Decay is the process that ultimately turns all organic matter back into carbon dioxide and water, the final destiny of every living thing before reincarnation into new plant material. You would think that as an energy-yielding process, decay would just run its full course until only carbon dioxide and water remain. But in some parts of the world, this is not the case. My first experience with this shortfall was through drawing water for a bath along the southern coast of South Africa. The water was clear, but it was the color of tea that had steeped far too long--- an intense, deep, reddish brown. Slipping into the tub, the bather is converted into a strange creature of even stranger reddish hue at the bottom of a very large teacup.
The creeks and rivers in this so-called fynbos region drain this stained water (aka blackwater) from extremely nutrient poor, sandy soils derived from sandstone mountains that were themselves formed from nutrient poor sandy soils ages ago, maybe even more than once. It appears that to do the job of complete decay to water and carbon dioxide, microbes at the lower end of the decay chain need mineral nutrients that aren't there, so decay stops with complex mixtures of so-called polyphenolic compounds, and these compounds, on account of a lot of carbon-carbon double bonds absorb light, giving them the color of tea. Indeed, this same class of compounds gives tea its color as well.
Such blackwater streams occur in many regions of the world, wherever streams have their headwaters in swamps, marshes, or highly weathered, nutrient-poor sand. Their waters are essentially rainwater with little access to fresh sources of soluble minerals from the weathering of parent rock. Perhaps the most spectacular example is the largest tributary of the Amazon River, the Rio Negro (named for the color of its waters). Whereas the Amazon originates in the Andes Mountains where there is plenty of parent rock yielding freshly weathered minerals, the Rio Negro drains only the low-lying, heavily leached, swampy land east of the Andes. The waters of the Rio Negro are much like the bath water I experienced in South Africa. Google Earth reveals this over-steeped tea color wherever the river flows over shallow sand bars. The white sand, like my white skin in that bathtub takes on a reddish hue.
When the “white waters” of the Amazon meet the “blackwaters” of the Rio Negro at Manaus, they mix gradually for many miles, flowing parallel like teams of horses making their way to the sea.
On a much smaller scale than in the Amazon Basin, the coastal plains of Florida have many blackwater streams. Like the Rio Negro, they drain swamps developed on very sandy, nutrient poor soils. My favorite is the Sopchoppy River whose name is as pleasant to pronounce as it is obscure in meaning. Its clear blackwaters coalesce from the swamps of its birth in the Apalachicola National Forest, and flow through the piney flatwoods in a narrow, winding channel about 10 to 15 feet deep. The flatwoods may be sun-scorched and baking, but in the channel water oaks and titi provide shady relief, banks are mossy and dripping, and the sandbanks on the insides of bends are blinding white.
Cypress and tupelo (aka Ogeechee Lime) grow at the water's edge or in the water itself, but the Sopchoppy is not kind to many living things. Most of the cypress and tupelo fail to reach their full potential, perhaps starved of nutrients, or perhaps toppled or broken too frequently by floods. My favorite tupelo is a tough survivor, ancient in visage, but perhaps just hard-living, hollowed by rot, much wider at the base than the crown, with fluted, gnarled roots radiating out to grip the sandbars and stream-bottom. Every year it produces copious, pink-blushed fruits with airy pockets designed to float indefinitely in hopes of landing in a propitious site. Its chances are not good, but this tree has been hanging on for a long, long time, so who knows, it may have some offspring downstream.
The waters of the Sopchoppy are delightful to drink but are so acidic (pH 4 to 4.5) that they exceed what many fishes and invertebrates can tolerate. It is a flashy stream, for its headwaters are small, the soils of the flatwoods are like sieves, delivering rainwater to the stream by a short circuit, and local rainfall ranges from none to deluges. After long rainless periods, you can stroll the river bottom, hardly getting your feet wet, but after a couple of intense storms, the flatwoods are under water for a quarter mile beyond the riverbank. At moderate water, several miles of floating in an inner tube offer a summer delight, but at low water the float is longer and requires vigilance against butt-stickers and submerged logs. Stopping at one of the sand bars, the tracks of gomphid dragonfly nymphs crisscross the shallows, and here and there, the dark waters of small tributaries join the main stream. To glide quietly along on these black waters within the high banks is to float temporarily in another world.
But no matter what the speed of your float, or how often you enjoy the hospitality of a sand bank, you are likely to enjoy the company of tupelo fruits the whole way.
I ran into the river types in the Amazonas area of Ecuador. The “yellow” rivers – not “white” ones there. Glacially fed ultimately, large, usually silty. And the Black rivers, fed from the surrounding land. The yellow ones, like the Agua Rico (out of landing place, Lago Agrio – and others, depending on the trip route), the highways of the rain forest. Big “canoes” of industrial size and strength, manufactured. Painted yellow with CocaCola ads painted on them. Carrying machinery, vehicles, etc. and you would reach some kind of cove or literal jumping-off place and get into a tiny, hand-hewn, canoe, holding maybe 8 people and canoist making at most 10, and wend your way to your scubby destination – or maybe fancier ones. But reached always via the narrow black waters.
And in Florida, on the farm, near Gainesville, there was “the creek.” The entry to the farming area, a sand road off the highway, leading to the sandier lanes to houses and fields had a little bridge and there was a crick in the creek’s course and we would go there. It was a kind of pool, holding a bunch of cousins and uncles. It was deep copper, almost black, and you could see your skin being amber and clear as you swam or stood near the surface. We knew it was clean, and just another colour. There wasn’t enough length in the pool for actual swimming, you just jumped, paddled stayed out of the small deeper area. Good times and they come back to me very strongly reading your accounts. Love it, Walter!
We have kayaked the Sopchoppy where it runs into the sea -- we paddled upstream between narrow banks on brackish water, ever watchful for large reptiles. Your essay brought back fond memories. The Apalachicola region is such a special place.