The smell is often unmistakable. A characteristic odor of rotten eggs, sour mud, or methane wafts from the water. These odors are rarely constant: they become more pronounced in hot weather, during thunderstorms, or whenever the sediment is disturbed. Visually, you can see bubbles rising regularly to the surface and bursting, particularly at the end of the day. If you take a sample from the bottom, the mud is black, oily, and very soft.
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Unpleasant odors & bubbles coming from the bottom
Identify the source of odors
and restore a healthy foundation
What you see
What this means
These odors are not “natural”; they are a warning sign of complete anoxia at the bottom. Oxygen has completely disappeared from the deeper layers. The immediate consequence: aerobic bacteria die off, making way for anaerobic bacteria. That is where the problem begins.
This change in the microbial flora triggers putrefactive fermentation, which produces toxic gases:
- H₂S (Hydrogen Sulfide): Responsible for the rotten egg smell.
- NH₃ (Ammonia): An invisible gas that is extremely harmful to fish.
- CH₄ (Methane): A greenhouse gas produced by decomposition.
This is a typical sign of a body of water saturated with organic matter, where water circulation is insufficient.
Why act now?
Beyond the unpleasant odor for neighbors and passersby, this fermentation is an ecological time bomb:
- The Algae Vicious Cycle: Anaerobic bacteria have a major drawback: they make phosphorus and nitrogen soluble. These nutrients rise to the surface and act as a massive fertilizer for algae and invasive plants. The more decomposition occurs at depth, the more algal blooms intensify at the surface
- Lethal Toxicity: Hydrogen sulfide and ammonia are highly toxic substances. Even at low concentrations, they irritate the gills and can cause sudden fish deaths.
- Sediment Degradation: The seabed becomes more acidic and unstable. Without intervention, the mud becomes “biologically dead” and very costly to restore
The TASO Solution
deep oxygenation & bioremediation
Masking the odor has no lasting effect: we need to address the root cause.
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Each protocol is tailored to the initial assessment, the characteristics of the body of water, and its intended uses.
