Invasive species Lemna L. (Lemnaceae) in the flora of Bulgaria

Background and Purpose: During the investigations of flora of Bulgaria new species from genus Lemna have been found in Bulgaria. Materials and methods: They were conducted during the period 2010 - 2015 for which purpose we explored diverse pools in different parts of Bulgaria (hot and cold swamps, spillages of rivers and streams, hot mineral waters). The species were determined by Flora of North America. Results: In the flora of Bulgaria we found the following new (invasive) species L. minuta KUNTH., L. obscura (AUSTIN) Daubs, L. perpusilla TORR. and L. valdiviana PHILIPI. Their morphology, chorology and ecology was recorded and data about the accompanying species are also given. Conclusion: Finding these Lemna species in several distant locations in our country is a clear indication that the species is transferred on the territory of Bulgaria a long time ago. The species are most likely invading from neighboring fields in Southeast Europe - Greece, Romania, Turkey and others

Treatment of wastewater originating from aquaculture and biomass production in laboratory algae bioreactor using different carbon sources

The aim of present study was to explore the effect of different carbon sources on biomass accumulation in microalgae Nannochloropsis oculata and Tetraselmis chuii and their ability to remove N and P compounds during their cultivation in aquaculture wastewater. Microalgae cultivation was performed in laboratory bioreactor consisted from 500 mL Erlenmeyer flasks, containing 250 mL wastewater from semi closed recirculation aquaculture system. The cultures were maintained at room temperature (25-27ºC) on a fluorescent light with a light: dark photoperiod of 15 h: 9 h. The microalgae species were cultivated in wastewater with different carbon sources: glucose, lactose and saccharose. The growth of strains was checked for 96 h period. In the present study, N. oculata and T. chuii showed better growth in wastewater from aquaculture with saccharose carbon source during the experiment. The most effective reduce of nitrate and total nitrogen was proved in N. oculata cultivated in wastewater with glucose as carbon source. T. chuii cultivated in wastewater containing glucose showed 8.27% better cleaning effect in ammonium compared with N. oculata. T. chuii grew in wastewater with glucose as carbon source showed 19.5% better removal effect in phosphate compared with N. oculata strain

Treatment of wastewater originating from aquaculture and biomass production in laboratory algae bioreactor using different carbon sources

The aim of present study was to explore the effect of different carbon sources on biomass accumulation in microalgae Nannochloropsis oculata and Tetraselmis chuii and their ability to remove N and P compounds during their cultivation in aquaculture wastewater. Microalgae cultivation was performed in laboratory bioreactor consisted from 500 mL Erlenmeyer flasks, containing 250 mL wastewater from semi closed recirculation aquaculture system. The cultures were maintained at room temperature (25-27ºC) on a fluorescent light with a light: dark photoperiod of 15 h: 9 h. The microalgae species were cultivated in wastewater with different carbon sources: glucose, lactose and saccharose. The growth of strains was checked for 96 h period. In the present study, N. oculata and T. chuii showed better growth in wastewater from aquaculture with saccharose carbon source during the experiment. The most effective reduce of nitrate and total nitrogen was proved in N. oculata cultivated in wastewater with glucose as carbon source. T. chuii cultivated in wastewater containing glucose showed 8.27% better cleaning effect in ammonium compared with N. oculata. T. chuii grew in wastewater with glucose as carbon source showed 19.5% better removal effect in phosphate compared with N. oculata strain