Affiliations: Marine Ecology Laboratory, Ocean University of China,
Qingdao 266003, China | Department of Environmental Science and Engineering,
Qingdao University, Qingdao 266071, China
Abstract: Enhanced UV-B (280–320 nm) radiation resulting from ozone
depletion is one of global environmental problems. Not only marine organisms
but also marine ecosystems can be affected by enhanced UV-B radiation. The
effects of UV-B radiation on interaction of macro-algae and micro-algae were
investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the
materials in this study. The results demonstrated that UV-B radiation could
inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were
both mono-cultured, and the growth inhibition of algae was more significant
with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit
the growth of Ulva pertusa in mixed culture, and the growth inhibition was more
significant when increasing the initial cell density. However, Ulva pertusa
could inhibit the growth of Alexandriurm tamarense in early phase and stimulate
the growth in latter phase when they were grown in mixed culture. Lower initial
cell density (10^2 cell/mi) of Alexandriurm tamarense could
inhibit the growth of Ulva pertusa under UV-B radiation treatment, however,
with the initial cell density increasing (10^3 and
10^4 cell/ml), the growth of Ulva pertusa was stimulated
under lower dose of UV-B radiation and inhibited under higher dose of UV-B
radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva
pertusa showed more positive inhibition to the growth of Alexandrium tamarense
under UV-B radiation treatment.
