When sky goes a dark purple, you know it’s about to get ugly. And if you hear something about acid rain, you’re likely to cringe. This is understandable because we all know what it does to our waterways.
The acid rain alter the chemical makeup of streams and lakes, throwing off its naturalal balance and throwing fish out of whack. You might think it’s been taken care of since they cleaned up those smokestacks in eighties, but the reality is that damage lingers within sediment and soil. Long after emissions subside, this lingering acidity continues to impact water quality and help to explain why some waters flourish different than others remain barren.
Understanding Acid Rain Effects On Fish
How Acid Rain Alters Water Chemistry
Not magic, just chemistry. And one that favors some species over other. PH doesn’t just affect fish; it affects their physiology.
Physiological Impact on Fish Gills
Fish aren’t immune to acidity. They’ve got delicate gill used for exchanging oxygen and carbon dioxide. When water gets acidic enough, it accumulate hydrogen ions on the gills, blocking exchange process.
Even with an abundance of oxygen in the water, the fish will suffocate. Acute stress. A sudden drop in pH can result in mass die offs.
Species Sensitivity and Biodiversity Loss
Different types of fish don’t react to acidity the same way. Some have adapted to be able to livig within a lower pH environment. For example, pike and bass can withstand a broader range of pH while brook trout and brown trout is more sensitive.
As the sensitive fish go extinct, the hardy ones moves in. Biodiversity decreases and the system begins to simplify. You end up with a monoculture of tough, aggressive species.
You lose variety of interactions between animal that make a lake vibrant. The process involve a lot of aluminum, which is a key ingredient that gets washed out off the soil by acid rain. The dissolved aluminum is then toxic to aquatic life.
Toxic Aluminum and Delayed Effects
It also bind to the gill surfaces causing them to swell up and close. It’s a delayed effect so damage occurs days or even weeks following the rain. This makes it harder to manage and predict.
It takes some time before you notice your fish gasping on top of the water, and by then the chemical reaction has already took hold. Buffering capacity is a key way a body of water protect itself. Limestone or granite bedrock can neutralize acidity.
Water Buffering Capacity and Bedrock
Lakes with soft water (low mineral content) don’t have that protective measure and is susceptible to being acidified. You’ll see what appears to be a barren bottom in really clear water. There is little to no life, from fish to plants to insects.
This means this lake is on an acid-rain-damaged system. The acid rain has literal beat the ecosystem bare. You can’t even restore it easy or cheaply.
Adding liming material to neutralize the acid is just first step. But it doesn’t stop with fish; insect and amphibians also falls victim to these high acidity levels. Amphibian skin is especially susceptible to high acidity and their eggs won’t hatch proper when exposed to low pH.
Impact on Amphibians and the Food Chain
When the amphibians go, it cause the food chain to collapse further, leaving mammals and birds who depend on them either starving or has to relocate to find new food. You can think of a healthy lake as a community, whereas an acidified lake becomes struggle. It is a sharp contrast between a healthy ecosystem and one that are failing.
Long-Term Environmental Recovery Challenges
Nature have her limits. Though we might be able to control our emissions, the damage to the soils is not something we could of easily fix. The acids trapped in the ground remain a long term threat, and will leaks into the waters for decades to come.
It’s up to us then, to practice some long-term conservation. We must monitor water quality (pH), restore wetlands, and protect headwaters. We want stability.
Waters that are able to bounce back after being stressed. That’s not the case with acid rain. It is a reminder of our impact on the environment and what happens when waters can’t recover.
