This is a very thoughtful informative discussion. I will put a link to it in the Common Pond Q&A Archives section.
The main important scientific fact noted by 'jpsdad' so far is: "The nutrients in your ponds are going to support vegetative growth. It is up to you to control those nutrients and to direct those nutrients by whatever means you have available and find desirable."
Practically all natural growth activities of plant and animals within the pond are based on nutrient accumulation and nutrient availability. These “feed” or stimulate the growth of all living things in the pond. Sometimes more productivity is actually desired for specific goals usually those are for more and bigger fish. Although too much of anything then becomes a "problem".
Ponds and lakes even very large lake systems are nutrient traps especially those that do not have flow through systems. Flow through water flushes out some nutrients and also it adds nutrients depending on conditions. Even the large lake system of Lake Winnipeg drainage basin in Manitoba Canada has this nutrient accumulation fact of nature that is not considered problematic. https://www.sciencedirect.com/science/article/abs/pii/S0380133015000532.
TN stands for total nitrogen, TP = total phosphorus.
As noted in the discussions above, once nutrients are bound-up in the pond the only way to get them out is to take something containing nutrients out of the pond. Everything that grew in the pond contains nutrients. The fewer nutrients you get in the pond the less organic material that needs to be removed to maintain a steady balance of nutrients which I don't know is even practical to do. PONDS ARE NUTRIENT TRAPS BECOMMING MORE ENRICHED WITH NUTRIENTS EACH YEAR! Ponds are collection basins
. More nutrients means more plants of some sort that will grow.
No.5 above Nutrient sequestration. Sequester means to remove or withdraw into solitude or retirement; seclude.
Ponds deal with or remove nitrogen, phosphorus, and dissolved chemicals from water through a combination of physical, chemical, and biological processes. These naturally occurring processes adsorb/absorb, transform, sequester, and remove the nutrients and other chemicals from water in the pond. The main biological processes are uptake (or assimilation) by plants, algae, and bacteria and transformation processes conducted by microbes.
Natural sequestration of nutrients has been discussed in a few articles about Floating Islands in Pond Boss magazine. Floating islands provide added substrate for rooted plant growth that can sequester dissolved nutrients to improve water quality, increase fish production, while reducing the amount of algae growth, all dependent on size of the island/s and concentration of nutrients in the pond.
Floating islands nutrients Mar-Apr 12 TRADING NUTRIENTS FOR FISH. Using Floating Islands Moving Water and Microbes. Bruce Kania tells about turning excess nutrients into fish using floating islands. Discusses yellow perch harvest.
Jan-Feb 2016. HARVESTING THE BOUNTY BEYOND THE SHORELINE. Bruce Kania explains how harvest can produce more harvest. Innovative methods to recycle excess nutrients into harvestable fish.
Dealing With Phosphorus.
Here is another version of phosphorus accumulation in ponds that I modified and enhanced from Midwest Ponds blog about Pond Phosphorus.
Phosphate (P) is the most growth limiting nutrient in freshwater environments. Although now, nitrogen (nitrate) is being recognized and learned to play a big part in the bluegreen algae toxicity realm. Phosphorus is rare, but it packs a HUGE punch for plant growth. Varying the amount of phosphate in any aquatic environment will have very large impacts on the overall ecological state and health of the water body especially for the amount of plant growth.
Most management strategies are implemented to limit or at least reduce phosphorus from entering any watershed. If you ever test your water (and you should test your water), any level of dissolved P (ortho P or soluable P) above 0.03ppm (0.03mg/L as 30 micrograms/L) is considered high and in need of a change in management strategy especially if you are dealing with plant / algae problems. This is why most lake associations, municipalities, and even whole states have banned phosphorus-containing lawn fertilizers; as the phosphate easily runs off into streams that eventually empty into lakes making them over fertile (eutrophic).
On the small scale, adding fish food to the pond is also a big contributor to fish manure and increasing P. This is a consequence of feeding the fish or actually adding fertilizer to the pond to produce more and bigger fish. Nutrients when out of “balance” result in nuisance over abundant problematic plant growth, usually algae. NOTE: some goals for the pond deal with actively adding fertilizers to the pond to create plankton blooms, decrease light penetration to minimize rooted vegetation AND increase food chain productivity to grow more fish and hopefully bigger fish. Too much plankton bloom can produce problems. This practice of increasing the productivity adds more accumulated nutrients and organic sediment to the pond that speeds the pond aging process and increases the rate of organic muck accumulation. Organic muck and nutrient accumulations, result in lower water quality and eventually more harmful algae blooms. All consequences good or bad of both eventual natural enrichment and long term artificial fertilization.
If you can manage more of your phosphate input, you are ahead of the nutrient management game if fewer plants are desired. Plants use phosphate to build roots, and algae needs it to grow its cell walls and other cell parts, so if we can somehow cycle it out of the pond environment, you will have more clear water and less overall plant growth in the pond.
Many ponds with a planktonic algae (green water) problems are high in phosphates. The planktonic and filamentous algae reproduces as high plant biomass in high phosphate environments and can become very hard to manage, especially if the algae is troublesome, over abundant and not the beneficial types.
So where does dissolved phosphate come from?
Any manure…..and urine…..and any dead material inputs (mostly leaves), fish foods, and it can be a big portion of your supply source or watershed water. Phosphate moves through the environment. Phosphorus can be tied up in all types of plants, animals, and insects and a majority of it collects as dead materials in the bottom sediments. For managing P our job is to store as much phosphorus in the critters as we can and then do a diligent harvest of materials out of our pond. That means developing and maintaining a healthy, stable ecosystem. The more critters a pond has the more P is bound up in animal materials. Invertebrates that grow in the pond and then emerge as adult insects out pf the pond remove some P that they accumulated while growing before emerging or leaving the pond.
We can also tie up phosphate with flocculating agents; most commonly alum as aluminum sulfate, and a few other products. These products are fantastic at grabbing phosphate and making it inert. That is, the flocculate does not allow the trapped phosphate to react or be absorbed by anything. Flocculate products can effectively remove reactive dissolved phosphate from the water column and sink it to the bottom. It also will grab anything that has open phosphate sites in its cell structure. Planktonic algae have these open sites, and are susceptible to flocculates. The flocculating products used properly will “glom” the detritus, silt, and microscopic critters together and eventually sink them to the bottom. HOWEVER THESE TREATMENTS ARE TEMPORARY because new phosphorus sources and nutrient inputs are continually being added to the pond from many sources. Reducing as many nutrient input sources as you can helps reduce the annual input of more phosphorus.
Proper aeration increases your pond’s ability to sequester and concentrate nutrients including phosphate because aeration allows more critters who accumulate phosphorus (sequester) to grow in the pond (fish, insects, etc.). Aeration can increase the fish and critter biomass that live in all the pond habitats by as much as three times more biomass. Removing fish then removes phosphorus that has moved up through the food chain of the pond. As ponds become very old, removing tons of bottom sediment in a pond rebuilding process returns the pond back to the low phosphorus condition. It is then up to you to properly manage a rejuvenated or renewed pond toward your goals. Too bad we cannot rejuvenate our unhealthy old aging human bodies.
Here is some advanced and a little technical reading material of how the chemical processes work within wetlands and ponds for the main nutrients N, P and available carbon (C). The link discusses wetlands but the facts also apply to ponds and informs you how phosphorus and nitrogen, as teh main plant foods, behave in your pond. Basically all the shallow areas of your pond with plants function the same as a wetland. http://www.wetlands-initiative.org/nutrient-removal