The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were stu...The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.展开更多
This study focused on daily variations and harmful algal bloom features of toxic dinoflagellate Prorocentrum lima(Ehrenberg)F.Stein(P.lima),1878 in middle summer period(9th July-6th August 2013)in the Dardanelles.Harm...This study focused on daily variations and harmful algal bloom features of toxic dinoflagellate Prorocentrum lima(Ehrenberg)F.Stein(P.lima),1878 in middle summer period(9th July-6th August 2013)in the Dardanelles.Harmful algal bloom of P.lima was recorded for the first time in the Turkish Straits System.Density of P.lima reached to 2.40×10^(6)cells/L and exhibited four excessive blooms over 1.0×10^(6)cells/L during the study.The contribution of P.lima to both Prorocentrum spp.and dinoflagellates reached to 100%,particularly at the moment of the harmful algal bloom attested by regresion(R≥0.70)and correlation findings(R≥0.80).Nutrient concentrations were lower than previous levels due to excessive blooms.Concentrations of NO^(-)_(2)+NO^(-)_(3),PO^(-3)_(4)and SiO_(4)varied between 0.20 and 0.78μmol/L[(0.44±0.17)μmol/L],0.08 and 0.18μmol/L[(0.12±0.03)μmol/L]and 0.25 and 0.65μmol/L[(0.41±0.09)μmol/L]respectively.During the bloom,nutrient ratios were more different than redfield ratios due to eutrophication(NO^(-)_(2)+NO^(-)_(3)/PO^(-3)_(4)=4.04±1.74;SiO_(4)/PO^(-3)_(4)=3.79±1.24;SiO_(4)/NO^(-)_(2)+NO^(-)_(3)=1.04±0.36).Chlorophyll a concentration reached to 8.52μg/L(average:4.82±2.29 mg/L)in the bloom period.Temperature[(24.70±0.44)°C],salinity[(22.9±0.49)ppt],pH(8.23±0.15)and dissolved oxygen levels(7.35±0.60 mg/L)were approximately constant.The compact bloom of P.lima,similar to excessive blooms of other dinoflagellates and diatoms,was associated not only with eutrophication,but also with ocean warming interactions.Results revealed that it will be possible to reach to millions of cell number of P.lima(2.40×10^(6)cells/L)in eutrophied waters characterized by high chlorophyll a biomass(8.52μg/L).展开更多
基金The work was supported by the National Natural Sci-ence Foundation of China(Nos.41706126,41876173 and 41606176).
文摘The effects of different types of ultraviolet(UV)radiation(UVR,wavelength=280-400 nm)and light intensities on cell growth,pigment composition,UV-absorbing compounds(UVACs),and chlorophyll a(Chl a)fluorescence were studied in dinoflag-ellate Prorocentrum lima cultured outdoors for 16 days and indoors for 18 days.In the outdoor experiment,UVA radiation(320-400 nm)increased the growth rate of this dinoflagellate when solar light intensities were<12%;decreased growth rates were observed when intensities were>12%.Exposure to UVB radiation(280-320 nm)alleviated the negative effects of UVA.In the indoor ex-periment,UVA and low doses of UVB enhanced growth rates.Addition of low doses of UVB to UVA exposure resulted in higher contents of Chl a and photoprotective pigments compared with UVA exposure only.The results of both experiments showed that UVB is the primary signal of UVAC synthesis.High-dose UVB exposure accelerated growth rates when UVAC contents were maintained at high levels,suggesting that the latter plays a key role in UVR damage protection.Furthermore,the repair rate was en-hanced by UVB exposure after 16 days of culture.This study confirms the positive effects of UVA and UVB on the growth of P.lima,with the latter enhancing the photoprotective and recovery pathways of the species.
文摘This study focused on daily variations and harmful algal bloom features of toxic dinoflagellate Prorocentrum lima(Ehrenberg)F.Stein(P.lima),1878 in middle summer period(9th July-6th August 2013)in the Dardanelles.Harmful algal bloom of P.lima was recorded for the first time in the Turkish Straits System.Density of P.lima reached to 2.40×10^(6)cells/L and exhibited four excessive blooms over 1.0×10^(6)cells/L during the study.The contribution of P.lima to both Prorocentrum spp.and dinoflagellates reached to 100%,particularly at the moment of the harmful algal bloom attested by regresion(R≥0.70)and correlation findings(R≥0.80).Nutrient concentrations were lower than previous levels due to excessive blooms.Concentrations of NO^(-)_(2)+NO^(-)_(3),PO^(-3)_(4)and SiO_(4)varied between 0.20 and 0.78μmol/L[(0.44±0.17)μmol/L],0.08 and 0.18μmol/L[(0.12±0.03)μmol/L]and 0.25 and 0.65μmol/L[(0.41±0.09)μmol/L]respectively.During the bloom,nutrient ratios were more different than redfield ratios due to eutrophication(NO^(-)_(2)+NO^(-)_(3)/PO^(-3)_(4)=4.04±1.74;SiO_(4)/PO^(-3)_(4)=3.79±1.24;SiO_(4)/NO^(-)_(2)+NO^(-)_(3)=1.04±0.36).Chlorophyll a concentration reached to 8.52μg/L(average:4.82±2.29 mg/L)in the bloom period.Temperature[(24.70±0.44)°C],salinity[(22.9±0.49)ppt],pH(8.23±0.15)and dissolved oxygen levels(7.35±0.60 mg/L)were approximately constant.The compact bloom of P.lima,similar to excessive blooms of other dinoflagellates and diatoms,was associated not only with eutrophication,but also with ocean warming interactions.Results revealed that it will be possible to reach to millions of cell number of P.lima(2.40×10^(6)cells/L)in eutrophied waters characterized by high chlorophyll a biomass(8.52μg/L).
