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1.
Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton community.Lipids play an important role in copepod diapause,which is part of their over-summering strategy.We investigated how different fatty acids and lipid classes,including wax esters,changed during over-summering of C.sinicus during three cruises in June and August 2011 and November 2010,corresponding to the pre-,during and post-diapause periods,respectively.Large amounts of lipids were accumulated,mainly wax esters as previously found in C.finmarchicus during its diapause,and most of the storage lipids were used during over-summering.Wax ester polyunsaturated fatty acids(PUFAs) showed the most variation of the fatty acids(FAs),while the percentage composition of FAs in polar lipids was relatively stable.Selective use of wax ester PUFAs has already been shown to play important roles in the winter diapause of Calanus species in other regions,and our FA results show that this is the case for the Yellow Sea Cold Bottom Water(YSCBW) population that diapauses in summer.  相似文献   

2.
The Yellow Sea Cold Water Mass(YSCWM),one of the most vital hydrological features of the Yellow Sea,causes a seasonal thermocline from spring to autumn.The diel vertical migration(DVM) of zooplankton is crucial to structural pelagic communities and food webs,and its patterns can be affected by thermocline depth and strength.Hence,we investigated zooplankton community succession and seasonal changes in zooplankton DVM at a fixed station in the YSCWM.Annual zooplankton community succession was affected by the forming and fading of the YSCWM.A total of 37 mesozooplankton taxa were recorded.The highest and lowest species numbers in autumn and spring were detected.The highest and lowest total densities were observed in autumn(14 464.1 inds./m3) and winter(3 115.4 inds./m3),respectively.The DVM of the dominant species showed obvious seasonal variations.When the YSCWM was weak in spring and autumn,most species(e.g.Paracalanus parvus,Oithona similis,and Acartia bifilosa) stayed above the thermocline and vertically migrated into the upper layer.Calanus sinicus and Aidanosagitta crassa crossed the thermocline and vertically migrated.No species migrated through the stratification in summer,and all of the species were limited above(P.parvus and A.crassa) or below(C.sinicus and Centropages abdominalis)the thermocline.The YSCWM disappeared in winter,and zooplankton species were found throughout the water column.Thus,the existence of thermocline influenced the migration patterns of zooplankton.Cluster analyses showed that the existence of YSCWM resulted in significant differences between zooplankton communities above and below the thermocline.  相似文献   

3.
This study aims to analyze the spatial and temporal variations of the abundance and biodiversity of pelagic copepods and their relationships with the environmental factors in the North Yellow Sea(NYS). These variations were analyzed on the basis of the survey data of the NYS in four seasons from 2006 to 2007. A total of 31 copepod species that belong to 17 genera, 13 families and 4 orders were identified in the four seasons. Of these copepods, the species belonging to Calanoida is the most abundant component. The dominant species include Calanus sinicus, Centropages abdominalis, Paracalanus parvus, Acartia bifilosa, Oithona plumifera, and Corycaeus affinis. C. sinicus is the most important and widely distributed dominant species in all of the seasons. The dominant species have not shown any significant variation for the past 50 years. However, the richness of warm-water species increased. The abundance of copepods significantly varied among different seasons: the average abundance was higher in spring(608.2 ind m~(-3)) and summer(385.1 ind m~(-3)) than in winter(186.5 ind m~(-3)) and autumn(128.0 ind m~(-3)). Factor analyses showed a high correlation between the spatial distributions of dominant copepods and environmental parameters, and Chl-a was the most important factor that influenced the distribution of copepods. This research can provide the fundamental information related to zooplankton, especially pelagic copepods. This research is also beneficial for the long-term monitoring of zooplankton ecology in the NYS.  相似文献   

4.
We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels(0,36,72,108,144 and 180 J/m2),and thereafter subjected to PAR,darkness,or red or blue light during a 2-h repair stage,each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers(CPDs),chlorophyll a(Chl a),phycoerythrin,and UV-B-absorbing mycosporinelike amino acids(MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation(36 and 72 J/m 2) promoted the growth of C. ocellatus; however,increased UV-B radiation gradually reduced the C. ocellatus growth(greater than 72 J/m2). The MAAs(palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition,photorepair was inhibited by red light,so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase,greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore,PAR,red light,and blue light play different roles during the repair processes for damage induced by UV-B radiation.  相似文献   

5.
With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-weight relationship,age composition,growth pattern,mortality,and exploitation rates of the yellow goosefish in the Yellow Sea.Total length(TL) of females and males ranged from 173 to582 mm and 178 to 500 mm,respectively.The length-weight relationships were also estimated for females and males.Age classes from 2 to 4 years predominated in the samples.The von Bertalanffy growth function(VB GF),estimated based on non-linear least-squares methodology,showed significant differences between sexes.Females attained a greater estimated asymptotic total length(765 mm TL) compared to males(579 mm TL).The VBGF did not differ significantly between stocks of the northern Yellow Sea and the southern Yellow Sea.Estimated natural instantaneous mortality rate(M) ranged from 0.25/a to 0.33/abased on four age-and length-based methods.Total instantaneous mortality rate(Z) of total samples calculated by the age-based catch curve method was 0.591/a and the average fishing mortality(F) was 0.30/a.Estimated exploitation rate(E) was approximately 0.5,indicating that the population of L.litulon in the Yellow Sea may be sustainable.These results provide a reference for the present status of L.litulon and information for the management.  相似文献   

6.
We evaluated the effects of ultraviolet-B(UV-B) radiation and different light conditions on the repair of UV-B-induced damage in carpospores of C hondrus ocellatus Holm(Rhodophyta) in laboratory experiments. Carpospores were treated daily with different doses of UV-B radiation for 48 days,when vertical branches had formed in all treatments; after each daily treatment,the carpospores were subjected to photosynthetically active radiation(PAR),darkness,red light,or blue light during a 2-h repair stage. Carpospore diameters were measured every 4 days. We measured the growth and cellular contents of cyclobutane pyrimidine dimers(CPDs),chlorophyll a,phycoerythrin,and UV-B-absorbing mycosporine-like amino acids(MAAs) in carpospores on Day 48. Low doses of UV-B radiation(36 and 72 J/m 2) accelerated the growth of C. ocellatus. However,as the amount of UV-B radiation increased,the growth rate decreased and morphological changes occurred. UV-B radiation significant damaged DNA and photosynthetic pigments and induced three kind of MAAs,palythine,asterina-330,and shinorine. PAR conditions were best for repairing UV-B-induced damage. Darkness promoted the activity of the DNA darkrepair mechanism. Red light enhanced phycoerythrin synthesis but inhibited light repair of DNA. Although blue light,increased the activity of DNA photolyase,greatly improving remediation efficiency,the growth and development of C. ocellatus carpospores were slower than in other light treatments.  相似文献   

7.
Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a (Chl-a) levels. The Chl-a growth rates (k) ranged from 0.60–1.67 d−1, while microzooplankton grazed the Chl-a at rates (g) of 0.29–0.62 dt-1. The addition of C. sinicus enhanced the Chl-a growth rate (Z) by 0.004–0.037 d−1 ind.−1 L. C. sinicus abundance ranged from 84.1–160.9 ind. m−3, which occupied 90.7%–99.1% of the copepod (>500 μm) population. The in-situ increase in phytoplankton by C. sinicus community was estimated to be 0.000 4–0.005 9 d−1. These results showed that microzooplankton were the main grazers of phytoplankton, while C. sinicus induced a slight increase in the levels of phytoplankton.  相似文献   

8.
The Yellow Sea Warm Current (YSWC) is one of the principal currents in the Yellow Sea in winter. Former examinations on current activity in the Yellow Sea have not observed a stable YSWC because of the positioning of current meters. To further understand the YSWC, a research cruise in the southern Yellow Sea was carried out in the winter of 2006/2007. Five moorings with bottom-mounted acoustic Doppler current profilers (ADCP) were deployed on the western side of the central trough of the Yellow Sea. The existence and distributional features of the YSWC were studied by analyzing three ADCP moorings in the path of the YSWC in conjunction with conductivity-temperature-depth (CTD) data over the observed area in the southern Yellow Sea. The results show the following. (1) The upper layer of the YSWC is strongly influenced by winter cold surge; its direction and speed often vary along a south-north axis when strong cold surges arrive from the north. (2) The YSWC near the bottom layer is a stable northwest flowing current with a speed of 4 to 10 cm/s. By combining the analyses of the CTD data, we speculate that the core of the YSWC may lie near the bottom. (3) On a monthly average timescale, the YSWC is stably oriented with northward flow from the sea surface to the sea floor.  相似文献   

9.
Samples were collected monthly from the sea area around Zhangzi Island,northern Yellow Sea,from July 2009 to June 2010.Vertical net towing was used to examine spatial and temporal variability in zooplankton abundance and biomass.Overall,C alanus sinicus and Saggita crassa were the dominant species found during the study period,while the amphipod T hemisto gracilipes was dominant in winter and spring.Vast numbers of the ctenophore species of the genus Beroe were found in October and November.It was not possible to count them,but they constituted a large portion of the total zooplankton biomass.Zooplankton species diversity was highest in October,and species evenness was highest in April.Zooplankton abundance(non-jellyfi sh)and biomass were highest in June and lowest in August,with annual averages of 131.3 ind./m3and 217.5 mg/m3,respectively.Water temperature may be responsible for the variations in zooplankton abundance and biomass.B eroe biomass was negatively correlated with other zooplankton abundance.Longterm investigations will be carried out to learn more about the infl uence of the environment on zooplankton assemblages.  相似文献   

10.
Bare patches in alpine meadow are the main manifestation of its degradation. The change of bare patches in an alpine meadow in the Yellow River Source Zone during 2018-2019 was studied in relation to the disturbances caused by plateau pika(Ochotona curzoniae) population and simulated grazing via artificial mowing both independently and interactively. The disturbance was set at three levels of high, medium and no disturbance(control group). Bare patches were mapped by from unmanned aerial vehicle(UAV) images with fine resolution of 1 cm obtained in August 2018 and August 2019 in ArcGIS. The results showed that the total area of bare patches decreased by 112.05 m~2 in sub-plots devoid of pika disturbance but increased by 126.37 m~2 in other subplots. The highest rate of increase is 89.02%. The individual effect of pika exceeds the joint effect of pika and mowing disturbances. The sole effect of mowing is lower than the joint effect of pika disturbance and intensive mowing, but higher than the joint influence of pika disturbance and moderate mowing. Strong pika disturbance(14 per sub-plot) caused the influence of mowing from moderate to intensive to increase by five-fold. The area of bare patches treated with moderate mowing and no pika disturbance decreased at the highest pace(-37.22%). Intensive mowing and medium density pikas(100 pikas/ha) are considered the thresholds at which the bare patches start to expand. Even if the meadow is mowed at the medium and high intensity, the area of bare patches can be significantly reduced if plateau pika population is controlled to a low level. ANOVA analysis and longterm macro-scale satellite-derived results reveal that pika disturbance is more important in causing the bare patches to change than simulated grazing. Therefore, it is more important to control the number of pikas than to reduce grazing intensity to prevent the expansion of bare patches in the degraded alpine meadow in the study area.  相似文献   

11.
An MOM2 based 3-dimentional prognostic baroclinic Z-ordinate model was established to study the circulation in eastern China seas, considering the topography, inflow and outflow on the open boundary, wind stress, temperature and salinity exchange on the sea surface. The results were consistent with observation and showed that the Kuroshio intrudes in large scale into the East China Sea continental shelf East China, during which its water is exchanged ceaselessly with outer sea water along Ryukyu Island. The Tsushima Warm Current is derived from several sources, a branch of the Kuroshio, part of the Taiwan Warm Current, and Yellow Sea mixed water coming from the west of Cheju Island. The water from the west of Cheju Island contributes approximately 13% of the Isushima Warm Current total transport through the Korea Strait. The circulation in the Bohai Sea and Yellow Sea is basically cyclonic circulation, and is comprised of coastal currents and the Yellow Sea Warm Current. Besides simulation of the real circulation, numerical experiments were conducted to study the dynamic mechanism. The numerical experiments indicated that wind directly drives the East China Sea and Yellow Sea Coastal Currents, and strengthens the Korea Coastal Current and Yellow Sea Warm Current. In the no wind case, the kinetic energy of the coastal current area and main YSWC area is only 1% of that of the wind case.Numerical experiments also showed that the Tsushima Warm Current is of great importance to the formation of the Korea Coastal Current and Yellow Sea Warm Current.  相似文献   

12.
The mantis shrimp O ratosquilla oratoria is an ecologically and economically important species in the Western Pacific. In present study, the population genetic structure of O ratosquilla oratoria from the Yellow Sea and East China Sea was examined with mitochondrial DNA control region sequences. In total, 394 samples were collected from 18 locations and 102 haplotypes were obtained. For the Yellow Sea, the overall nucleotide diversity and haplotype diversity were 0.006 9 and 0.946 8, respectively; while across all the East China Sea locations, the overall nucleotide diversity and haplotype diversity were 0.027 94 and 0.979 0, respectively. The results of AMOVA and pairwise F_(ST)(0.145 2, P 0.001) revealed moderate differentiation between the Yellow Sea and East China Sea populations of O. oratoria. However, neither the neighbor-joining tree nor haplotype network showed clades with geographic pattern, which indicated considerable gene flow was existed between the Yellow Sea and East China Sea, and supporting the high larval dispersal ability in this species. Mismatch distribution analysis and neutrality tests suggested that O. oratoria has undergone population expansion event, and the Pleistocene glacial cycles might have an impact on the historical demography of O. oratoria. The genetic information obtained in this study can provide useful information for sustainable improvements for capture fisheries management strategies.  相似文献   

13.
自１８５５ 年黄河改道北行至今,山东省的渤海湾海岸线向海方面推移了１９ｋｍ ,黄河泥沙的造陆面积达２８２７ｋｍ２ ,而在江苏省北部从双洋口至小丁港１５０ｋｍ 的海岸线上共失去土地１３２０ｋｍ２ 以上。作者认为,可以疏通明清黄河故道作为引黄工程,利用黄河携带的大量泥沙淤积于黄海沿岸,以减缓黄海岸线的侵蚀,还可抑制黄河泥沙沉积而造成的渤海的淤积。  相似文献   

14.
The Yellow Sea Cold Water Mass （YSCWM） was suggested as an over-summering site of the dominant copepod species Calanus sinicus in coastal Chinese seas. Population abundance and structure were investigated by monthly sampling along three transects across the northern boundary of the YSCWM during 2009-2010. Results show that thermal stratification existed from June to October and that the vertical thermal difference increased with depth. Generally, total abundance was lowest in October and highest in June, and the female/male sex ratio was highest in February and lowest in August. Evident spatial differences in abundance were observed during the existence of the YSCWM. In June, total abundance averaged 158.8 ind/m~ at well-stratified stations, and 532.1 ind/m3 at other stations. Similarly, high abundances of 322.0 and 324.4 ind/m3 were recorded from July to August inside the YSCWM, while the abundance decreased from 50.4 to 1.9 ind/m3 outside the water mass. C. sinicus distribution tended to even out over the study area in September when the YSCWM disappeared. We believe that the YSCWM may retard population recruitment in spring and preserve abundant cohorts in summer. The summer population was transported to neritic waters in autumn. In addition to low temperatures, stable vertical structure was also an essential condition for preservation of the summer population. C. sinicus can survive the summer in marginal areas in high abundance, but the population structure is completely different in terms of C5 proportion and sex ratio.  相似文献   

15.
Lan  Jian  Wang  Yi  Wang  Gang 《中国海洋湖沼学报》2010,28(6):1275-1280
The Cold Eddy in the East China Sea (CEECS) is located about 150 km southwest of Cheju Island. This region experiences a complex current system under the influences of the Yellow Sea Warm Current (YSWC), the Yellow Sea Coastal Current (YSCC), and the northward Kuroshio residual. To identify the strength of the CEECS, a simple subsurface intensity index is developed. Because the CEECS can be traced by temperature minimum, the intensity index is determined by the difference in sea temperature averaged across cores within and surrounding the region. Based on SODA, the CEECS subsurface intensity index time series can be calculated, with which the inter-annual variation of the CEECS is analyzed.  相似文献   

16.
Direct current observations in the Yellow Sea interior are very scarce due to intense fishing and trawling activities. Most previous studies on tides in the area were based on coastal measurements or satellite altimeter sea levels and have not been rigorously compared with direct measurements. In this paper, tidal currents are studied with current profiles from three bottom-moored Sontek Acoustic Doppler Profilers （ADPs） deployed in the southern Yellow Sea in summer of 2001 and 2003. The measured current series were dominated by tidal currents. Maximum velocities are between 40-80 cm/s at the mooring stations. M2 current is the most dominant primary tidal constituent, while MS4 and M4 are the most significant shallow water tides with much smaller amplitudes than the primary tides.  相似文献   

17.
Assemblages of benthic foraminifera in a sediment core (C02) near the western margin of the southern Yellow Sea Mud were studied to decipher the phase evolution of Holocene paleoenvironmental changes associated with the Holocene marine transgression. It appears that during the early Holocene (11.2–10.1 kyr BP), the faunal was dominated by low salinity and shallow water species Cribrononion subincertum, Buccella frigida and Ammonia beccarii, reflecting a near coast depositional environment. A rapid increase of the relative abundance of Ammonia compressiuscula between 10.1–9.3 kyr BP indicates that the sea level rose rapidly during that time period. From 9.3–7.7 kyr BP, the benthic foraminiferal assemblage was dominated by high percentage of A. compressiscula, suggesting that the sea level was relatively stable. An obvious transition of benthic foraminifera, from the A. compressiuscula-dominated assemblage to an Ammonia ketienziensis-dominated assemblage, occurred between 7.7–6.2 kyr BP, possibly corresponding to a second sea level rapid rise period in the Yellow Sea during the Holocene. This transition may correspond to the gradually strengthened Yellow Sea warm current (YSWC) and finally is established the modern-type circulation in the Yellow Sea. It may also mark the formation of the Yellow Sea cold bottom water (YSCBW) during that period. Since then, the benthic foraminiferal assemblage based on core C02 was dominated by typical YSCBW species, A. ketienziensis, Astrononion italicum and Hanzawaia nipponica, at 6.2–4 kyr BP. A non-deposition period occurred since ～4 kyr BP, which possibly related to the hydrology changes caused by the East Asia monsoon. The two obvious benthic foraminiferal transitions recorded in core C02 during the early and middle Holocene provide evidence that the Yellow Sea has undergone a two-phase rapid sea level rise during the Holocene marine transgression.  相似文献   

18.
The Yellow Sea (YS) environmental and ecological changes during the Holocene are driven by the interactions between the Yellow Sea Warm Current (YSWC), the East Asian Winter Monsoon (EAWM) and the Kuroshio Current (KC). We report marine biomarker records of brassicasterol, dinosterol and C37 alkenones in core ZY1 and core ZY2 from the South Yellow Sea (SYS) to reconstruct the spatial/temporal variations and possible mechanisms of phytoplankton primary productivity and community structure changes during the Mid-late Holocene. The contents of the corresponding biomarkers in the two cores are similar, and they also reveal broadly similar temporal trends. From 6 kyr to 3 kyr, the biomarker contents in the two cores were relatively low with small oscillations, followed by a distinct increase at about 3 kyr indicating productivity increases caused by a stronger EAWM. The alkenone/brassicasterol ratio (A/B) is used as a community structure proxy, which also showed higher values in both cores since 3 kyr, indicating increased haptophyte contribution to total productivity. It is proposed that the YS community structure has been mainly influenced by the YSWC, with stronger YSWC influences causing an increase in haptophyte contribution since 3 kyr. Some differences of the biomarker records between ZY2 and ZY1 suggest spatial variations in response to YSWC and KC forcing. When the KC was intensified during the periods of 6–4.2 kyr and 1.7–0 kyr, the YSWC extended eastward, exerting more influence on core ZY1. On the other hand, when the KC weakened during 4.2–1.7 kyr, the YSWC extended westward, exerting more influence on the ZY2.  相似文献   

19.
Community structure changes of macrobenthos in the South Yellow Sea   总被引：3，自引：0，他引：3  
The ecological environment in the Yellow Sea has changed greatly from the 1950s to 1990s and this has had significant impact on marine organisms. In this study, data on soft-sediment macrobenthos occurring in depths from 25 m to 81 m in the South Yellow Sea were used to compare changes in community structure. The agglomerative classification (CLUSTER) and multidimensional scaling (MDS) methods were applied. Five communities were recognized by cluster analysis: 1. The Yellow Sea Cold Water Mass community dominated by cold water species, which changed slightly in species composition since the 1950s; 2. The mixed community with the coexistence of cold water species and warm water species, as had been reported previously; 3. The polychaete-dominated eurythermal community in which the composition changed considerably as some dominant species disappeared or decreased; 4. The Changjiang (Yangtze) River Estuarine community, with some typical estuarine species; 5. The community affected by the Yellow Sea Warm Current. The greatest change occurred in the coastal area, which indicated that the change may be caused by human activities. Macrobenthos in the central region remained almost unchanged, particularly the cold water species shielded by the Yellow Sea Cold Water Mass. The depth, temperature and median grain size of sediments were important factors affecting the distributions of macrobenthos in the South Yellow Sea.  相似文献   

20.
The concentration of suspended load can be determined by its linear relationship to turbidity. Our results present the basic distribution of suspended load in North Yellow Sea. In summer, the suspended load concentration is high along the coast and low in the center of the sea. There are four regions of high concentration in the surface layer: Penglai and Chengshantou along the north of the Shandong Peninsula, and the coastal areas of Lüshun and Changshan Islands. There is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. And there is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. The distribution features in the 10 m and bottom layer are similar to the surface layer, however, the suspended load concentration declines in the 10 m layer while it increases in the bottom layer. And in the bottom layer there is a low suspended load concentration water mass at the region south of 38°N and east of 123°E extending to the southeast. In general, the lowest suspended load concentration in a vertical profile is at a depth of 10 to 20 m, the highest suspended load concentration is in the bottom near Chengshantou area. In winter, the distribution of suspended load is similar to summer, but the average concentrations are three times higher. There are two tongue-shaped high suspended load concentration belt, one occurring from surface to seafloor, extends to the north near Chengshantou and the other invades north to south along the east margin of Dalian Bay. They separate the low suspended load concentration water masses in the center of North Yellow Sea into east and west parts. Vertical distribution is quite uniform in the whole North Yellow Sea because of the cooling effect and strong northeast winds. The distribution of suspended load has a very close relationship to the current circulation and wind-induced waves in the North Yellow Sea. Because of this, we have been able to show for the first time that the distribution of suspended load can be used to identify water masses.  相似文献   

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