The Genetic Structure and Diversity of Repomucenus curvicornis Inhabiting Liaoning Coast Based on Mitochondrial COⅠ Gene and Control Region

[Object] This study was conducted to explore the genetic diversity and structure of the wild Repomucenus curvicornis inhabiting Liaoning Coast, China. [Method] The mitochondrial COⅠ gene and control region（CR） were PCR amplified from the wild R. curvicornis populations from the Liaodong Bay（n=22） and the northern Yellow Sea（n=18）, sequenced and analyzed for genetic diversity. [Result] The contents of A, T, C and G of 624 bp COⅠ gene were 24.09%, 31.04%, 25.28%, and 19.59%, and those of 460 bp CR fragment were 32.96%, 32.80%, 14.86% and 19.38%, respectively. The total number of variable sites, average number of nucleotide differences（ k）, haplotype diversity（H） and nucleotide diversity（π） based on COⅠ gene were 38, 4.67,（0.96±0.02） and（0.007 5±0.004 2）, and those based on CR fragment were 26, 3.35,（0.97 ±0.02） and（0.007 3±0.004 3）, respectively. Based on mitochondrial COⅠ gene and CR, the genetic diversity of Liaodong Bay population was lower than that of the northern Yellow Sea population. The AMOVA analysis based on CR fragments revealed almost significant genetic divergence between the Liaodong Bay and the northern Yellow Sea populations, while there was no significant genetic divergence based on COⅠ gene. The results showed that CR and COⅠ gene are effective molecular markers for detecting the genetic diversity of R. curvicornis population, while CR is more reliable than COⅠ gene in detecting the genetic structure. [Conclusion] CR is an appropriate marker for genetic analysis of marine fish population.

Relationship between environmental factors and plankton in the Bayuquan Port, Liaodong Bay,China：a five-year study

To understand the relationship between the plankton community and environmental factor and water quality in the Bayuquan Port of Liaodong Bay, China, and investigations were carried ou during six dif ferent periods(April 2009, April 2010, October 2011, April 2012, October 2012, and Apri 2013). This area was characterized by high levels of nutrient and suspended solids(SPS) during surve periods, and eutrophication led to the occurrence of red tides in April and October 2012 and April 2013 Our analyses revealed that the plankton communities of Bayuquan Port lacked stability and were af fecte seriously by external disturbance(e.g., oceanographic engineering and river runof f). Our data indicate tha oil, dissolved inorganic nitrogen(DIN), SPS, and chlorophyll a(Chl- a) were key factors that regulated th phytoplankton and zooplankton communities. The partial redundancy analysis(partial RDA) suggested tha oil and SPS were the most important environmental variables af fecting the phytoplankton community i April 2010 and 2012, whereas DIN concentration played a governing role in zooplankton dynamics. Oi and Chl-a concentrations af fected signifi cantly the zooplankton community in October 2012. Therefore, th plankton communities could refl ect both dynamic changes in coastal environmental factors and the ongoin eutrophication process caused by anthropogenic activities in this area.

Seasonal Variation of Environmental Variables and Phytoplankton Community Structure and Their Relationship in Liaodong Bay of Bohai Sea,China

In this paper, systematic studies on the changes in concentrations of the environmental factors and the net-phytoplankton community, and the relationship between them in the Liaodong Bay, Bohai Sea during 2013 are presented. The PCA results showed that higher levels of nutrients and dissolved heavy metals in the river-estuary-bay system were closely related to the river runoff. Since the influences of industrial and anthropogenic activities, the Liaodong Bay coastal areas are facing a huge environmental challenge of nutrients and heavy metal pollution. Net-phytoplankton community structure showed obvious seasonal succession, among which the dominant and(or) key species were the main factors affecting community structure change and stability. Under certain environmental conditions, the dominant species and(or) key species dominated the phytoplankton community structure succession. The Bio-ENV results suggested that the seawater temperature, nutrient, Cu, Pb, Zn, and Cd in Liaodong Bay are important environmental variables that affect the phytoplankton community structure. Anthropogenic activities have significantly contributed to the changes in concentrations of environmental factors and the net-phytoplankton community structure and stability, and the relationship between them.

Characterization and Expression Analysis of a Complement Component Gene in Sea Cucumber(Apostichopus japonicus)

The complement system plays a crucial role in the innate immune system of animals. It can be activated by distinct yet overlapping classical, alternative and lectin pathways. In the alternative pathway, complement factor B(Bf) serves as the catalytic subunit of complement component 3(C3) convertase, which plays the central role among three activation pathways. In this study, the Bf gene in sea cucumber(Apostichopus japonicus), termed Aj Bf, was obtained by rapid amplification of c DNA ends(RACE). The full-length c DNA of Aj Bf was 3231 bp in length barring the poly(A) tail. It contained an open reading frame(ORF) of 2742 bp encoding 913 amino acids, a 105 bp 5'-UTR(5'-terminal untranslated region) and a 384 bp 3'-UTR. Aj Bf was a mosaic protein with six CCP(complement control protein) domains, a VWA(von Willebrand factor A) domain, and a serine protease domain. The deduced molecular weight of Aj Bf protein was 101 k Da. Quantitative real time PCR(q RT-PCR) analysis indicated that the expression level of Aj Bf in A. japonicus was obviously higher at larval stage than that at embryonic stage. Expression detection in different tissues showed that Aj Bf expressed higher in coelomocytes than in other four tissues. In addation, Aj Bf expression in different tissues was induced significantly after LPS or Poly I:C challenge. These results indicated that Aj Bf plays an important role in immune responses to pathogen infection.

Source apportionment and ecological risk assessment of PAHs in surface sediments from the Liaodong Bay,northern China

The sources and ecological risk from sixteen polycyclic aromatic hydrocarbons in surface sediment in the Liaodong Bay were investigated from 2014 to 2015.The total concentrations of PAHs ranged from 88.5 to 347.1 ng/g,and the high value occurred in the central region of the Liaodong Bay.Cluster analysis identified two site clusters representing the coastal region affected by land-based pollution and the central region of the Liaodong Bay.Principal component analysis-multiple linear regression and diagnostic ratios suggested that PAHs contaminants originated from a mixture of combustion and petroleum sources,and the major was combustion sources.Based on sediment quality guideline,naphthalene,acenaphthylene,acenaphthene,phenanthrene and dibenz[a,h]anthracene may occasionally cause adverse biological effects in some stations.The toxic equivalent concentrations of carcinogenic PAHs indicated low carcinogenic risk for the Liaodong Bay.The ecological risk and toxic pollution levels of PAHs were higher in the central region than in the coastal region along the Liaodong Bay.

Seasonal variation in species composition and abundance of demersal fish and invertebrates in a Seagrass Natural Reserve on the eastern coast of the Shandong Peninsula,China

Seagrass habitats are structurally complex ecosystems, which support high productivity and biodiversity. In temperate systems the density of seagrass may change seasonally, and this may influence the associated fish and invertebrate community. Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China. To study the functioning of a seagrass habitat in northern China, demersal fish and invertebrates were collected monthly using traps, from February 2009 to January 2010. The density, leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured. The study was conducted in a Seagrass Natural Reserve(SNR) on the eastern coast of the Shandong Peninsula, China. A total of 22 fish species and five invertebrate species were recorded over the year. The dominant fish species were Synechogobius ommaturus, Sebastes schlegelii, Pholis fangi, Pagrus major and Hexagrammos otakii and these species accounted for 87% of the total number of fish. The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98% of the total abundance of invertebrates. There was high temporal variation in species composition and abundance. The peak number of fish species occurred in August–October 2009, while the number of individual fish and biomass was highest during November 2009. Invertebrate numbers and biomass was highest in March, April, July and September 2009. Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass, Zostera marina.

Isolation, Identification, and Quantitative Determination of Saponin in Apostichopus japonicus by HPLC-DAD

Apostichopus japonicus is an important invertebrate that is widely used as a tonic food in Asian countries.The purpose of this study is to purify and identify a class of compound,the saponins,from the body wall of A.japonicus,and to establish a new me-thod to determine the quantity of saponins in the sea cucumber.In this study,the saponins of A.japonicus,cladoloside A(CA),were ob-tained from 80%ethanol extract by column chromatography for the first time and were characterized using the spectral method.The resulting purified saponins were then profiled using ^(1)HNMR,^(13)CNMR,and ESI-MS,which revealed the CA molecular formula of C_(53)H_(82)O_(2) and contained a triterpenoid backbone,a methylglucopyranosyl moiety,a quinovopyranosyl,and two xylopyranosyls.A me-thod for the quantitative determination of CA,comprising microwave-assisted extraction,high-performance liquid chromatography,and diode array detector method,was established.Extraction efficiency was optimized by changing microwave power,extraction sol-vent,volume,time,and temperature.Results showed that under the optimum conditions(extraction time of 10 min,temperature of 45℃,and solvent of 25 mL 70%ethanol under 400 W),the detection limit of CA was 0.0015 mg mL^(−1),and the recoveries of CA from samples at spiking levels of 10,20,and 50μg g^(−1) ranged from 90.1%-104%.The proposed method was successfully applied to ana-lyze the saponins in different tissues of A.japonicus collected in different seasons.The method developed in this study can provide quantitative technical support for the quality control of A.japonicus.

Microbial community coexisting with harmful alga Karenia mikimotoi and microbial control of algal bloom in laboratory

Algicidal bacteria have been frequently isolated from algal blooming areas.However,knowledge regarding the microbial communities coexisting with microalgae and their potential application in preventing harmful algal blooms(HABs)is limited.In this study,we investigated the composition of the microbial community coexisting with harmful alga Karenia mikimotoi and its responses to algal control via nutrient stimulation or by adding algicidal strain in microcosms.The microorganisms inhabiting the K.mikimotoi culture consisted of 24 identifi ed phyla,including dominant Proteobacteria(relative abundance 76.24%±7.28%)and Bacteroidetes(22.67%±8.32%).Rhodobacteraceae,Phaeodactylibacter,and Maritimibacter predominated during the algal cultivation.Both the added nutrient and fermentation broth of algicidal strain Pseudoalteromonas QF1 caused a massive death of K.mikimotoi and substantial changes in the coexisting microbial community,in which Rhodobacteraceae and Phaeodactylibacter signifi cantly decreased,while Halomonas and Alteromonas increased.Core operational taxonomic units(OTUs)analysis indicated that 13 OTUs belonging to Rhodobacteraceae,Maritimibacter,Marivita,Nisaea,Phaeodactylibacter,Citreicella,Halomonas,Alteromonas,Marinobacter,Muricauda,and Pseudoalteromonas dominated the changes of the microbial communities observed in the K.mikimotoi culture with or without treatments.Collectively,this study indicated that microbial community inhabiting K.mikimotoi culture includes potential algicidal bacteria,and improves our knowledge about microbial community succession during biocontrol of K.mikimotoi via nutrient stimulation or by adding isolated algicidal strains.

Toxic Algae and Early Warning Management in Yellow Sea and Bohai Sea of China

The research status of toxic algae in Yellow Sea and Bohai Sea are reviewed from the aspects of toxicity characteristics,toxic mechanism and early warning management,and the existing toxic algae and their toxicity in Yellow Sea and Bohai Sea are analyzed in the paper. The early warning level of toxic algae in Yellow Sea and Bohai Sea of China is put forward,and the research direction of shellfish poisoning in future is summarized.

Species Composition and Protection of Fish Eggs and Larvae in Spawning Ground of Liaodong Bay

[Objective] The paper was to explore the species composition, number distribution and seasonal dynamics of fish eggs and larvae in Liaodong Bay in 2008. The protection and exploitation status of spawning ground in Liaodong Bay was analyzed, and the corresponding protection measures were put forward. [Methods] The species composition of fish eggs and larvae in spawning ground of Liaodong Bay was investigated by horizontal trawling associated with vertical trawling with zooplankton net in May, July, September and October in 2008. [Result] It was found that 7 724 eggs and 229 larvae of fishes belonging to 32 taxa were collected, in which 29 taxa were identified as species, belonging to 9 genera, 21 families and 28 orders, 2 taxa were identified to only family level, and one failed to be identified. The main spawning groups were Cynoglossus joyneri, Engraulis japonicus, Johnius belengerii, Larimichthys polyactis, Konosirus punctatus, Sardinella zunasi, and Scomberomorus niphonius, and the main spawning ground was found in northern waters and Changxing Island waters in Liaodao Bay. There was slightly less spawning species in 2008 compared with 1998, especially the number of fish eggs and larvae decreased greatly. [Conclusion] The effective measures for protection of spawning grounds in Liaodong Bay are suggested, including control of fishing intensity, development of artificial reefs, establishment of germplasm resources reserves, and standardization of compensation standards for marine ecological damage.

Spatial-temporal shifting patterns and in situ conservation of spotted seal(Phoca largha)populations in the Yellow Sea ecoregion

Understanding the habitat shifting pattern is a prerequisite for implementing in situ conservation of migratory species.Spotted seals(Phoca largha)inhabiting the Yellow Sea ecoregion(YSE)comprise a small population with independent genes and represent a charismatic flagship species in this region.However,this population has declined by 80%since the 1940s,and increased support from the countries around the YSE is urgently needed to address the potential local extinction risk.A time-series niche model and life-history weighted systematic conservation planning were designed on the basis of a satellite beacon tracking survey(2010–2020)of the YSE population.The results showed clustering and spreading shifting patterns during the breeding and migratory seasons,respectively.The closed-loop migration route formed in the YSE indicated that this population might be geographically isolated from populations in other breeding areas around the world.The conservation priority area(CPA),with an area of 19632 km^(2)(3.58%of the total YSE area),was the most effective response to the potential in situ risk.However,nearly 80%of the CPA was exposed outside the existing marine protected areas(MPAs).Future establishment of MPAs in China should strategically consider the conservation gap identified herein,and it is recommended for Korea’s closed fishing season to be spatially set in the western Korean Peninsula from May to August.This study also exemplified that the lack of temporal information would lead to the dislocation of niche modeling for migratory species represented by spotted seals.Attention should be paid to protecting small and migratory populations in marine biodiversity conservation planning.

大连市南部海域休闲渔业发展的SWOT分析

大连市是我国东北地区最重要的港口城市、滨海旅游胜地和著名的海洋科技城,在发展海洋休闲渔业方面有许多优势。本文对大连市南部海域发展休闲渔业的外部环境和内部环境进行了分析,并在SWOT分析基础之上揭示了发展休闲渔业所面临的优势与劣势、机遇与挑战。通过对大连南部海域发展休闲渔业现状进行了全面分析,并在综合、比较、分析的基础上,提出大连市南部海域休闲渔业发展的对策。

Comparison of Two Methods to Assess the Size Structure of Phytoplankton Community Assemblages, in Liaodong Bay, China

Liaodong Bay is one of the largest semi-enclosed bays located in Bohai Sea,in northeast China.It is an important feeding and spawning place,even wintering and breeding migration base for many marine organisms.The size structure of phytoplankton communities is a key feature of marine ecosystems and can be used as an indicator for algae disaster,but the methods to evalute is still challenging.Here,we compared the size-fractionated chlorophyll-a method with a high-throughout sequencing method in an evaluation of the size structure of phytoplankton assemblages in Liaodong Bay,China,in 2014.The proportion of picophytoplankton was estimated at just 19%according to the results based on size-fractionated chlorophyll-a,which likely represents a severe underestimation.The sequencing method confirmed that many kinds of phytoplankton species appeared in more than one size-fractionated filter membrane,with some even dominating where the filter membrane pore size was greater than the individual phytoplankton size.According to the sequencing method,the phytoplankton assemblages in Liaodong Bay were dominated by picophytoplankton(average proportion=44%),followed by the nanophytoplankton(average 32%),a composition that is more consistent with other studies.The sequencing method provides a more robust way to assess the size structure and taxonomic diversity of marine phytoplankton communities.

Numerical Simulation of Bohai Oil Spill in the Winter Sea Ice Period

The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing winter oil spill accidents. This study applied the three-dimensional free surface to establish a high-resolution hydrodynamic model and simulate tidal distributions in the Bohai Sea. Then, the oil spill model of the open sea area and thermodynamic model were combined to establish a numerical model for the Bohai oil spill during the winter sea ice period. The hydrodynamic model and sea ice growth and melting model were verified, and the parameters were adjusted based on the measured values, which indicate that the numerical model established in this paper is of high accuracy,stability and ubiquity. Finally, after checking the calculations repeatedly, the diffusion coefficient for the Bohai Sea was determined to be 1.0×10^(–7 )m^2/s. It is better that the comprehensive weathering attenuation coefficient is lower than that of a non-winter oil spill, with 1.3×10^(–7 )m^2/s being the most appropriate coefficient. This study can provide the reliable technical support for the operational safety and reduction in losses caused by winter oil spill accidents for the petroleum industry.

Cryopreservation of strip spawned sperm using programmable freezing technique in the blue mussel Mytilus galloprovincialis

In this study, a programmable freezing technique has been developed for strip spawned sperm in the blue mussel, M ytilus galloprovincialis. The optimized key parameters include cooling rate, endpoint temperature, thawing temperature, sugar addition and sperm to oocyte ratio. The sperm quality was assessed by the fertilization rate or the integrity of sperm component and organelle. The highest post-thaw sperm fertilization rate was 91%, which was produced with sperm cryopreserved in 8% dimethyl sulfoxide at the cooling rate of-4°C/min from 2°C to-30°C before being plunged into liquid nitrogen for at least 12 h, thawed in a 20°C seawater bath and fertilized at sperm to egg ratio of 50 000:1. The addition of glucose, sucrose or trehalose to 8% dimethyl sulfoxide could not further improve fertilization rates. The fluorescent assessments showed that the post-thaw sperm plasma membrane integrity and acrosome integrity were significantly damaged in comparison with fresh sperm.

Unraveling the skatole biodegradation process in an enrichment consortium using integrated omics and culture-dependent strategies

3-Methylindole(skatole)is regarded as one of the most offensive compounds in odor emission.Biodegradation is feasible for skatole removal but the functional species and genes responsible for skatole degradation remain enigmatic.In this study,an efficient aerobic skatole-degrading consortium was obtained.Rhodococcus and Pseudomonas were identified as the two major and active populations by integrated metagenomic and metatranscriptomic analyses.Bioinformatic analyses indicated that the skatole downstream degradation wasmainly via the catechol pathway,and upstream degradation was likely catalyzed by the aromatic ring-hydroxylating oxygenase and flavin monooxygenase.Genome binning and gene analyses indicated that Pseudomonas,Pseudoclavibacter,and Raineyella should cooperate with Rhodococcus for the skatole degradation process.Moreover,a pure strain Rhodococcus sp.DMU1 was successfully obtained which could utilize skatole as the sole carbon source.Complete genome sequencing showed that strain DMU1 was the predominant population in the consortium.Further crude enzyme and RT-qPCR assays indicated that strain DMU1 degraded skatole through the catechol ortho-cleavage pathway.Collectively,our results suggested that synergistic degradation of skatole in the consortium should be performed by diverse bacteria with Rhodococcus as the primary degrader,and the degradation mainly proceeded via the catechol pathway.

Chromosome-scale genome assembly of brownspotted flathead Platycephalus sp.1 provides insights into demersal adaptation in flathead fish

Flatheads are valuable commercial fish species endemic to the Indo-West Pacific.Due to their economic value and unique biological traits,such as metamorphosis and camouflage,they serve as ideal marine organisms for studies on demersal adaptation and evolution.The brown-spotted flathead(Platycephalus sp.1)is the most widely distributed in the northwestern Pacific.Despite the lack of a valid scientific name,it has been long recognized and exploited in the marine fisheries of China,Japan,and Korea.In the current study。

Health risk ranking of antibiotic resistance genes in the Yangtze River

Antibiotic resistance is an escalating global health concern,exacerbated by the pervasive presence of antibiotic resistance genes(ARGs)in natural environments.The Yangtze River,the world's third-longest river,traversing areas with intense human activities,presents a unique ecosystem for studying the impact of these genes on human health.Here,we explored ARGs in the Yangtze River,examining 204 samples from six distinct habitats of approximately 6000 km of the river,including free-living and particle-associated settings,surface and bottom sediments,and surface and bottom bank soils.Employing shotgun sequencing,we generated an average of 13.69 Gb reads per sample.Our findings revealed a significantly higher abundance and diversity of ARGs in water-borne bacteria compared to other habitats.A notable pattern of resistome coalescence was observed within similar habitat types.In addition,we developed a framework for ranking the risk of ARG and a corresponding method for calculating the risk index.Applying them,we identified water-borne bacteria as the highest contributors to health risks,and noted an increase in ARG risks in particle-associated bacteria correlating with heightened anthropogenic activities.Further analysis using a weighted ARG risk index pinpointed the ChengdueChongqing and Yangtze River Delta urban agglomerations as regions of elevated health risk.These insights provide a critical new perspective on ARG health risk assessment,highlighting the urgent need for strategies to mitigate the impact of ARGs on human health and to preserve the ecological and economic sustainability of the Yangtze River for future human use.

Occurrence and health risks of semi-volatile organic compounds in face masks

Face masks contribute greatly to the protection of human health in the epidemic of corona virus disease 2019(COVID-19).However,the extensive use of masks has brought new challenges to the environment and human health,such as vast plastic and plastic particle waste[1,2].

Effect of the exposure to suspended solids on the enzymatic activity in the bivalve Sinonovacula constricta

Aquatic animals are susceptible to sudden changes of their living environment but they adopt strategies to cope with adverse environmental challenges.Contamination by suspended solids,often associated with a dramatic change in the concentrations of important water-quality variables is a frequent occurrence in China's coastal waters and estuaries.Here we studied the impact of suspended solids on the activities of the antioxidant enzymes superoxide dismutase(SOD)and catalase(CAT),as well as adenosine triphosphates(including Na^(+)K^(+)-ATPase,Mg^(++)-ATPase,Ca^(++)-ATPase)and H^(+)K^(+)-ATPase in the gills and visceral mass tissues of the molluscan bivalve Sinonovacula constricta exposed(4,8,12,16,20,and 24 days)to various concentrations of suspended solids.Our results showed that the antioxidant enzymes cooperated closely to effectively scavenge superoxide anion free radicals and H2O2(which can ultimately inhibit gill activity)through the modification of SOD and/or CAT enzymatic activities.ATPases activity(considered to be a sensitive indicator of toxicity)could play an effective role in the maintenance of functional integrity of the plasma membranes as well as some other intracellular functions.After the exposure,a decrease in the Nat K^(+)-ATPase,Mg^(++)-ATPase,and Ca^(++)-ATPase activity of the gills was observed suggesting that they were inhibited by the treatments.These results also indicated that,from day 4 to day 16,exposure to high concentrations of suspended solids had an inhibitory effect on the activity of H^(+)-K^(+)-ATPase in the visceral mass of S.constricta.However,after a period of adaptation the H^(+)-K^(+)-ATPase activity was restored to original levels.Our results suggest that long-term exposure to high levels of suspended solids disturb osmoregulation,gastric acid secretion and digestion,cause oxidative damage,as a consequence of antioxidant enzymes inactivation which eventually damages the gills,affect the food intake and transformation,ultimately resulting in systems failure and eventually death.