Phosphorus Pollution in your Pond: Sources, Impacts, Solutions

By West Bishop, Algae and Aquatic Research Scientist, SePRO Corporation (archived content)

So what’s the big deal about phosphorus?

     Perhaps you have observed the increase in regulatory standards being placed on phosphorus containing products (i.e. detergents, fertilizers) or the implementation of best management practices in regards to (buffer zones, rain gardens, stormwater regulations). Is this attention on phosphorus pollution warranted? Well let’s dive in and take a closer look at how phosphorus may impact your pond.

Sources

     Phosphorus is a critical nutrient for all life, especially plants, animals and humans. Common sources include: animal wastes, dead organic matter (such as leaves, grass and even fish food), fertilizer runoff (agriculture, golf course, lawn), and faulty septic systems. The concern is phosphorus typically ends up and accumulates in our precious freshwater resources. The internal cycling of historically accumulated phosphorus can also be a significant, ongoing source of phosphorus loading that can have devastating impacts in your pond.

Impacts

     Once present in aquatic systems, phosphorus can go from a key nutrient in plant and animal health to the culprit for negative water quality and algae blooms. You see, phosphorus is the common limiting nutrient for algae in freshwater (especially the bad types) and the primary component governing eutrophication (aging of ponds). Toxin and taste/odor producing cyanobacteria (blue-green algae) are particularly dependent on phosphorus levels to become dominant in your pond. This is because they are relatively poor competitors for phosphorus in the water column and require large amounts of phosphorus for optimal growth.

     So how do you know if you have a phosphorus problem? Well, looking at your watershed and characterizing inputs is one way, also just looking at how much muck you have built up or the amount and type of plant and algal growth you have may help. Is your pond water clear? Does it give off an odor at times? Have you experienced fish kills?

Solutions

     We have seen where phosphorus comes from and the devastating impacts it can cause in water resources, now, that is all just describing and characterizing the problem. So what can we actually do if phosphorus is a problem?

A few phosphorus fighting tips:

  1. Allow native plants to create a buffer strip along shoreline
  2. Stop erosion
  3. Monitor septic systems
  4. Manage existing plants & algaes
  5. Monitor watershed of your pond
  6. Minimize phosphorus in lawn fertilizers.

Be diligent, try to keep all things organic out of your pond. Your water will benefit!