Distribution,abundance,and realized niches of meroplankton by two different mesh size nets during spring 2017 in the Southern Yellow Sea,China

Meroplankton play a crucial role in both benthic and pelagic ecosystems.Existing quantitative research on estimating the quantities of meroplankton groups is both underrepresented and inaccurate.To investigate and evaluate the influence of varying mesh sizes(505 and 160μm)on the sampling efficiency of meroplankton,we conducted an examination using two commonly used plankton nets during the spring season in the Southern Yellow Sea(SYS).Our study revealed a total of 12 meroplankton groups,with 9 groups identified in the 505-μm mesh nets and 11 groups in the 160-μm mesh nets.The results demonstrated the superior collection efficiency of the 160-μm net compared to the 505-μm net across the majority of meroplankton groups.Furthermore,we focused on exploring the abundance,distribution patterns,and realized niches of meroplankton collected by the two mesh size nets,and observed that the distribution of meroplankton closely resembled the distribution of possible benthic adults in the SYS.Correlation analysis of the six dominant groups collected in the 160-μm mesh nets revealed that seawater temperature and salinity emerged as the key environmental factors driving variations in meroplankton abundance within the SYS.This study also found that a smaller mesh size net does not necessarily capture meroplankton more comprehensively.A comprehensive understanding of the ecological characteristics of meroplankton requires the combination of two types of nets for research.Our research significantly advances our understanding of the quantification,abundance,and distribution of meroplankton,serving as a valuable contribution to the broader landscape of detailed quantitative meroplankton studies.

Effect of Marine Planktonic Algal Particles on the Communication Performance of Underwater Quantum Link

As one of the main application directions of quantum technology,underwater quantum communication is of great research significance.In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links,based on the extinction characteristics of marine planktonic algal particles,the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively,the influence of marine planktonic algal particles on the fidelity of underwater quantum links,the generation rate of the security key,and the utilization rate of the channel is analyzed,and simulation experiments are carried out.The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles,quantum communication channel link attenuation shows a gradually increasing trend.In addition,the security key generation rate,channel fidelity and utilization rate are gradually decreasing.Therefore,the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles,and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.

Temporal change of plankton size structure preserved by Lugol's solution:a FlowCAM study

Plankton size structure is crucial for understanding marine ecosystem dynamics and the associated biogeochemical processes.A fixation step by acid Lugol’s solution has been commonly employed to preserve plankton samples in the field.However,the acid Lugol’s solution can bias the estimation of size structure and the preserved plankton size structure can vary with time.Here,we explore the impact of sample storage time on the size-structure of the plankton community preserved by Lugol’s solution.Two short-term experiments and one long-term experiment were conducted to explore the change of plankton community size structure with the storage time:covering from a week to a month,and to nearly seven months based on particle-size data obtained by continuous Flow Cytometer and Microscope(FlowCAM)measurements.We found a linear change of plankton size with the storage time in short-term periods(less than 3 months)with a decrease of the slope but an increase of the intercept for the normalized biomass size spectrum(NBS S).However,there were opposite trends for NBSS with increasing slope but decreasing intercept after3 months.The potential causes of the distinct patterns of the NBSS parameters are addressed in terms of the interplay between particle aggregation and fragmentation.We found large changes in plankton biovolume and abundance among different size classes,which may indicate a distinct effect of acid Lugol’s solution on various plankton size classes.The mechanism driving temporal change in the size-structure of the Lugolfixed plankton community was further discussed in terms of particle aggregation and fragmentation.Finally,we emphasize that the effect of storage time should be taken into account when interpreting or comparing data of plankton community acquired from samples with various storage durations.

The Relevance of Biological and Hydrodynamic Timescale in the Growth of Plankton

The relationship between hydrodynamic mesoscale structures and plankton formation in the wake of an island, as well as its interaction with a coastal upwelling, is investigated. Our focus is on the process by which vortices create localized plankton blooms. A basic three-component model for marine ecology was utilized, as well as a coupled system of kinematic flow that mimicked the mesoscale features underlying the island. We show that the prevalence of localized plankton blooms is produced mostly by the prolonged residence times of nutrients and plankton in the island’s vicinity, as well as the confinement of plankton within vortices.

Size-dependent spatio-temporal dynamics of eukaryotic plankton community near nuclear power plant in Beibu Gulf,China

Pico-and nano-eukaryotic plankton are important members of marine ecosystems.To understand their community structure and spatio-temporal variations in the Beibu Gulf,and to study the impact of Changjiang Nuclear Power Plant(CNPP)located in the northwest coast of the Hainan Island on the eukaryotic plankton,we studied these issues in the coastal water near CNPP bimonthly from February 2018 to January 2019 via 18 S Illumina sequencing.The results reveal a higher genetic alphadiversity and less beta-diversity of the plankton community in small-size(0.45-5μm and 5-20μm)fractions than in large-size(20-200μm and>20μm)fractions.The small-sized phytoplankton,including Micromonas(Chlorophyta)and Minutocellus(Bacillariophyta),as well as heterotrophic plankton,including Paraphysomonas(Chrysophyceae),Ellobiopsis(Dinoflagellates),and Syndiniales(Dinoflagellates),took up a considerable proportion in eukaryotic plankton community.In addition,it showed a slight temperature increase and no significant difference in eukaryotic plankton community between the outfall of CNPP and other sampling sites,suggesting that the impact of the thermal discharge from the CNPP on local eukaryotic plankton community was limited.

Distribution characteristic and variation trend of planktonic dinoflagellate in the Taiwan Strait from 2006 to 2007

Based on 4 cruise surveys from July 2006 to October 2007 in the Taiwan Strait, the species composition, community structure and spatio-temporal distribution of dinoflagellate were studied. A total of 131 dinoflagellates belonging to 18 genera were identified. The population was dominated by hyperthermal and hyperhaline species accounting for 72.52% of the total species. Eurythermal and euryhaline species were the second most common one accounting for 25.19% of the total species. It was only 2.29% for neritic species. The maximum species number occurred in summer, while the maximum cell density appeared in spring. The average dinoflagellate cell density was 404.96x104 cells/m3. It showed that the dinof]agellate cell density increased from the nearshore waters to the open sea and from the north to the south. Compared with the results during 1984-1985, the horizontal distribution pattern and seaeonal variation of the dinofiagellate have not changed significantly, but the dinoflagellate cell density increased by 3.01 times. Further analysis of the dinoflagellate abundance variations both in the spatial and temporal aspects, indicated that the abundance of dinoflagellate increased more significantly in cold seasons, and there was a larger increase in the north of the Taiwan Strait. Besides, the dinoflagellate community structure changed notably. It showed that the diversity and evenness index were relatively high, and the proportion of dinoflageliate cell density to the total phytoplankton increased.

Multivariate Analysis of Community Structure Variation of Plankton and Zoobenthos in Municipal Polluted River

[Objective] The plankton and macrobenthos samples in municipal polluted river were analyzed by different methods, so as to explore the method suitable for biological data analysis in heavy polluted area. [Method] Shannon-Wiener diversity index, cluster analysis of multivariate statistical analysis and MDS （Non-matric Multi- dimentional Scaling）analysis were used to analyze biological data of phytoplankton, zooplankton and Zoobenthos collected from the representative municipal polluted river in Pearl River Delta. The sediment samples were also collected to determine. Pb, Cd, Hg, Cr, As, Cu, Ni, Zn, as well as CODe, and NH3-N of porewater. Hakanson potential ecological risk index method was used to evaluate the ecological risk. [Re- suit] Shannon-Wiener diversity index analysis results can not effectively reflect the difference of pollution status of various stations in heavy polluted area; despite the presence of some problems, multivariate analysis method is superior to the Shannon-Wiener diversity index method in biological monitoring of heavy polluted river in the city. [Conclusion] The paper provided theoretical basis for biological data analysis in heavy polluted area.

Plankton respiration in the northern South China Sea during summer and winter

Plankton respiration is an important part of the carbon cycle and significantly affects the balance of autotrophic assimilation and heterotrophic production in oceanic ecosystems. In the present study, respiration rates of the euphotic zone plankton community（CR_（eu））, size fractionated chlorophyll a concentration（Chl a）, bacterial abundance（BAC）, and dissolved oxygen concentration（DO） were investigated during winter and summer in the northern South China Sea（n SCS）. The results show that there were obvious spatial and temporal variations in CR_（eu） in the n SCS（ranging from 0.03 to 1.10 μmol/（L·h））, CR_（eu） in winter（（0.53±0.27） μmol/（L·h）） was two times higher than that in summer（（0.26±0.20） μmol/（L·h））, and decreased gradually from the coastal zone to the open sea. The distribution of CR_（eu） was affected by coupled physical-chemical-biological processes, driven by monsoon events. The results also show that CR_（eu） was positively correlated with Chl a, BAC, and DO, and that BAC contributed the highest CR_（eu） variability. Furthermore, the results of the stepwise multiple linear regression suggest that bacteria and phytoplankton were the dominant factors in determining CR_（eu）（R^2 = 0.82, p〈0.05） in the n SCS. Based on this relationship, we estimated the integrated water column respiration rate（CRint） within 100 m of the investigated area, and found that the relationship between the biomass of the plankton community and respiration may be nonlinear in the water column.

QUANTITATIVE DISTRIBUTION OF NET PHYTOPLANKTON IN GREAT WALL BAY, ANTARCTICA

Samples of phytoplankton were obtained in February, 1985, in Great Wall Bay, Antarctica. Among the 31 species of phytoplankton identified, the cold - water species rank highest in proportion. The cell number of phytoplankton averaged 162. 5×104 cells/m3 in the bay. The most dominant species are Chaetoceros socialis Lauder, Rhizosolenia. alata f. inermis (Castr. ) Hustedt and Biddulphia striatas Karsten. The former species mainly appeared in the bay and the latter two species aggregated at the bay mounth.

Plankton community composition in the Three Gorges Reservoir Region revealed by PCR-DGGE and its relationships with environmental factors

To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrophoresis fingerprinting. Bacterial and eukaryotic operational taxonomic units （OTUs）, generated by DGGE analysis of the PCR-amplified 16S and 18S rRNA genes, were used as surrogates for the dominant ＂biodiversity units＂. OTU composition among the sites was heterogeneous; 46.7% of the total bacterial OTUs （45） and 64.1% of the eukaryotic OTUs （39） were identified in less than half of the sampling sites. Unweighted pair group method with arithmetic averages （UPGMA） clustering of the OTUs suggested that the plankton communities in the Xiangxi Rive sites were not always significantly different from those from the Yangtze River sites, despite clear differences in their environmental characterizations. Canonical correspondence analysis （CCA） was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of NO3^--N, dissolved oxygen （DO）, and SiO3^2--Si, whereas, the eukaryotic community was mainly correlated with the concentrations of DO, PO4^3--P, and SiO3^2--Si.

Relationship between petroleum hydrocarbon and plankton in a mesocosm experiment

A mesocosm experiment was carried out from May 26 to June 1, 1998 at the location of 30'52'N, 122'36'E, the Changjiang Estuary, in order to measure the influence of petroleum hydrocar- bon to the ecosystem, furthermore, to estimate the environmental capacity. In the experiment, it is found that the petroleum hydrocarbon can, in some degree, enhance the growth of diatom, but inhibit the growth of dinoflagellate. In general, the petroleum hydrocarbon can inhibit the growth of both Phytoplankton and zooplankton, and can the inhibit the growth of total plankton (including phytoplankton and zooplankton) as well. A kinetic model was presented to estimate the uptake/release rate constants of petroleum hydrocarbon by plankton, and thereafter, the uptake and release rate constants (k1, k2), bioconcentration factor (BCF) as well as the petroleum bydrocarbon influenced influenced uptake and release rate constants of nutrients by phytoplankton (kup, krel) were obtained. The results imply that the bioconcentration of petroleum hydrocarbon by plankton is fairly large and petroleum hydrocarbon caused no significant influence on the uptake of N- NO3, but significant influence on that of P -PO4. In addition, the application of kinetic model for the bioconcentration of volatile organic toxic compound by organism suggests that the uptake of petroleum hydrocarbon by plankton was an important process for the environmental capacity of petroleum hydrocarbon.

Spatial heterogeneity in a deep artificial lake plankton community revealed by PCR-DGGE fingerprinting

To explore the spatial heterogeneity of plankton communities in a deep artificial lake （Songhua Lake, China）, samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis （DGGE） analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes （84%） exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla （Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera）. Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis （RDA）. The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition.

Molecular identification of scallop planktonic larvae using species-specific microsatellites

The identification of scallop larvae is essential to understand the population structure and community dynamics and to assess the potential environmental impacts caused by scallop larvae released or escaped. However, the larvae identification by morphological characteristics is notoriously difficult, mainly due to the small size （usually being less than 150 μm） and vague morphological characteristics among different scallop species. A simple and accurate molecular method was developed to identify four economically farmed scallop species, the Zhikong scallop Chlamys farreri, the noble scallop C. nobilis, the bay scallop Argopecten irradians and the Yesso scallop Mizuhopecten yessoensis. The tests used the high degree of species-specific microsatellite markers, which was specified by transferability analyses, assessed by reference individuals and evaluated by BLAST searches. The sensitivity test indicated that the species-specific microsatellites were sensitive enough for the detection of 1% -2% larvae in mixed plankton samples. Larvae collected from scallop hatcheries and their effluents and from the artificially controlled crosses were well identified to the species/hybrid level. The results demonstrated that the one-step PCR-based assay was technically simple, inexpensive and robust in identification analyses, and also less sensitive to initial quality of template DNA extracted from the ethanol-preserved samples for several years.

Study on biological oceanography charateristics of planktonic copepods in waters north of Taiwan Ⅱ. Community characteristics

The Paper is the succession of the study on abundance distribution of planktonic copepods in the waters north of Taiwan, and the emphasis is laid on the analysis and discussion of the constructions and features of copepod community and the relationships with water environment. The results show as follows: a total of 237 species were identified and the construction of communtity was complex. The percentage of annual present species was only 32%. The mean values of diversity and homogeneity of the copepod community were 3. 714 and 0. 690 respectively, and their horizontal distribution patterns were higher in outshore area than in nearshore area. The copepods of the area could be divided into five ectotypes. Warm-water outshore high temperature and lower saline group and tropic oceanic high temperature and saline group could indicate the seasonal changes of the Taiwan Strait water and the Kuroshio surface water respectively. According to the various aspects of calculation and analysis, winter was different from other three seasons in environmental conditions. In spring, summer and autumn, Undinula valgaris was the meat dominant species and salinity was the main factor that affected the community feature values. The communities in the three seasons had the subtropic-tropic characteristics in which warm-water outshore species were dominant and tropic oceanic species accounted for also certain proportion. While in winter, the dominant species was Euchaeta manna and temperature was the main factor influencing the community feture values. The community had the tropic oceanic characteristics in which tropic oceanic species were dominant.

Comparison of Copepod Collection Efficiencies by Three Commonly Used Plankton Nets: A Case Study in Bohai Sea, China

Abstract Selection of net with a suitable mesh size is a key concern in the quantitative assessment of zooplankton, which is cru- cial to understand pelagic ecosystem processes. This study compared the copepod collecting efficiency of three commonly used plankton nets, namely, the China standard coarse net （505 gm mesh）, the China standard fine net （77 gin）, and the WP-2 net （200 μm） The experiment was performed at six stations in the Bohai Sea during the autumn of 2012. The coarse net substantially un- der-sampled small individuals （body widths 〈 672 gm） and led to the lowest species number in each tow, whereas the fine net col- lected all small copepod species but failed to collect rare species. The WP-2 net appeared to be a compromise of the two other nets, collecting both small copepods and rare species. The abundance of copepods collected by the coarse net （126.4±86.5 indm-3） was one to two orders of magnitude lower than that by the WP-2 net （5802.4 ± 2595.4 indm3）, and the value of the fine net （11117.0±4563.41 indm-3） was nearly twice that of the WP-2 net. The abundance of large copepods （i.e., adult Calanus sinicus） in the three nets showed no significant differences, but the abundance of small copepods declined with decreasing mesh size. The dif- ference in abundance resulted from the under-sampling of small copepods with body widths 〈 672 μm and 〈 266μm by the coarse and WP-2 nets, respectively.

Eocene Planktonic Foraminifera and the Age of the Youngest Marine Sediments in Tuna,Yadong,Southern Tibet

1 Introduction The collision evolution between the Indian plate and the Eurasian plate is one of the significant geological events since the Mesozoic.It has profoundly influenced the global tectonic framework and led to the formation of the Qinghai-Tibet Plateau,which has attracted extensive attention of global geologists and become a research hotspot(Butler,1995;Li and Wan,2003a and b;Wang et al.,2003;Aitchison et al.,2007).

Competitive Consumption of the Lake Kinneret (Israel) Plankton by <i>Hypophthalmichthys molitrix</i>and <i>Sarotherodon galilaeus</i>

An outdoor tank experiment was carried out for the assessing of the impacts of Sarotherodon galilaeus (Galilee Saint Peter’s Fish;Cichlidae) (SG) and Hypophthalmichthys molitriox (Silver Carp;Cyprinidae) (SC) on Lake Kinneret (Israel) plankton. In order to evaluate the interaction effect, the experiments were of replicated 2 × 2 factorial design: TG × SC. A lot of interaction effects were indicated showing that the effects of the two fishes were not independent and potentially competitors. SG suppressed most crustaceans and rotifers while increasing gross and net primary production and chlorophyll concentration. SC had less intense effects on zooplankton than SG. Although SC suppressed most crustaceans and rotifers, it had less interaction effects than SG. SC had no statistically significant effects on phytoplankton production or chlorophyll concentration. It is suggested that these experiments indicate that although the plankton community impacts of SG and SC do differ, both fishes utilize similar food resources in Lake Kinneret. Fingerlings of SG and SC are planted in Lake Kinneret annually aimed at the improvement of fishermen’s income and prevention of water quality deterioration. SC is known as efficient consumer of Microcystis. It is therefore recommended to limit SC introduction to periods when Microcystis is abundant.

Study on biological oceanography characteristics of planktonic copepods in waters north of Taiwan Ⅰ. Abundance distribution

On the basis of the investigation materials of 6 cruise in the waters north of Taiwan from 1987~1990, the distribution characteristics of planktonic copepods are discussed in the study from three aspects of abundance distribution, community feature and indicative species. The paper is the first part of the study. The results show as follows: the highest abundance of copepods occurred in spring and the lowest one in winter, while the abundance in summer and autumn was between the above two seasons. The copepod abundance in the west of the Kuroshio front was higher than that in the east of the front. There was a distribution tendency that higher abundance occurred in outshore area in summer and in nearshore area in winter, which corresponded with the trend of seasonal swings of the Kuroshio front. The higher copepod abundance appeared generally in the mixed areas of various water masses, especially in nearshore side of upwelling of the Kuroshio sub-surface water. However, in the Kuroshio subsurface main water, the abundance was low because of some factors such as low concentration of dissolved oxy gen and so on. The vertical distribution trend was that the copepopd abundance decreased with the in crease of depth, and the diurnal vertical migration regularities of some species were probably the one of reasons that caused the abnormal distributions in some local waters.

Stable carbon and oxygen isotopes of four planktonic foraminiferal species from core-top sediments of the Indonesian throughflow region and their significance

Horizontal and vertical distributions of δ^18 and δ^13 were investigated in shells of four planktonic foraminiferal species, Globigerinoides ruber, Globigerinoides sacculifer, Pulleniatina obliquiloculata and Neogloboquedrina dutertrei, from a total of 62 core-top sediment samples from the Indonesian throughflow region. Results were compared to modern hydrologic conditions in order to explore potential of proxies in reconstructing fluvial discharge and upper ocean water column characteristics in this region. Our results show that, in the Makassar Strait, both of depleted δ^18 and δ^13 of these four species were linked to freshwater input. In the Bali Sea,however, depleted δ^18 and δ^13 for these species may be due to different reasons. Depleted δ^18 was a result of freshwater input and as well influenced by along-shore currents while depleted δ^13 was more likely due to the Java-Sumatra upwelling. Comparison of shell δ^18 records and hydrographic data of World Ocean Atlas 2005 suggests that G. ruber and G. sacculifer calcify within the mixed-layer, respectively at 0–50 m and 20–75 m water depth, and P. obliquiloculata and N. dutertrei within the upper thermocline, both at 75–125 m water depth. N.dutertrei calcifies at slightly deeper water depth than P. obliquiloculata does. In general, δ^13 values of both G.ruber and G. sacculifer are larger than those of P. obliquiloculata and N. dutertrei at all sites, possibly related to depth habitats of these species and vertical distribution of nutrients in the Indonesian throughflow region.

Difference of planktonic ciliate communities of the tropical West Pacific, the Bering Sea and the Arctic Ocean

Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats.