UV radiation is known to affect aquatic primary producers and their grazers. However, little has been documented on its effects on zooplankton grazing. In this study, the authors investigated the effects of photosynth...UV radiation is known to affect aquatic primary producers and their grazers. However, little has been documented on its effects on zooplankton grazing. In this study, the authors investigated the effects of photosynthetically active radiation （PAR, 400–700 nm）, ultraviolet-A （UV-A, 320–400 nm） and ultraviolet-B （UV-B, 280–320 nm） radiation on grazing, mortality and lipids oxidation of the copepod Acartia pacifica collected from the Xiamen Bay. After 30 min of the exposures, the copepod was fed in darkness with the diatom Phaeodactylum tricornutum at two cell concentrations （2.5 × 10 4 and 2.5 × 10 5 cells/ml）. At the low cell concentration, the individuals pre-exposed to PAR （218.0 W/m 2 ）＋UV-A （48.2 W/m 2 ） or PAR＋UV-A＋UV-B （2.1 W/m 2 ） showed suppressed clearance and grazing activities compared with those receiving PAR alone, by 22.7% and 17.1% for clearance and by 22.6% and 5.5% for grazing rates, respectively. However, the suppression on clearance and grazing became indistinctive at the high food concentration. Exposures to UV-A and UV-B led to increased lipid oxidation and higher mortality, furthermore, the mortality linearly increased with enhanced oxidation of lipid.展开更多
In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentrat...In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentration and respiration rate was measured using oxygen electrode.It was found that the lethal effect of residual chlorine on L.euchaeta increased with enhanced concentration and prolonged duration.The medium lethal concentration （LC 50 ） of chlorine for L.euchaeta in 24 h was about 0.58 mg/L and the safe concentration was about 0.21 mg/L.However,the grazing and respiration of L.euchaeta decreased by 32.6% and 18.9% when exposed to 0.2 mg/L residual chlorine for 4 h.It indicated that the physiological activities of zooplankton could be suppressed by the residual chlorine less than the safety concentration.Therefore,both survival and physiological activities of the organisms living in the thermal （nuclear） power plant discharging waters should be considered when carrying out the ecological risks assessment.展开更多
基金The Changjiang Scholars and Innovative Research Team Program under contract No. IRT0941Shanghai Municipal Natural Science Foundation under contract No. 11ZR1449900Visiting Scholarship of State Key Laboratory of Marine Environmental Science, Xiamen University under contract No. MELRS0919
文摘UV radiation is known to affect aquatic primary producers and their grazers. However, little has been documented on its effects on zooplankton grazing. In this study, the authors investigated the effects of photosynthetically active radiation （PAR, 400–700 nm）, ultraviolet-A （UV-A, 320–400 nm） and ultraviolet-B （UV-B, 280–320 nm） radiation on grazing, mortality and lipids oxidation of the copepod Acartia pacifica collected from the Xiamen Bay. After 30 min of the exposures, the copepod was fed in darkness with the diatom Phaeodactylum tricornutum at two cell concentrations （2.5 × 10 4 and 2.5 × 10 5 cells/ml）. At the low cell concentration, the individuals pre-exposed to PAR （218.0 W/m 2 ）＋UV-A （48.2 W/m 2 ） or PAR＋UV-A＋UV-B （2.1 W/m 2 ） showed suppressed clearance and grazing activities compared with those receiving PAR alone, by 22.7% and 17.1% for clearance and by 22.6% and 5.5% for grazing rates, respectively. However, the suppression on clearance and grazing became indistinctive at the high food concentration. Exposures to UV-A and UV-B led to increased lipid oxidation and higher mortality, furthermore, the mortality linearly increased with enhanced oxidation of lipid.
基金The National Maritime Bureau's special fund for scientific research on public causes under contract No. 200905010-12special research fund for the national non-profit institutes under contract No. 2008M15
文摘In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentration and respiration rate was measured using oxygen electrode.It was found that the lethal effect of residual chlorine on L.euchaeta increased with enhanced concentration and prolonged duration.The medium lethal concentration （LC 50 ） of chlorine for L.euchaeta in 24 h was about 0.58 mg/L and the safe concentration was about 0.21 mg/L.However,the grazing and respiration of L.euchaeta decreased by 32.6% and 18.9% when exposed to 0.2 mg/L residual chlorine for 4 h.It indicated that the physiological activities of zooplankton could be suppressed by the residual chlorine less than the safety concentration.Therefore,both survival and physiological activities of the organisms living in the thermal （nuclear） power plant discharging waters should be considered when carrying out the ecological risks assessment.
