Stories

Have you ever sat on a rock by a creek, surrounded by the dark greenish-blue water flowing past  smooth stones, with the birds singing in the trees, enjoying the peace and quiet of nature all around you? If you haven’t done it lately – it’s a magical way to spend some time.

The next time you’re out there, contemplating life, consider this: there is oxygen in that water.  Not just any oxygen…but dissolved oxygen or “DO”. Oxygen that is mixed into the water itself – not fizzy like sparkling water (that’s CO2), just good old O2 suspended in the water (H2O), supporting the life of the stream.  How wild is that?

At first it sounds kind of strange, doesn’t it? Well, if you’re a fish, it doesn’t sound strange at all.  Fish do not have lungs like we do, so they cannot breathe air from the surface. Instead, they pull oxygen out of the water with their gills. So, there must be breathable air floating around in the water, right? Well, it is a little more scientific than that, and a lot more fascinating.

Oxygen gets into the water in a few separate ways. Some of it comes from the atmosphere, stirred in by wind or through “aeration” as water moves over stones, rocks and riffles in the creek. Waterfalls can also churn the creek water and aerate it, however, we do not have any waterfalls here in Chesterfield, South Carolina. Air can also come from aquatic plants and algae because they release oxygen during photosynthesis. Just like the trees in your backyard. Either way, the results are the same: tiny invisible bits of oxygen molecules (O2) end up suspended in the water, and that is what fish, and all sorts of underwater creatures rely on to survive.

Our land stewardship team here at Southern 8ths is out in the field regularly conducting water quality testing, and one of the first things we check is how much dissolved oxygen is present. If there is plenty of DO, that is a good sign! It usually means that the water is healthy – clean, moving, and full of life. But when oxygen levels are low, that can be a red flag about the overall health of the stream ecosystem. There may be pollution upstream, too much algae soaking up the oxygen, or not enough flow and aeration to keep the water fresh. In low-oxygen water, fish can struggle to survive – kind of like us humans trying to breath in a heavily polluted city. In some cases, the fish just leave and travel to healthy streams or, if DO drops too rapidly due to algae blooms or other contamination, there can be “fish kills” with many dead fish and other organisms.

Water That is why DO is such a big deal in environmental science, even if it sounds like just another abbreviation. When we talk about “oxygen levels,” we are not being fancy – we are really talking about whether the water is safe for all types of life.

It’s kind of sneaky and beautiful, isn’t it — this life-giving oxygen is just there, doing its job, quietly supporting every frog, turtle, and minnow that swims by. It does not make a fuss, it does not show off. But without it, the whole underwater world starts to fall apart.

And here is the thing – most people do not know any of this, and our Carolina Wildlands team is learning every day, with each water sample we take, we cannot help but feel a little wonder about it all.

Who knew oxygen had such a double life – in the air AND in the water?  We ALL depend on it.