Allelopathic growth inhibition of Heterosigma akashiwo by the three Ulva spcieces (Ulva Pertusa, Ulva Linza, Enteromorpha intestinalis) under laboratory conditions

Allelopathic effects of several concentrations of fresh tissue,dry powder and dry tissue of three bloom-forming green macroalgae Ulva pertusa,Ulva linza and Enteromopha intestinalis on the red tide microalga Heterosigma akashiwo were evaluated in microcosms systems.The effects of macroalgae culture medium filtrate were investigated on H.akashiwo using initial or semi-continuous filtrate addition.Preliminary studies on the algicidal effects of one aqueous and four organic solvent extracts from the macroalgae on the microalga were carried out to confirm the existence of allelochemicals in the tissue of these macroalgae.The dry powder of U.pertusa was extracted with methanol,and the methanol extracts were partitioned to petroleum ether phase,ethyl acetate phase,butanol phase and distilled phase by liquid-liquid fractionation.The bioassays of the activity of every fraction were carried out on H.akashiwo.The resultant microcosms assay showed that the growth of H.akashiwo was strongly inhibited by using fresh tissues,dry powder or dry tissue of these three macroalgae,while aqueous and methanol extracts of both macroalgae had strong inhibitory effects on the growth of H.akashiwo,and the EC 50 values for methanol extract of U.pertusa,U.linza or E.intestinalis were 0.016,0.028×10-12 or 0.033×10-12,respectively.While the other three organic solvent extracts（acetone,ether and chloroform） had no apparent effect on its growth,this suggests that the allelochemicals from these three macroalgae had relatively high polarities.The activity of petroleum ether phase,ethyl acetate phase,butanol phase and distilled phase of U.pertusa methanol extract was carried out on H.akashiwo indicating that petroleum ether phase and ethyl acetate phase had stronger algicidal effect on H.akashiwo.The inhibition effect of the ethyl acetate phase was not as strong as that of petroleum ether phase,and effective concentration of petroleum ether phase was 17 mg/L for H.akashiwo.However,no significant algicidal effects were observed on the butanol phase and distilled water phase.These three macroalgae＇s culture medium filtrate exhibited no apparent growth inhibitory effect on the microalga under initial filtrate addition whereas the growth of H.akashiwo was significantly inhibited under semi-continuous filtrate addition,which suggests that continuous release of small quantities of rapidly degradable allelochemicals from the fresh tissue of both macroalgae was effective in inhibiting the growth of H.akashiwo.     

Secondary production of Ampelisca mississippiana Soliman and Wicksten 2007 (Amphipoda, Crustacea) in the head of the Mississippi Canyon, northern Gulf of Mexico

Annual production was calculated for the dominant ampeliscid amphipod Ampelisca mississippiana [Soliman, Y., Wicksten, M., 2007. Ampelisca mississippiana a new species (Amphipoda: Gammaredea) dominated the head of the Mississippi Canyon (Northern Gulf of Mexico). Zootaxa, submitted] at the head of the Mississippi Canyon in the northern Gulf of Mexico. Average densities were 12,094±2499 ind m⁻², with secondary production of 6.93 g dry wt m⁻² yr⁻¹, based on the “size-frequency method” [Hynes-Hamilton, H.B.N., Coleman, M., 1968. A simple method for assessing the annual production of stream benthos. Limnology and Oceanography 13, 569–573; Menzies, C.A., 1980. A note on the Hynes-Hamilton method of estimating secondary production. Limnology and Oceanography 25(4), 770–773], with a production/biomass (P/B) ratio of 3.11. Growth rates of this magnitude are comparable to available data for freshwater and shallow marine ampeliscids, but are unexpectedly high for deep-ocean habitats. Growth efficiency appeared to be approximately 35% (Growth/Assimilation×100).     

中国近海核果螺属和小核螺属(腹足纲,骨螺科,红螺亚科)的分类研究

核果螺属(Drupa)和小核果螺属(Drupella),隶属于骨螺科(Muricidae)、红螺亚科(Rapaninae)。它们为暖水性较强的热带种类,主要分布于南中国海(海南岛以南),栖息于潮间带至浅海珊瑚礁或岩礁质环境中。对中国科学院海洋生物标本馆收藏的骨螺科标本进行了整理分类,共鉴定出2属,7种。并对以往使用混乱的种名进行了修订。     

4种养殖扇贝的群体遗传多样性及特异性AFLP标记研究

应用AFLP技术对我国4种主要养殖扇贝进行了遗传分析.虾夷扇贝、海湾扇贝、华贵栉孔扇贝、栉孔扇贝4种养殖扇贝群体中,种内遗传相似度依次分别为0.841 5,0.786 3,0.719 0和0.673 1,香侬氏指数分别为43.52,58.87,80.16和92.83,栉孔扇贝和华贵栉孔扇贝的遗传多样性水平明显高于海湾扇贝和虾夷扇贝;AFLP标记共享位点分布表明,在4种扇贝中栉孔扇贝与华贵栉孔扇贝之间的共享位点最多,同时4种扇贝的种间遗传相似度也以栉孔扇贝和华贵栉孔扇贝之间为最高(0.769 5),海湾扇贝和虾夷扇贝之间为最低(0.662 6),揭示所研究的几种扇贝中栉孔扇贝和华贵栉孔扇贝的遗传关系最近(遗传距离为0.262 1);找到了21个种内特异性AFLP标记和种间共享标记,可用于种质鉴定和分子辅助分类.     

Total oxyradical scavenging capacity and cell membrane stability of haemocytes of the Arctic scallop, Chlamys islandicus, following benzo(a)pyrene exposure

Industrial activities, notably oil and gas industries, are expanding in the Arctic. Most of the biomarkers were developed using temperate organisms living at temperatures above 10 °C. Little is known about the biomarker responses of organisms living between −1.88 and 5 °C. Therefore, assessment of the toxicity of chemicals to cold-water adapted species is required. In this study, the Arctic scallop, Chlamys islandicus, was selected as a key species for bio-monitoring because of wide distribution in Arctic waters and its commercial value. Test animals, stored in seawater at 2 °C, were injected with benzo(a)pyrene (diluted in cod liver oil 5 mg ml⁻¹) in the adductor muscle every 24 h for four days giving a final dose of 0, 74 and 90.6 mg kg⁻¹ wet weight for control, low and high dose, respectively. The biomarkers used were total oxyradical scavenging capacity (TOSC) in the digestive gland and cell membrane stability of haemocytes. TOSC values were significantly reduced (ca. 30%) in exposed groups (P<0.05), indicating a depletion in oxyradical molecular scavengers. The antioxidant defences appeared to be overwhelmed by the reactive oxygen species as the plasma membranes of haemocytes were destabilised (P<0.05) probably due to lipid peroxidation. These data indicate that reactive oxygen species (ROS) were produced by Arctic scallops via the metabolisation of benzo(a)pyrene at 2 °C.     

木榄属3种红树植物的遗传变异和亲缘关系分析

用随机扩增多态性DNA(RAPD)和inter-简单重复序列(ISSR)分子标记技术对木榄属(Bruguiera)3种红树木榄(Bruguiera gynmorrhiza)、海莲(B．serangula)、尖瓣海莲(B．serangula var．rhynchopetala)进行遗传亲缘关系研究。12个RAPD引物和10个ISSR引物分别扩增出240和191条带,多态位点百分率分别为38．75％和52．88％,ISSR检测到的多态位点率高于RAPD。运用Nei指数法计算木榄-海莲、木榄-尖瓣海莲、海莲-尖瓣海莲之间的遗传距离．RAPD分析结果为0．47、0．36、0．29,ISSR分析结果为0．62、0．4l、0．32。同时运用UPGMA统计法进行聚类分析,结果显示,海莲和尖瓣海莲聚为一组,木揽单独一组。结合宏观形态和等位酶资料,作者把尖瓣海莲确定为海莲的变种。     

Biological identification and determination of optimum growth conditions for four species of Navicula

Four species in the genus Navicula were isolated using the serial dilution method. Based on scanning electron microscopy(SEM) and sequence comparisons of two segments of genes(small ribosomal subunit and large subunit of Rubisco), the species were identified as Navicula perminuta, N. pseudacceptata, N. vara, and N. rhynchocephala. Based on phylogenetic analysis and culture trials, there was a close relationship between N. perminuta and N. vara. Growth of these species was evaluated using measurements of optical density at 680 nm(OD680) under various environmental factors. Results showed that the optimum culture conditions were 25℃, 50–100 μmol photons m-2 s-1, pH 8.0, and salinities from 25 to 30. However, the favorable salinity for N. perminuta was surprisingly high at 35. Nutrient requirement analysis demonstrated that growth of Navicula depended on the availability of SiO32-. Their relative growth rates(RGR) peaked at the highest tested level(0.25 mmol/L). The optimal concentrations of NO3- and PO43- were 3.6 mmol/L and 0.18 mmol/L, respectively. Culture of these Navicula species for abalone or sea cucumber aquaculture should take these factors into consideration.     

Generation and analysis of expressed sequence tags from the salt-tolerant eelgrass species, Zostera marina

Zosteramarina, a monocotyledonous angiosperm, is one of themost important seagrass species. To investigate the salt-tolerancemechanismand discover salt-tolerant genes in Z. marina, a cDNA library was constructed. Single-pass sequencing of the 5' ends of 4 081 clones yielded 4 002 high quality expressed sequence tags (ESTs), which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from100-1 500 bp. Basic Local Alignment Search Tool (BLASTX) analysis revealed that 1 664 unigenes had significant homology to known genes in the National Center for Biotechnology Information (NCBI) non-redundant (nr) database (E-value≤5-10). Among them, the twomost abundant genes encoded metallothionein (157 ESTs) and chlorophyll a/b-binding protein (38 ESTs), accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes (KEGG), 1 462 unigeneswere assigned to 1 161 pathways (E-value≤5-10). A total of 938 unigenes were assigned Gene Ontology (GO) terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes formetallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z.marina.     

Etropus crossotus, an annual flatfish species; age and growth of the fringed flounder in South Carolina

Fringed flounder, Etropus crossotus, a small flatfish common along the southeastern coast of the US, were collected along the South Carolina coast in the fall of 1992, and in the North Inlet estuary from August 1992 until July 1994. Standard length was 82% of total length and the relationship between standard length and wet weight showed near-isometric growth with no significant differences between males and females. Dry weight was 21% of wet weight and ash-free dry weight 14% of wet weight with no significant differences between sexes. Daily increments in the sagittal otoliths were used for age determination. No annual structures could be identified. The maximum age was about 14.5 months. Age-at-length was not different between the sexes. The relationship between age and length was exponential, with age (in days) equalling an e power of 4.242 + 0.135 × standard length (in cm). Back-calculated hatch dates and catches of early juveniles indicated a spawning season that lasted from March to October. Females started to be sexually mature at 7 to 7.5 cm standard length, but 50% maturity was reached at 8 to 8.5 cm. Females could grow to that size within one spawning season. Individuals hatched early in the spawning season could produce eggs in the latter portion of that season's spawning period.     

o,p′-DDT induction of vitellogenesis and its inhibition by tamoxifen in Nile tilapia (Oreochromis niloticus)

In order to investigate the mechanism by which o,p′-DDT disrupts endocrine functioning of Nile tilapia in vivo, the estrogenicity of o,p′-DDT was investigated in conjunction with 17β-estradiol (E₂) and tamoxifen. Mature, male tilapia were treated intraperitoneally with o,p′-DDT (60 mg/kg, one dose) or E₂ (5 mg/kg, four doses) in the presence or absence of tamoxifen (5 mg/kg, six doses) for 12 days and then plasma vitellogenin (Vtg) (measured as alkaline-labile phosphorous), E₂, and testosterone (T) were measured. Vtg levels were increased dramatically by E₂ (1744±171 μg/ml) and moderately by o,p′-DDT (82±15 μg/ml) compared with controls (23±3.5 μg/ml). Tamoxifen alone had no effect on Vtg production, but inhibited both E₂ and o,p′-DDT stimulated vitellogenesis. T levels were reduced with E₂ administration (1688±383 pg/ml) and declined further with the combined treatment of E₂ and tamoxifen (281±70 pg/ml), compared with controls (6558±1438 pg/ml). Tamoxifen or o,p′-DDT alone did not affect T levels, but their combined treatment did (2069±647 pg/ml). The results of this study suggest that o,p′-DDT is weakly estrogenic in male tilapia, and that this activity may be mediated through the estrogen receptor.     

饲料中添加戊糖乳杆菌HC-2对黄曲霉毒素B1刺激下的凡纳对虾肝胰腺显微结构、基因表达及酶活性的影响

为探究饲料中添加戊糖乳杆菌HC-2对黄曲霉毒素B1(AFB1)刺激下的凡纳对虾肝胰腺显微结构、基因表达及肝胰腺酶活性的影响,将健康的凡纳对虾(900尾)随机分成三组,分别投喂基础饲料、添加AFB1(500μg/kg)饲料以及添加AFB1(500μg/kg)+戊糖乳杆菌HC-2(5×10⁸ CFU/g)饲料6周。在试验结束后,分别取三组对虾的肝胰腺进行显微观察以及免疫相关基因和肝胰腺酶活性的测定。AFB1+HC-2组肝胰腺组织同AFB1组相比损伤程度较轻。同对照组相比, AFB1组和AFB1+HC-2组的肝胰腺免疫基因Rab、GST、mucin-likePM、Dorsal、Relish、Pro-PO的相对表达量均呈现显著下调(P<0.05),且同AFB1组相比, AFB1+HC-2组的免疫相关基因GST、Dorsal、Pro-Po的相对表达量下调的较少(P<0.05)。同对照组相比,AFB1组和AFB1+HC-2组的碱性磷酸酶活性(AKP)明显上升,且AFB1+HC-2组的AKP活性要高于AFB1组。同对照组相比,AFB1组和AFB1+HC-2组中谷胱甘...     

台湾海峡多管水母属——新种及基于线粒体COI序列分析鉴定多管水母

报道了中国台湾海峡多管水母属一新种——台湾多管水母(Aequorea taiwanensis n.sp.),详细描述其形态特征,并基于线粒体COI基因片段序列,比较、分析了该新种和乳突多管水母、锥状多管水母的序列差异及遗传距离。形态学和分子学数据都支持台湾多管水母为多管水母属有效种。3种多管水母mtCOI基因片断序列在种间存在明显的多态性,3种多管水母的种间序列差异为9.10%~11.9%,种间遗传距离为0.097~0.130,说明该基因片段适用于多管水母属种、种以下阶元及地理种群甄别和种间系统进化学分析。结合其他学者研究结果,认为mtCOI序列差异10%~20%可以作为多管水母属及其他水螅水母纲动物同属种间差异的标准。     

Morphometric or morpho-anatomal and genetic investigations highlight allopatric speciation in Western Mediterranean lagoons within the Atherina lagunae species (Teleostei, Atherinidae)

Current distribution of Atherina lagunae poses an interesting biogeographical problem as this species inhabits widely separate circum-Mediterranean lagoons. Statistical analyses of 87 biometric parameters and genetic variation in a portion of the cytochrome b gene were examined in four populations of A. lagunae from Tunisian and French lagoons. The results suggested a subdivision into two distinct Atherinid groups: one included the French lagoonal sand smelts and the second included the Tunisian ones. Tunisian lagoonal sand smelts were distinguished from the French ones by the lower number of lateral line scales, vertebrae, pectorals and first dorsal fin rays and the higher number of lower and total gillrakers. In addition, A. lagunae from Tunisian lagoons are characterised by short preorbital length, developed operculum, broad interorbital space, larger head, robust body and a relatively small first dorsal fin which is positioned backwards. In addition, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 87 individuals from Tunisia and France. The high correlation between the results of the molecular phylogenetic tree and biometric statistical data analysis suggested that two different sibling species or at least sub-species or semi-species have colonised the lagoons. In addition, our analyses suggested that the evolution of A. lagunae probably occurred in two steps including marine sympatric speciation within the large Atherina boyeri complex and a post-Pleistocene colonisation of the lagoons.     

Catch, survey and life-history data for shrimp (Pandalus borealis) off Jan Mayen

The Jan Mayen area has an extreme environment with low temperatures and infrequent, but abrupt temperature changes. The shrimp population here is considered to be on its edge of distribution. The life-history parameters are in the same range as in other high-latitude shrimp populations and are characterized by slow growth, large size at maturation and extended longevity. Irregular and sporadic commercial exploitation limit fishing mortality and give the population life-history parameters not previously seen in other areas. The Jan Mayen shrimp are large compared to, e.g., the Barents Sea shrimp and can reach a maximum carapace length (L_max) of 37 mm and an age of 10–11 years. The large size at sex transformation (L₅₀, >24 mm) and analyses of length–frequency distributions indicate that the shrimp may be 6–7 years of age before changing sex. The change in L_max and L₅₀ observed during the study period is probably caused by increased natural mortality due to sudden temperature changes or due to increased predation, rather than increased growth rates. The life-history strategy of shrimp in the Jan Mayen area can be explained by factors such as depth, temperature and population density variations caused by fluctuation in recruitment and mortality.The shrimp fisheries in the Jan Mayen area began in the late 1970s and reached an annual landing of 2000 tonnes in 1985, and since then landings have oscillated around 500 tonnes depending on a combination of factors. The survey indices of stock biomass varied between 3000 and 6600 tonnes. For most years, the highest shrimp densities are at a depth of 200–299 m, while large shrimp (and therefore also female shrimp) are dominant at depths greater than 300 m.Fish community data were studied as the composition of the demersal fish community is an integrated response to environmental conditions and as predation affects the shrimp stock. Polar cod and capelin are the most abundant fish species in the study area. A high number of blue whiting was registered in 1979, but the number declined in 1980 and 1981 as temperature decreased. During the surveys in 1994 and 1995, no blue whiting was registered. A few individuals were found again in the 1999 samples. The number of Greenland halibut has declined from the beginning of the 1980s to the 1990s.     

Barnacle distribution in Lough Hyne Marine Nature Reserve: a new baseline and an account of invasion by the introduced Australasian species Elminius modestus Darwin

The distribution and abundances of the following species of barnacles were established in autumn 2001 within the Lough Hyne Marine Nature Reserve: Cthamalus stellatus, Cthamalus montagui, Semibalanus balanoides, Elminius modestus, Balanus crenatus and Verruca stroemia. The results of the survey showed a clear distinction between the vertical distribution and the abundance of barnacle species inside Lough Hyne, and those sites sampled in the Rapids and outside the Lough. The Lough is now dominated by the introduced Australasian species E. modestus. This species was first recorded outside Lough Hyne in 1956. By 1988 it was found occasionally throughout the Lough, and appreciable numbers were recorded in 1990–1991. It has now replaced all other species in some parts of the North Basin. At sites subject to freshwater influence it is totally dominant, including in the highly sheltered Goleen site where intertidal barnacles have not previously been recorded. It is suggested that, once established in the North Basin, the sheltered nature of the Lough, combined with high summer temperatures and limited circulation, fostered retention of larvae and heavy spatfall of E. modestus.     

大菱鲆体重性状遗传参数及选育遗传进展研究

本研究估计了大菱鲆收获体重性状的遗传参数和选育遗传进展。数据共包括3个世代（G0,G1,G2）的508个全同胞家系10952尾个体。G0,G1,G2的体重估计遗传力分别为0.11±0.08,0.18±0.09,0.17±0.07;世代间估计遗传力为0.19±0.04。每一世代母本和共同环境效应分别为0.10±0.04,0.14±0.04,0.13±0.03;世代间为0.12±0.01。G0和G1世代选择差分别为,18.24g和21.19g。对应的G1和G2世代的遗传进展为22.06g,11.93g;百分比表示分别为6.36%,3.52%。连续两代选择之后总遗传进展为10.10%。以上结果说明针对大菱鲆体重性状的选育项目是成功的。     

黄河三角洲关键种泥螺Bullacta exarata对沉积物-水体界面溶解氧和营养盐通量的影响

泥螺自2001因养殖目的引入黄河三角洲以来,随着分布范围的扩大和种群数量的增长,已成为当地潮间带的关键种。泥螺给当地民众带来较高收入,但其对底栖生态系统的潜在影响还不清楚。为了明确该种群的生物扰动对底栖微藻和微生物的初级生产,以及对水体-沉积物界面营养盐交换的影响,开展了该项实验。结果表明,在光照条件下,泥螺能显著影响沉积物-水体界面的溶解氧DO通量;在黑暗及无生物处理组的恢复期,泥螺能显著增加两界面间氨氮的通量。底栖微藻和小型生物在黑暗条件下也能增加氨氮的通量;但在有光照条件下,上述微藻和小型底栖动物对沉积物-水体界面间溶解氧和氨氮通量的影响不明显。实验结果为更深入理解泥螺对生态系统的影响提供重要理论支持。     

条斑紫菜杂交重组品系(A-18)的筛选与特性分析

为筛选出藻体生长快且颜色与野生型色泽相近的条斑紫菜新品系,本研究从条斑紫菜绿色突变体和红色突变体种内杂交产生的后代中,分离出了优良品系A-18。日龄60 d时的叶状体平均长度、长宽比和单株湿质量,A-18品系分别为84.95 cm、49.46和0.52 g,分别是条斑紫菜野生型品系（WT）的3.12、7.01和1.36倍。日龄60 d时叶状体的叶绿素a和总藻胆蛋白含量,A-18品系分别为8.37和53.81 mg/g,均与WT品系较接近。日龄60 d时的叶状体平均厚度,A-18品系仅为20.22 μm,比WT品系降低了29%。另外,A-18品系的壳孢子放散总量为916.01万个/贝壳,是WT品系的1.55倍。综上所述,A-18品系具有生长快、长宽比值大、藻体薄、壳孢子放散量大等优良特性,且藻体颜色与野生型色泽相近,有望在生产中运用。     

Investigating the effect of ballasting by CaCO3 in Emiliania huxleyi: I. Formation, settling velocities and physical properties of aggregates

To investigate the role of ballasting by biogenic minerals in the export of organic matter in the ocean, a laboratory experiment was conducted comparing aggregate formation and settling velocity of non-calcifying and calcifying strains of the coccolithophore Emiliania huxleyi. Experiments were conducted by making aggregates using a roller table and following aggregate properties during incubation for a period of 40 days. Size, shape, and settling velocities of aggregates were described by image analysis of video pictures recorded during the roller tank incubation. Our results show that biogenic calcite has a strong effect on the formation rate and abundance of aggregates and on aggregate properties such as size, excess density, porosity, and settling velocity. Aggregates of calcifying cells (AGG_CAL) formed faster, were smaller and had higher settling velocities, excess densities, and mass than those of non-calcifying cells (AGG_NCAL). AGG_CAL showed no loss during the duration of the experiment, whereas AGG_NCAL decreased in size after 1 month of incubation. Potential mechanisms that can explain the different patterns in aggregate formation are discussed. Comparison of settling velocities of AGG_CAL and AGG_NCAL with aggregates formed by diatoms furthermore indicated that the ballast effect of calcite is greater than that of opal. Together these results help to better understand why calcite is of major importance for organic matter fluxes to the deep ocean.