Abundance, biomass and composition of spring ice algal and phytoplankton communities of the Laptev Sea （Arctic）

Abundance,biomass and composition of the ice algal and phytoplank-ton communities were investigated in the southeastern Laptev Sea in spring 1999.Diatoms dominated the algal communities and pennate diatoms dominated the dia-tom population.12 dominant algal species occurred within sea ice and underlyingwater column,including Fragilariopsis oceanica,F.cylindrus,Nitzschiafrigida,N.promare,Achnanthes taeniata,Nitzschia neofrigida,Naviculapelagica,N.vanhoef fenii,N.septentrionalis,Melosira arctica,Clindrothecaclosterium and Pyrarnimonas sp.The algal abundance of bottom 10 cm sea icevaried between 14.6 and 1562.2×10~4 ceils l~(-1)with an average of 639.0×10~4cells l~(-1),and the algal biomass ranged from 7.89 to 2093.5μg C l~(-1)with an av-erage of 886.9μg C l~(-1),which were generally one order of magnitude higherthan those of sub-bottom ice and two orders of magnitude higher than those ofunderlying surface water.The integrated algal abundance and biomass of lower-most 20 cm ice column were averagely 7.7 and 12.2 times as those of upper 20 mwater column,respectively,suggesting that the ice algae might play an importantrole in maintaining the coastal marine ecosystem before the thawing of sea ice.Icealgae influenced the phytoplankton community of the underlying water column.However,the“seeding”of ice algae for phytoplankton bloom was negligible be-cause of the iow phytoplankton biomass within the underlying water column.     

Effects of strontium-induced stress on marine microalgae Platymonas subcordiformis （Chlorophyta： Volvocales）

1 INTRODUCTION Heavy metal pollution in marine environment has always been a serious problem over the last several decades, because most of the heavy metal species that enter marine environment accumulated there without decomposition. Strontium is a minor…     

Study on the Tripolyphosphatase （TPPase） Property of Bighead Carp （Aristichthys nobilis） Myosin Subfragment-1

Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2 was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2 under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2 . The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.     

Notes on Two Marine Ciliates from the Yellow Sea,China： Placus salinus and Strombidium apolatum（Protozoa, Ciliophora）

The living morphology and infraciliature of two rare marine ciliates, Placus salinus Dietz, 1964 and Strombidium apolatum Wilbert and Song, 2005, collected from the coastal waters near Qingdao, China, were investigated by in vivo observation and protargol impregnation technique. The improved diagnosis for Placus salinus is as follows: medium-sized marine Placus, in vivo (50–60)μm×(30–40)μm; cell elliptical to barrel-shaped; 28–31 somatic kineties; single macronucleus usually ellipsoid and one micronucleus located in the indention of the macronucleus; one contractile vacuole posteriorly positioned. Strombidium apolatum is characterized by: marine strombidium (40–60)μm×(30–45)μmm in vivo, cordiform in shape with somewhat pointed posterior end and conspicuous apical protrusion; extrusomes prominent, about 15μm in length and evenly arranged along the circle kinety; about 16 collar and 5–6 buccal membranelles; one elongate macronucleus and one micronucleus; circle and ventral kineties consisting of about 53 and 45 dikinetids respectively.     

First Record and Redefinition of the Qingdao Population of Marine Ciliate Cardiostomatella vermiformis （Kahl, 1928） Corliss, 1960 （Protozoa, Ciliophora）

The living morphology and infraciliature of a marine ciliate, Cardiostomatella vermiformis isolated from a sand beach of the Jiaozhou Bay near Qingdao, China, were investigated by live observation, protargol and silver carbonate impregnation methods. Both the morphological and morphometric data largely agree with former records. Based on the data obtained, an improved diagnosis for Cardiostomatella vermiformis is supplied: Large marine Cardiostomatella with cylindrical body shape and several prolonged caudal cilia; cells in vivo about (90–500) μm×(30–120) μm; macronucleus beaded; single contractile vacuole caudally positioned; buccal apparatus conspicuously small, genus typical; three to six postoral kineties; 96-130 somatic kineties. This species is recorded for the first time in China.     

Age and Growth of Chub Mackerel （Scomberjaponicus） in the East China and Yellow Seas Using Sectioned Otolith Samples

Although chub mackerel (Scomberjaponicus) is a primary pelagic fish species,we have only limited knowledge on itskey life history processes.The present work studied the age and growth of chub mackerel in the East China and Yellow Seas.Agewas determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercialpurse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawn-ing ground in May 2006.The difference between the assumed birth date of 1 st April and date of capture was used to adjust the agedetermined from counting the number of complete translucent rings.The parameters of three commonly used growth models,the vonBertalanffy,Logistic and Gompertz models,were estimated using the maximum likelihood method.Based on the Akaike InformationCriterion (AIC),the von Bertalanffy growth model was found to be the most appropriate model.The size-at-age and size-at-maturityvalues were also found to decrease greatly compared with the results achieved in the 1950s,which was caused by heavy exploitationover the last few decades.     

Morphological Studies on the Infraciliature of a Planktonic Ciliate, Tintinnopsis brasiliensis （ Ciliophora ： Tintinina）

A poorly-described marine planktonic ciliate, Tintinnopsis brasiliensis Kofoid ＆ Campbell, 1929, collected from the Taiping Cape of Qingdao, China, was morphologically investigated based on permanent preparation after protargol impregnation and was compared with other related congeners. According to the infraciliature, three ciliary groups can be recognized, which reveals a very stable structure among specimens and denotes that the pattern of infraciliature is, apart from the features of the lorica, a highly reliable criterion for species identification.     

A study on the Antarctic circumpolar wave mode-A coexistence system of standing and traveling wave

The Antarctic circumpolar wave （ACW） has become a focus of the air-sea coupled Southern Ocean study since 1996, when it was discovered as an air-sea coupled interannual signal propagating eastward in the region of the Antarctic Circumpolar Current （ACC）. In order to analyze the mechanism of discontinuity along the latitudinal propagation, a new idea that ACW is a system with a traveling wave in the Southern Pacific and Atlantic Ocean and with a concurrent standing wave in the southern Indian Ocean is proposed in this paper. Based on the ideal wave principle, the average wave parameters of ACW is achieved using a non-linear approximation method, by which we find that the standing part and the traveling part possess similar radius frequency, proving their belonging to an integral system. We also give the latitudinal distribution of wave speed with which we could tell the reason for steady propagation during the same period. The spatial distribution of the propagation reveals complex process with variant spatial and temporal scales--The ENSO scale oscillation greatly impacts on the traveling process, while the result at the south of Australia indicates little connection between the Indian Ocean and the Pacific, which may be blocked by the vibration at the west of the Pacific. The advective effect of ACC on the propagation process should be examined clearly through dynamical method.     

Effect of temperature and photoperiod on maturation of Cephalothrix hongkongiensis （Nemertea： Palaeonemertea）

The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few species have been studied under well-controlled laboratory conditions. In this work, the effects of temperature and photoperiod on gonad development and spawning of Cephalothrix hongkongiensis were observed by rearing worms under different temperatures and photoperiods. Worms reared at 4℃ and 6℃ showed no growth or gonadal development, and all died within 109 days. At 8℃ and 12℃, gonads could be seen from 90 days to the termination of the 360-day experiment, but no spawning was observed. Worms maintained at 16, 24, and 28℃ showed both gonadal development and spawning, and matured faster at higher temperatures. Under a fixed temperature(16℃), photoperiod did not have any significant impact on maturation and spawning. It is likely that temperature plays a major role in regulating the maturation and reproductive cycle of C. hongkongiensis.     

2020年土耳其MW5.7地震InSAR同震形变特征与破裂滑动分布

为准确认识2020-06-14土耳其MW5.7地震的发震位置、构造特点以及地震危险性,利用D-InSAR技术对Sentinel-1A数据进行处理,基于GACOS进行大气校正,获得视线向（line of sight,LOS）同震形变场。降轨LOS向同震形变场显示,断层北侧抬升,最大抬升形变量约8.87 cm;南侧沉降,最大沉降量约-7.75 cm。以LOS向同震形变为约束,先采用贝叶斯自举优化法反演发震断层几何参数,然后使用有限断层方法反演地震破裂滑动分布。结果显示,断层走向约257.48°±0.65°、倾角约79.69°±0.98°、滑动角约154.2°±3.8°,震中位置为（40.754°E,39.389°N）,破裂区域长度约8 km、宽度约6 km,破裂的最浅埋深约0.8 km、最大埋深约8.9 km,最大滑动量约0.57 m,对应深度约4.278 km。地震释放地震矩约4.54×1017 Nm,对应矩震级MW5.7,与土耳其灾害和紧急情况管理局公布的结果一致。此次土耳其地震受近东西向的潜伏断层控制,以右旋走滑为主兼具少量的逆冲特性。地震造成部分地区的库伦破裂应力增量超过0.1 bar,这些区域未来的地震危险性值得关注。     

A preliminary phylogenetic analysis of Luidia (Paxillosida: Luidiidae) from Chinese waters with cytochrome oxidase subunit I (COI) sequences

Luidia Forbes (Paxillosida: Luidiidae) are common soft bottom sea stars with 49 described species. Because of substantial morphological diversity, the taxonomy of the genus is complex and hasn’t been resolved definitely. In order to resolve general taxonomic issues, and determine species boundaries and phylogenetic relationships within the genus Luidia, the sequences of cytochrome oxidase subunit I (COI) gene from 24 specimens of Luidia, belonging to eight taxa in Chinese waters, were studied. Three sequences of two species in genus Luidia from GenBank were used to analyze the phylogenetic relationships. The molecular phylogeny exhibited three main clades, each with strong bootstrap support: Clade A including Luidia quinaria from the Sea of Japan; Clade B including seven nominal species (L. quinaria von Martens, L. yesoensis Goto, L. changi Liu, Liao and Li, L. orientalis Fisher, L. avicularia Fisher, L. longispina Sladen and L. hardwicki Gray) from Chinese waters; and Clade C including L. maculata Müller & Troschel from Chinese waters. Our molecular phylogeny results support the morphological Quinaria-Group and Alternata-Group assigned by Döderlein. Seven nominal species we sampled do not exhibit genetic distances that are large enough to recognize them as separate species. Cryptic species may exist in’ Luidia quinaria’ from the Yellow Sea and the Sea of Japan. Meaningful morphological characters need further investigation in Luidia.     

A new species of Eunice (Polychaeta: Eunicidae) from Hainan Island, South China Sea

Ataxonomic survey of benthic marine animals from coastal regions of Hainan Island, South China Sea, revealed specimens of a new species of Eunice (Polychaeta: Eunicida: Eunicidae), Eunice uschakovi n. sp., collected from the intertidal zone. The species belongs to the group of Eunice that has yellow tridentate subacicular hooks and branchiae scattered over an extensive region of the body. It resembles E. miurai and E. havaica in having both bidentate and tridentate falcigers, but can be readily distinguished by branchial features. Comparisons between E. uschakovi and the two related species are presented.     

Assessment and analysis of rockfall-caused tree injuries in a Turkish fir stand: A case study from Kastamonu-Turkey

Rockfalls can cause serious damage to people,property,facilities and transportation corridors.Furthermore,rockfalls are major hazards in mountain areas with negative impacts on individual trees and forested ecosystems.We conducted a study of rockfall events on 117 mapped(91% of total trees in the stand with1.3 m in height and5 cm diameter at breast height)Turkish fir trees(Abies bornmuelleriana Mattf.)in a stand within the Kayaarkasi-Topular Village,Inebolu district, Kastamonu province of Turkey.The study site of 0.35 Ha is located on the transition zone of frequently passing rockfall fragments(～40 cm in diameter) generally causing healable injuries.Parameters of trees and injuries were recorded and analysed as to injury number,height and size.Bivariate correlation analysis were used to investigate the relationships between:a)diameter at breast height and number of injuries per tree,b)diameter at breast height and total injury size,c)the number of injuries and total injury size and d)the number of injuries per tree and distance from the source of the rockfall area.Results indicate that the average height of injury,average number of injuries and average injury area to be 81.3 cm(STDEV:49.8),7.46(STDEV:4.4)and 628.6 cm2 (STDEV:678.2),respectively.In total 84% of all injuries were recorded within 160°sector at the upslope side of trees and callus tissue that had closed wounds was observed in 79.1% of all injuries. Furthermore 14.5% of injured trees had callus tissue in the process of closing wounds while 6.4% of injuries had not formed any callus tissue.The most common injury types were bark and wood injuries. Bivariate correlation analysis indicated strong relationships between diameter at breast height and the number of injuries(rs=0.524),injury number and total injury area(rs=0.653)and distance from rockfall area and injury numbers relations(rs=-0.518).A weaker relationship was found between diameter at breast height and total injury area(rs=0.363).These results indicate that bigger trees are more prone to rockfall injuries.As expected,trees further from the rockfall area seem to be less prone to rockfall injuries.From our results,it can be inferred that the protection of people and property can be increased through the maintanance of forest in areas immediately below areas prone to rockfall.This stand is still managed in selective forest management system.In order to protect the settlement at the deposition zone it has to manage for protective goals with uneven-aged and multilayered stand structure.     

Biodiverse rotifer assemblage(Rotifera: Eurotatoria) of floodplain lakes of the Brahmaputra basin of lower Assam,northeast India: composition and ecosystem diversity

The study aims to ascertain the hypothesis on the rich rotifer biodiversity of the floodplain lakes(beels) of the Brahmaputra river basin and to use these metazoans to assess trophic status or to characterize habitat variations of wetlands. The plankton samples collected from four beels of lower Assam revealed 160 Rotifera species belonging to 35 genera and 19 families. The richness is of biodiversity value as ~38.0% and ~57.0% of the rotifer species known till date from India and northeast India(NEI), respectively. One species each is new to the Oriental region and NEI, and three species are new to Assam; 23 species merit global biogeography interest and several exhibit distribution values in the Indian sub-region. The diverse Lecanidae Brachionidae Lepadellidae Trichocercidae and speciose littoral-periphytic L ecane Lepadella Trichocerca, and richness of Brachionus spp. following removal of aquatic macrophytes are noteworthy. Overall rotifer composition showed homogeneity amongst beels while lower monthly richness and community similarities affirmed heterogeneity within individual beels. We propose L/B quotient based on L ecane : Brachionus species ratios to characterize habitat variations of the sampled wetlands. Sláde?ek's B/T quotient based on B rachionus : T richocerca species ratios affirmed general 'meso-trophic' status of diff erent beels. Our results provided little insight on the influence of individual abiotic factors but the canonical correspondence analyses asserted higher cumulative influence of ten abiotic parameters on Rotifera richness in each beel.     

A new record of the freshwater jellyfish Craspedacusta sowerbii Lankester, 1880 (Hydrozoa) in Southeastern Anatolia (Turkey)

We report the first record of the invasive freshwater jellyfish Craspedacusta sowerbii Lankester in Kralk1z1 Dam Lake,Southeastern Anatolia,Turkey.The medusa was found only in August,2008 when average surface water temperatures were 26.9℃.     

Morphological Studies on Four Brackish Water Ciliates of the Class Spirotrichea(Protista,Ciliophora)

We reinvestigate the morphology of two oligotrich and two hypotrich ciliates collected from the coasts of north and south China, viz., Parallelostrombidium obesum Liu et al., 2015, Spirostrombidium apourceolare Liu et al., 2013, Protogastrostyla pulchra(Pereyaslawzewa, 1886) Gong et al., 2007, and Uncinata bradburyae(Gong et al., 2001) Luo et al., 2015. All the populations match well with the original samples identified in previous studies. Supplemental taxonomic data were supplied for these four species of the new populations. The species Parallelostrombidium obesum is characterised by its dorsal-ventrally flattened body shape with anterior and posterior ends transversely truncating, as well as two thigmotactic membranelles and girdle kinety that spirals around the cell one and a half times. Spirostrombidium apourceolare is characterised by its elongate ellipsoidal and dorsal-ventrally flattened body shape, two thigmotactic membranelles, about 11-27 ovoid macronuclear nodules, and girdle kinety that spirals around the cell twice with two undulations. Protogastrostyla pulchra is characterised by its elongate body shape and unique, caudally located food vacuole. Based on the new populations, we described the smaller cortical granules, clustered around dorsal bristles for the first time. The new population of Uncinata bradburyae shares the diagnostic features with the type population, which include prominent beak-like projection in anterior region, the conspicuous gap of adoral zone, proximalmost adoral membranelles distinctly elongated, and infraciliature.     

中国多丝藻科Myrionemataceae(Phaeophyta)3个新记录属和9个新记录种

已知多丝藻科(索藻目,褐藻门)约有50种,我国仅仅报道2种。记述多丝科的美丝藻属Compsonema、小孢藻属Microsponigum和原水云属Protectocarpus等3个中国新记录属,以及球状美丝藻Compsonema coniferum、多线美丝藻C.myrionematoides、匍匐美丝藻C.serpens、放射百丝藻Hecatonema diffusum、繁育百丝藻H.distromatica、初级百丝藻H.primarium、球形小孢藻Microspongium globosum、考氏多丝藻Myrionema corunnae、原水云Protectocarpus speciosus等9种中国新记录种。研究的标本采集于中国海区,保存在中国科学院海洋研究所海洋生物标本馆(AST)。     

Taxonomic description of a new marine ciliate,Euplotes qingdaoensis n. sp. (Ciliophora: Euplotida)

The characteristics and infraciliature of a new euplotid ciliate,Euplotes qingdaoensis n.sp.,discovered from the coastal waters of Jiaozhou Bay,northern China,were studied using live observation and silver impregnation.The new marine species is characterized by a slightly fl attened body(90–110 μm×70–80 μm,in vivo),an adoral zone of 26–29 membranelles,10 strong frontoventral and fi ve transverse cirri,two caudal cirri,a single left marginal cirrus,seven dorsal kineties,a middle kinety with about 15 pairs of basal bodies,a silverline system of the double-eurystomus type,and a C-shaped macronucleus.