Limnological Aspects of a Shallow Pond Used as Receiver Aquaculture Wastes and for Agricultural Irrigation

Abstract

Water samples, zooplankton community and sediment samples were analyzed at three sites in a pond receiving wastes, bi-weekly for seven months, covering the rainy and dry seasons. Water quality parameters failed to show significant differences between the sites for turbidity, total suspended solids, dissolved oxygen, transparency, conductivity, alkalinity and total phosphorous. Only temperature was different between the seasons. In the case of sediment, only aluminum (Al) was not different during the experimental period when highest calcium (Ca) concentrations were reported. The relative abundance of Rotifera during the sampling period reached 80-96% (rainy season) and 59-98% (dry season) in total zooplankton. Current study demonstrated that the water quality of shallow pond associated with allochthonous materials from aquaculture farm significantly influenced the structure of zooplankton assemblage due to high nutrient concentrations, conductivity, alkalinity and chlorophyll-a causing more fertilized water. However, heavy rains (February-April) and continuous water flow favored aeration (dissolved oxygen >5.2 ± 1 mg L-1). The use of pond water for agricultural irrigation or for other purposes, must be analyzed more effectively, avoiding problems caused by its usage.

Effect of light/dark cycles on the growth of Haematococcus pluvialis in mixotrophic cultivation with alternative culture media

“…Microalga strain H. pluvialis (CMEA 227 C1) was cultured in the laboratory in triplicate using three different culture media: WC (Guillard & Lorenzen, 1972), inorganic fertilizer, NPK (10:10:10) (Scardoeli-Truzzi & Sipaúba-Tavares, 2017) and macrophyte extract, ME (Eichhornia crassipes) (Sipaúba-Tavares et al, 2009) (Table 1). To produce the inorganic fertilizer medium (NPK 10:10:10), approximately 50 g L -1 of inorganic fertilizer was dissolved and added to 1 L of distilled water.…”

“…A 70 mL samples was collected, and diluted with distilled water up to 1.4 L, at which point 2.5 mL NPK was added. Vitamin B complex was added to NPK and ME culture media at rate of 0.02 g L -1 per culture flask (Sipaúba-Tavares et al, 1999, 2009. Molasses hydrolysis was prepared by adding 0.4% (w/w) hydrochloric acid (4 M HCL) with 20 min of incubation time at 80°C to convert sucrose into glucose and fructose.…”

“…However, culture media can be highly specialized and sometimes difficult to obtain on local markets. To reduced production costs and increase algal biomass, alternative culture media for microalgae such as inorganic fertilizers and aquatic plants, are being used (Sipaúba-Tavares et al, 1999, 2009Scardoeli-Truzzi & Sipaúba-Tavares, 2017). Inorganic fertilizer has a well-defined composition with high nitrogen and phosphorous contents, whilst macrophytes play dominant and supporting roles in…”

“…Nutrients composition of different culture media: NPK, WC and ME (macrophyte extract)(Sipaúba-Tavares et al, 2009; Scardoeli-Truzzi & Sipaúba-Tavares, 2017).…”