جستجوی مقالات مرتبط با کلیدواژه "عناصر مغذی" در نشریات گروه "شیلات"

In this study, the effects of different levels of biofertilizer containing phosphate solubilizing bacteria on aerobic digestion of Nile tilapia (Oreochromis niloticus) sludge were investigated in vitro under a completely randomized design. Three experimental treatments including aerobic digestion of Nile tilapia solid sludge without adding biofertilizer (control) and aerobic digestion of solid sludge with adding biofertilizer containing phosphate solubilizing bacteria (Pseudomonas putida strain P13 and Pantoea agglomerans strain P5) at levels of 0.1% and 0.2% were used in triplicate. The aerobic digestion containers with a capacity of 1 L (9 containers) were kept in a shaker incubator at 30ºC for 28 days. The results showed that the concentration of phosphate, potassium, and iron nutrients on the 14th day of the experiment in the biofertilizer treatments were significantly higher than the control, but their concentrations on the 28th day in the biofertilizer-0.1% treatment were significantly higher than other treatments )p<0/05). The manganese concentration on the 14th and 28th days in the biofertilized-0.1% treatment was higher than other treatments (p<0/05). The results of the present study indicated that the aerobic digestion of fish sludge for two weeks with adding biofertilizer containing phosphate solubilizing bacteria (P. putida strain P13 and P .agglomerans strain P5) by counting 107 of each bacteria per mL (CFU/mL) at 0.1% improved the release and dissolution of nutrients.

In this study, relationship between summer dynamics of chlorophyll a, nutrient, temperature, pH, salinity, dissolved oxygen, phytoplankton diversity and density are investigated in Gomishan wetland. Based on results, 5 branches of phytoplankton (13 genus and 15 species) has identified in summer. Cyanophyta and Bacillariophyta have the most phytoplankton diversity and Chlorophyta and Cyanophyta have the most cell density. At 4, 5 and 6 stations under the influence of agricultural drainage, urban and industrial wastewaters, the blooming of Cyanobacteria and Chlorophyta has occurred. The eutrophic level obtained eutrophic (mild) and hypereutrophic at these stations. Pearson correlation result shows that log Chla is significant with salinity at the level of p <0.05 and is significant with water temperature and orthophosphate at the level of p <0.01. According to the results, limited exchange of the Caspian Sea water has an effective role on environmental stress of the area that includes increased nutrient concentrations, temperature, salinity, concentration and density of the algal harmful species. To preventing harmful algal blooms, wastewater treatment from the primary pollution sources and using of aerobic stabilization ponds in the presence of resistant microalgae including chlorella, chlamydomonas and chroococcus is suggested.