A dead forest bleeds for years, its decomposition products flowing slowly into the soil, leached out by rains to turn tributaries as black as night. Those dark tributaries join forces, darkening streams heading inexorably to the sea. At last, the blood of the forest flows out into the surf zones, spreading a dark brown stain hundreds of yards wide, carried down shore by persistent currents.
I had been thinking about this topic for a couple of years, but was motivated to finally publish it after seeing a recent (February 10, 2021) article in Hakai Magazine, an ePub devoted to coastal environmental subjects. The title was “The Environmental Threat You’ve Never Heard Of.” The lead sentence is, “It’s called Coastal Darkening, and scientists are just beginning to explore.
To quote from that article, “Coastal waters around the world are steadily growing darker. This darkening—a change in the color and clarity of the water—has the potential to cause huge problems for the ocean and its inhabitants.
“Some of the causes behind ocean darkening are well understood… During heavy rains, for instance, organic matter—primarily from decaying plants and loose soil—can enter the ocean as a brown, light-blocking slurry. This process is well documented in rivers and lakes, but has largely been overlooked in coastal areas.”
In the coastal city of Panama City, Florida, entire patches of cypress forests were destroyed a few years ago, thus producing lots of decaying plant matter.
What can destroy a forest? The unstoppable force of a category 5 hurricane. In this instance, it was Hurricane Michael striking Panama City and the surrounding Florida Panhandle on October 10, 2018.
Ironically, although I had retired just days before, I attended an Office of Naval Research Workshop on diving, and had bragged to one of the attendees that Panama City was in a very lucky geographical location. We had not been hit by a hurricane since Hurricane Opal in 1995. And that was only a Category 4 hurricane.
Only a few days later, Panama City’s luck changed, horribly. Category 5 Hurricane Michael made a bee-line for Panama City, pushing a wave of water that swept away much of the community of Mexico Beach, just twelve miles east of the first landfall of Michael’s eye at Tyndall Air Force Base in Panama City.
The above radar imagery was captured on my iPad, using Foreflight aviation software while we safely sat in a hotel room in Birmingham, AL. The redder the color, the stronger the rainfall. Green represented low rainfall intensity near the eyewall.
After returning from our hurricane safe haven in Birmingham, AL to our damaged home on Panama City Beach, and as soon as the airspace opened up again, I surveyed some of the damage from the air. A month after the storm, areas along the Gulf Coast were closed to normal aircraft due to drones surveying the damage along Mexico Beach, and providing assistance to personnel looking for human remains.
However, there were no restrictions to flying along the path of the hurricane, northeast of Panama City. So, on November 4th I launched in that direction and discovered that a huge swath of cypress trees had been flattened about 40 miles north of Mexico Beach. Since cypress trees love water, there were of course creeks running through the midst of them. The Florida Panhandle watershed runs inexorably south towards the Gulf of Mexico (GOM).
Fourmile Creek ran through the area I photographed. It is a tributary feeding the Chipola River. The Chipola in turn dumps into the Apalachicola River, the primary flow into Apalachicola Bay, home of the famous Apalachicola oysters.
A year or so later, as seen on Google Earth imagery of the affected area in Florida, some of the low-lying greenery began to return to the Fourmile Creek area. However, the skeletal remains of the flattened Cypress forest were still clearly evident.
My next flight was on December 18, 2018, after the coastal airspace had been opened back up to general aviation traffic. That was over two months after the hurricane hit shore.
On Sept 2, 2020, almost two years after the hurricane, I was flying from east to west along the coast, back towards Panama City. As I approached Mexico Beach, I saw a clearly defined dark area in the otherwise clear sea water. I snapped several photos as I got closer to the still struggling town. They are shown in sequence below, starting from furthest west, approaching town center.
The largest area of devastation of cypress forests surrounded Fourmile Creek which runs southeast before emptying into the Chipola River.
Due east of Panama City, the appropriately named Cypress Creek also empties into the Chipola River as the river feeds the Dead Lakes. In turn, the Chipola empties into the Apalachicola River southeast of Wewahitchka.
Nearer to Mexico Beach, there is yet another Cypress Creek which drains into both the Intracoastal Waterway at its northern end, and the GOM at its southern end. In the next aerial photo of Mexico Beach, Cypress Creek can be seen pouring its darkness into the ocean. Cypress Creek also drains a large swampy area of destroyed cypress trees.
Remarkably, the greatest dark water offender on the September 2020 flyover was Salt Creek, with its outfall that lay two miles to the northwest of Cypress Creek.
Cypress trees have been in Florida for at least 6,500 years. During that time, their populations must have weathered tens of thousands of hurricanes. In spite of being knocked down due to being rooted in wet, soggy soil, and frequently rotting as a result, the overall population is well adapted to black water. Their blood, or rot if you will, produces more of the black water habitat that the cypress trees favor. Throughout the southeastern United States, Cypress forests (with isolated communities often called “domes”) remain ideal habitat for many species of fish, birds and mammals.
Tourists flock to the Gulf Coast’s so-called “Miracle Strip” of clean water and white sand that stretches from Pensacola Beach to Mexico Beach and slightly beyond. On a macro scale, the water and beaches are kept clear by the effects of the Loop Current, and its eddies, bringing clear Gulf water up towards the Gulf shores.
While the dark water periodically spilling into the normally clear Gulf of Mexico beaches may be repulsive to tourists, an experimental study described in the Haikai article notes that black water outfalls may favor certain zooplankton, providing a new food species for local fishes.
So, to this scientist at least, it may that in the Gulf of Mexico, periodic outpourings of dark water caused by heavy rains, tropical storms and hurricanes may be what is required to balance the estuary and marine ecosystem.
In other words, the concerns stated in the Haikai article may not apply to the west coast of Florida. Of course, to know for sure, further study is required.
In retrospect, when looking down upon flattened forests of trees, it seems nature is harsh. But nature works for the end game; survival of the environment. In Florida, the environment has survived hurricanes, and their effects on forests and water, for millennia.
Of greater concern to Florida might be the permanent destruction of the cypress forests by man, rather than hurricanes. Nature can recover from hurricanes, but cannot recover from man’s misguided intentions. After all, forests buffer the effects of hurricanes. Without them, Florida would lay flat and naked before every onslaught of a sometimes violent Nature.