Ecology by definition is the relationship between organisms and their environment
The term “natural balance” often arises in discussion regarding pond keeping. Unfortunately, many people defer to this believing it will serve them well in their overstocked and poorly filtered ponds. Although their are filter feeders and detritivours, these will not occur in sufficient numbers to be solely relied on in overstocked ponds
The fact is the typical backyard pond is not natural - it is manmade. As such, a totally natural approach will not suffice regardless of the pond keepers standards |
Our ponds are small closed systems with Eutrophic loads while we expect Oligotrophic visibility and characteristics
In the case of watergardens, hobbyists often expect everything to survive in harmony when introduced in just a weekend or two. The bio diversification is limited in our backyards coupled with an atypically high fish load. These parameters do not compare to a natural pond or lake that is many times larger and has evolved over a long period of time with a mature food web
A working balance can be difficult to achieve and can require a lengthy maturation process. Once man meddles, it seems he must constantly do so. Water quality is paramount as must be viewed as a 24 hr. 365 day proposition
Bacteria,
Phytoplankton, Zooplankton, Macrophytes and of course Koi are the main ecological players that a pond keeper should have a grasp of. Koi, being the keystone species, will suffer if the system develops a weak link |
Algae, primary producers, are ubiquitous and ready to welcome the neophyte hobbyist. Initially viewed with panic, with time and knowledge comes an understanding that algae are not harmful and draining the pond to rectify the situation will only delay system maturation . Both string and planktonic algae are natural and impossible to prevent - but they can be controlled
A planktonic [free floating] algae bloom will turn the entire pond green very quickly and often subside in the same manner once the resources, namely phosphorus and nitrogen, have been exhausted
String algae is a green plant that typically grows on the liner, stone and waterfalls. A short carpet is desired, long strands are a cosmetic nuisance and can be removed physically or controlled with products like pond balance and barley straw |
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These are small to microscopic animals comprised of 3 main categories - Protozoa, Rotifers and Crustaceans/insect larvae
The term plankton [same applies with phytoplankton] means "a lack of OR very little controllable motility". In other words, they free float around in the water column with the water currents
Some examples of Zooplankton that are of consequence to the pond keeper are potentially lethal protozoa parasites such as obligate Costia and Tichodina while Crustaceans like Daphnia are beneficial and utilized to feed planktivours like our koi fry
Rotifers are commonplace although in aquatic environments they prefer the littoral zone. Zooplankton fill a vital niche in the food chain feeding on bacteria + algae and themselves providing food for fry and small fish |
Only fully grasped in the last 25 years, the microbial loop consists of tiny microscopic organisms including bacteria, ciliates and flagellates
These nano and pico sized plankton break down DOM (dissolved organic matter) which we find accumulating on the bottoms of our ponds. In ponds with ineffectual filters and/or no bottom drains the DOM levels often accumulate to such levels that the detritus goes anaerobic. At this point pathogenic bacteria begin to proliferate potentially causing a disease state in our fish. This matter can also become suspended in the the water column causing turbidity
Ideally it is best to remove this debris with a bottom drain which operates like a vacuum, removing particulate to a settlement chamber |
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Submersed plants obviously play a large role as oxygenators [Photosynthesis : Respiration ratio]. Remember, waterplants consume oxygen at night, even the roots of emergent bog plants - so a good aeration system needs to be in place. The so called "oxygenators" can actually kill fish during nightfall
Plants are primary producers in complex food webs found in nature. Therefore, the fauna found in a watergarden will be more much substantive than that found in a barren swimming pool like koi pond. Vegetable filters are also great at supporting colonies of bacteria for nitrification, filter feeders to remove algae and root systems to trap larger solids
In a koi pond scenario, plants are best setup sequestered from the koi [in a header pond for example]. One must realize that they take some time to get established so you must rely on other forms of filtration and not solely on a vegetable filter, particularly in the Spring
Remember, oxygenating plants will remove O2 during cellular respiration [at night] so the irony is that if you have a lot of oxygenating plants, aeration becomes more critical than in a comparable pond with a smaller plant population |
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