Depending on whether marine life can move or is stationary, hurricanes have varying effects on it.
Seagrass and oysters must remain where they are whereas marine mammals and fish frequently migrate to deeper water.
Trees that are uprooted, homes that are demolished, and other devastation are readily apparent when powerful hurricanes make landfall. It’s not always as evident what occurs in marine habitats where they stir up sediment and churn water.
Along the Florida peninsula, the US state where storms most frequently make landfall, a wide variety of marine life can be found. Coral reefs exist in the Florida Keys. Temperate marshes and seagrass meadows can be found close to the panhandle. Additionally, the plants and animals differ in how they react to hurricanes depending on the locale.
According to Melissa May, an assistant professor of marine biology at Florida Gulf Coast University, not all hurricanes have the same consequences.
According to her, a storm surge might mimic an extremely high tide and leave some marine habitats largely unaffected by the hurricane.
However, the aftermath of a storm can also have disastrous repercussions, such as changes in salinity and an increase in silt and bacteria.
What occurs to marine life when a hurricane hits?
The National Oceanic and Atmospheric Administration estimates that the Atlantic basin, which encompasses the Atlantic Ocean, Gulf of Mexico, and Caribbean Sea, will see the development of roughly 10 hurricanes per year.
A hurricane’s intensity can generate waves as high as 60 feet, mixing warmer surface water with cold water from the depths. According to NOAA, its currents can stir up dirt 300 feet below the surface.
Fish and marine mammals can migrate to calmer, deeper waters. Following the blacktip sharks’ travels during a tropical storm in 2001, researchers discovered that they departed the area before the storm made landfall and returned after five to 13 days.
Lower barometric pressure, changes in water temperature, and other cues, according to scientific theory, warn fish that a storm is approaching. A 2019 study discovered that gray triggerfish moved to deeper water before hurricanes as a result of stronger waves at the surface churning up the water at the seafloor.
Dolphins and other marine mammals may become trapped in ponds, levees, and other freshwater environments if they are unable to flee the hurricane’s path.
Fish can also die during hurricanes.
According to the US Geological Survey, 9.4 million saltwater fish perished after Hurricane Andrew in 1992. It’s possible that sediment obstructed their gills or that pressure shifts caused fatal nitrogen gas bubbles to build in their blood.
The same storm stirred up sediment in freshwater areas, making the water anoxic, or lacking oxygen. In Louisiana, an estimated 187 million fish perished.
Hurricanes also have an effect on marine life that is still or moves slowly. As a result of hurricanes, “seagrass beds and oyster reefs have been buried by shifting sediment,” Valerie Paul, head scientist at the Smithsonian Marine Station, wrote in an email to Insider. If there is a lot of storm surge and wave movement, the seagrass may be literally uprooted, according to May.
Nearly 250 newborn sea turtles were washed ashore by Hurricane Ian, and the Brevard Zoo’s Sea Turtle Healing Center took care of them until they could be released back into the ocean.
Some types of coral depend on waves to split them up and spread them across the ocean. Hurricanes can also bring in colder water, which can lessen the impacts of coral bleaching, which occurs when corals expel symbiotic algae that provide oxygen and waste removal in response to too-warm water. However, extremely powerful waves can also destroy and displace corals.
What transpires in the ocean following a hurricane?
Litter and rubbish can linger in bodies of water for months or even longer after a strong storm passes.
With Hurricane Ian, “there was a lot of debris in our estuaries,” May remarked. Gasoline and other pollutants poured into Estero Bay from dozens of vehicles and boats.
According to May, sewage can enter streams and introduce pathogens like enterococcus and E. coli.
Hurricane-related rain and flooding also increase the amount of freshwater in maritime habitats. Any species that can’t withstand significant fluctuations in salinity may find this uncomfortable, according to Paul.
However, significant or long-term variations in salt concentrations are rarely tolerated by marine life. For instance, the saltier ocean water that Hurricane Ian brought ashore had an impact on the alligator population on Sanibel Island, which it severely battered.
Alligators may withstand saline water for a while, but they cannot survive there permanently, according to Chris Lechowicz of the Sanibel-Captiva Conservation Foundation.
Marine dolphins, on the other hand, can only survive in freshwater for a brief period of time before experiencing negative consequences. After Hurricane Katrina, bottlenose dolphins may have developed a fatal skin condition as a result of excessive exposure to freshwater.
Other effects of freshwater exist as well. Rivers often have higher quantities of nutrients from coastal runoff and far more debris than ocean water, according to May.
Large algae blooms are more likely to emerge when river water from a hurricane is pushed into the sea environment.
Reuters/Marco Bello
The hurricane had “these cascading effects,” May remarked. For instance, following Hurricane Ian, algae blooms prevented sunlight from penetrating the seagrass, a key source of nutrition for manatees. An already vulnerable population of sea cows in Florida was under stress as a result of this.
May emphasized that hurricanes are natural occurrences. In fact, she claimed, “our ecosystems are built to occasionally kind of get wiped out.” However, they also require enough time to recover before the next one arrives.
According to NASA, while the frequency of hurricanes may not increase, they may become more powerful due to increased floods and storm surges, both of which are harmful to marine life.
