Affiliations: Division of Life Science and Technology, Ocean
University of China, Qingdao 266003, China | Department of Environmental Science and Engineering,
Qingdao University, Qingdao 266071, China
Abstract: Effects of elevated CO_2 (5000μl/L) on
sensitivity comparison of six species of algae and interspecific competition of
three species of algae were investigated. The results showed that, the cell
densities of six species of algae grown in elevated CO_2
significantly increased compared to those in ambient CO_2
(360μl/L), and with the time prolonged, the increasing extent
increased. Therefore, elevated CO_2 can promote the growth of
six species of algae. However, there were differences in sensitivity between
six species of algae. Based on the effects of elevated CO_2
on biomass, the sensitive order (from high to low) was Platymanas
sp., Platymanas subcordiformis, Nitzschia closterium, Isochrysis galbana Parke
8701, Dunaliella salina, Chlorella sp., on the condition of solitary
cultivation. Compared to ambient CO_2, elevated
CO_2 promoted the growth of three species of algae,
Platymanas subcordiformis, Nitzschia closterium and Isochrysis galbana Parke
8701 under the condition of mixed cultivation. The sensitivity of the three
species to elevated CO_2 in mixed cultivation changed a lot
compared to the condition of solitary cultivation. When grown in elevated
CO_2 under the condition of mixed cultivation, the sensitive
order from high to low were Nitzschia clostertium, Platymonas subcordiformis
and Isochrysis galbana Parke 8701. However, under the condition of solitary
cultivation, the sensitive order in elevated CO_2 was
Isochrysis galbana Parke 8701, Nitzschia clostertium, Platymonas
subcordiformis, from sensitive to less sensitive. On the day 21, the dominant
algae, the sub-dominant algae and inferior algae grown in elevated
CO_2 did not change. However, the population increasing
dynamic and composition proportion of three algal species have significantly
changed.
