Comparative growth characteristics and interspecific competitive interaction of two cyanobacteria, Phormidium autumnale and Nostoc sp.
This study examined the growth characteristics and competitive interaction of two cyanobacteria, Phormidium autumnale GJ_2B_I1 and Nostoc sp. DS_2B_I1, which were newly isolated from a southeast river (Nakdong) during the cyanobacterial harmful algal bloom (CyanoHAB) season in Korea. As major environmental parameters, the water temperature (25 and 30°C) and alkalinity (19 to 78 mg CaCO3 L-1 ), and nitrate concentration (1.5 to 3.5 mg NO3 -N L-1 ) were selected based on the water environmental monitoring data during the CyanoHAB season. Unlike P. autumnale, Nostoc sp. has a relatively high growth rate under both monoculture and co-culture and prefers the maximum environmental conditions (30°C and 78 mg CaCO3 L-1 /pH-9) during the CyanoHAB season. In addition, the growth of P. autumnale is relatively unaffected by alkalinity. Nitrogen stress also has a limiting effect in the interspecific interactions of both cyanobacterial strains. All other cases except for Nostoc sp. in a co-culture showed a considerable increase in growth rate with increasing nitrogen content (from 1.5 to 3.5 mg NO3 -N L-1 ), showing 20 - 64% under the minimum field conditions (25°C and 19 mg CaCO3 L-1 /pH-7) and 18 - 140% under the maximum field conditions. The results show that the growth of P. autumnale can be stimulated by enhanced nitrogen stress. On the other hand, Nostoc sp. is less affected by nitrogen stress compared to P. autumnale. Therefore, it has excellent potential to be a major group of CyanoHABs because of their relatively high growth rate, particularly in a range of nitrogen tested. This article is protected by copyright. All rights reserved.
['Yadav|Seema|S|', 'Anam|Giridhar Babu|GB|', 'Ahn|Young-Ho|YH|https://orcid.org/0000-0002-4657-8858']
competitive interaction phormidium autumnale nostoc sp temperature Alkalinity nitrate