Bioassay of the morphogenetic activity with doubly sterile-filtered water collected from various sampling sites across the lagoon.
(A) A dilution series of the seawater collected in 2011 with UCM was tested to estimate the potential morphogenetic activity on axenic Ulva gametes. The control of axenic growth is shown for comparison. To estimate the MS2-like activity, the cell numbers of the germlings were counted 14 days after inoculation. (B) To estimate the MS6-like activity, the percentage of algae with a normal cell wall was evaluated 7 days after the first cell wall deformation was observed in axenic control cultures. Error bars represent (A) confidential intervals (P = 0.95; n = 60 individual algae) or (B) standard deviations (n = 60 individual algae). The dotted line indicates the maximum growth and development under axenic conditions.