deeper or offshore in search of favorable temperatures and food.
• Larval survival: Many fish and invertebrates time spawning with predictable upwelling. A miss can leave larvae in warm, unproductive waters, lowering recruitment.
• Seabirds and marine mammals: With fewer forage fish near the coast, predators may travel farther, skip breeding, or suffer higher mortality.
• Coral reefs and coastal ecosystems: Warm, clear conditions can push corals toward bleaching, particularly if marine heatwaves stack up. Mangroves and seagrasses also feel heat and light stress dynamics.
• Harmful algal blooms (HABs): While strong upwelling often dominates with diatom blooms, weak-upwelling, warm, stratified conditions can sometimes favor dinoflagellates or cyanobacteria. The net risk depends on local seed populations and nutrients.

Economically, fisheries, diving, and wildlife tourism can see leaner weeks to months. Socially, communities tightly linked to seasonal catch may face income gaps and food-security concerns.

How unusual is this?

Historical records suggest the Gulf of Panama has been reliably windy in winter for decades, making the 2025 miss stand out. But “rare” doesn’t mean “impossible.” Other eastern boundary and tropical upwelling systems have seen sudden shifts:

• Pacific Northwest, USA (2005): A heavily delayed upwelling season led to low productivity and a well-documented hypoxia event.
• Northeast Pacific “Blob” (2014–2016): Prolonged warmth and altered winds suppressed upwelling strength, with large ecosystem impacts.
• Humboldt and Benguela systems: Intermittent relaxations or wind anomalies cause episodic collapses or booms in fisheries.

The lesson: Upwelling is robust but not invincible. It responds quickly to atmospheric nudges and background ocean state.

Climate context: variability vs. change

It’s tempting to label any anomaly as climate change, but the honest picture is layered:

• Year-to-year variability: El Niño–Southern Oscillation (ENSO) shifts wind patterns and thermocline depth. Many coastal anomalies track ENSO’s rhythm.
• Decadal patterns: The PDO and Atlantic modes tweak the odds of strong vs. weak upwelling years.
• Long-term warming: A hotter ocean strengthens stratification and loads the dice toward reduced upwelling efficiency unless winds intensify proportionally. Marine heatwaves, now more frequent and longer, raise the baseline risk for corals and fish.

In 2025, weak winds appear to be the immediate cause; long-term warming likely made it easier for the surface ocean to stay hot and stratified once upwelling faltered.

Practical indicators to watch (and where to find them)

You can track upwelling season strength with a few public data streams:

• Wind speed and direction: Satellite wind maps (e.g., from ASCAT) and coastal weather stations. Look for sustained strong northerly to northeasterly winds in Dec–Apr.
• SST maps: Free products from NOAA, CMEMS, and NASA show coastal temperature drops during normal upwelling. If waters stay warm (> seasonal norm), upwelling may be weak.
• Chlorophyll-a: NASA OceanColor or Copernicus datasets reveal blooms. A green coastal strip in winter is a good sign; persistent blue hints at low productivity.
• Local reports: Fishers, dive operators, and research stations often provide timely observations on water clarity, thermocline depth, and catch shifts.

Tip: Track anomalies, not just absolute values—compare weekly conditions to the long-term average for the time of year.

What managers and communities can do

Even if winds are beyond local control, planning can blunt the impacts:

• Early warning: Set triggers based on wind and SST anomalies to alert fishers and tourism operators when an upwelling season looks weak.
• Adaptive fisheries management: Flexible seasonal closures or effort limits can protect spawning stocks when recruitment is at risk.
• Diversify livelihoods: Support alternative income streams (e.g., ecotourism, aquaculture tailored to warm conditions) to buffer bad seasons.
• Habitat protection: Healthy mangroves, seagrasses, and reefs are more resilient to heat and nutrient swings. Protecting them pays off in tough years.
• Monitoring partnerships: Citizen science on temperature, water color, and species sightings can complement instruments and satellites.

Common misconceptions, clarified

• “No upwelling means dead seas.” Not quite. Warm, clear water can still host life, just less of the cool-season abundance and often with a different mix of species.
• “It’s all El Niño’s fault.” El Niño is a frequent driver, but local wind jets, ITCZ shifts, and longer-term warming also play roles. Each event is a blend.
• “If winds return next year, everything bounces back.” Some parts rebound quickly, but missed recruitment can ripple for years in long-lived species or sensitive habitats.

What to expect next

Seasonal upwelling in the Gulf of Panama has a strong climatological backbone. Odds are good that the winds will return in a subsequent winter, though not necessarily at full strength. What matters is whether 2025 was a one-off nudge—or an early sign of more frequent weak seasons as the climate warms.

Keep an eye on:

• The next winter’s wind strength and duration
• How quickly SST drops and chlorophyll rises when winds return
• Signs of ecosystem lag, such as slow forage-fish recovery or coral stress carryover

FAQ

• What exactly is “upwelling”?
  It’s the rise of deep, cold, nutrient-rich water to the sunlit surface, usually powered by wind and Earth’s rotation. It fuels high productivity and fisheries.

• Why did Panama’s upwelling fail in 2025?
  Researchers point to unusually weak seasonal winds. Without enough wind stress, the mechanism that lifts cold, nutrient-rich water stalled.

• Was El Niño to blame?
  El Niño often weakens or shifts wind patterns in the tropics, so it’s a prime suspect. But other climate patterns and long-term warming likely influenced conditions too.

• How does this affect fish and fisheries?
  Less upwelling means fewer nutrients, smaller plankton blooms, and potentially lower survival for young fish. Catches can dip or shift in where and when fish are available.

• Could harmful algal blooms increase?
  Warm, stratified conditions can favor some HAB species, but outcomes vary by location and nutrient sources. It’s a risk to monitor, not a certainty.

• Will upwelling come back?
  Most likely, yes. The seasonal wind engine in the region is strong climatologically. The question is how variable it becomes and how often weak years recur.

• Does this tie to Panama Canal operations?
  Indirectly at best. The canal depends mainly on freshwater supply from rainfall. However, the same climate patterns shifting winds can also affect rainfall elsewhere in Panama.

Bottom line

The 2025 non-event in the Gulf of Panama is a clear reminder: coastal ocean productivity is a climate-sensitive service. When winds falter, the ocean’s nutrient elevator slows, food webs thin, and heat builds. Watching the wind, SST, and chlorophyll in real time—and planning for swings—can help communities navigate what is likely to be a bumpier future.

Source & original reading: https://www.sciencedaily.com/releases/2026/04/260426012253.htm