Tannins and blackwater rivers

View of the blackwater on the Ogeechee River

The Ogeechee and Canoochee Rivers are considered ‘blackwater’ rivers. 

A blackwater river is typically a slow-moving waterway flowing through forests, swamps, or wetlands. As vegetation decays, tannins seep into the ground water or drain into lakes and streams, making a transparent, acidic water that is darkly stained, resembling black tea. Because of this blackwater rivers typically have a lower (more acidic) pH level.

Tannins are found commonly in the bark of trees, wood, leaves, buds, stems, fruits, seeds, and roots, and help to protect the individual plant species. For example, tannins stored in the bark of trees protect the tree from being infected by bacteria or fungi. Similar properties are extended to the waterways as it seeps into the river.

Additionally, less light penetration due to the darker water colors, means these waterways generally have less vegetation in the water. However, algae blooms can happen when there is a drought, which lowers the water level and allows sunlight to reach the bottom of the riverbed.

Swimming in a blackwater river

Tannins are also found in wine, tea, and berries, and are safe for human consumption. Historians note that early colonists and mariners would fill casks from blackwater rivers. In the days before treated water sources, it was a safer, healthier alternative. They didn’t understand that this water carried fewer microbes because of its chemical makeup, but they knew it worked. 

Blackwater streams also have high levels of dissolved organic carbon (DOC) due to the breakdown of the same plant material that cause the tannins. Because of this, blackwater rivers usually have high levels of (harmless) bacteria that feed on the DOC, causing a low oxygen levels.

The term tannin is from the Latin tannum and refers to the use of oak and other bark in tanning hides into leather. Scientifically, it refers to any large polyphenolic compound that can form strong complexes with various macromolecules. These compounds are most commonly found in organic, plant-based items.

Flora: Tillandsia usneoides

Spanish moss
Tillandsia usneoides

Spanish moss isn’t really a moss at all; it’s an epiphyte or air plant. Botanically, it is closely related to the pineapple and absorbs nutrients and water through the air and rainfall. It does occasionally flower but it is rarely seen. The silver-gray plant grows in long, hair-like clumps, hanging from trees in subtropical climates.

According to botanical guides, it has “threadlike stems up to 6 to 7.5 metres (about 20 to 25 feet) long. The leaves, also threadlike, are about 2.5 to 7.5 centimetres (1 to 3 inches) long.”

Spanish Moss growing on live oak tree, South Carolina

It is commonly found living on the southern live oak (Quercus virginiana) and bald-cypress (Taxodium distichum) in the lowlands, swamps, and marshes of the southeastern United States and can be found as far west as Texas and southern Arkansas. It does not harm or kill the trees it lives on.

William Bartram described it, and its uses, in his 1770s travels to the area:

When fresh, cattle and deer will eat it in the winter season. It seems particularly adapted to the purpose of stuffing mattrasses, chairs, saddles, collars, &c. and for these purposes, nothing yet known equals it. The Spaniards in South America, and the West-Indies, work it into cables that are said to be very strong and durable; but, in order to render it useful, it ought to be thrown into shallow ponds of water, and exposed to the sun, where it soon rots, and the outside furry substance is dissolved. It is then taken out of the water, and spread to dry; when, after a little beating and shaking, it is sufficiently clean, nothing remaining but the interior, hard, black, elastic filament, entangled together, and greatly resembling horse-hair.

In the modern era, Spanish moss has been used for building insulation, mulch, packing material, mattress stuffing, and fiber. It was even used in the padding of car seats by Henry Ford who had a home in Richmond Hill and a dealership in Savannah.

Popular Science, June 1937, page 32

The etymology for “Spanish moss” is not known although it is often supposed it is related to a term used by French settlers in the southeastern U.S. in the 1700s. They called it barbe Espagnol, or Spanish beard, referring to the long beards popular among Spanish explorers of the era. It has become an iconic image of the South, including in Southern gothic literature and in folklore.


Image from NYPL Digital Collections. Live Oak Avenue, Bonaventure Cemetery, Savannah, Ga. Stereograph. 1880. The description on the reverse reads, in part: “The majority if these trees are of the Live Oak species, with but few others. The latter have long since passed away, but the sturdy oaks, with their hoary beard of moss, still defy the gales of the Atlantic and wintry blasts; and their rustling leaves whisper a ceaseless lullaby to the quiet and peaceful sleepers at their feet.”

May Seeds So Summer Feeds

Watch your garden grow

Having fresh veggies is easy and fun.

Share your photos with Ogeechee Riverkeeper. Send in your sprout pictures to info@ogeecheeriverkeeper.org or tag us on social media.

Thank you to Peyton and Whitley for demonstrating!

Materials needed:
– Empty egg cartons (preferably paper/cardboard cartons)
– Spray water bottle
– Seed packets: tomatoes, zucchini, summer squash, watermelons, okra, sweet peppers, and/or marigold seeds & potting soil (can be ordered online or any other ag/garden supply store)
-OR- old potato(es), if you are not able to get seeds and potting soil

For seed packets:

  1. Poke small holes in the bottom of each “egg” for water to drain out.
  2. Fill each “egg” with soil, push a finger in the middle of the dirt up to the first or second knuckle (kids with small fingers)
  3. Drop in seeds (check package for amount of seeds per “egg”).
  4. Use a water spray bottle and spritz each “egg”.
  5. Check seed sunlight/shade preferences. Since egg cartons are light, you can move them around the yard for sun/shade needs!
  6. Once the seeds sprout and start to outgrow the cartons, you can replant them in a garden bed, large pot, etc. You can plant them directly into the ground in their paper/cardboard “egg” because they will decompose; if you used styrofoam cartons, you will need to transplant them.
  7. Make sure to separate each egg either by tearing or cutting.
Seedlings

Additional resources


For old potatoes:

  1. Let a few potatoes grow sprouts, also known as “eyes”. These cannot be eaten so instead of throwing them away, you can plant them and they need very little care.
  2. Cut the potato in half or leave whole in most soil types, leaving the eyes exposed. They will sprout in sun or shade.
  3. Water right after you plant them and then let them do the rest of the work.
  4. Water 1-2 times per week if it has not rained.
  5. After potatoes stems have finished flowering, you can go on a scavenger hunt for the fresh, new potatoes in the soil!

    Potato eyes beginning to sprout
Potato sprouting

Additional resources


Need to know what will grow best in our watershed? Visit the UGA Extension Service or the USDA hardiness zone maps.

Remember to share your photos with Ogeechee Riverkeeper. Send in your gardening pictures to info@ogeecheeriverkeeper.org or tag us on social media with #ORKoutside.


Activity is open to all ages and meets the needs or can be combined with other activities for the following Georgia Standards of Excellence in science, earth systems and meteorology, depending on how in depth your activity is.

  • S1L1. Obtain, evaluate, and communicate information about the basic needs of plants and animals.
  • S2L1. Obtain, evaluate, and communicate information about the life cycles of different living organisms.
  • SBO4.C. Obtain, evaluate, and communicate information to analyze the impact of plant diseases and pests on plant defense systems and agriculture.
  • H.E1.5: Students will demonstrate the ability to use decision making skills to enhance health.

Flora: Ilex vomitoria

Catesby, M., natural history of Carolina, Florida, and the Bahama Islands, ed. 2, vol. 2: t. 57 (1754)

Yaupon
Ilex vomitoria

This species of holly is an evergreen shrub and can be found throughout the southeast. It flowers in April and May and produces red berries in September and October. These berries are generous food source for birds, armadillo, black bear, fox, raccoon and more.

The plant is hardy can can thrive in salt spray, sandy soil, constant wind, harsh sunlight, and high temperatures. They are often found on streambanks, in dunes, woodlands and floodplains. All of these conditions mean it flourishes in the Ogeechee River basin.

Photo by Marcus, Joseph A., Austin, TX

Ossabaw Island, bounded to the north by the Ogeechee River, plays an important role in the history of yaupon. Yaupon is the only plant native to the Americas that contains caffeine. Early native populations made tea from its dried leaves and there are some stories of them using its berries in ceremonies and to see visions.

The popularity of the yaupon’s effects made it a traded commodity. Evidence of yaupon tea has been found as far afield as Cahokia, Illinois, near the Mississippi River. One of the places where yaupon could be harvested was Ossabaw Island. It was so plentiful that the Creek Indians named the island ‘asapo’, which translates as “land of holly” or “holly growing place.” There is evidence of natives used Ossabaw as a seasonal village, for harvesting yaupon and other foods, dating back at least 4,000 years.

Chief Saturiwa prepares his men for battle, from Plate XI of Jacques le Moyne des Morgues’ engraving of Fort Caroline”, Jacques le Moyne and Theodor De Bry.

Yaupon tea never gained popularity over traditional camellia sinesis tea when Europeans began moving to the colonies, but it has many similar properties. It contains antioxidants and caffeine, though its tannic properties are slightly different. There are reports of it being used as a substitute for coffee and tea during the Civil War. It eventually fell out of favor socially because it was readily available and became associated with poor, rural people.

Yaupon tastes similar to a light black or a green tea. Some local restaurants and beverage companies are now “rediscovering” the tea drink.

Fauna: Lepomis auritis

Redbreast sunfish by Duane Raver, 1975

Redbreast sunfish
Lepomis auritis

The redbreast sunfish is native to eastern North America and makes its home in freshwater rivers. A relatively small fish, it is considered full grown by the time it is two inches long. The largest one on record measured just 12 inches. They primarily eat immature insects.

Usually olive colored with dark fins, the male’s breast and belly will turn bright orange when spawning. The male makes a nest in sandy material, then guards the eggs and fry after the female lays. Auritis means “big-eared” in Latin and refers to the long tabs that extend behind their eyes.

Redbreast sunfish, caught in Georgia. Shared via Wikimedia Commons.

The redbreast sunfish thrive in waters with flowing current and a stable pH. They like to live in natural structures near riverbanks, like overhanging branches which offer shade and protected habitats. Clearing bank debris, lack of current, or a change in pH levels quickly and dramatically affect the population.

Flathead catfish, an invasive species, is a predator and decimated the redbreast sunfish in other nearby watersheds. Thus far, the Ogeechee and Canoochee Rivers have not been infested with flathead catfish.

Art by Caroline Rose

Citizens are asked to report sightings of these detrimental catfish to Ogeechee Riverkeeper or the Georgia Environmental Protection Division immediately. Snap a photo and email to info@ogeecheeriverkeeper.org with the approximate location of the sighting.

Flathead Catfish, (Pylodictis olivaris): Mississippi River @ Goose Island across from Northeast Power ramp, Marion County, Missouri.