Halocarbon emissions by selected tropical seaweeds exposed to different temperatures

Four tropical seaweeds, Gracilaria manilaensis Yamamoto & Trono, Ulva reticulata Forsskål, Kappaphycus alvarezii (Doty) L.M.Liao and Turbinaria conoides (J.Agardh) Kützing, collected from various habitats throughout Malaysia, were subjected to temperatures of 40, 35, 30, 25 20 °C in the laboratory. An exposure range 21–38 is reported for Malaysian waters. The effect temperature exposures on halocarbon emissions seaweeds determined 4 28 h after treatment. emission rates a suite six halocarbons commonly emitted by bromoform (CHBr3), dibromomethane (CH2Br2), diiodomethane (CH2I2), iodomethane (CH3I), dibromochloromethane (CHBr2Cl) dichlorobromomethane (CHBrCl2), measured using cryogenic purge-and-trap sample preparation system coupled gas chromatography–mass spectrometry. rate CHBr3 was highest all under tested, followed CH2Br2, CH2I2. affected change duration, but overall responses unique each seaweed species. Larger decreases CHBr3, CH2I2 CHBr2Cl found K. T. at 40 °C. In both cases there >90% (p < 0.05) reduction Fv/Fm value suggesting that photosynthetic actitivity severely compromised. After period, strong negative correlations (r = −0.69 −0.95; p 0.01) observed between CH2Br2 U. reticulata, conoides. This suggests potential decrease these especially where increase prolonged event. Strong also seen chlorophyll carotenoid pigment contents 0.48 0.96 −0.49 −0.96; 0.05). These results suggest regulation production versus reactive oxygen species an area worthy further exploration.