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1.
Distribution of dominant zooplankton species along a latitudinal gradient in China sea during spring
Dominant species of zooplankton community vary with latitude. Though China possesses a vast coastal area in northwestern Pacific, studies on the latitudinal dominant species gradient are rare. We collected zooplankton samples from Haizhou Bay(34.56?–35.19?N, 119.51?–120.30?E), Yueqing Bay(28.14?–28.38?N, 121.10?–121.21?E) and Dongshan Bay(23.65?–23.90?N, 117.45?–117.60?E) in May 2012 and May 2013 to preliminarily characterize the latitudinal dominant species distribution. All the samples were collected vertically using a 0.505 mm mesh plankton net with 0.8 m in mouth diameter from bottom to surface. Calanus sinicus, Aidanosagitta crassa, Labidocera euchaeta, Zonosagitta nagae, Acartia pacifica and Paracalanus parvus were found to be dominant. C. sinicus was the most dominant species and the unique one occurred in all three bays. With latitude decreasing, both the abundance and proportion of C. sinicus declined sharply. Cluster analysis showed that the 6 dominant species could be divided into 3 groups, based on their occurrences in the three bays. Our results suggested that the distribution of dominant species along the coast of China has a significant latitudinal gradient. C. sinicus which widely distributes in the coastal water of the northwestern Pacific can well adapt to the temperature at different latitudes. The high abundance in Haizhou Bay indicated that C. sinicus was an exemplary warm-temperate species, and more commonly occurs in the north of China seas. The ecological characteristics of dominant species change from warm-temperate type in high-latitudinal bays to warm water type in low-latitudinal bays. 相似文献
2.
Three new spades and a new variety of nannoplankton, Chrysochromulina papillata, Gaysochromulina chiton var. minuta, Paraphysomonas simplexocorbita and Paraphysomonas bisorbulina are reported in this paper. All were isolated from the preliminary culture samples of seawater collected from Jiaozhou Bay, Shandong, China. The three species occurred at Station 1(120° 14.56′ E, 36°4′N) in November 1984, the new variety at Station 2 (120° 16.35° E,36°4.5′N) in January, 1985. The morphological features, especially the structures of the scales of these new nannoplankton,. are described. The differences between the new species and the related ones are discussed; their movement and nutrition, and the temperature and salinity of their biotopes are also mentioned. 相似文献
3.
I Introduction Phytoplankton play an important role in the primary production of ocean (Ning et al., 1995). They are impor-tant biological mediators of carbon turnover in seawater ecosystems (Zhu et al., 1993). Phytoplankton in Jiaozhou Bay have been preliminarily studied on the subjects of community structure, primary productivity and carbon budget (Qian et al., 1983; Guo et al., 1992; Jiao et al., 1994). It has been found that seasonal variation of phytoplankton cell abundance presents w… 相似文献
4.
Bay scallops were introduced from the east coast of the U.S. into China to shorten the economic turn-over from 2 to 1 year.
Parent scallops were carried to Qingdao on Dec. 20, 1982 and stocked in indoor tanks at controlled temperature and fed with
a mixture ofPhaeodictylum tricornutum, Pyramimonas sp. andChlorella sp. They spawned on Jan. 26 of the next year. The larvae were reared at a temperature of 18–21°C and fed withIsochrysis galbana, Pyramimonas sp. andChorella sp. In 4 weeks’ growing, the spats averaged 827 μm. They attained a height of 6.9 mm on May 9. In the middle of May, the
seed scallops were transferred to Luoyuan Bay in Fujian Province, and Jiaozhou Bay, as well as the area off Taiping Jiao Cape,
Qingdao, Shandong Province for experimental culture in plastic netcages suspended on a single line raft.
Bay scallops cultured in Luoyuan Bay grew to an averaged shell height of 10.4 mm. In Jiaozhou Bay and the Taiping Jiao Cape
culture area, they grew to 50 mm in average shell height (marketable size) and 26 g in average weight by late September; and
attained 59 mm in average shell height (R. 39–75 mm) and 46 g in average weight in late December. The ovary and testis could
be distinguished by color in August. In early September, eggs and sperms were collected for our laboratory where the second
generation of seed scallops was successfully reared to suitable size for growing outdoor and breeding. This species can be
harvested within a year after fertilization of the eggs, so we consider it suitable for culture in the Yellow Sea and East
China Sea. This is the first reported successful introduction of Atlantic mollusks to the China Seas.
This paper was published in Chinese inOceanologia et Limnologia Sinica
17 (5): 367–374, 1986. 相似文献
5.
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 revealed the spatiotemporal variations
of the ambient Si(OH)4:NO3 (Si:N) concentration rations and the seasonal variations of (Si:N) ratios in Jiaozhou Bay and showed that the Si:N ratios
were <1 throughout Jiaozhou Bay in spring, autumn, and winter. These results provide further evidence that silicate limits
the growth of phytoplankton (i.e. diatoms) in spring, autumn and winter. Moreover, comparison of the spatiotemporal variations
of the Si:N ratio and primary production in Jiaozhou Bay suggested their close relationship. The spatiotemporal pattern of
dissolved silicate matched well that of primary production in Jiaozhou Bay.
Along with the environmental change of Jiaozhou Bay in the last thirty years, the N and P concentrations tended to rise, whereas
Si concentration showed cyclic seasonal variations. With the variation of nutrient Si limiting the primary production in mind,
the authors found that the range of values of primary production is divided into three parts: the basic value of Si limited
primary production, the extent of Si limited primary production and the critical value of Si limited primary production, which
can be calculated for Jiaozhou Bay by Equations (1), (2) and (3), showing that the time of the critical value of Si limitation
of phytoplankton growth in Jiaozhou Bay is around November 3 to November 13 in autumn; and that the time of the critical value
of Si satisfaction of phytoplankton growth in Jiaozhou Bay is around May 22 to June 7 in spring. Moreover, the calculated
critical value of Si satisfactory for phytoplankton growth is 2.15–0.76 μmol/L and the critical value of Si limitation of
phytoplankton growth is 1.42–0.36 μmol/L; so that the time period of Si limitation of phytoplankton growth is around November
13 to May 22 in the next year; the time period of Si satisfactory for phytoplankton growth is around June 7 to November 3.
This result also explains why critical values of nutrient silicon affect phytoplankton growth in spring and autumn are different
in different waters of Jiaozhou Bay and also indicates how the silicate concentration affects the phytoplankton assemblage
structure. The dilution of silicate concentration by seawater exchange affects the growth of phytoplankton so that the primary
production of phytoplankton declines outside Jiaozhou Bay earlier than inside Jiaozhou Bay by one and half months. This study
showed that Jiaozhou Bay phytoplankton badly need silicon and respond very sensitively and rapidly to the variation of silicon.
This study was funded by NSFC (No. 40036010) and subsidized by Special Funds from National Key Basic Research Program of P.
R. China (G19990437), the Postdoctoral Foundation of Ocean University of Qingdao, the Director's Foundation of the Beihai
Monitoring Center of the State Oceanic Administration and the Foundation of Shanghai Fisheries University. 相似文献
6.
ＩＮＴＲＯＤＵＣＴＩＯＮＮａｎｄＰｉｎｐｕｔｔｅｄｉｎｔｏＪｉａｏｚｈｏｕＢａｙｂｙｒｉｖｅｒｓａｎｄｂｙｓｅｗａｇｅｅｆｆｌｕｅｎｔｓｏｆｃｉｔｉｅｓ ,ｈａｖｅｍａｄｅｔｈｅＢａｙｂｅｃｏｍｅｍｏｒｅａｎｄｍｏｒｅｅｕｔｒｏｐｈｉｃｄａｙｂｙｄａｙ .Ｓｈｅｎ ( 1994)ｔｈｏｕｇｈｔｔｈａｔｐｈｙｔｏｐｌａｎｋｔｏｎｇｒｏｗｔｈｗａｓｌｉｍｉｔｅｄｂｙｔｈｅｃｈａｎｇｅｆｒｏｍｎｉｔｒｏｇｅｎｔｏｐｈｏｓｐｈｏｒｏｕｓ ;ａｎｄｔｈａｔｔｈｅｓｉｌｉｃａｔｅｃｏｎｃｅｎｔｒａｔｉｏｎｉｎＪｉａｏｚｈ… 相似文献
7.
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 (12 seasonal investigations) provided
by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation of the ambient concentration
Si∶DIN and Si∶16P ratios and the seasonal variation of Jiaozhou Bay Si∶DIN and Si∶16P ratios showing that the Si∶DIN ratios
were <1 throughout the year in Jiaozhou Bay; and that the Si∶16P ratios were <1 throughout Jiaozhou Bay in spring, autumn
and winter. The results proved that silicate limited phytoplankton growth in spring, autumn and winter in Jiaozhou Bay. Analysis
of the Si∶DIN and Si∶P ratios showed that the nutrient Si has been limiting the growth of phytoplankton throughout the year
in some Jiaozhou Bay waters; and that the silicate deficiency changed the phytoplankton assemblage structure.
Analysis of discontinuous 1962 to 1998 nutrient data showed that there was no N or P limitation of phytoplankton growth in
that period. The authors consider that the annual cyclic change of silicate limits phytoplankton growth in spring, autumn
and winter every year in Jiaozhou Bay; and that in many Jiaozhou Bay waters where the phytoplankton as the predominant species
need a great amount of silicate, analysis of the nutrients N or P limitation of phytoplankton growth relying only on the N
and P nutrients and DIN∶P ratio could yield inaccurate conclusions. The results obtained by applying the rules of absolute
and relative limitation fully support this view.
The authors consider that the main function of nutrient silicon is to regulate and control the mechanism of the phytoplankton
growth process in the ecological system in estuaries, bays and the sea.
The authors consider that according to the evolution theory of Darwin, continuous environmental pressure gradually changes
the phytoplankton assemblage's structure and the physiology of diatoms. Diatoms requiring a great deal of silicon either constantly
decrease or reduce their requirement for silicon. This will cause a series of huge changes in the ecosystem so that the whole
ecosystem requires continuous renewal, change and balancing. Human beings have to reduce marine pollution and enhance the
capacity of continental sources to transport silicon to sustain the continuity and stability in the marine ecosystem.
This study was funded by the NSFC (No. 40036010) and subsidized by Special Funds from the National Key Basic Research Program
of P. R. China (G199990437), the Postdoctoral Foundation of Ocean University of Qingdao, the Director's Foundation of the
Beihai Monitoring Center of the State Oceanic Administration and the Foundation of Shanghai Fisheries University. 相似文献
8.
Observations on gonad development of 84 species of marine fishes in Jiaozhou Bay waters showed the breeding periods of more
than 50 of these species are mostly from April to August, with peaks between May to June. A great many of the species spawn
in the warm season, only a few species in the cold season. The number of spawning species increases with the rise and decreases
with the fall in water temperature. The absolute fecundity of 50 teleost species, which usually increases with body length
and weight, was estimated to range from about 300 to 9,000,000 eggs. The reproductive patterns of fishes in Jiaozhou Bay waters
are discussed.
This paper was presented at the IV International Congress of Ecology, held at Syracuse, USA in August, 1986.
Contribution No. 1553 from the Institute of Oceanology, Academia Sinica. 相似文献
9.
In the present research, the strain SLYY-3 was isolated from sediments of Jiaozhou Bay, Qingdao, China. The strain SLYY-3, which produced a bacteriocin-like substance(BLS), was characterized to be a strain of Bacillus subtillis by biochemical profiling and 16 S r DNA sequence analysis. It is the first time to report that Bacillus subtilis from Jiaozhou Bay sediments could produce a BLS. The BLS of B. subtillis SLYY-3 exhibited strong inhibitory activity against gram-positive bacteria(including Staphylococcus aureus and B. subtillis) and some fungi(including Penicillium glaucum, Aspergillus niger and Aspergillus flavus). The antimicrobial activity was detected from culture in the exponential growth phase and reached its maximum when culture entered into stationary growth phase. It was thermo-tolerant even when being kept at 100℃ for 60 min without losing any activity and stable over a wide p H range from 1.0 to 12.0 while being inactivated by proteolytic enzyme and trypsin, indicating the proteinaceous nature of the BLS. The BLS was purified by precipitation with hydrochloric acid(HCl) and gel filteration(Sephadex G-100). SDS-PAGE analysis of the extracellular peptides of SLYY-3 revealed a bacteriocin-like protein with a molecular mass of 66 k Da. Altogether, these characteristics indicate the potential of the BLS for food industry as a protection against pathogenic and spoilage microorganisms. 相似文献
10.
The community structure and seasonal dynamics of plankton in Bange Lake,northern Tibet,China 总被引：1，自引：1，他引：0
The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at-2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10~7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass(including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity. 相似文献
11.
We cultured different-sized fractions of dominant phytoplankton species, Skeletonema costatum, Chaetoceros curvisetus, and Thalassiosira nordenskiöldii, collected in different sea areas in various seasons, and measured and compared their C, N, P, Si contents. The N content of these species is similar, while the C, P, and Si contents of S. costatum from eutrophic Changjiang (Yangtze River) estuary are higher than those from Jiaozhou Bay (JZB), particularly the content of Si. The C, N, P, and Si contents of cultured phytoplankton in JZB increase with size fraction augmentation, and the percentages of C, N, and P follow the same trend, while the percentage of Si remain constant. Moreover, S. costatum from small-sized fraction assimilated Si more easily than C. curvisetus and T. nordenskiöldii, which is explained by the dominance of S. costatum under the conditions of low SiO3-Si concentration in JZB. The C, N, P, and Si contents of cultured S. costatum collected during summer and winter are higher, which is consistent with the phytoplankton blooming seasons in JZB. The SiO3-Si concentration of seawater during spring restrain the growth of phytoplankton, supported by the fact that the N, P, and Si contents and their ratios in cells of cultured S. costatum are low in spring season. 相似文献
12.
COUPLED PHYSICAL-ECOLOGICAL MODELLING IN THE CENTRAL PART OF JIAOZHOU BAY Ⅱ.COUPLED WITH AN ECOLOGICAL MODEL 总被引：2，自引：0，他引：2
Sharpies‘ 1-D physical rrozlel maploying tide-wind driven turbulence closure and surface heating-cooling physics, was coupled with an eculogical rnodet with 9-biochemical components: phytoplankton, zooplankton, shellfish, autotmphic and heterotrophic bacterioplankton, dissolved organic carbon (DOC), suspended detritus and sinking particles to simulate the armual evolution of ecosystem in thecentral part of Jiaozhou Bay. The coupled modeling results showed that the phytoplankton shading effectcould reduce seawater temperamre by 2℃, so that photosynthesis efficiency should be less than 8% ; that the loss of phytoplankton by zooplankton grazing in winter tended to be compensated by phytoplankton advection and diffusion from the otrtside of the Bay; that the incidem irradiance intensity could be the mostimportant factor for phytoplankton grcr, wth rate; and that it was the bacterial secondary prnduction that maintained the maximum zooplankton biomass in winter usually observed in the 1990s, indicating that themicrobial food loop was extremely important for ecosystem study of Jiaozhou Bay. 相似文献
13.
14.
Manila clam(Ruditapes philippinarum) was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010. The annual variations of major elemental composition, organic content, fatness and element ratio of Manila clam were examined. The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest. The results indicated that the variation trend of carbon content in shell(Cshell) was similar to that in clam(Cclam). Such a variation was higher in summer and autumn than in other seasons, which ranged from 9.10 ± 0.13 to 10.38 ± 0.09 mmol g-1 and from 11.28 ± 0.29 to 12.36 ± 0.06 mmol g-1, respectively. Carbon content of flesh(Cflesh) showed an opposite variation trend to that of shell in most months, varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g-1. Nitrogen content of shell(Nshell) and flesh(Nflesh) changed seasonally, which was relatively low in spring and summer. Nshell and Nflesh varied from 0.07 ± 0.009 to 0.14 ± 0.009 mmol g-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g-1, respectively. Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g-1 with a falling tend except for a high value in March 2010. Phosphorus content of clam(Nclam) fluctuated largely, while phosphorus content of shell(Pshell) was less varied than that of flesh(Pflesh). Pshell varied from 0.006 ± 0.001 to 0.016 ± 0.001 mmol g-1; while Pflesh fluctuated between 0.058 ± 0.017 and 0.293 ± 0.029 mmol g-1. Pclam ranged from 0.015 ± 0.002 to 0.041 ± 0.006 mmol g-1. Carbon and nitrogen content were slightly affected by shell length, width or height. Elemental contents were closely related to the reproduction cycle. The removal amounts of carbon, nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92×104 t, 1420 t and 145 t, respectively. The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus, the main causes of eutrophication, and to maintain the ecosystem health of Jiaozhou Bay. 相似文献
15.
Shu Yang Xiurong Han Chuansong Zhang Baiye Sun Xiulin Wang Xiaoyong Shi 《中国海洋大学学报(英文版)》2014,13(6):926-934
The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 μg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level(including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema(mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus(spring) →Chaetoceros(summer and autumn) → Coscinodiscus(winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950 s-2000 s. 相似文献
16.
GUO Shujin ZHU Mingliang ZHAO Zengxia LIANG Junhua ZHAO Yongfang DU Juan SUN Xiaoxia 《中国海洋湖沼学报》2019,(5)
To better understand the spatial-temporal variation in phytoplankton community structure and its controlling factors in Jiaozhou Bay,Qingdao,North China,four seasonal sampling were carried out in 2017.The phytoplankton community structure and various environmental parameters were examined.The phytoplankton community in the bay was composed of mainly diatoms and dinoflagellates,and several other species of Chrysophyta were also observed.Diatoms were the most dominant phytoplankton group throughout the year,except in spring and winter,when Noctiluca scintillans was co-dominant.High Si/N ratios in summer and fall reflect the high dominance of diatoms in the two seasons.Temporally,the phytoplankton cell abundance peaked in summer,due mainly to the high temperatures and nutrient concentrations in summer.Spatially,the phytoplankton cell abundance was higher in the northern part of the bay than in the other parts of the bay in four seasons.The diatom cell abundances show significant positive correlations with the nutrient concentrations,while the dinoflagellate cell abundances show no correlation or a negative correlation with the nutrient concentrations but a significant positive correlation with the stratification index.This discrepancy was mainly due to the different survival strategies between diatoms and dinoflagellates.The Shannon-Wiener diversity index(H')values in the bay ranged from 0.08 to 4.18,which fell in the range reported in historical studies.The distribution pattern of H' values was quite different from that of chlorophyll a,indicating that the phytoplankton community structure might have high biomass with a low diversity index.Compared with historical studies,we believe that the dominant phytoplankton species have been changed in recent years due mainly to the changing environment in the Jiaozhou Bay in recent 30 years. 相似文献
17.
Study on the dominant species of Pteropoda in East China Sea 总被引：2，自引：0，他引：2
1 INTRODUCTION Pteropoda is a group of marine pelagic mol- lusks, which belongs to Opisthobranchia of Gastro- poda. Although Pteropoda is not a major group in pelagic zooplankton in terms of abundance and number of species, their ecological characters are… 相似文献
18.
Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO3^--N, NO2^--N, NH4^ -N, SIO3^2--Si, PO4^3--P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq. ( 1 ) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C, the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D, the coefficient of water temperature‘s effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant-nutrient concentTations but low phytoplankton biomass in some waters is reasonably explained in this paper. 相似文献
19.
We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay. 相似文献
20.
During the 13th (1996–1997) and the 19th (2002–2003) Chinese National Antarctica Research Expeditions, we collected 60 discrete surface seawater samples along the
cruise from the Chanjiang River (Yangtze) estuary (30°59′S, 122°26′E) through Taiwan Strait, the South China Sea, and the
Eastern Indian Ocean to Prydz Bay, Antarctica (69°10′S, 74°30′E), and analyzed them for the 226Ra specific activity. The 226Ra specific activity of the Chanjiang River estuary surface water (3.15 Bq/m3) was found to be the highest among all the surface samples because of the desorption of 226Ra from riverine particles. Between Chanjiang River estuary and 40°S, 226Ra specific activity was found to be relatively uniform with a mean value of 1.07 Bq/m3 (n = 19, SD = 0.14), similar to that of the open ocean. From 40°S to 65°S, 226Ra specific activity increased intensively, then decreased moderately further southwards. Near the Antarctic shore, it increased
again, to 2.31 Bq/m3. This distribution was controlled by a combination of deep water upwelling, Southern Ocean fronts, water mixing and the continental
226Ra import. In Prydz Bay and the adjacent sea area, the mean 226Ra activity value was 2.26 Bq/m3 (n = 31, SD = 0.28), with a relatively higher value outside of the bay and low 226Ra activity value in the center of the bay. This was consistent with the topography and hydrological setting of the bay. In
addition, we extended the study area northward to the Arctic, by combining the published 226Ra dataset for surface water from the Bering Sea to the Japan Sea. We also discuss the 226Ra distribution of high latitude oceanic surface water and its mechanisms. 相似文献