Volatile bromocarbons produced by Falkenbergia stages of Asparagopsis spp.(Rhodophyta)

Volatile halocarbons released by 12 Falkenbergia phase isolates of Asparago psis taxiformis and Asparagopsis armata collected from widely scattered geo graphical locations were identified using a purge and trap technique and ga s chromatography/mass spectrometry. Production of the compounds under norma l and high irradiance was quantified where possible. Bromoform (CHBr3), dib romomethane (CH2Br2), 1,2-dibromoethylene (C2H2Br2, dibromochloromethane (C HBr2Cl), and tribromoethylene (C2HBr3) were identified as algal products. C 2H2Br2 and C2HBr3 have not previously been recorded as natural products. Co nsiderable qualitative and quantitative differences existed between isolate s in the halocarbons released. The rates of CHBr3 and C2H2Br2 production we re negatively correlated. Increased irradiance invariably resulted in highe r rates of release of halocarbons. Initial rates of production ranged betwe en <8 and 866 ng g(-1) fresh weight (EW) h(-1) for CHBr3, <3 and 59 ng ng g (-1) FW h(-1) for CH2Br2, and <0.4 and 17 ng g(-1) FW h(-1) far C2H2Br2.