2020 Vol. 42, No. 12
Display Method:
2020, 42(12): 1-13.
doi: 10.3969/j.issn.0253-4193.2020.12.001
Abstract:
The spatial distribution of Cu, Cr, Cd, Pb, Ni and Co in the Jiaozhou Bay seawater and their distribution among different size fractions were investigated. The distribution mechanism of trace metals and the influence of environmental factors such as plankton activity and salinity during the distribution process were also discussed. The results showed that the highest values for most trace metals were distributed along north and northeast coast, while Cd and Pb also presented high value areas in the mouth and middle of the bay respectively. The trace metals in the Jiaozhou Bay seawater were mostly partitioned in the <1 kDa fraction with an average value of 70.1%, of which the percentages of Cu and Cd were up to 79.0% and 77.6% respectively, while Pb was only 58.2%. Similarly, the bulk dissolved organic carbon was also mostly partitioned in the <1 kDa size fraction with an average value of 73.1%. Spectroscopic properties indicated that low molecular weight (LMW, <1 kDa) fractions which mainly composed of humic-like organic matters contained more effective functional groups like hydroxyl and carboxyl groups and had higher complexing capacities with trace metals. There were significant positive correlations between chlorophyll a concentrations and high molecular weight (HMW, >1 kDa) proportions, indicating that primary production by phytoplankton in the euphotic zone was the major source of HMW dissolved organic matters in seawater and influenced complexation between trace metals and dissolved organic matters. The top area of the Jiaozhou Bay with lower salinity was characterized with higher proportions of large size components, which may be resulted from the combined effects of biological activity, terrestrial input and salinity.
The spatial distribution of Cu, Cr, Cd, Pb, Ni and Co in the Jiaozhou Bay seawater and their distribution among different size fractions were investigated. The distribution mechanism of trace metals and the influence of environmental factors such as plankton activity and salinity during the distribution process were also discussed. The results showed that the highest values for most trace metals were distributed along north and northeast coast, while Cd and Pb also presented high value areas in the mouth and middle of the bay respectively. The trace metals in the Jiaozhou Bay seawater were mostly partitioned in the <1 kDa fraction with an average value of 70.1%, of which the percentages of Cu and Cd were up to 79.0% and 77.6% respectively, while Pb was only 58.2%. Similarly, the bulk dissolved organic carbon was also mostly partitioned in the <1 kDa size fraction with an average value of 73.1%. Spectroscopic properties indicated that low molecular weight (LMW, <1 kDa) fractions which mainly composed of humic-like organic matters contained more effective functional groups like hydroxyl and carboxyl groups and had higher complexing capacities with trace metals. There were significant positive correlations between chlorophyll a concentrations and high molecular weight (HMW, >1 kDa) proportions, indicating that primary production by phytoplankton in the euphotic zone was the major source of HMW dissolved organic matters in seawater and influenced complexation between trace metals and dissolved organic matters. The top area of the Jiaozhou Bay with lower salinity was characterized with higher proportions of large size components, which may be resulted from the combined effects of biological activity, terrestrial input and salinity.
2020, 42(12): 93-100.
doi: 10.3969/j.issn.0253-4193.2020.12.010
Abstract:
Observations were carried out at Nanliu River, Dafeng River, Qinjiang River, Maoling River and Fangcheng River in the Beibu Gulf to analyze the distribution characteristics and fluxes of nutrient in February (dry season) and August (flood season) 2018. The results showed that significantly variations of nutrient concentration were observed, and the nutrient concentrations in the Fangcheng River, Maoling River and Qinjiang River in the dry season were higher than that in the flood season, while the nutrient concentrations in the Dafeng River and Nanliu River in the flood season were higher than that in the dry season. Nitrate (\begin{document}${\rm {NO}}_3^- $\end{document} ![]()
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Observations were carried out at Nanliu River, Dafeng River, Qinjiang River, Maoling River and Fangcheng River in the Beibu Gulf to analyze the distribution characteristics and fluxes of nutrient in February (dry season) and August (flood season) 2018. The results showed that significantly variations of nutrient concentration were observed, and the nutrient concentrations in the Fangcheng River, Maoling River and Qinjiang River in the dry season were higher than that in the flood season, while the nutrient concentrations in the Dafeng River and Nanliu River in the flood season were higher than that in the dry season. Nitrate (
2020, 42(12): 101-109.
doi: 10.3969/j.issn.0253-4193.2020.12.011
Abstract:
Based on the data of pH and environmental parameters from 2011 to 2017, using the method of grid statistics and time-space matrix, contrastive analysis of pH in each environmental unit and the correlation of pH and environmental factors were studied. Furthermore, the differences of relevant factors affecting different seasons, regions and water levels were analyzed. The results showed that: (1) during from 2011 to 2017, the spatial distribution of pH was relatively stable in the Bohai Sea, the average value of surface pH in environmental units was from 7.95 to 8.38, the bottom was from 7.89 to 8.35, the absolute variation of average value was 1−1.5 standard deviations; (2) the time series of pH in each environmental unit tend to change synchronously, but there were differences among the units due to the different spatial distribution, the distribution characteristic of surface pH in winter was consistent with the saline; (3) there was a significant positive correlation between pH and chlorophyll a content in the Bohai Sea, and the surface pH varied seasonally, which was obviously consistent with distribution and variation characteristics of chlorophyll a, therefore, biological factor played an important role in regulating the pH of surface water; (4) the low value region of pH in Bohai Sea bottom in August was consistent with the formation of hypoxic zones by regional water stratification, and it was found that the bottom pH was positively correlated with dissolved oxygen; (5) the characteristic information of acidification indicators was further displayed by gridding processing technology and time-space matrix analysis method, which provided a good technical support for long-time scale analysis and research under climate change.
Based on the data of pH and environmental parameters from 2011 to 2017, using the method of grid statistics and time-space matrix, contrastive analysis of pH in each environmental unit and the correlation of pH and environmental factors were studied. Furthermore, the differences of relevant factors affecting different seasons, regions and water levels were analyzed. The results showed that: (1) during from 2011 to 2017, the spatial distribution of pH was relatively stable in the Bohai Sea, the average value of surface pH in environmental units was from 7.95 to 8.38, the bottom was from 7.89 to 8.35, the absolute variation of average value was 1−1.5 standard deviations; (2) the time series of pH in each environmental unit tend to change synchronously, but there were differences among the units due to the different spatial distribution, the distribution characteristic of surface pH in winter was consistent with the saline; (3) there was a significant positive correlation between pH and chlorophyll a content in the Bohai Sea, and the surface pH varied seasonally, which was obviously consistent with distribution and variation characteristics of chlorophyll a, therefore, biological factor played an important role in regulating the pH of surface water; (4) the low value region of pH in Bohai Sea bottom in August was consistent with the formation of hypoxic zones by regional water stratification, and it was found that the bottom pH was positively correlated with dissolved oxygen; (5) the characteristic information of acidification indicators was further displayed by gridding processing technology and time-space matrix analysis method, which provided a good technical support for long-time scale analysis and research under climate change.
2020, 42(12): 110-118.
doi: 10.3969/j.issn.0253-4193.2020.12.012
Abstract:
The sea surface temperature(SST), salinity(SSS), dissolved oxygen (DO), chlorophyll a(Chl a) and surface partial pressure of carbon dioxide(pCO2) was determined by underway measurement system in the Qiongzhou Strait in summer 2011 and 2014, and the spatiotemporal variations of pCO2 were analyzed and its control factors were explained. The averages of pCO2 in surface sea water were (516±29) μatm and (533±15) μatm, sea-air CO2 fluxes were (8.4±1.7) mmol/(m2·d) and (4.5±0.4) mmol/(m2·d) in summer 2011 and 2014, the Qiongzhou Strait acted as strong atmospheric CO2 source and was more higher than the adjacent and similar sea areas. The upwelling forced the CO2-enriched subsurface water to intrude the surface water and elevated pCO2 in the east mouth, also promoted biological productivity and absorbed CO2 from sea water, and also made the pCO2 drop and DO rise sharply in the vicinity of west mouth in summer 2011. The upwelling was weak in east mouth and vertical mixing was strong along ship-track in summer 2014, the distributions of pCO2 and DO were obviously different from that in summer 2011. Narrow channel effect was significant in the middle of Qiongzhou Strait, high water transportation speed with strong mixing resulted in weak photosynthetic activity, they altogether maintained high pCO2 in summer 2011 and 2014.
The sea surface temperature(SST), salinity(SSS), dissolved oxygen (DO), chlorophyll a(Chl a) and surface partial pressure of carbon dioxide(pCO2) was determined by underway measurement system in the Qiongzhou Strait in summer 2011 and 2014, and the spatiotemporal variations of pCO2 were analyzed and its control factors were explained. The averages of pCO2 in surface sea water were (516±29) μatm and (533±15) μatm, sea-air CO2 fluxes were (8.4±1.7) mmol/(m2·d) and (4.5±0.4) mmol/(m2·d) in summer 2011 and 2014, the Qiongzhou Strait acted as strong atmospheric CO2 source and was more higher than the adjacent and similar sea areas. The upwelling forced the CO2-enriched subsurface water to intrude the surface water and elevated pCO2 in the east mouth, also promoted biological productivity and absorbed CO2 from sea water, and also made the pCO2 drop and DO rise sharply in the vicinity of west mouth in summer 2011. The upwelling was weak in east mouth and vertical mixing was strong along ship-track in summer 2014, the distributions of pCO2 and DO were obviously different from that in summer 2011. Narrow channel effect was significant in the middle of Qiongzhou Strait, high water transportation speed with strong mixing resulted in weak photosynthetic activity, they altogether maintained high pCO2 in summer 2011 and 2014.
2020, 42(12): 119-128.
doi: 10.3969/j.issn.0253-4193.2020.12.013
Abstract:
Volatile halocarbons (VHCs) produced in the oceans are important carriers for chlorine, bromine, and iodine to enter into the atmosphere. Marine algae can produce VHCs that have an ozone-depleting potential. Marine microalgae in particular have been shown to be major contributors of VHCs in the atmosphere. However, little is known about the influences of environmental factors on the production of VHCs by marine microalgae. In this study we examined the influence of different light intensities (20 μmol/(m2·s), 70 μmol/(m2·s) and 140 μmol/(m2·s)) and nitrate concentrations (1 mg/L, 5 mg/L, 10 mg/L and 50 mg/L) on the growth of Prorocentrum donghaiense and Phaeodactylum tricornutum and the releases of four VHCs (CH3I, CH2Br2, CHBr2Cl and C2HCl3) by these two microalgae. Unialgal cultures of these two kinds of microalgae were conducted in axenic and sealed glass vessels. The VHCs were extracted and analyzed by gas chromatography coupled to purge-and-trap preconcentration system. The releases of VHCs by these two microalgae were affected by light intensity and nitrate concentration, while their influences on different VHCs were various. The release of CH3I was significantly affected by light intensity and nitrate concentrations. Within a certain range, the amount of CH3I released from the two microalgae raised with the increase of light intensity. Moreover, our results showed that increasing the nitrate level above 5 mg/L could promote the production of CH3I by these two microalgae.
Volatile halocarbons (VHCs) produced in the oceans are important carriers for chlorine, bromine, and iodine to enter into the atmosphere. Marine algae can produce VHCs that have an ozone-depleting potential. Marine microalgae in particular have been shown to be major contributors of VHCs in the atmosphere. However, little is known about the influences of environmental factors on the production of VHCs by marine microalgae. In this study we examined the influence of different light intensities (20 μmol/(m2·s), 70 μmol/(m2·s) and 140 μmol/(m2·s)) and nitrate concentrations (1 mg/L, 5 mg/L, 10 mg/L and 50 mg/L) on the growth of Prorocentrum donghaiense and Phaeodactylum tricornutum and the releases of four VHCs (CH3I, CH2Br2, CHBr2Cl and C2HCl3) by these two microalgae. Unialgal cultures of these two kinds of microalgae were conducted in axenic and sealed glass vessels. The VHCs were extracted and analyzed by gas chromatography coupled to purge-and-trap preconcentration system. The releases of VHCs by these two microalgae were affected by light intensity and nitrate concentration, while their influences on different VHCs were various. The release of CH3I was significantly affected by light intensity and nitrate concentrations. Within a certain range, the amount of CH3I released from the two microalgae raised with the increase of light intensity. Moreover, our results showed that increasing the nitrate level above 5 mg/L could promote the production of CH3I by these two microalgae.
2020, 42(12): 14-25.
doi: 10.3969/j.issn.0253-4193.2020.12.002
Abstract:
Neon flying squid Ommastrephes bartramii is a cephalopod species of economically importance distributed in the North Pacific Ocean. Because of short lifespan, their abundances mainly depend on the recruitments and the marine environment during their early life stages will directly affect the recruitments. Using fishery data collected by Chinese squid-jigging fleets in the Northwest Pacific Ocean from 2004 to 2015 and the sea surface temperature (SST) of spawning and feeding grounds, which were divided into different numbers of subareas, correlation analysis and random forest model were used to screen out the subareas that CPUE has significant relationships with Ps (the proportion of favorable-SST in spawning grounds) of spawning grounds and Pf (the proportion of favorable-SST in feeding grounds) of feeding grounds during spawning and feeding periods. The Ps and Pf were used as input variables of the neural network model to forecast recruitments based on spawning ground and feeding ground, respectively, and the advantages and disadvantages of the model and forecast accuracy were analyzed. The results show that the schemes of dividing spawning ground into 5°×5° and feeding field into 2.5°(longitude)×4°(latitude) were optimal. The ranges of subareas selected by random forests are largely consistent with those selected by correlation analysis, both random forests and correlation analysis can identify potential subareas associated with CPUE, and both have forecasting accuracy of >90%. However, the subareas selected by the random forest are better and the forecast accuracy is higher than those selected by correlation analysis. In addition, the model based on the spawning ground is more accurate and stable than that based on feeding ground.
Neon flying squid Ommastrephes bartramii is a cephalopod species of economically importance distributed in the North Pacific Ocean. Because of short lifespan, their abundances mainly depend on the recruitments and the marine environment during their early life stages will directly affect the recruitments. Using fishery data collected by Chinese squid-jigging fleets in the Northwest Pacific Ocean from 2004 to 2015 and the sea surface temperature (SST) of spawning and feeding grounds, which were divided into different numbers of subareas, correlation analysis and random forest model were used to screen out the subareas that CPUE has significant relationships with Ps (the proportion of favorable-SST in spawning grounds) of spawning grounds and Pf (the proportion of favorable-SST in feeding grounds) of feeding grounds during spawning and feeding periods. The Ps and Pf were used as input variables of the neural network model to forecast recruitments based on spawning ground and feeding ground, respectively, and the advantages and disadvantages of the model and forecast accuracy were analyzed. The results show that the schemes of dividing spawning ground into 5°×5° and feeding field into 2.5°(longitude)×4°(latitude) were optimal. The ranges of subareas selected by random forests are largely consistent with those selected by correlation analysis, both random forests and correlation analysis can identify potential subareas associated with CPUE, and both have forecasting accuracy of >90%. However, the subareas selected by the random forest are better and the forecast accuracy is higher than those selected by correlation analysis. In addition, the model based on the spawning ground is more accurate and stable than that based on feeding ground.
2020, 42(12): 26-33.
doi: 10.3969/j.issn.0253-4193.2020.12.003
Abstract:
In this paper, the time series analysis model ARIMA (1, 2, 0) was applied to simulate and predict the stock of small yellow croaker (Larimichthys polyactis) based on the monitoring catches data of canvas stow net in the southern Yellow Sea from 2003 to 2014 and verified by the monitoring catches data of 2015 and 2016. The results showed that the simulated and actual values for the catch yield from 2003 to 2014 were correlated significantly (p<0.05) and the correlation coefficient was 0.881. The relative error between predicted and actual value in 2015 and 2016 were respectively 6.73% and 22.75%, the overall relative error was 14.74% and the regression equation fitted the real situation better, which illustrated that the time series analysis model ARIMA (1, 2, 0) can be applied to simulate the catches trend of L. polyactis and predict the catch stock, especially superior in short-term forecasting. However, in any case the fixed model of L. polyactis is not always suitable for all data analysis, and the values of p, d and q in ARIMA model are considered to be variable according to different time series. Therefore, the optimal values of p, d and q should be determined based on the guidance and analysis of relevant theories in order to avoid copying directly the fixed model.
In this paper, the time series analysis model ARIMA (1, 2, 0) was applied to simulate and predict the stock of small yellow croaker (Larimichthys polyactis) based on the monitoring catches data of canvas stow net in the southern Yellow Sea from 2003 to 2014 and verified by the monitoring catches data of 2015 and 2016. The results showed that the simulated and actual values for the catch yield from 2003 to 2014 were correlated significantly (p<0.05) and the correlation coefficient was 0.881. The relative error between predicted and actual value in 2015 and 2016 were respectively 6.73% and 22.75%, the overall relative error was 14.74% and the regression equation fitted the real situation better, which illustrated that the time series analysis model ARIMA (1, 2, 0) can be applied to simulate the catches trend of L. polyactis and predict the catch stock, especially superior in short-term forecasting. However, in any case the fixed model of L. polyactis is not always suitable for all data analysis, and the values of p, d and q in ARIMA model are considered to be variable according to different time series. Therefore, the optimal values of p, d and q should be determined based on the guidance and analysis of relevant theories in order to avoid copying directly the fixed model.
2020, 42(12): 34-43.
doi: 10.3969/j.issn.0253-4193.2020.12.004
Abstract:
Using fishery data of Scomber japonicus from Chinese light-purse seine fishing on the high seas of the Northwest Pacific Ocean from May to November during 2014 to 2017, and the environmental remote sensing data, the habitat suitability index (HSI) model of Scomber japonicus was constructed based on fish catch and nos of hauls, respectively. Applying sea surface temperature, sea level anomaly, chlorophyll a concentration, the suitability index model of each environmental variable was established by one-dimensional exponential regression fitting. The weight of each environmental factor was determined by linear programming method to improve the prediction precision of HSI model for fishing ground. The prediction accuracy of the HSI model was verified with the actual fishing data from May to November in 2018, and the results showed that in the sea areas with HSI values over 0.7, the fishing catches accounts for 77.29% for HSI model based on fish catch and 76.79% for HSI model based on nos of hauls respectively, which indicates that the HSI model based on different environmental factor weights can better predict the central fishing ground of Scomber japonicus on the high seas of the Northwest Pacific Ocean.
Using fishery data of Scomber japonicus from Chinese light-purse seine fishing on the high seas of the Northwest Pacific Ocean from May to November during 2014 to 2017, and the environmental remote sensing data, the habitat suitability index (HSI) model of Scomber japonicus was constructed based on fish catch and nos of hauls, respectively. Applying sea surface temperature, sea level anomaly, chlorophyll a concentration, the suitability index model of each environmental variable was established by one-dimensional exponential regression fitting. The weight of each environmental factor was determined by linear programming method to improve the prediction precision of HSI model for fishing ground. The prediction accuracy of the HSI model was verified with the actual fishing data from May to November in 2018, and the results showed that in the sea areas with HSI values over 0.7, the fishing catches accounts for 77.29% for HSI model based on fish catch and 76.79% for HSI model based on nos of hauls respectively, which indicates that the HSI model based on different environmental factor weights can better predict the central fishing ground of Scomber japonicus on the high seas of the Northwest Pacific Ocean.
2020, 42(12): 44-53.
doi: 10.3969/j.issn.0253-4193.2020.12.005
Abstract:
The photosynthetic active radiation (PAR) plays a significant role in regulating ocean primary productivity, so it may indirectly affect the abundance and spatial distribution of cephalopods. In this study, we examined the relationship between photosynthetic active radiation and Ommastrephes bartramii stocks in the Northwest Pacific Ocean, and evaluated the impacts of the anomalous climatic environments on the squid stocks, based on the fishery data during 2006−2015 obtained from the squid-jigging Science and Technology Group of Shanghai Ocean University and the remotely satellite data of PAR. The results indicated that catch per unit effort (CPUE), latitudinal gravity center (LATG), PAR and its spatial distribution exhibited significant monthly variation. From July to November, the suitable range of PAR was 36−39 E/(m2·d) in July, 33−36 E/(m2·d) in August, 24−27 E/(m2·d) in September, 18 E/(m2·d) in October and 12 E/(m2·d) in November. The most favorable PAR was 36 E/(m2·d), 33 E/(m2·d), 27 E/(m2·d), 18 E/(m2·d), 12 E/(m2·d), respectively, from July to November. The results showed that a significant positive relationship (p<0.05) was found between CPUE and PAR, and further a significantly positive correlation (p<0.05) was found between CPUE and the monthly percentages of suitable PAR accounting for the whole fishing ground. Meanwhile, the LATG varied with the mean latitude of the most preferred PAR in each month. Finally, under the anomalous climatic environments, the CPUE in the La Niña years is higher than that in the El Niño years, which may be caused by the higher PAR in the La Niña years. Our findings indicated that the PAR strongly affected the abundance and spatial distribution of O.bartramii in the Northwest Pacific Ocean.
The photosynthetic active radiation (PAR) plays a significant role in regulating ocean primary productivity, so it may indirectly affect the abundance and spatial distribution of cephalopods. In this study, we examined the relationship between photosynthetic active radiation and Ommastrephes bartramii stocks in the Northwest Pacific Ocean, and evaluated the impacts of the anomalous climatic environments on the squid stocks, based on the fishery data during 2006−2015 obtained from the squid-jigging Science and Technology Group of Shanghai Ocean University and the remotely satellite data of PAR. The results indicated that catch per unit effort (CPUE), latitudinal gravity center (LATG), PAR and its spatial distribution exhibited significant monthly variation. From July to November, the suitable range of PAR was 36−39 E/(m2·d) in July, 33−36 E/(m2·d) in August, 24−27 E/(m2·d) in September, 18 E/(m2·d) in October and 12 E/(m2·d) in November. The most favorable PAR was 36 E/(m2·d), 33 E/(m2·d), 27 E/(m2·d), 18 E/(m2·d), 12 E/(m2·d), respectively, from July to November. The results showed that a significant positive relationship (p<0.05) was found between CPUE and PAR, and further a significantly positive correlation (p<0.05) was found between CPUE and the monthly percentages of suitable PAR accounting for the whole fishing ground. Meanwhile, the LATG varied with the mean latitude of the most preferred PAR in each month. Finally, under the anomalous climatic environments, the CPUE in the La Niña years is higher than that in the El Niño years, which may be caused by the higher PAR in the La Niña years. Our findings indicated that the PAR strongly affected the abundance and spatial distribution of O.bartramii in the Northwest Pacific Ocean.
2020, 42(12): 54-61.
doi: 10.3969/j.issn.0253-4193.2020.12.006
Abstract:
Mangrove growing on the tidal flat is of important value for the estuarine plant community compositions and coastal protection against wind and wave. This study aims to explore the spatial distribution pattern and associated influencing factors of estuarine mangrove based on the soaking and sinking experiment of aboriginal Aegiceras corniculatum embryo and observations on water salinity, plant community structure and geomorphology of the tidal flat along the estuaries of Nanliujiang River and Dafengjiang River. Our results show that the distribution pattern of mangrove along Nanliuujiang River and Dafengujiang River estuaries exhibits a mode of “pure mangrove (e.g. mixture of Aegiceras corniculatum, Kandelia candel, Sonneratia apetala)→mixture of mangrove and semi-mangrove (Hibiscus tiliaceus, Clerodendrum inerme Gaertn)→mixture of mangrove, semi-mangrove and non-mangrove→mangrove mosaic→sparse mangrove seedlings” from sea to land. However, mangrove at the landward limitation of the Dafeng River estuary is characterized by a mixture of mangrove, mangrove seedlings and semi-mangrove. Besides, the time length of mangrove socking dominates the spatial distribution pattern of the estuarine mangrove while the time length of landward transport of tidal current affects the extreme location of the mangrove landward growth. A suitable tidal flat is an essential condition for the mangrove development and growth.
Mangrove growing on the tidal flat is of important value for the estuarine plant community compositions and coastal protection against wind and wave. This study aims to explore the spatial distribution pattern and associated influencing factors of estuarine mangrove based on the soaking and sinking experiment of aboriginal Aegiceras corniculatum embryo and observations on water salinity, plant community structure and geomorphology of the tidal flat along the estuaries of Nanliujiang River and Dafengjiang River. Our results show that the distribution pattern of mangrove along Nanliuujiang River and Dafengujiang River estuaries exhibits a mode of “pure mangrove (e.g. mixture of Aegiceras corniculatum, Kandelia candel, Sonneratia apetala)→mixture of mangrove and semi-mangrove (Hibiscus tiliaceus, Clerodendrum inerme Gaertn)→mixture of mangrove, semi-mangrove and non-mangrove→mangrove mosaic→sparse mangrove seedlings” from sea to land. However, mangrove at the landward limitation of the Dafeng River estuary is characterized by a mixture of mangrove, mangrove seedlings and semi-mangrove. Besides, the time length of mangrove socking dominates the spatial distribution pattern of the estuarine mangrove while the time length of landward transport of tidal current affects the extreme location of the mangrove landward growth. A suitable tidal flat is an essential condition for the mangrove development and growth.
2020, 42(12): 62-71.
doi: 10.3969/j.issn.0253-4193.2020.12.007
Abstract:
Increasing atmospheric CO2 concentration leads to ocean acidification, which might affect phytoplankton to varying degrees. Phytoplankton in coastal waters may be affected by seawater acidification and alkalization. In this experiment, Thalassoosira punctigera (diatom) was used to investigate its growth, photosynthesis, dark respiration, cell size, chlorophyll a content, biogenic silica content and chlorophyll fluorescence at seven pCO2 levels (25 μatm, 50 μatm, 100 μatm, 200 μatm, 400 μatm, 800 μatm, 1 600 μatm). The results showed that, compared with 400 μatm, the growth rate and chlorophyll a content in seawater acidification (pCO2 > 400 μatm) and alkalization (pCO2 < 400 μatm) treatments were significantly reduced, but the degree of decrease was greater under the condition of alkalization. In addition, cells showed lower photosynthesis rates and maximum quantum yield of PSII (Fv/Fm) and relative maximum electron transport rate (
Increasing atmospheric CO2 concentration leads to ocean acidification, which might affect phytoplankton to varying degrees. Phytoplankton in coastal waters may be affected by seawater acidification and alkalization. In this experiment, Thalassoosira punctigera (diatom) was used to investigate its growth, photosynthesis, dark respiration, cell size, chlorophyll a content, biogenic silica content and chlorophyll fluorescence at seven pCO2 levels (25 μatm, 50 μatm, 100 μatm, 200 μatm, 400 μatm, 800 μatm, 1 600 μatm). The results showed that, compared with 400 μatm, the growth rate and chlorophyll a content in seawater acidification (pCO2 > 400 μatm) and alkalization (pCO2 < 400 μatm) treatments were significantly reduced, but the degree of decrease was greater under the condition of alkalization. In addition, cells showed lower photosynthesis rates and maximum quantum yield of PSII (Fv/Fm) and relative maximum electron transport rate (
2020, 42(12): 72-81.
doi: 10.3969/j.issn.0253-4193.2020.12.008
Abstract:
The qualitative and quantitative analyses on betaine lipids of microalgae were conducted by means of the quadrupole flight time ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-Q-TOF-MS) using electron spraying ionization. As a result, 133 betaine lipids including 53 DGCC, 41 DGTS and 39 DGTA were identified from 14 species of microalgae in four major phyla. DGCC was the dominant betaine lipid in dinoflagellates and haptophytes, while DGTS was the main betaine lipid in chlorophytes. There were two main types of betaine lipid in diatoms: DGCC in centric diatom and DGTA in pennate diatom. The differences of fatty acid of betaine lipid in marine microalgae were only observed at the phyla and class levels, but at lower taxonomic levels the differences were less stable. DGCC existed in diatoms, dinoflagellates and chlorophytes, which contained C14−C18 saturated and unsaturated fatty acids and C20 and C22 polyunsaturated fatty acids. The difference in DGCC is that saturated C14−C18 fatty acids existed in dinoflagellates, while the fatty acids of odd carbon numbers C19 occurred only in diatoms. The results of description and molecular characterization of betaine lipid in microalgae can be served in future investigation in chemotaxonomy, physiology, ecological role of microalgae and functional properties of these phosphorous-lacking polar lipids.
The qualitative and quantitative analyses on betaine lipids of microalgae were conducted by means of the quadrupole flight time ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-Q-TOF-MS) using electron spraying ionization. As a result, 133 betaine lipids including 53 DGCC, 41 DGTS and 39 DGTA were identified from 14 species of microalgae in four major phyla. DGCC was the dominant betaine lipid in dinoflagellates and haptophytes, while DGTS was the main betaine lipid in chlorophytes. There were two main types of betaine lipid in diatoms: DGCC in centric diatom and DGTA in pennate diatom. The differences of fatty acid of betaine lipid in marine microalgae were only observed at the phyla and class levels, but at lower taxonomic levels the differences were less stable. DGCC existed in diatoms, dinoflagellates and chlorophytes, which contained C14−C18 saturated and unsaturated fatty acids and C20 and C22 polyunsaturated fatty acids. The difference in DGCC is that saturated C14−C18 fatty acids existed in dinoflagellates, while the fatty acids of odd carbon numbers C19 occurred only in diatoms. The results of description and molecular characterization of betaine lipid in microalgae can be served in future investigation in chemotaxonomy, physiology, ecological role of microalgae and functional properties of these phosphorous-lacking polar lipids.
2020, 42(12): 82-92.
doi: 10.3969/j.issn.0253-4193.2020.12.009
Abstract:
In recent years, the water quality of the Liaohe Estuary has been declining, and a large input of nitrogen has increased the burden on the environment. The denitrification process releases nitrogen from sediments into the atmosphere in the form of N2O and N2, which reduces the nitrogen load in the estuarine ecosystem. In this study, quantitative PCR was used to determine the levels of four denitrification functional genes narG, nirK, norB and nosZ present in the surface sediments of the Liaohe Estuary. The narG gene, which dominates nitrate reduction, was found to be the most abundant. The nirK-type denitrification functional gene was sequenced by high-throughput sequencing. The results showed that the genus of denitrifying bacteria in the Liaohe Estuary was mainly Devosia, Phaeobacter, Alcaligenes, Pseudomonas. The abundance of denitrification function genes is mainly affected by sediment properties, except that norB gene is significantly related to many environmental factors. The community structure and diversity of nirK type denitrifying bacteria are mainly affected by salinity, pH, dissolved oxygen and\begin{document}${\rm {NO}}_2^- $\end{document} ![]()
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In recent years, the water quality of the Liaohe Estuary has been declining, and a large input of nitrogen has increased the burden on the environment. The denitrification process releases nitrogen from sediments into the atmosphere in the form of N2O and N2, which reduces the nitrogen load in the estuarine ecosystem. In this study, quantitative PCR was used to determine the levels of four denitrification functional genes narG, nirK, norB and nosZ present in the surface sediments of the Liaohe Estuary. The narG gene, which dominates nitrate reduction, was found to be the most abundant. The nirK-type denitrification functional gene was sequenced by high-throughput sequencing. The results showed that the genus of denitrifying bacteria in the Liaohe Estuary was mainly Devosia, Phaeobacter, Alcaligenes, Pseudomonas. The abundance of denitrification function genes is mainly affected by sediment properties, except that norB gene is significantly related to many environmental factors. The community structure and diversity of nirK type denitrifying bacteria are mainly affected by salinity, pH, dissolved oxygen and
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