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1.
The spatial and temporal variability of the phytoplankton community structure in Daya Bay, South China Sea, were identified by using HPLC-CHEMTAX analytical techniques. The highest chlorophyll a(Chl a) concentrations were observed during summer(with an average value of 0.84 μg/L) and lowest ones during winter(with an average value of 0.33 μg/L). CHEMTAX processing revealed the seasonal succession of phytoplankton species in Daya Bay. During winter, diatoms were the dominant phytoplankton species and contributed 41.5% to total Chl a. Based on Chl a concentration, the average ratio of dinofl agellates to total phytoplankton biomass substantially increased with increasing temperature and nitrogen to phosphorus(N/P) ratio, reaching 52.2% in spring. Nutrient limitation shifted from phosphorus to nitrogen during summer. Moreover, this period was associated with the predominance of diatoms, which accounted for 71.1% of Chl a. Prasinophytes and cryptophytes were the other two dominant groups and particularly dominated during winter. Cyanobacteria became an important group during summer and autumn. Canonical correspondence analysis suggested that chrysophytes, dinofl agellates, and cryptophytes were strongly associated with high nitrate concentration, ammonium, dissolved inorganic nitrogen(DIN), and N/P ratio, and were negatively associated with temperature and phosphate. Diatoms and cyanobacteria were strongly associated with temperature, phosphate, and salinity, and are negatively influenced by nitrate, ammonium, DIN, and N/P ratio. Microscopic observations and pigment HPLC information were in good agreement for diatoms and dinofl agellates in the bay. This study demonstrated the usefulness of pigment analysis in investigating the distribution of phytoplankton groups in a complex physical environment, such as Daya Bay.  相似文献   

2.
Maowei Sea(MWS) is the largest oyster maricuture bay in Southwest China. Surface water from 12 sampling sites were collected during the dry season to study the composition and distribution of different forms of nitrogen(N) and phosphorus(P) beginning from the inner bay to the bay mouth in the MWS. An improved multi-parameter eutrophication index was developed and applied for the evaluation of the water quality in the MWS. Dissolved inorganic nitrogen(DIN), dissolved organic nitrogen(DON), and particulate nitrogen(PN) averagely accounted for 11.28%, 65.32%, and 23.39% of total N(TN) pool, dissolved inorganic phosphorus(DIP), dissolved organic phosphorus(DOP), and particulate phosphorus(PP) averagely accounted for 54.58%, 30.31%, and 15.12% of total P(TP) pool, respectively. DON and DIP were respectively the dominant forms of N and P in surface water of the MWS, during the study period. Concentration trends of DIN, DIP, DOP, PN, dissolved silicate(DSi), total organic carbon(TOC), chemical oxygen demand(COD) decreased from the inner bay to the bay mouth, suggesting that the MWS may be largely influenced by land-based inputs. Based on nutrient contents and stoichiometry, it likely that phytoplankton growth in the MWS is strongly limited by DIP during the dry season. Results from the improved eutrophication index revealed that the water quality in the MWS is in a state of moderate to poor eutrophication(average EI = 0.953). The eutrophication state decreased from the inner bay to the bay mouth. Nitrate(NO3-N), DON, DIP, DOP, and DSi showed significant positive correlations with eutrophication index(r2 = 0.52 – 0.78, P < 0.05), implying that these nutrients are among the significant factors, which could be used in evaluating the eutrophication status of the MWS.  相似文献   

3.
Relationships between phytoplankton community composition and environmental variables in the East China Sea (ECS) and Yellow Sea (YS) were investigated using geochemical and molecular microbiology methods. The diversity of phytoplankton was characterized using cultivation-independent PCR-based denaturing gradient gel electrophoresis (DGGE). Groups resulting from unweighted pair-group method with arithmetic averages clustering of the DGGE profiles showed good consistency with the eco-environmental characteristics of the sea area they belonged to. Additionally, the clustering results based on DGGE fingerprinting and those based on morphological compositions were practically identical. The relationship of phytoplankton diversity to environmental factors was statistically analyzed. Temperature, dissolved inorganic nitrogen (DIN), and silicate-Si were found significantly related to the phytoplankton community composition. Canonical correspondence analysis (CCA) was performed to reveal the relationship between community composition and these three environmental factors. Generally, values of the ECS are clearly separated from those of the YS in the CCA biplot, due to mainly the effect of temperature and DIN.  相似文献   

4.
Using a three-dimensional coupled biophysical model,we simulated the responses of a lowtrophic ecosystem in the East China Sea(ECS)to long-term changes in nutrient load from the Changjiang(Yangtze)River over the period of 1960–2005.Two major factors aff ected changes in nutrient load:changes in river discharge and the concentration of nutrients in the river water.Increasing or decreasing Changjiang discharge induced different responses in the concentrations of nutrients,phytoplankton,and detritus in the ECS.Changes in dissolved inorganic nitrogen(DIN),silicate(SIL),phytoplankton,and detritus could be identified over a large area of the ECS shelf,but changes in dissolved inorganic phosphate(DIP)were limited to a small area close to the river mouth.The high DIN:DIP and SIL:DIP ratios in the river water were likely associated with the diff erent responses in DIN,DIP,and SIL.As DIP is a candidate limiting nutrient,perturbations in DIP resulting from changes in the Changjiang discharge are quickly consumed through primary production.It is interesting that an increase in the Changjiang discharge did not always lead to an increase in phytoplankton levels in the ECS.Phytoplankton decreases could be found in some areas close to the river mouth.A likely cause of the reduction in phytoplankton was a change in the hydrodynamic field associated with the river plume,although the present model is not suitable for examining the possibility in detail.Increases in DIN and DIP concentrations in the river water primarily led to increases in DIN,DIP,phytoplankton,and detritus levels in the ECS,whereas decreases in the SIL concentration in river water led to lower SIL concentrations in the ECS,indicating that SIL is not a limiting nutrient for photosynthesis,based on our model results from 1960 to 2005.In both of the above-mentioned cases,the sediment accumulation rate of detritus exhibited a large spatial variation near the river mouth,suggesting that core sample data should be carefully interpreted.  相似文献   

5.
Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment,southwestern China,to understand phytoplankton community structure and environmental factors.The relationship between phytoplankton community structure and environmental factors including hydrological,meteorological,physical,and chemical variables were explored using multivariate analysis.A total of 81 taxa of phytoplankton were identified,which were mainly composed of chlorophyta,bacillariophyta,and cyanobacteria.The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring.The abundance of phytoplankton ranged from 0.24×104 cells/L to 33.45×106 cells/L,with the minimum occurring during February 2010 and the maximum during July 2009.The phytoplankton community was dominated mainly by cyanobacteria from April to September,and by bacillariophyta and pyrrophyta from October to March.Canonical correspondence analysis showed that temperature,pH values,and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary.Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values,while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.  相似文献   

6.
The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters.In this study,phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009.It was found that dinoflagellates,Prorocentrum donghaiense and Karenia mikimotoi,and diatoms,Skeletonema spp.and Paralia sulcata,were the major taxa dominating the phytoplankton community.Cluster analysis,non-metric multidimensional scaling(NMDS) and analysis of similarities(ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples.The analyses categorized the samples into three groups at a similarity level of 30%.Group Ⅰ was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region.Group Ⅱ,which was dominated by the diatom Skeletonema spp.and represented the red tide of Skeletonema spp.,was situated around Group Ⅰ in the sea area west of 122°50'E.Group Ⅲ was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups Ⅰ and Ⅱ.Group Ⅲ was further divided into two subgroups(Ⅲ-S1 and Ⅲ-S2) at a similarity level of 40%.Group Ⅲ-S1 was characterized by the presence of the benthic diatom P.sulcata,representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling.GroupⅢ-S2 was dominated by dinoflagellates and represented red tides formed by P.donghaiense and K.mikimotoi.A gradual change of red-tide causative species was observed from the estuary to the offshore sea area,from diatoms to armored dinoflagellates and then unarmored dinoflagellates.Environmental factors associated with each group,and thus affecting the distribution of phytoplankton and red tides,are discussed.  相似文献   

7.
A large-scale bloom occurred from May to June in 2011 in sea area near Qinhuangdao of the Bohai Sea, leading to huge damage of the scallop culture industry. Similar blooms have been observed in this region for three years. The causative species of the bloom, which dominated the phytoplankton community with the maximum cell density around 109 cell/L, could not be identified with morphological features due to the small cell size (~2 mm). A pigment analytical method was then adopted to analyze the pigment profile of the phytoplankton samples collected from the blooming sea area. It was found that pico-sized (<2 mm), nano-sized (2-20 mm), and bulk phytoplankton samples had similar pigment profile, representing the pigment signature of the bloom-causative species. The major pigments detected included 19-butanoyloxyfucoxanthin (But-fuco), fucoxanthin (Fuco), diadinoxanthin (Diad) and chlorophyll a (Chl a), and high content of But-fuco was the most significant characteristics of the phytoplankton samples. Based on the pigment composition and content, the bloom-causative species could be tentatively identified as pelagophyte, "type 8" group of haptophyte, or silicoflagellate. Some unique features of the bloom, such as the extremely high cell density, small-sized and But-fuco containing cells, occurring in early summer, and the feeding-cessation effects on scallops, suggest it be a "brown tide" event similar to those reported in the east coast of the United States of America. The recurrent "brown tide" events and their dramatic impacts on the shellfish mariculture industry in Qinhuangdao need close attention in the coming years.  相似文献   

8.
STUDY ON THE PHYTOPLANKTON.IN A LARGE RESERVOIR   总被引:6,自引:0,他引:6  
A comprehensive study on the community structure and function of the phytoplankton in Taipinghu Reservoir, the largest reservoir (9400 ha) in Anhui Province, China, was carried out dur ing 1985- 1986. A total of 175 species of algae belonging to 8 phyla and 87 genera was noted. The composition of phytoplankton was dominated by species of Chlorophyta, Cyanophyta and Bacillariophyta. The species number, cell density and biomass of the three groups were respectively 88%, 86.5% and 78.9% of the total phytopiankton. The weighted annual average biomass was 1.52 mg/L and cell density was 1.43 x 106 ind/L. The growth maximum was observed in summer. Diatoms were abundant in the region adjoining a river. A large number of flagellated algae such as Euglena and Chromulina occurred in the artificial fish culture bay.It can be inferred from the algal composition and total nitrogen concentration (1.48mg/L) that this reservoir is a mesotrophic water body that had undergone slight natural eutrophication.Presented are an  相似文献   

9.
Dissolved nutrient concentration in the Huanghe(Yellow) River at Lijin was monitored during a water-sediment regulation period and a subsequent rainstorm from 14 June to 19 July, 2005. This study provides detailed information on nutrient concentrations in the Huanghe River during the water-sediment regulation and rainstorm periods, and is of signifi cance for the downstream area of the Huanghe River and the Bohai Sea. The average concentrations of nitrate, nitrite and ammonia were 304.7 μmol/L, 0.19 μmol/L, and 1.10 μmol/L, respectively, while the average concentrations of dissolved inorganic phosphorus(DIP) and dissolved silicate(DSi) were 0.23 μmol/L and 122.9 μmol/L, respectively. Nutrient concentrations during the water-sediment regulation period were mainly infl uenced by the dilution effect, fl oodplain effect and sediment resuspension while dilution and erosion effects were the main factors during the rainstorm. The fl uxes of dissolved inorganic nitrogen(DIN), DIP and DSi during the water-sediment regulation and rainstorm periods accounted for 20.4%, 19.5%, 16.7% and 4.97%, 6.45%, 5.47% of the annual nutrient fl uxes, respectively. Discharge was the main factor infl uencing the fl uxes of nutrients during both the watersediment regulation and the rainstorm periods.  相似文献   

10.
Glass-plate sampling during 1988- 1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface mierolayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.  相似文献   

11.
Systematic studies of the changes in dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) and their effects on phytoplankton over the last 30 years in the Bohai Sea are presented. The amount of sewage disposal, use of fertilizer and the Huanghe River runoff were found to have a significant influence on the DIN or DIP concentrations in the Bohai Sea over the last 30 years. Moreover, the changes in DIN and DIP resulted in changes in the limiting nutrients of phytoplankton in the Bohai Sea from nitrogen in the early 1980s to nitrogen-phosphorus in the late 1980s, and then to phosphorus after the 1990s. In addition, changes in nitrogen and phosphorus had a significant effect on the phytoplankton community structure. The half saturation constant (K s) was used to evaluate the effect of nutrients on the phytoplankton community structure in the Bohai Sea over the last 30 years. Cell abundance percentages of dominant phytoplankton species with high K s values for phosphorus and low K s values for nitrogen have decreased since the 1980s, while those of dominant phytoplankton species with low K s values for phosphorus and high K s values for nitrogen increased during this period.  相似文献   

12.
This study on the distribution of phosphate and its relation to phytoplankton biomass in Western Xiamen Harbor using marine ecosystem enclosures to isolate the culture water from the tidal currents and salinity changes outside indicated that the phytoplankton biomass variation closely related to dissolved inorganic phosphorus (DIP) in the seawater as described by the equation: [Chl-a]=A×e−B[PO4]. The biomass changes lagged by about two days the corresponding DIP. The research also dealt with the minimal DIP concentration for stopping diatom bloom and the possible maximal diatom biomass was estimated from the DIP external concentration in the seawater. The threshold of DIP initiatingSkeletonema costatum red tide was calculated for use as an index to forecast its red tides. In addition, the relationships between a dinoflagellate red tide and nutrients are discussed. The results showed that the multiplication of dinoflagellate was not entirely dependent on the nutrients in the seawater. Project 39570145 supported by the NSFC and Fujian Science Foundation (No. D94010).  相似文献   

13.
INTRODUCTIONPhosphorusisakeynutritiveelementforthegrowthofmarinephytoplankton .Recently ,be causeofenvironmentalpollution ,theeutrophicationproblemsincoastalandoceanicwatershavebe comemoreandmoreserious.Theenvironmentecologicalresponseinthelong termtothef…  相似文献   

14.
A bloom of the dinoflagellate Scrippsiella trochoidea was detected for the first time in inner Tolo Harbor, Hong Kong in 2 000. Water samples were collected at eight stations along a transect passing through a red tide patch for microscopic analysis of phytoplankton composition and high-performance liquid chromatography (HPLC) analysis of phytoplankton pigments. During the bloom, the density of dinoflagellates was 1.1×106 cells L−1 within the patch and 8.6×105 cells L−1 outside the patch where the phytoplankton community was dominated by diatoms. After the bloom the S. trochoidea began to decrease in density and was replaced by diatoms as the dominating bloom-causing organisms at all stations, and the density of dinoflagellates at most stations was less than 1.0 × 106 cells L−1. The status of S. trochoidea as the causative species of the bloom was indicated by the presence of peridinin, the marker pigment for dinoflagellates. The shift from dinoflagellates to diatoms was marked by the decline of peridinin and the prevalence of fucoxanthin. Phytoplankton pigment markers also revealed the presence of other minor phytoplankton assemblages such as cryptomonads and blue-green algal.  相似文献   

15.
INTRODUCTIONKnowledgeofthedistributionandcompositionofthechlorophyllandcarotenoidpigmentsincoastalmarinewatersprovidesinformationonthephytoplanktonbiomassandalsoonitschemotaxon omy ,thecontributionofriverineinputs,andtheearlydegradationroutesoccurringi…  相似文献   

16.
To understand the relationship between the plankton community and environmental factors and water quality in the Bayuquan Port of Liaodong Bay, China, and investigations were carried out during six different periods (April 2009, April 2010, October 2011, April 2012, October 2012, and April 2013). This area was characterized by high levels of nutrient and suspended solids (SPS) during survey periods, and eutrophication led to the occurrence of red tides in April and October 2012 and April 2013. Our analyses revealed that the plankton communities of Bayuquan Port lacked stability and were affected seriously by external disturbance (e.g., oceanographic engineering and river runoff). Our data indicate that oil, dissolved inorganic nitrogen (DIN), SPS, and chlorophyll a (Chl-a) were key factors that regulated the phytoplankton and zooplankton communities. The partial redundancy analysis (partial RDA) suggested that oil and SPS were the most important environmental variables affecting the phytoplankton community in April 2010 and 2012, whereas DIN concentration played a governing role in zooplankton dynamics. Oil and Chl- a concentrations affected significantly the zooplankton community in October 2012. Therefore, the plankton communities could reflect both dynamic changes in coastal environmental factors and the ongoing eutrophication process caused by anthropogenic activities in this area.  相似文献   

17.
Effects of nitrogen (N) and phosphorus (P) from different sources and at different concentrations on the growth of Levanderina fissa (= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate (μ max) and half-saturation nutrient concentration (K S) were 0.37 divisions/d and 8.49 μmol L?1 for N, and 0.39 divisions/d and 1.99 μmol L?1 for P, respectively. Based on K S values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N (DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P (DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.  相似文献   

18.
Relationships between phytoplankton community composition and environmental variables in the East China Sea (ECS) and Yellow Sea (YS) were investigated using geochemical and molecular microbiology methods. The diversity of phytoplankton was characterized using cultivation-independent PCR-based denaturing gradient gel electrophoresis (DGGE). Groups resulting from unweighted pair-group method with arithmetic averages clustering of the DGGE profiles showed good consistency with the eco-environmental characteristics of the sea area they belonged to. Additionally, the clustering results based on DGGE fingerprinting and those based on morphological compositions were practically identical. The relationship of phytoplankton diversity to environmental factors was statistically analyzed. Temperature, dissolved inorganic nitrogen (DIN), and silicate-Si were found significantly related to the phytoplankton community composition. Canonical correspondence analysis (CCA) was performed to reveal the relationship between community composition and these three environmental factors. Generally, values of the ECS are clearly separated from those of the YS in the CCA biplot, due to mainly the effect of temperature and DIN.  相似文献   

19.
依据香港特别行政区环境保护署于1999—2007年106个航次的调查资料,结合国家海洋局南海分局于1998—2007年10个航次的调查资料,简要描述和分析大鹏湾海水中可溶性无机氮(DIN)和可溶性无机磷(DIP)含量的多年平均分布变化。结果表明,DIN和DIP含量均夏、冬季较高,而春、秋季较低;受香港和深圳等陆源排放影响,四季吐露港西部和沙头角海区域的DIN和DIP含量普遍比其他区域高;夏季南澳养殖场附近水域的DIN也明显较高,可能与养殖场的饵料投放有关。大鹏湾海水中平均氮磷原子比大于16,而DIN和DIP的平均含量分别为0.069和0.009 mg/L。夏季,由于外海高盐水的入侵,底层水中DIN和DIP含量明显高于表层。9 a调查期间,大鹏湾香港海区海水中DIN和DIP含量的年际变化呈较明显下降趋势,而氮磷原子比的年际变化则呈上升趋势。  相似文献   

20.
Two surveys were performed for determining bacteria biomass (BB), temperature, salinity, chlorophyll a (chl-a) and nutrient concentrations at 11 stations with three sampling depths in the high-incidence regions of red tide in the East China Sea (ECS) in the spring of 2006. Temperature and salinity increased from nearshore to offshore region and from high latitude to low latitude in the two cruises of 2006. BB were between 0.3–5.2 mgC m−3 (about 2.1 mgC m−3 on average) and 0.2–6.0 mgC m−3 (about 2.7 mgC m−3 on average) respectively in the two cruises. BB in the surface layer decreased from the Changjiang River estuary to high sea and from low latitude to high latitude. The results showed that bacterial growth was regulated by temperature, primary production and inorganic nutrient concentrations depending on different hydrographic conditions. In the surface and middle layers where the primary production can supply enough organic substrate, temperature was the main factor to control bacteria biomass. BB showed a good correlation between the surface and middle layers in both cruises. The distribution of nutrients during both cruises showed a similar decreasing trend from nearshore region and high latitude to offshore region and low latitude. High BB values were mainly recorded from samples in the middle layer where chl-a concentrations were also high, indicating primary production being strongly correlated with temperature over the ECS shelf. In the offshore area, phosphate and silicate became limiting factors for phytoplankton growth with indirect influence on BB. Bacteria played an important role in nitrogen regeneration process turning organic nitrogen to inorganic forms such as NH4 +. The increasing ratio of NH4 +/DIN could be a proof of that.  相似文献   

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