Effects of an oil-based substrate (The Water Cleanser (TM)) and bacterial additives on nitrogen and phosphorous dynamics in freshwater crayfish (Cherax cainii, Austin and Ryan 2002) aquaculture

Two experiments were conducted to evaluate the efficacy of an oil-based substrate, The Water Cleanser (TM) (TWC). The first experiment studied the effects two substrates of different oil composition (TWC, TWC +), and a commercial bacterial additive (Bio-Aid) on concentrations of nitrogen and phosphorous in indoor aquaria. The second experiment studied the effects of TWC, a bacterial additive, and a combination (TWC + B) on concentrations of nitrogen and phosphorous, phytoplankton abundance and diversity in outdoor freshwater crayfish (Cherax cainii, Austin and Ryan, Invertebr Syst 16:357-367, 2002) tanks. In the first experiment, the concentration of TAN decreased more rapidly with BioAid, whilst the maximum concentrations of NO2-N and NO3-N were reduced with the substrates. The concentration of orthophosphate was reduced in aquaria with TWC + . In the second experiment, concentrations of TAN, NO2-N, NO3-N and total phosphate were not significantly affected by TWC. After addition of TWC + B, there was a significant decrease in the concentrations of nitrate and total phosphate, and a higher abundance of phytoplankton was maintained than with other treatments. Additionally, a population Bacillus sp. was found on the substrate surface. TWC had no adverse effects on phytoplankton abundance or diversity, or C. cainii physiology, weight gain or survival. TWC and TWC + were effective bioremediators of eutrophic water, whilst a combination of TWC + B was effective in short term bioremediation and in promoting phytoplankton abundance in C. cainii tank culture.

Automated summary

Two experiments were conducted to evaluate the effectiveness of an oil-based substrate called The Water Cleanser (TWC). The results showed that TWC can reduce nitrogen and phosphorous concentrations and promote phytoplankton abundance.