Cause Analysis of Orah Yellowing and Its Measures

Orah is a hybrid of ＂Temple＂ tangor and ＂Dancy＂ tangerine, and due to its excellent performance in cultivation in Wuming of Guangxi Province for three years, it has been popularized in Guangxi, Chongqing, Sichuan and Yunnan rapidly, with a planting area over 130 000 hm^2. However, there also have been some problems existing in practical production, such as leaf yellowing and canker. The causes for leaf yellowing mainly include the physiologic type and the diseases and pests type. This paper analyzed the causes and put forwards corresponding countermeasures.

Effects of Different Yellowing Conditions on Neutral Aroma Components and Smoking Quality of Flue-cured Upper Leaves

A heated air circulation standard curing barn was used for baking tobacco leaves, and the effects of different yellowing conditions during the baking process on contents of neutral aroma components and smoking quality of upper leaves were studied by setting different yellowing time and color-fixing time. The results showed that during the baking process, only by prolonging the yellowing time by 24 h on the basis of control, the content of every kind of neutral aroma components in- creased obviously and the content of solanone increased by nearly 2.20 times. It was unfavorable for the degradation and accumulation of aroma components when only prolonging color-fixing time by 24 h. Prolonging both yellowing time and color- fixing time by 24 h mainly promoted the accumulation of chlorophyll degradation product neophytadiene, which increased by 33.24%, while the degradation and ac- cumulation of some aroma components were inhibited, indicating that only prolonging the yellowing time by 24 h could promote the accumulation of various kinds of neu- tral aroma components and improve the quality of tobacco leaves. The regression models were established of neutral aroma components in the first and second prin- cipal components to total aroma content, which were y=x＋0.053 47 （R^2=0.919 7） and y=x＋0.147 5 （R^2=0.698 4）, respectively, and they were verified to be feasible.

Fine-mapping and transcriptome analysis of the photosensitive leaf-yellowing gene CaLY1 in pepper(Capsicum annuum L.)

Leaf color is directly related to altered photosynthesis.Hence,leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes,for cultivating new varieties of popular horticultural plants,and for identifying hybrid purity(as markers).Here,we constructed a^(60)Co-γF_(2)population from the leaf-yellowing mutant R24 via radiation mutation with the inbred line WT21 of pepper.Genetic analysis showed that the leaf-yellowing of the mutant was controlled by a single recessive gene.By applying the Bulk Segregation Analysis and Kompetitive Allele Specific PCR markers,the leaf-yellowing gene CaLY1(Capsicum annuum Leaf yellow 1)was mapped on chromosome 9,SNP5791587-SNP6011215,with a size of 214.5 kb.One non-synonymous mutated gene Capana09g000166 was found in the interval.The gene encoded a Psb X,which is the core complex of PSⅡ.Transcriptome analysis further showed that 2301 differentially expressed genes were identified under shading treatment for 24 h in R24.The Gene Ontology enrichment pathways were related to photosynthesis light harvesting,cell wall,activity of quercetin 3-O-glucosyltransferase and flavonoid metabolic process,which likely regulate the response of pepper leaves to different light levels.Functional enrichment analysis indicated that the most abundant pathways were photosynthesis antenna proteins and metabolic.

A multi-omics approach identifies bHLH71-like as a positive regulator of yellowing leaf pepper mutants exposed to high-intensity light

Light quality and intensity can have a significant impact on plant health and crop productivity.Chlorophylls and carotenoids are classes of plant pigments that are responsible for harvesting light energy and protecting plants from the damaging effects of intense light.Our understanding of the role played by plant pigments in light sensitivity has been aided by light-sensitive mutants that change colors upon exposure to light of variable intensity.In this study,we conducted transcriptomic,metabolomic,and hormone analyses on a novel yellowing mutant of pepper(yl1)to shed light on the molecular mechanism that regulates the transition from green to yellow leaves in this mutant upon exposure to high-intensity light.Our results revealed greater accumulation of the carotenoid precursor phytoene and the carotenoids phytofluene,antheraxanthin,and zeaxanthin in yl1 compared with wild-type plants under high light intensity.A transcriptomic analysis confirmed that enzymes involved in zeaxanthin and antheraxanthin biosynthesis were upregulated in yl1 upon exposure to high-intensity light.We also identified a single basic helix–loop–helix(bHLH)transcription factor,bHLH71-like,that was differentially expressed and positively correlated with light intensity in yl1.Silencing of bHLH71-like in pepper plants suppressed the yellowing phenotype and led to reduced accumulation of zeaxanthin and antheraxanthin.We propose that the yellow phenotype of yl1 induced by high light intensity could be caused by an increase in yellow carotenoid pigments,concurrent with a decrease in chlorophyll accumulation.Our results also suggest that bHLH71-like functions as a positive regulator of carotenoid biosynthesis in pepper.

New Discoveries in Study on Hydrocarbons From Thermal Degradation of Heterotrophically Yellowing Algae

Green autotrophic alga Chlorella protothecoides contains a very small quantity of hydrocarbons. Heterotrophic culture of this alga results in the cells yellowing, chlorophyll disappearing, protein decreasing and lipid increasing remarkably. The quantities of hydrocarbons from them directly and from the thermal degradation of the cells at or below 200℃ are very low. These hydrocarbons are characterized by predominance of high molecular weight normal alkanes with maximum at C23-C25. When these heterotrophi-cally yellowing cells are thermally degraded at 300℃ , the aliphatic hydrocarbons increase greatly, 32 times that of the green autotrophic ones at the same temperature. Meanwhile, the low molecular weight normal alkanes with C17 as the peak become predominant instead of the original ones of high molecular weight. The actual potential of microplanktonic algae in producing hydrocarbons should be much greater than what people have recognized before.

Advance in yellowing mechanism and the regulation technology of post-harvested broccoli

Yellowing is one of the main problems of quality deterioration in the storage,transportation,and sales of post-harvested broccoli,which seriously affects the commodity value of broccoli.Therefore,it is of significance to understand the mechanism of the process and develop effective regulation technology.In this review,we expounded the changes in the appearance of the flower ball,bud morphology,and calyx cell structure,as well as endogenous pigment metabolism,accompanying the yellowing process of broccoli.In addition,recent research on the molecular mechanism of yellowing was summarized from the aspects of transcriptome analysis and transcription regulation.Finally,the progress on the control technology of broccoli yellowing was reviewed.

Yellowing of fresh-cut spinach(Spinacia oleracea L.)leaves delayed by UV-B applications

In present work,the effects of UV-B treatments on quality of fresh-cut spinach leaves were studied.For this purpose,spinach leaves grown in glasshouse were harvest,cleaned and placed into polystyrene foam dishes and wrapped by stretch film.After packaging,freshcut spinach leaves were treated with UV-B irradiation and were stored at 5℃ temperature for 12 days.Total soluble solids,visual quality,L^*a^*b^* values,and also hue angle values of samples were determined during storage.Total soluble solids content of samples in control group has been higher than those from samples in UV-B treatments,however,visual quality was lower than the other treatments.According to L*values of the samples,it is found that lower ultraviolet irratiation(UV-B)treatments caused yellowing of samples,and also same result was obtained by b^* and a^* values of fresh-cut spinach leaves.Similarly,hue angles values of samples treated with UV-B for 6min was higher compared with the other treatments.Consequently,yellowing of fresh-cut spinach leaves was decreased,and visual quality scores of samples was increased through ultraviolet irradiation treatments.

Pathogenesis and clinical management of arboviral diseases

Arboviral diseases are viral infections transmitted to humans through the bites of arthropods,such as mosquitoes,often causing a variety of pathologies associated with high levels of morbidity and mortality.Over the past decades,these infections have proven to be a significant challenge to health systems worldwide,particularly following the considerable geographic expansion of the dengue virus(DENV)and its most recent outbreak in Latin America as well as the difficult-tocontrol outbreaks of yellow fever virus(YFV),chikungunya virus(CHIKV),and Zika virus(ZIKV),leaving behind a substantial portion of the population with complications related to these infections.Currently,the world is experiencing a period of intense globalization,which,combined with global warming,directly contributes to wider dissemination of arbovirus vectors across the globe.Consequently,all continents remain on high alert for potential new outbreaks.Thus,this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today(DENV,ZIKV,YFV,and CHIKV)discussing their viral characteristics,immune responses,and mechanisms of viral evasion,as well as important clinical aspects for patient management.This includes associated symptoms,laboratory tests,treatments,existing or developing vaccines and the main associated complications,thus integrating a broad historical,scientific and clinical approach.

King's College criteria and the Clichy-Villejuif criteria require adjustments for assessing acute liver failure due to yellow fever

BACKGROUND Acute liver failure(ALF)is a severe condition characterized by rapid deterioration of liver function in individuals without preexisting liver disease.Liver transplantation(LT)is the most impactful treatment.Yellow fever(YF)is an infectious disease that primarily affects the liver and has a high mortality rate.However,LT can be a viable option for treating rare cases with extensive liver involvement.However,the criteria for assessing the severity of ALF and determining the indications for transplantation have not been specifically validated for cases caused by YF.AIM To present necessary adjustments to established scoring systems for ALF secondary to YF.METHODS This was an observational,retrospective,single-center study.Fourteen consecutive patients with confirmed ALF due to YF were monitored in the intensive care unit by a specialized liver transplant team during a three-month epidemic outbreak in Brazil.During hospitalization,general supportive therapeutic measures were implemented,and the patients were regularly assessed using the King's College criteria and the Clichy-Villejuif criteria to determine the severity of liver failure.LT is considered a viable measure for patients with signs of end-stage liver failure.RESULTS Eight of 14(57%)patients developed severe neurological alterations within the first 96 hours after hospital admission.Four patients underwent emergency LT,and despite a moderate viral infection of the graft after transplantation,the 5-year survival rate was 50%.Although the King's College criteria and the Clichy-Villejuif criteria are the main scoring systems for ALF,they are insufficient for predicting the risk of mortality in this context,primarily because of low serum bilirubin levels in the final stage of the disease and significant disparities between coagulation abnormalities and patient severity.CONCLUSION To ensure good applicability in cases of YF-induced ALF,the authors suggest adaptations to the King's College and Clichy-Villejuif criteria.

Influences of Bacterial Degradation on Gases Generated by Pyrolysis of Heterotrophically Yellowing Algae

The large amount of microplanktonic algae in nature are not all thermally degraded directly into organic matter from their original green autotrophic state. When the algae are old or dead and deposited at the bottom of lake or ocean, some changes may take place in the cells, including the disappearance of the chlorophyll, the

A novel transcription factor FnMYB4 regulates pigments metabolism of yellow leaf mutants in Fragaria nilgerrensis

The strawberry species Fragaria nilgerrensis Schlechtendal ex J.Gay,renowned for its distinctive white,fragrant peach-like fruits and strong disease resistance,is an exceptional research material.In a previous study,an ethyl methane sulfonate(EMS)mutant library was established for this species,resulting in various yellow leaf mutants.Leaf yellowing materials are not only the ideal materials for basic studies on photosynthesis mechanism,chloroplast development,and molecular regulation of various pigments,but also have important utilization value in ornamental plants breeding.The present study focused on four distinct yellow leaf mutants:mottled yellow leaf(MO),yellow green leaf(YG),light green leaf(LG),and buddha light leaf(BU).The results revealed that the flavonoid content and carotenoid-to-chlorophyll ratio exhibited a significant increase among these mutants,while experiencing a significant decrease in chlorophyll and carotenoid contents compared to the wild type(WT).To clarify the regulatory mechanisms and network relationships underlying these mutants,the RNA-seq and weighted gene coexpression network(WGCNA)analyses were employed.The results showed flavonoid metabolism pathway was enriched both in MO and YG mutants,while the chlorophyll biosynthesis pathway and carotenoid degradation pathway were only enriched in MO and YG mutants,respectively.Subsequently,key structural genes and transcription factors were identified on metabolic pathways of three pigments through correlation analyses and quantitative experiments.Furthermore,a R2R3-MYB transcription factor,FnMYB4,was confirmed to be positively correlated with flavonoid synthesis through transient overexpression,virus-induced gene silencing(VIGS),and RNA interference(RNAi),accompanying by reoccurrence and attenuation of mutant phenotype.Finally,dual-luciferase(LUC)and yeast one-hybrid assays confirmed the binding of FnMYB4 to the FnFLS and FnF3H promoters,indicating that FnMYB4 positively regulates flavonoid synthesis.In addition,correlation analyses suggested that FnMYB4 also might be involved in chlorophyll and carotenoid metabolisms.These findings demonstrated the pivotal regulatory role of FnMYB4 in strawberry leaf coloration.

黄河流域生态保护迈向高质量发展的特征——植被绿度、生产力和降水利用效率的差异性变化

Globally,vegetation has been changing dramatically.The vegetation-water dynamic is key to understanding ecosystem structure and functioning in water-limited ecosystems.Continual satellite monitoring has detected global vegetation greening.However,a vegetation greenness increase does not mean that ecosystem functions increase.The intricate interplays resulting from the relationships between vegetation and precipitation must be more adequately comprehended.In this study,satellite data,for example,leaf area index(LAI),net primary production(NPP),and rainfall use efficiency(RUE),were used to quantify vegetation dynamics and their relationship with rainfall in different reaches of the Yellow River Basin(YRB).A sequential regression method was used to detect trends of NPP sensitivity to rainfall.The results showed that 34.53%of the YRB exhibited a significant greening trend since 2000.Among them,20.54%,53.37%,and 16.73%of upper,middle,and lower reach areas showed a significant positive trend,respectively.NPP showed a similar trend to LAI in the YRB upper,middle,and lower reaches.A notable difference was noted in the distributions and trends of RUE across the upper,middle,and lower reaches.Moreover,there were significant trends in vegetation-rainfall sensitivity in 16.86%of the YRB’s middle reaches—14.08%showed negative trends and 2.78%positive trends.A total of 8.41%of the YRB exhibited a marked increase in LAI,NPP,and RUE.Subsequently,strategic locations reliant on the correlation between vegetation and rainfall were identified and designated for restoration planning purposes to propose future ecological restoration efforts.Our analysis indicates that the middle reach of the YRB exhibited the most significant variation in vegetation greenness and productivity.The present study underscores the significance of examining the correlation between vegetation and rainfall within the context of the high-quality development strategy of the YRB.The outcomes of our analysis and the proposed ecological restoration framework can provide decision-makers with valuable insights for executing rational basin pattern optimization and sustainable management.

Improving the nutritional values of yellow mealworm Tenebrio molitor(Coleoptera: Tenebrionidae) larvae as an animal feed ingredient: a review

Yellow mealworm larvae(YML;Tenebrio molitor) are considered as a valuable insect species for animal feed due to their high nutritional values and ability to grow under different substrates and rearing conditions. Advances in the understanding of entomophagy and animal nutrition over the past decades have propelled research areas toward testing multiple aspects of YML to exploit them better as animal feed sources. This review aims to summarize various approaches that could be exploited to maximize the nutritional values of YML as an animal feed ingredient. In addition, YML has the potential to be used as an antimicrobial or bioactive agent to improve animal health and immune function in production animals. The dynamics of the nutritional profile of YML can be influenced by multiple factors and should be taken into account when attempting to optimize the nutrient contents of YML as an animal feed ingredient. Specifically, the use of novel land-based and aquatic feeding resources, probiotics, and the exploitation of larval gut microbiomes as novel strategies can assist to maximize the nutritional potential of YML. Selection of relevant feed supplies, optimization of ambient conditions, the introduction of novel genetic selection procedures, and implementation of effective post-harvest processing may be required in the future to commercialize mealworm production. Furthermore, the use of appropriate agricultural practices and technological improvements within the mealworm production sector should be aimed at achieving both economic and environmental sustainability. The issues highlighted in this review could pave the way for future approaches to improve the nutritional value of YML.

Targeted mutations of BnPAP2 lead to a yellow seed coat in Brassica napus L.

The yellow seed trait is preferred by breeders for its potential to improve the seed quality and commercial value of Brassica napus.In the present study,we produced yellow seed mutants using a CRISPR/Cas9 system when the two BnPAP2 homologs were knocked out.Histochemical staining of the seed coat demonstrated that proanthocyanidin accumulation was significantly reduced in the pap2 double mutants and decreased specifically in the endothelial and palisade layer cells of the seed coat.Transcriptomic and metabolite profiling analysis suggested that disruption of the BnPAP2 genes could reduce the expression of structural and regulated genes in the phenylpropanoid and flavonoid biosynthetic pathways.The broad suppression of these genes might hinder proanthocyanidin accumulation during seed development,and thereby causing the yellow seed trait in B.napus.These results indicate that BnPAP2 might play a vital role in the regulatory network controlling proanthocyanidin accumulation.

Physical and mechanical properties and microstructures of submarine soils in the Yellow Sea

In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.

Numerical study on local scour characteristics around submarine pipelines in the Yellow River Delta silty sandy soil under waves and currents

Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational safety.With the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference method.The volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is established.The rationality of the numerical model is verified using a self-built waveflow flume.On this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is analyzed.The results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable scour.The maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of scour.This study can provide a valuable reference for the protection of submarine pipelines in this area.

Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species

Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic studies.However,the commonly used LCAs proxies are mainly based on C_(37) alkenones,and it is still lack of the studies about the distribution and in-dications of LCAs with different chain lengths other than C_(37) alkenones.Here,the composition and distribution of LCAs were ana-lyzed in surface sediments from the southern Yellow Sea(SYS)and a sedimentary core(A02-C)from the central Yellow Sea(YS)mud area.The results showed that C_(37),C_(38) and C_(39) alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C_(38:2)Et,C_(37:2)Me,C_(37:3)Me,C_(38:2)Me,C_(38:3)Et,C_(38:3)Me,C_(39:2)Et and C_(39:3)Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3%,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,respectively.Then the relationships of U_(38Me)^(K)-U_(38Et)^(K) and U_(37)^(K')-U_(38Et)^(K) indicate that LCAs are mainly derived from Emiliania huxleyi(E.huxleyi).High ratios of total C_(37) alkenones to total C_(38) alkenones(K_(37)/K_(38))(1-1.2)were found in the central SYS,corresponding to the relatively high abundance of E.huxleyi;while low ratios of K_(37)/K_(38)(0.7-0.9)were observed at nearshore area of the SYS where Gephyrocapsa oceanica(G.oceanica)has rela-tively high abundance.The spatial distribution of K_(37)/K_(38) ratio is also consistent with that of coccolithophores nannofossil in the sediments.In addition,K_(37)/K_(38) ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 kyr.This suggests that the relative abundance of E.huxleyi decreased gradually,caused by the changes in the Yellow Sea Warm Current(YSWC)and the East Asian Winter Monsoon(EAWM)during this period.

Simultaneous removal of sulfur dioxide and nitrogen oxide from flue gas by phosphorus sludge:The performance and absorption mechanism

Developing low-cost and green simultaneous desulfurization and denitrification technologies is of great significance for sulfur dioxide(SO_(2))and nitrogen oxide(NO_(x))emission control at low temperatures,especially for small and medium-sized coal-fired boilers and furnaces.Herein,phosphorus sludge,an industrial waste from the production process of yellow phosphorus,has been developed to simultaneously eliminate SO_(2)and NO_(x)from coal-fired flue gas.The key factors affecting the experimental results indicate that desulfurization and denitrification efficiency of over 95%can be achieved at a low temperature of 55℃.Further,the absorption mechanism was investigated by characterizing the solid and liquid phases of the phosphorus sludge during the absorption process.The efficient removal of SO_(2)is attributed to the abundance of iron(Fe^(3+))and manganese(Mn^(2+))in the absorbent.SO_(2)can be rapidly catalyzed and converted to SO_(4)^(2-)by them.The key to NOx removal is the oxidation of NO toward watersoluble high-valent nitrogen oxides by oxidizing reactive substances induced via yellow phosphorus,which are then absorbed by water and converted to NO_(3)^(-).Meanwhile,yellow phosphorus is oxidized to phosphoric acid(H_(3)PO_(4)).The spent absorption slurry can be reused through wet process phosphoric acid production,as it contains sulfuric acid(H_(2)SO_(4)),nitric acid(HNO_(3)),and H_(3)PO_(4).Accordingly,this is a technology with broad application prospects.

Morphological,phylogenetic and metabolite profile of Prorocentrum clipeus,a newly recorded epiphytic dinoflagellate in the northern Yellow Sea

More than 30 species of benthic Prorocentrum have been identified,some of which produce okadaic acid(OA)and its derivatives,dinophysistoxins(DTXs),which cause diarrhetic shellfish poisoning(DSP).Increasing numbers of benthic Prorocentrum species have been reported in tropical and subtropical waters of China.In contrast,only a few benthic Prorocentrum species have been reported in temperate waters.In this study,morphological descriptions obtained using light microscopy,scanning electron microscopy and molecular characterization of one Prorocentrum clipeus strain isolated from the Yellow Sea are presented.Prorocentrum clipeus cells were nearly circular in shape,with a collar,ridge,and one protrusion.The periflagellar area was wide U-shaped,with two curved projections on platelet 1a.Nine periflagellar platelets of different sizes were observed.The morphology closely fits that of the species isolated from other locations.Phylogenetic analysis based on the molecular sequences of the small subunit(SSU)rDNA,internal transcribed spacer(ITS),and large subunit(LSU)rDNA was performed.A comprehensive metabolomic analysis incorporating target,suspect and non-target screenings was first applied to investigate the intracellular and extracellular metabolite profiles of the current isolate of P.clipeus.According to the results of the target and suspect screenings,179 metabolites or toxins produced by DSP-related algal species,including OA,dinophysistoxin-1(DTX1),dinophysistoxin-2(DTX2)and pectenotoxin-2(PTX2),were not detected.Non-target screening involving feature-based molecular networking(FBMN)provided a global view of major metabolites produced by the P.clipeus DF128 strain and revealed 23 clusters belonging to at least 13 compound classes,with organometallic compounds,lipids and lipid-like molecules,phenylpropanoids and polyketides,and benzenoids as major types.To date,this is the first record of the characterization of P.clipeus in samples from Chinese waters.Our results support the wide distribution of epibenthic Prorocentrum species.

Spatial patterns of zooplankton abundance,biovolume,and size structure in response to environmental variables:a case study in the Yellow Sea and East China Sea

The Yellow Sea(YS)and East China Sea(ECS)are highly dynamic marginal seas of the northwestern Pacific Ocean.To gain an in-depth understanding of zooplankton community structure,zooplankton abundance,biovolume,and size structure in summer 2017 in the YS and ECS were assessed using ZooScan imaging analysis.Zooplankton abundance and biovolume ranged 2.94–1187.14 inds./m^(3)and 3.13–3438.51 mm^(3)/m^(3),respectively.Based on the biovolume data of the categorized size classes of 26 identified taxonomic groups,the zooplankton community was classified into five groups,and each group was coupled with distinctive oceanographic features.Under the influence of the Yellow Sea Cold Water Mass,the Yellow Sea offshore group featured the lowest bottom temperature(10.84±3.42℃)and the most abundant Calanoids(mainly in the 2–3 mm size class).In the Yellow Sea inshore group,Hydrozoans showed the largest biovolume and dominated in the 3–4-mm and>5-mm size classes.The East China Sea offshore group,which was affected by the Kuroshio Branch Current,featured high temperature and salinity,and the lowest bottom dissolved oxygen(2.58±0.5 mg/L).The lowest values of zooplankton abundance and biovolume in the East China Sea offshore group might be attributed to the bottom dissolved oxygen contents.The East China Sea inshore group,which was mainly influenced by the Zhejiang-Fujian Coastal Current and Changjiang Diluted Water,was characterized by high chlorophyll a and the largest biovolume of carnivorous Siphonophores(280.82±303.37 mm^(3)/m^(3)).The Changjiang River estuary offshore group showed the most abundant Cyclopoids,which might be associated with the less turbid water mass in this region.Seawater temperature was considered the most important factor in shaping the size compositions of Calanoids in different groups.