en aquaculture aquaculture پژوهشي Orginal research papers <p></p> <p>The effects of light intensity (&micro; mol m^-2 s^-1) and different levels of Nitrogen was made on the biomass and lipid of microalgae <em>Chaetoceros calcitrans </em>under&nbsp; laboratory conditions in the north of Iran in 2016. The pure strand of <em>C. calcitrans </em>with F/2 media (8 sets of 3 flasks) were placed in front of the light source at values of 80, 160, and 240 &micro; mol m^-2 s^-1. The cell count was collected in lasted 7 days. Every day cells were counted recorded. Maximum cell densities were approximately 279, 299, 395 and 402&times;10⁶cells ml^&minus;1in 25, 50, 75 and 100 % nutrient levels respectively, up to the 20^th day of media enrichment, also maximum cell density was 98&times;10⁶cells ml^&minus;1 in 100% nutrient level and 240 &micro; mol m^-2 s^-1 up to the 20^th day. Results showed that the lipid yield decreased significantly with increasing light levels. The total lipid was significantly higher (14.41%) in control compare with 25, 50, 75 and 100% nutrient levels. The total lipid at 80, 160, and 240 &micro; mol m^-2 s^-1 were 13.31, 12.09 and 10.17% respectively. The production and storage of lipids by microalgae in response to variations in environmental factors are specific for each microalgae species.</p> Chaetoceros calcitrans, Light, Nutrient levels, Experimental conditions 986 993 http://jifro.ir/browse.php?a_code=A-10-2557-1&slc_lang=en&sid=1 M. Akbarnejad mahsa.akbarnejad@yahoo.com 100319475328460038486 100319475328460038486 No 1 Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran. H. Rajabi Islami houman.rajabi@yahoo.com 100319475328460038487 100319475328460038487 Yes Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran. M. Javaheri Baboli mehranjavaheri@gmail.com 100319475328460038488 100319475328460038488 No 2 Department of Fisheries Science, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran. M. Shamsaie Mehrgan drshamsaie@gmail.com 100319475328460038489 100319475328460038489 No 1 Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran. Y. Filizadeh y.filizadeh@scu.ac.ir 100319475328460038490 100319475328460038490 No 3 Department of Agriculture, Agronomy and Plant Breeding, Shahid Chamran University, Ahvaz, Iran.