By Michelle Kennedy

While June and July may denote summer, these months also indicate the beginning of the hurricane season in the Atlantic Ocean. Here in Connecticut, where Future Frogmen is mainly stationed, we have entered hurricane season, and its peak is fast approaching. Last year, there were 18 named storms, three of which were “major” category storms. Already this season, four named storms have formed in the Atlantic.

Photo by George Desipris via Pexels — *Photo by George Desipris via* *Pexels*

While many communities on land fearing the devastation caused by hurricanes, marine communities face equally, if not more, dangerous risks. The National Oceanographic and Atmospheric Administration (NOAA) explains that hurricanes can “destroy coral reefs, mix up the water column, redistribute bottom sediments, and increase pollution via storm-water runoff.” Mixing the water column leads to temperature changes and decreased oxygen levels, which is harmful to all marine life. Additionally, as a result of massive waves, some species of fish are forced to leave coastal estuaries and occupy deeper waters for safety.

Swimming to deeper waters, however, is not a guaranteed safe haven. A paper published in Scientific Reports explains that not only are shallower habitats affected, but fish as deep as 120 feet are significantly impacted by hurricanes as well. The violent waves produced during hurricanes result in rough undercurrents and widespread pollution along the seafloor. Immediately following Hurricane Maria in 2017, for example, NOAA teams found “479 displaced vessels and 3,668 hazardous chemical containers” along the ocean floor. The scattered debris in deeper water can be just as harmful to marine organisms as the pounding waves in shallow water.

As mentioned above, hurricanes churn up the water column. When deeper water mixes with surface waters, marine organisms face many threats to their survival. One issue is a significant change in ocean temperature. In the ocean, water near the surface tends to be warmer than deeper water due to more sunlight. When cold water from the deep mixes with warmer surface water, the overall temperature across many depth layers may change significantly. The water column can take as long as two weeks to settle again, impacting organisms after the hurricane itself has struck. As a result of this fluctuation in ocean temperature, some organisms become stressed.

One specific organism that is extremely vulnerable to changes in its environment is the marine coral. When marine corals become stressed, they may lose their nutrients and die. Because coral reefs provide a habitat to a plethora of other organisms, their loss can impact the entire food chain. Read more about coral reefs here.

In addition to temperature changes, deeper water has less dissolved oxygen. This is due to the combination of lack of sunlight, which makes photosynthesis impossible, and less overall contact with the air. Ocean Conservancy explains that when deep water and water along the surface mix, it can cause the amount of dissolved oxygen in shallower waters to decrease. In turn, many organisms living in shallower waters will suffocate and die.

Interestingly, hurricanes may also have some positive effects. Hurricane Science points out that “Rainfall gives a boost to wetlands and flushes out lagoons, removing waste and weeds.” They also highlight that hurricane waves re-distribute bottom sediments, which may revitalize nutrients in marshy areas.

Additionally, when hurricanes churn up the water column, there is some evidence to suggest that this may counteract rising ocean temperatures. Because the water from below is colder, mixing it in with the surface water could mitigate the effects of rising ocean temperatures. While there is evidence suggesting an alleviation to rising ocean temperatures, many acknowledge that this solution is a short-term fix. More research must be done to better understand if mixing the water column does, in fact, hinder rising ocean temperatures.

Global warming and hurricanes are more interconnected than you might think. NASA explains that hurricanes are formed due to warm air and water near the surface of the ocean rising into the atmosphere. When this warm, moist, air rises, the surrounding air rushes in to fill the void. This “new” air is then heated by the ocean and rises upwards again. The moist air that has been pushed upwards now cools and forms clouds. The cooled air, now in the form of a cloud, and the warmer, rising air begin to spin and gain momentum.

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Because hurricanes are initially formed by warm air being heated by the ocean, it makes sense that global warming would have an effect on hurricanes. Geophysical Dynamics Fluid Laboratory explains that ocean temperatures rising due to human-induced global warming “imply very substantial increases in hurricane destructive potential.” While the number of hurricanes will not necessarily increase, substantial evidence concludes that individual hurricanes will be stronger. Stronger hurricanes, coupled with rising sea levels increases the potential for more coastal flooding and destruction.

Hurricanes wreak havoc on all terrestrial and marine life due to their grave consequences. While we all have seen pictures of the desolation on land following a hurricane, many of us are less familiar with the multitude of risks marine organisms face during a hurricane. Along with hurricanes threatening oceanic species, human-induced global warming will only make the situation worse. Due to the magnitude of global warming, along with the hurricanes that have already been seen this year, scientists expect this to be one of the most intense seasons yet.

Harrowing Hurricanes