The coordinates will take you to a small roadside waterfall that looks regular at first, but once you take a deeper look it actually shows some intersting earth science.
The waterfall in question is part of a small creek that flows into the Toe Ink Swamp, then out to the Chickahominy River. You may be wondering to yourself about what is so interesting with this waterfall that someone would make an Earthcache out of it, the answer is Iron Oxidation! Once you look at the creek you will see orange tinted water, which is caused by Iron Oxidizing bacteria inhabiting the water.
Iron Oxidation is the thing that makes a bike chain rust. The bacteria chews away at metal overtime eventually causing it to dissapeer. The Titanic has been on the bottom of the ocean for 112 years as of 2025 and experts suggest its lifespan may be limited to 30 years left due to these processes of Iron Oxidation. In some cases wood even lasts longer under water due to the lack of oxygen, and fungi to harm it. 17th century wreckages have been recovered 300 years later largely remaining intact. Now you may be curious, "Well hold on, how does this apply to creek water?". Trust me we will get to that.
What exactly is Iron Oxidation? Hold your horses! We are gonna get nerdy for a second!
- "Oxidation is the loss of electrons or increase in the oxidation state of an atom, ion, or molecule in a chemical reaction.", definition from What Is Oxidation? Definition and Examples
- The chemical compound of Oxidation is 4 Fe + 3 O2 + 6 H2O → 4 Fe(OH)3 or 2Fe2O3·6H2O . What usually happens is when water, Iron, and Oxygen collide the chemical reaction by the formula above occurs. Over time rusting will eat the iron or other kinds of metal until it is gone! Iron Oxidation occurs a bit slower underwater because of the lack of Oxygen.
How is Iron Oxidation happening in the creek?
The water in this creek must contain a minimum of 0.1 mgs of Iron for the process to occur. So that means high Iron concentrations are coming from the soil. Iron Oxidation in bodies of water commonly happens when de-oxygenated water reaches a point of more/excessive oxygenation, thats when the Iron Oxidizing Bacteria kick in and produce an " insoluble reddish-brown gelatinous slime". This slime spreads throughout the water produces that iconic iron-colored tint you can observe. Very similar to how your hands will look after you rub them all over something rusty. This 'slime' stains the creek bed as you can see here. The bottom almost looks completely orange in some spots. Based on my observations here, it appears that the Iron Oxidated slime has completely stained the algae giving it a rusty look. The Iron Oxidizing bacteria are known to inhabit what is called the transition zone. The transition zone is basically where oxygen starts to be more abundant in the ecosystem. For example; a still water swamp land to a flowing stream.
Environmental effects
- The Iron Oxidizing bacteria in this body of water break down and deplete the iron resources in nearby soil.
- Abundant Iron levels in creeks can also increase PH to high acidic levels from 5.5 to 8.2 on average. Fish can handle this but the problem lies when it merges with the swamp in about 100 feet creating a confluence and rapidly dropping PH levels which could kill the fish.
- Iron Oxidation happens quite often in our underground aquifers which don't get excessive oxygen. This can create conditions where there is too much Iron which is not great for you.
LOGGING TASKS
- At the posted coordinates observe the water going downstream. A significant Oxydizing event happens at the waterfall. Take a picture of the water right there, then move downstream into the woods, and to the waypoint. Take another photo. Is the water color different or relatively the same?
- Now move back to the posted coordinates and go upstream. Take a picture. (The creek goes under the road). Does the water look any different than it did at the waterfall, or downstream?
3. Does the water appear Orange / Iron Oxydized to you?
4. Look close to the waterfall. Do you see any buildups of "redness" on the creek wall?
5. At the posted coordinates observe the flow rate
If there is stagnant non flowing water, A
If there is no water at all, B
If there is fast flowing water, C
If there is a slower stream of water, D
Also please send me a photo of the streams flow rate with your answers
Credits
Corrosion and the Environment
Iron-oxidizing bacteria: an unusual natural phenomenon | Panhandle Outdoors
Iron-oxidizing bacteria - Wikipedia
What Is Oxidation? Definition and Examples
Happy Earthcaching!