“However, when the weeds die off at the end of the season, won't that decompose into muck? As opposed to treating it before it can grow? I really enjoyed not seeing the underwater weeds in our pond last year, as the previous year they were abundant.”
COMMENTARY
Muck accumulation is based on the amount of organic matter blown or washed into the pond PLUS all living material that grew and died in the pond. HOW those dead organic materials decompose determines the rate of muck accumulation. Generally in about all ponds on the average, dead plankton by itself in the water column will create around 1” of bottom muck each year. Killed, dead weeds add to the accumulation. How well that muck is biodigested depends on how well the beneficial decomposing bacteria are able to thrive in the sediments. Many algaecides and herbicides KILL all sorts of beneficial bacteria in the water column plus those in the surface sediments. Thus that impacted bacterial community will often benefit from good bacterial strains being reseeded into the pond ecosystem after the pond has received “chemical war” imposed on it based on the type and degree or amount of chemicalization. A Univ. affiliated company in Wisconsin (Natural Lake Biosciences) promotes their science based bacterial products after "weed & algae " killing 'herbicides' have been used.
When the pond is continually receiving and accumulating more plant growing nutrients, one is naïve when they think that preventing all plant growth will significantly eliminate or reduce the bottom muck because they do not understand how nature and ecosystems truly function. Bottom muck accumulates because the sediments are NOT well oxygenated and are unhealthy usually because the sediments are ANAEROBIC (no infused oxygen). Anaerobic decay is a very, very slow process and produces IMO numerous bad things in the pond sediment such as methane, carbon dioxide, hydrogen sulfide, ammonia, and acidic conditions, that all result in black sediments and no presence of good invertebrates. Hydrogen sulfide is toxic to fish and probably all invertebrates that live in the sediments.
Conversely AEROBIC decay with ample oxygen is fast, ‘clean’, lacks the biogas products, and has a good community of invertebrates who are quickly composting the organic materials. Well oxygenated sediments usually lack muck accumulations which is why public beaches usually have no muck accumulations due mainly to good periodic wave action that thrashes, mixes and oxygenate the beach sediments. Mixing bottom sediments oxygenates them and promotes rapid decay of organic materials. This is why agricultural organic residue relatively quickly disappears from farm fields - healthy dirt with a diverse community of decomposers in aerobic conditions.
Firstly one should understand the benefit and function of good types of underwater weeds. They naturally compete against other more ‘problematic’ types of plants. There are good types of aquatic plants and problematic types of invasive, rampant growing plants.
Potomegoton pusillus aka slender or small pondweed.
I consider it a primary invader similar to Chara that technically is a ‘stem’ form of algae. Some species of pond weeds are very beneficial, too much is problematic. Beneficial because they use / consume nutrients and competes with FA and provides good habitat for fish and invertebrates. GC relish small pondweed and tilapia will eat it when the filamentous is gone. When a pond has ample amounts of most forms of pondweed,,, usually almost no FA is present. When both are abundant this means the pond has too many nutrients and is a sign the pond is trending toward over eutrophication (too many nutrients) and the nutrient composition is not in balance. Too much of one thing and not enough of something else for a proper balance within the ecosystem. Knowing what creates a natural balance is key to properly managing a high quality pond.
Ponds each day, week, month, and year accumulate and also recycle in one way or another more nutrient fertilizers. It is what they do. Those nutrients and organic materials once in the pond are entrapped within the pond system or basin. Ponds are nutrient traps. Nature is always, always adding more nutrients to the pond basin..
More nutrients stimulate more plant growth of some sort. Some pond owners even intentionally fertilize the pond to make it to ultimately grow more fish. Adding more nutrients (fertilizer) to water with sunlight demands the pond grows more plants. Thinking more nutrients does not grow more plants is like fertilizing the land and trying to keep ALL grass and all weeds from growing in the dirt surrounding the house. Unreasonable and impractical, plus it’s unwise always using chemicals to keep no plants growing in the dirt surrounding the house. Best practice is to maintain a good stand of grass to hopefully minimize growths of the unwanted weeds. IMO this concept should be used for managing a pond. More natural pond management with few if any chemicals.
Nature eventually demands some sort of growth will happen when sunlight, nutrients and water are present. Nature’s law. When using repetitive frequent chemicals,,,,,, then eventually nature does manage to grow a form of resistant and tolerant type of plant to tolerate the frequent chemicalizations. These tolerant plants in chemicalized ponds are very difficult to stop from growing in that repetitively chemical infused habitat. Examples of this concept are development antibiotic resistant bacteria such as MRAS infections, and variations of COVID. There are very resistant types of algae that develop in ponds that have been routinely chemicalized. It is impossible to stop nature from doing what it has been doing for millions of years. In the end, nature always finds a way. Regrowth does happen even after nuclear contamination.
Chemically sterilizing a pond for many years using harsh, unwise and / or illegal chemicals can eventually over many years of use,,,,,, turn that pond into a chemical dump which can turn it into a chemical problem or biohazard. ALL chemicals added to a pond ecosystem have to be somehow processed and hopefully degraded within the pond basin. Those that are not biodegraded then accumulate. Chemical accumulations from constant and unwise treatments make that pond a financial liability. Who would buy that property knowing its unwise chemical history? Will the fish living in the frequent chemically infused water be really safe to eat and will health sensitive swimmers be really safe in the water especially when the contaminated sediments are getting redistributed by the many activities that influence and disrupt some bottom sediments of a pond? What is the value of having good health? IMO a time will come when all pond systems, before being sold, will be required to be tested for contaminants.
