Heat Waves and Heavy Rains
We’re halfway through summer and it’s already been a scorcher. If it feels hotter than normal—or the new normal—you can blame El Niño conditions, which officially developed in the Pacific in June. But don’t expect relief anytime soon, they’re predicted to strengthen to historic levels this winter.
What does that mean for Tampa Bay and the estuary? On one hand, we’re likely to see less tropical activity in the Atlantic basin—hooray! Although that doesn’t mean we can let our guards down. It just takes one, as they say.
On the other hand, we’re likely to keep feeling the heat into the winter months. And those summer rains that finally returned bringing much needed relief to our parched lawns and natural areas? They’re likely to stick around, too.
Will we call 2026/2027 the year with no winter? Only future historians know the answer to that question. However, if it’s anything like the winter of 1998/1999, we’re likely to see environmental effects in the estuary from both the excess heat and rain. In fact, there was a dip in seagrass coverage in 1999 that was directly tied to the strong El Niño event the preceding winter.
Shallow waterbodies, like the Tampa Bay estuary, are more impacted by extreme temperatures, i.e., they heat up and cool down much faster than deeper water bodies. As extreme temperatures become more extreme, many marine animals and plants can’t handle the heat (or cold). In fact, marine heat waves are increasingly impacting ecosystems as climate change progresses.
In Tampa Bay, the areas closer to the Gulf tend to stay cooler as marine waters flow in and flush out with the tides. But the further into the bay, away from the Gulf, you go, the less tidal flushing an area experiences. Shallow areas and those with the least tidal flushing are particularly affected by higher air temperatures.
Like Old Tampa Bay.
Seagrasses in Old Tampa Bay have been slower to recover from recent losses. Since temperature is known to affect seagrass coverage, TBEP staff have been collecting data on seafloor temperature in Old Tampa Bay for the past few summers. Using the data they collect, scientists can look for evidence that ties temperature trends to seagrass recovery, potentially solving one more piece in the Old Tampa Bay puzzle.
With the heat we’ve already experienced this summer and high temperatures expected to persist, this year’s data will be especially interesting. We’re about halfway through the sampling season now. If you’d like to follow along, you can find the data on our GitHub.
Finally, while we’re still uncovering how the ecosystem responds to extreme heat, we know what the consequences will be for the extra rain this El Niño will bring—higher nitrogen loads. More rain means more stormwater runoff, which means more nutrients and pollution getting into the bay. When nitrogen loads increase, seagrass coverage decreases.
It might end up being a tough year or two for seagrass in the bay. Areas like Old Tampa Bay with high stormwater runoff input, shallow depth, and less tidal flushing to flush out nutrients and lower temperature, are likely to be the hardest hit. Limiting your fertilizer use continues to be one of the best ways you can help.
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