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USA - What Happens to Animals in The Ocean During a Hurricane?

When strong hurricanes hit land, the uprooted trees, destroyed homes, and other devastation are highly visible. What happens in the marine environments where they churn water and disrupt sediment isn't always as obvious.

A vast array of marine life lives along the Florida peninsula, the US state where hurricanes make landfall most often. The Florida Keys have coral reefs. Near the panhandle, there are temperate marshes and seagrass meadows. And the plants and animals in these various regions respond differently to hurricanes.

And not all hurricanes have the same effects, said Melissa May, an assistant professor of marine biology at Florida Gulf Coast University.

A storm surge can act like an unusually high tide and leave some marine environments relatively undisturbed during the hurricane itself, she said.

But a storm's aftermath can have its own devastating effects, from changes in salinity to an influx of sediment and bacteria.

What happens to marine life during a hurricane?

In a typical year, about 10 hurricanes will develop in the Atlantic basin, which includes the Atlantic Ocean, Gulf of Mexico, and Caribbean Sea, according to the National Oceanic and Atmospheric Administration.

The force of a hurricane can create 60-foot waves that churn together cold water from the depths with the warmer surface water. Its currents can stir up sediment as deep as 300 feet, according to NOAA.

Many marine mammals and fish can move to deeper, calmer waters. Researchers followed the movements of blacktip sharks during a 2001 tropical storm and found they left the area before it made landfall and returned after five to 13 days.

Scientists have hypothesized that lower barometric pressure, temperature changes in the water, and similar cues alert fish that a storm is imminent. A 2019 study found that increased waves at the surface stirring water at the seafloor prompted gray triggerfish to move to deeper water before hurricanes.

If dolphins and other marine mammals don't manage to escape the path of the hurricane, they can become trapped in ponds, levees, and other freshwater habitats where they can't survive.

Hurricanes can be deadly for fish, too.

After 1992's Hurricane Andrew, an estimated 9.4 million saltwater fish died, the US Geological Survey found. Sediment may have clogged their gills or the pressure changes may have formed deadly nitrogen gas bubbles in their blood.

The same storm swirled sediment in freshwater environments and turned the water anoxic, meaning oxygen-deficient. An estimated 187 million fish died inLouisiana.

Hurricanes also impact stationary or slow-moving marine life. After hurricanes, "seagrass beds and oyster reefs have been buried by shifting sediment," said Valerie Paul, head scientist at the Smithsonian Marine Station, in an email to Insider. "If you have lots of storm surge and wave action, that can physically uproot the seagrass," May said.

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