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chlorophyll a increase induced by surface winds in the northern South China Sea

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Acta Oceanologica Sinica 2012年第4期31卷 76-88页

作者： GAO Shan WANG Hui LIU Guimei HUANG Liangmin SONG Xingyu College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China National Marine Environmental Forecasting Center State Oceanic AdministrationBeijing 100081China State Key Laboratory of Oceanography in the Tropics Guangzhou 510301China Key Laboratory of Marine Bio-resources Sustainable UtilizationChinese Academy of SciencesGuangzhou 510301China

The response of chlorophyll a （Chl a） concentration to wind stress is analyzed in the South China Sea （SCS）, using in-situ data of Chl a and remote sensing data （QuikScat-sea surface wind （SSW）, AVHRR-sea surface temperature （SST）, AVISO merged-sea level anomalies （SLA）, SeaWiFS- derived Chl a and MODIS Terra-derived Chl a） in August/September/October 2004, 2006 and 2009. The variability of SSW, SST and SLA 7 d before in-situ Chl a sampling （including the work day of in^situ Chl a sampling） with the same latitude and longitude of the study area are investigated, and the correlation coefficients are calculated between these hydrographic factors and in-situ Chl a concentration. The results show that the Chl a-SSW correlation coefficients at upper layers （such as 0 m and 25 m） are more significant than those at deeper layers （such as 50, 75 and 100 m） 1 3 d before, which indicates that there is a time lag of strong surface winds stimulating phytoplankton bloom. By analyzing the relationship among the daily remote sensing derived （RS- derived） SSW, SST, SLA and 3 d averaged SeaWiFS/MODIS-derived Chl a concentration in the northern SCS in September 2004 and 2009 respectively, it shows that the intensity and speed of surface winds could have great influence on extend of Chl a increase. If surface winds reach 4-5 m/s over, Chl a concentration would increase 1-3 d after the process of strong surface winds in open sea area of the northern SCS mainly during September.

关键词： South China Sea phytoplankton bloom chlorophyll a surface wind vertical ,nixingand upwelling

chlorophyll a photoelectrochemical cells with different metal electrodes

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Chinese Journal of Chemistry 1996年第2期14卷 147-151页

作者： Han, YY Zhou, W Lu, SF Zhou, RL SHANDONG TEACHERS UNIV DEPT CHEMJINAN 250014SHANDONGPEOPLES R CHINA

A photosensitive electrode was prepared by electrodepositing a membrane of chlorophyll a (Chla) on a SnO2 optical transparent electrode, with which and a metal counter electrode a Chla photoelectrochemical cell was formed. Photoinduced current (I-i) and photoinduced voltage (V-i) of the cell were measured. The dependence of I-i on the properties of metal electrodes was obvious, which was illustrated with mechanism bf Chla photoelectrical effects. I-i in this work was as high as 2x10(-5) A . cm(-2).

关键词： chlorophyll a photoelectrochemical cell photoinduced current

Interannual variability of remotely sensed chlorophyll a during an autumn monsoon transitional period in the Taiwan Strait

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Acta Oceanologica Sinica 2014年第5期33卷 72-80页

作者： ZHANG Caiyun HONG Huasheng State Key Laboratory of Marine Environmental Science Xiamen University Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems Xiamen University

The time series of multiple sources of satellite data are used to examine the interannual variability of chlorophyll a concentration （Chl a） and its relation to the physical environment during the autumn monsoon transitional period in the Taiwan Strait （TWS）. The satellite data included the Chl a concentration and sea surface temperature （SST） derived from the Moderate Resolution Imaging Spectroradiometer （MODIS）/ Aqua as well as the multi-sensors merged wind products from 2002 to 2012. The results show that the average Chl a concentration of the whole TWS is mainly contributed by the northern TWS. The average Chl a in the northern TWS is 3.6 times that in the southern TWS. The maximum variability of Chl a is located in the frontal regions between the cold Zhe-Min Coastal Water and the strait warm water. The temporal change of Chl a concentration is different in the northern and southern TWS. The changes in the relative strength of the cold and warm water masses is suggested to be the dominant processes in controlling the phytoplankton growth in the northern TWS, while there is wind-induced mixing in the southern TWS. Additionally, La Nina events exhibited complex effects on the interannual variability of Chl a concentration in autumn. The longterm time series of physical and biological observations are especially needed to better understand how the TWS complex ecosystem responds to climate variations.

关键词： chlorophyll a front wind-induced mixing autumn interannual variability Taiwan Strait

Algae （Microcystis and Scenedesmus） absorption spectra and its application on chlorophyll a retrieval

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Frontiers of Earth Science 2013年第4期7卷 522-530页

作者： Di WU Maosi CHEN Qiao WANG Wei GAO Satellite Environment Center Ministry of Environmental Protection Beijing 100094 China USDA UV-B Monitoring and Research Program Natural Resource Ecology Laboratory Colorado State University Fort Collins CO 80521 USA Department of Ecosystem Science and Sustainability Colorado State University Fort Collins CO 80521 USA

Blue algae and green algae are the dominant phytoplankton groups that contribute to the eutrophication and the water bloom in inland water of China. The absorption coefficients （spectra） of the algae, which do not change with its intrinsic optical characteristics and the observation geometry, are strictly additive quantities. The characteristics of the absorption spectra of the two algae are presented. The pure blue algae and the pure green algae cultured in the laboratory environment are diluted and mixed at ten volume ratios. The Quantitative Filter Technique was applied to measure their absorption spectra. The ＂hot-ethanol extraction＂ method was chosen to calculate their concentration of chlorophyll a. The retrieval algorithm developed in this study extracts the mapping information between each individual alga and their chlorophyll a concentration via Continuous Wavelet Transform, and retrieves the chlorophyll a concentration of each alga in their mixture using a trust region optimizer. The results show that the retrieved and the measured chlorophyll a concentrations of the blue algae and the green algae components in the ten mixture match well with the average relative error of 5.55%.

关键词： algae absorption coefficient spectra chlorophyll a trust region Continuous Wavelet Transform

Spatio-temporal variability of chlorophyll a and its responses to sea surface temperature, winds and height anomaly in the western South China Sea

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Acta Oceanologica Sinica 2013年第1期32卷 48-58页

作者： GAO Shan WANG Hui LIU Guimei LI Hai National Marine Environmental Forecasting Center State Oceanic Administration College of Environmental Science and Engineering Ocean University of China

To understand the response of marine ecosystem to environmental factors, the oceanographic （physical and biochemical） data are analyzed to examine the spatio-temporal distributions of chlorophyll a （Chl a） associated with surface temperature, winds and height anomaly for long periods （1997-2008） in the western South China Sea （SCS）. The results indicate that seasonal and spatial distributions of Chl a are primarily in- fluenced by monsoon winds and hydrography. A preliminary Empirical Orthogonal Function （EOF） analysis of remotely sensed data is used to assess basic characteristics of the response process of Chl a to physical changes, which reveals interannual variability of anomalous low Chl a values corresponding to strong E1 Nifio （1997-1998）, high values corresponding to strong La Nifia （1999-2000）, low Chl a corresponding to moderate E1 Nifio （2001-2003）, upward Chl a after warm event in 2005 off the east coast of Vietnam. The variability of Chl a in nearshore and the Mekong River Estuary （MER） waters also suggests its response to these warm or cold processes. Considering the evidence for covariabilities between Chl a and sea surface temperature, winds, height anomaly （upwelling or downwelling）, cold waters input and strong winds mix- ing may play important roles in the spatial and temporal variability of high Chl a. Such research activities could be very important to gain a mechanistic understanding of ecosystem responses to the climate change in the SCS.

关键词： South China Sea chlorophyll a temperature wind upwelling

Influences of the Great Whirl on surface chlorophyll a concentration off the Somali Coast in 2017

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Acta Oceanologica Sinica 2021年第11期40卷 79-86页

作者： Lingxing Dai Bing Han Shilin Tang Chuqun Chen Yan Du State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanologyand China-Pakistan Joint Research Center on Earth SciencesChinese Academy of SciencesGuangzhou 510301China University of Chinese Academy of Sciences Beijing 100049China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China

The general features of the Great Whirl(GW)off the Somali Coast in 2017 and its influences on chlorophyll a(Chl a)concentration were studied by using satellite data and model *** show that GW,which initiated at7°N,53°E on June 13,had a lifetime of 153 d with an average amplitude of 16 cm and an average radius of 205 *** the formation of GW,the concentration of Chl a in the interior of GW showed a downward trend throughout its life cycle,except in early July and *** early July,the Chl a blooms in the interior of GW were attributed to the combined effect of three *** are eddy horizontal transportation,the deepening of the mixed layer caused by the monsoon and eddy pumping,and the upward transportation of nutrients caused by eddy-induced Ekman *** October,the Chl a blooms were probably due to the weakening of *** the period,water exchange occurred more frequently across the eddy,thus phytoplanktons were imported into the interior of GW.

关键词： Great Whirl chlorophyll a mixed-layer eddy-induced Ekman pumping summer monsoon

Distributions of chlorophyll a and carbon fixed strength of phyto-plankton in autumn of the southern Huanghai Sea waters

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Acta Oceanologica Sinica 2006年第3期25卷 68-81页

作者： ZHENG Guoxia SONG Jinming DAI Jicui WANG Yiming Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate School Chinese Academy of Sciences Beijing 100039 China Zhoushan Marine Eco-enviromnental Monitoring Station in Zhejiang Province Zhoushan 316004 China

chlorophyll a （Chl a） concentration and primary productivity （PP）, namely, carbon fixed strength of phytoplankton along four transects in the southern Huanghai Sea （SHS） were studied for their distribution features and controlling mechanisms based on the investigations from 17 October to 3 November 2005. The Chl a concentration in the study waters dynamically changed spatially. Surface Chl a concentrations ranged from 0.11 to 2.38 mg/m^3 with higher and lower values observed in the nutrient-laden inshore waters and central part of the SHS occupied by oligotrophic current, respectively. The vertical distribution of Chl a concentration showed a predominant pattern of subsurface concentration maximum profile. It followed the previous result of the deep dissolved oxygen concentration maximum profile, which was significantly correlated with phytoplankton and regional water mass. The primary productivity of carbon in autumn of the SHS, ranging from 95 to 1 634 rag/（ m^2· d） mainly varied with nutrient condition, especially phosphate concentration in seawater and hydrological condition. Furthermore, associating the present study results together with previous studies, the annual value of carbon fixed production of phytoplankton in the entire marginal seas of East China （including the Bohai Sea, the Huanghai Sea and the East China Sea） was estimated to be 222 Mt, which accounted for 2% of that in the global margins. Besides, it was as 16.2 times as the annual value of apparent carbon sink strength （ 13.96 Mt） in the marginal seas of East China. This multiple was different in different sea areas （ 3.0 in the Bohai Sea, 6. 7 in the Huanghai Sea and 81.6 in the East China Sea）.

关键词： chlorophyll a primary productivity carbon fixed strength southern Huanghai Sea

The distribution of chlorophyll a and its influencing factors in different regions of the Bering Sea

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Acta Oceanologica Sinica 2014年第6期33卷 112-119页

作者： KANG Jianhua CHEN Xingqun ZHANG Ming Third Institute of Oceanography State Oceanic Administration

The distribution of chlorophyll a （Chl a） and its relationships with physical and chemical parameters in different regions of the Bering Sea were discussed in July 2010. The results showed the seawater column Chl a concentrations were 13.41-553.89 mg/m2 and the average value was 118.15 mg/m2 in the study areas. The horizontal distribution of Chl a varied remarkably from basin to shelf in the Bering Sea. The regional order of Chl a concentrations from low to high was basin, slope, outer shelf, inner shelf, and middle shelf. The verti- cal distribution of Chl a was grouped mainly from single-peak type in basin, slope, outer shelf, and middle shelf, where the deep Chl a maxima （DCM） layer was observed at 25-50 m, 30-35 m, 36-44 m, and 37-47 m, respectively. The vertical distribution of Chl a mainly had three basic patterns： standard single-peak type, surface maximum type, and bottom maximum type in the inner shelf. The analysis also showed that the transportation of ocean currents may control the distribution of Chl a, and the effects were not simple in the basin of the Bering Sea. There was a positive correlation between Chl a and temperature, but no significant correlation between Chl a and nutrients. The Bering Sea slope was an area deeply influenced by slope current. Silicate was the factor that controlled the distribution of Chl a within parts of the water in the slope. Light intensity was an important environmental factor in controlling seawater column Chl a in the shelf, where Chl a was limited by nitrate rather than phosphate within the upper water. Meanwhile, there was a positive relationship between Chl a and salinity. Algal blooms broke out at Sta. B6 of the southwestern St. Lawrence Island and Stas F6 and F11 in the middle of the Bering Strait.

关键词： chlorophyll a distribution characteristics environmental influence factor algal bloom Bering Sea

Spatial and temporal variability and size fractionation of chlorophyll a in the tropical and subtropical Pacific Ocean

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Acta Oceanologica Sinica 2012年第3期31卷 120-131页

作者： ZHANG Dongsheng WANG Chunsheng LIU Zhensheng XU Xuewei WANG Xiaogu ZHOU Yadong Laboratory of Marine Ecosystem and Biogeochemistry State Oceanic AdministrationHangzhou 310012China

The spatial and temporal variability and size fractionation of chlorophyll a (Chl a) were investigated in the tropical and subtropical Pacific Ocean during four survey cruises from 2005 to *** surface Chl a (S-Chl a) concentration ranged from 0.002 to 0.497 mg/m3 and was obviously higher in the eastern Pacific than in the western and central *** vertical distribution of Chl a displayed a single peak pattern,and the maximum Chl a layer (MCL) was observed at a shallower depth in the eastern Pacific than in the western *** three size fractions of Chl a measurements in the surface water showed a similar distribution to total Chl a and were found in higher concentrations in the eastern Pacific than in the western and central *** dominated the phytoplankton in the surveyed tropical and subtropical Pacific ***,pico-Chl a (0.2-2 μm) accounted for a larger percentage of the total Chl a in the central Pacific than it did in the western Pacific and eastern *** the western Pacific,there seemed to be a latitudinal variability in the phytoplankton community composition where small-sized phytoplankton (＜2 μm) were more dominant in the tropical than in the subtropical western *** spatial and temporal variability and size fractionation of Chl a were controlled by hydrological and chemical characteristics and climate events,such as El Ni(n)o and La Ni(n)a.

关键词： chlorophyll a size fractionation Pacific Ocean