Effects of different phosphorus concentrations and N/P ratios on the growth and photosynthetic characteristics of <Emphasis Type="Italic">Skeletonema costatum</Emphasis> and <Emphasis Type="Italic">Prorocentrum donghaiense</Emphasis>

The effects of different phosphorus (P) concentrations (0.36, 3.6, and 36 μmol/L corresponding to low-, middle-, and high-P concentration groups, respectively) and nitrogen (N)/P ratios on the growth and photosynthetic characteristics of Skeletonema costatum and Prorocentrum donghaiense were studied. For both species, the high-P (HP) concentration group showed the greatest algal density and highest specific growth rate. Changes in the maximum efficiency of photosystem II (F _v /F _m ) were monitored under the various P and N/P conditions. The largest decrease in F _v /F _m was in the low-P (LP) group in S. costatum and in the HP group in P. donghaiense. There were high rapid light curves and photochemical quantum yields (Φ _PSII) for S. costatum in the HP group, while the actual photosynthetic capacity was higher in P. donghaiense than in S. costatum in the MP group. Under eutrophic but relatively P-restricted conditions, P. donghaiense had higher photosynthetic activity and potential, which could cause this dinoflagellate to increasingly dominate the phytoplankton community in these conditions. Under the same P concentration and N/P ratio, P. donghaiense had a larger relative maximum rate of electron transport and higher Φ _{PS II} values than those of S. costatum. These differences between P. donghaiense and S. costatum may explain the interaction and succession patterns of these two species in the Changjiang (Yangtze) River estuary from a photosynthesis perspective.     

Effects of nitrogen and phosphorus on the growth of <Emphasis Type="Italic">Levanderina fissa</Emphasis>: How it blooms in Pearl River Estuary

Effects of nitrogen (N) and phosphorus (P) from different sources and at different concentrations on the growth of Levanderina fissa (= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate (μ _max) and half-saturation nutrient concentration (K _S) were 0.37 divisions/d and 8.49 μmol L^?1 for N, and 0.39 divisions/d and 1.99 μmol L^?1 for P, respectively. Based on K _S values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N (DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P (DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.     

Inbreeding depression on growth and survival of full-sib family of Manila clam (<Emphasis Type="Italic">Ruditapes philippinarum</Emphasis>)

In present study, the inbreeding depression (ID) of growth and survival of Manila clam (Ruditapes philippinarum) was investigated at larval and juvenile stages. Nine inbred families (A ₂, B ₂, C ₂, D ₂, E ₂, F ₂, G ₂, H ₂ and I ₂) were established by mating within nine full-sib families with expected inbreeding coefficient of 0.25. Inbred families showed significant differences in shell length and hatching rate of D-larvae (straight-hinged larvae). The larvae of the nine inbred families grew slower than those of control group (CG), and their ID value ranged from 0.81% ± 6.09% to 16.10% ± 1.49%. The ID value of larval survival rate varied between 27.47% ± 9.36% and 70.50% ± 13.66%. The ID was also detected for juvenile growth in A ₂, B ₂, C ₂, and D ₂, which ranged from 4.60 ± 2.21 to 17.71 ± 7.73. The A ₂ family maintained the highest juvenile survival rate, whereas the other inbred families exhibited ID values varying between 62.79% ± 4.54% and 96.14% ± 0.87%. The linear relationship of estimated ID between growth and survival was negatively correlated (R = ?0.434, P < 0.05). The results of this study suggested that the ID of growth was common at the larval stage but was less prevalent at juvenile stage. In contrast, the ID of survival increased from larval to juvenile stage. A better understanding of the effect of inbreeding may aid to selective breeding of Manila clam.     

Screening and isolation of the algicidal compounds from marine green alga <Emphasis Type="Italic">Ulva intestinalis</Emphasis>

Twenty species of seaweed were collected from the coast of Zhejiang, China, extracted with ethanol, and screened for algicidal activity against red tide microalgae Heterosigma akashiwo and Prorocentrum micans. Inhibitory effects of fresh and dried tißsues of green alga Ulva intestinalis were assessed and the main algicidal compounds were isolated, purified, and identified. Five seaweed species, U. intestinalis, U. fasciata, Grateloupia romosissima, Chondria crassicaulis, and Gracilariopsis lemaneiformis, were investigated for their algicidal activities. Fresh tissues of 8.0 and 16.0 mg/mL of U. intestinalis dissolved in media significantly inhibited growth of H. akashiwo and P. micans, respectively. Dried tissue and ethyl acetate (EtOAc) extracts of U. intestinalis at greater than 1.2 and 0.04 mg/mL, respectively, were fatal to H. akashiwo, while its water and EtOAc extracts in excess of 0.96 and 0.32 mg/mL, respectively, were lethal to P. micans. Three algicidal compounds in the EtOAc extracts were identified as 15-ethoxy-(6z,9z,12z)-hexadecatrienoic acid (I), (6E,9E,12E)-(2-acetoxy-β-D-glucose)-octadecatrienoic acid ester (II) and hexadecanoic acid (III). Of these, compound II displayed the most potent algicidal activity with IC₅₀ values of 4.9 and 14.1 µg/mL for H. akashiwo and P. micans, respectively. Compound I showed moderate algicidal activity with IC₅₀ values of 13.4 and 24.7 µg/mL for H. akashiwo and P. micans, respectively. These findings suggested that certain macroalgae or products therefrom could be used as effective biological control agents against red tide algae.     

Carbon budget of bastard halibut<Emphasis Type="Italic">Paralichthys olivaceus</Emphasis> in relation to body weight and temperature

The effects of body weight and temperature on the carbon budget of the juvenile bastard halibut ,Paralichthys olivaceus ,were studied at temperature 13.5,18,21.5 and 24℃,respectively.The carbon intake,faecal and growth carbon were measured ,and the carbon respiration was calculated using the carbon budget equation (Cc=Gc Fc Rc),The combined relationship between different components of the carbon budgent,body weight and temperature could be described by regression equations:Cc=1.0206 W^0.8126E^0.1483T;Gc=0.0042w^1.4096(-5.11 T^3 285.90T^2-5173.72T 30314.03);Fc=0.0485W^0.7711e^0.1624T;Uc=1.4333W^0.6715e^0.1487t,Body weight had no significant effect on the carbon absorption efficiency and the conversion efficiency.     

Diel variation in metabolism and ammonia excretion of <Emphasis Type="Italic">Marphysa sanguinea</Emphasis> (Polychaeta: Eunicidae)

Polychaetes provide an excellent food resource for fish and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied. The worms were grouped according to their wet body weight into small (S; 1.24±0.06 g), medium (M; 4.00±0.30 g), and large (L; 8.54±1.08 g) categories. Their weight-specific metabolic rates, based on aerobic respiration (R), were measured at 16°C (±0.2°C) and classed as either routine (R _R) or standard (R _S) rates. Both respiration types decreased with increasing body weight. Respiration was described by R = a W ^b, where b was -0.400 9 and -0.532 0 for R _R and R _S, respectively. Diurnal changes in R _S for each group was relatively flat, with a slightly increasing trend with time, but was relatively stable as a whole. R _R of the diurnal variation of worms was higher than R S, but both had similar overall trends. The peak values of specific dynamic action (SDA) (R _SDA) in the S, M, and L groups were 2.704, 1.149, and 0.682 mg/(g?h), respectively. The durations of SDA were 13, 6, and 6 h, respectively and the energy expenditures of SDA were 377.98, 117.34, and 74.94 J/g, respectively. These data indicate that the metabolic rates were higher in smaller individuals, which is advantageous for their rapid growth.     

Molecular weight controllable degradation of <Emphasis Type="Italic">Laminaria japonica</Emphasis> polysaccharides and its antioxidant properties

In this study, molecular weight controllable degradation of algal Laminaria japonica polysaccharides（LPS） was investigated by ultrasound combined with hydrogen peroxide. Three main factors, i.e., ultrasonic power（A）, ultrasonic time（B）, and H₂O₂ concentration（C） were chosen for optimizing parameters by employing three-factors, three-levels BBD. The influence of degradation on structure change and antioxidant activities was also investigated. A second-order polynomial equation including molecular weight（Y） of Laminaria japonica polysaccharides and each variable parameter, i.e., ultrasonic power（A）, ultrasonic time（B）, and H₂O₂ concentration（C）, was established: Y=20718.67-4273.13A-4000.38B-1438.75C+2333.25AB+1511.00AC+873.00BC+2838.29A² + 2490.79B²+873.04C². The equation regression coefficient value（R² = 0.969） indicated that this equation was valid. The value of the adjusted determination coefficient（adjusted R² = 0.914） also confirmed that the model was highly significant. The results of selected experimental degradation conditions matched with the predicted value. FT-IR spectra revealed that the structures of LPS before and after degradation were not significantly changed. Antioxidant activities of LPS revealed that low Mws possessed stronger inhibitory than the original polysaccharides. The scavenging effects on superoxide radicals was the highest when IC50 of crude LPS was 4.92 mg mL^-1 and IC50 of Mw 18.576 KDa was 1.02 mg mL^-1, which was fourfold higher than initial polysaccharide.     

Effects of dietary genistein on GH/IGF-I axis of Nile tilapia <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>

There is considerable concern that isoflavones, such as genistein in fish feed composed of soybean protein, aff ects somatic growth in fish. Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant eff ect on growth performance in Nile tilapia (Oreochromis niloticus), but the higher level of genistein (3 000 μg/g) significantly depressed growth. This study was conducted to further examine the eff ects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I (GH/IGF-I) axis in Nile tilapia (O. niloticus). Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets, each containing either 0, 30, 300 or 3 000 μg/g genistein. Following an 8-week feeding period, plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh, ghrelin, gnrhs, ghr, npy, npyrs, pacap, ghrs, igf-I, igf-Ir, and igfbp3 were examined by real-time PCR. The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/g and 300 μg/g genistein. mRNA expression of genes along the GH/IGF-I axis remained unaff ected, except for igf-Ir, which was stimulated by the 300 μg/g genistein diet. While in fish fed the 3 000 μg/g genistein diet, the plasma GH and IGF-I levels decreased, and mRNA expression of gh, ghr2, npyr1, igf-I, and igf-Ir were also significantly depressed. In contrast, npy and igfbp3 mRNA expression were enhanced. This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O. niloticus.     

Biodeposition,respiration, and excretion rates of an introduced clam <Emphasis Type="Italic">Mercenaria mercenaria</Emphasis> in ponds with implications for potential competition with the native clam <Emphasis Type="Italic">Meretrix meretrix</Emphasis> in Shuangtaizi estuary,China

This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06–0.37 g/ (ind.·d), and the respiration rates were 0.31–14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18–36.70 and 1.44–14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×10⁵ t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×10³ t O₂ from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem.     

Immunogenicity and protective role of antigenic regions from five outer membrane proteins of <Emphasis Type="Italic">Flavobacterium columnare</Emphasis> in grass carp <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis>

Flavobacterium columnare causes columnaris disease in freshwater fish. In the present study, the antigenic regions of five outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli. The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purified recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella. Following vaccination of the fish their IgM antibody levels were examined, as was the expression of IgM, IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC IIβ, which are also involved in adaptive immunity. Interleukin genes (IL), including IL-1β, IL-8 and IL-10, and type I and type II interferon (IFN) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), significant increases in IgM antibody levels were observed in the fish vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM, IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fish. At four wpv, the fish were challenged with F. columnare, and the vaccinated fish showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the five OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fish and protection against F. columnare.     

Identification and bioinformatics analysis of microRNAs from the sporophyte and gametophyte of <Emphasis Type="Italic">Pyropia haitanensis</Emphasis>

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata (Porphyra haitanensis) is an economically important genus that is cultured widely in China. P. haitanensis is cultured on a larger scale than Pyropia yezoensis, making up an important part of the total production of cultivated Pyropia in China. However, the majority of molecular mechanisms underlying the physiological processes of P. haitanensis remain unknown. P. haitanensis could utilize inorganic carbon and the sporophytes of P. haitanensis might possess a PCK-type C₄-like carbon-fixation pathway. To identify microRNAs and their probable roles in sporophyte and gametophyte development, we constructed and sequenced small RNA libraries from sporophytes and gametophytes of P. haitanensis. Five microRNAs were identified that shared no sequence homology with known microRNAs. Our results indicated that P. haitanensis might posses a complex sRNA processing system in which the novel microRNAs act as important regulators of the development of different generations of P. haitanensis.     

Trends in major and minor meteorological variables and their influence on reference evapotranspiration for mid Himalayan region at east Sikkim,India

Estimation of evapotranspiration(ET) for mountain ecosystem is of absolute importance since it serves as an important component in balancing the hydrologic cycle.The present study evaluates the performance of original and location specific calibrated Hargreaves equation(HARG) with the estimates of Food and Agricultural Organization(FAO)Penman Monteith(PM) method for higher altitudes in East Sikkim,India.The results show that the uncalibrated HARG model underestimates ET_0 by 0.35 mm day~(-1) whereas the results are significantly improved by regional calibration of the model.In addition,this paper also presents the variability in the trajectory associated with the climatic variables with the changing climate in the study site.Nonparametric Mann-Kendall(MK) test was used to investigate and understand the mean monthly trendof eight climatic parameters including reference evapotranspiration(ET_0) for the period of 1985-2009.Trend of ET_0 was estimated for the calculations done by FAO PM equation.The outcomes of the trend analysis show significant increasing(p ≤ 0.05) trend represented by higher Z-values,through MK test,for net radiation(Rn),maximum temperature(Tmax) and minimum temperature(Tmin),especially in the first months of the year.Whereas,significant(0.01 ≥ p ≤0.05) decreasing trend in vapor pressure deficit(VPD)and precipitation(P) is observed throughout the year.Declining trend in sunshine duration,VPD and ET_0 is found in spring(March- May) and monsoon(June –November) season.The result displays significant(0.01≤ p ≤ 0.05) decreasing ET_0 trend between(June- December) except in July,exhibiting the positive relation with VPD followed by sunshine duration at the station.Overall,the study emphasizes the importance of trend analysis of ET_0 and other climaticvariables for efficient planning and managing the agricultural practices,in identifying the changes in the meteorological parameters and to accurately assess the hydrologic water balance of the hilly regions.     

Antialgal and antilarval activities of bioactive compounds extracted from the marine dinoflagellate <Emphasis Type="Italic">Amphidinium carterae</Emphasis>

With the global ban on the application of organotin-based marine coatings by the International Maritime Organization, the development of environmentally friendly, low-toxic and nontoxic antifouling compounds for marine industries has become an urgent need. Marine microorganisms have been considered as a potential source of natural antifoulants. In this study, the antifouling potential of marine dinoflagellate Amphidinium carterae, the toxic and red-tide microalgae, was investigated. We performed a series of operations to extract the bioactive substances from Amphidinium carterae and tested their antialgal and antilarval activities. The crude extract of Amphidinium carterae showed significant antialgal activity and the EC₅₀ value against Skeletonema costatum was 55.4 μg mL^?1. After purification, the isolated bioactive substances (the organic extract C) exhibited much higher antialgal and antilarval activities with EC₅₀ of 12.9 μg mL^?1 against Skeletonema costatum and LC₅₀ of 15.1 μg mL^?1 against Amphibalanus amphitrite larvae. Subsequently, IR, Q-TOFMS, and GC-MS were utilized for the structural elucidation of the bioactive compounds, and a series of unsaturated and saturated 16- to 22-carbon fatty acids were detected. The data suggested the bioactive compounds isolated from Amphidinium carterae exhibited a significant inhibiting effect against the diatom Skeletonema costatum and Amphibalanus amphitrite larvae, and could be substitutes for persistent, toxic antifouling compounds.     

Experimental study on large wood filtration performance by herringbone water-sediment separation structure

A herringbone water-sediment separation structure(hereinafter referred to as "herringbone structure") has been shown to be effective in separating coarse inorganic debris; however, less is known regarding the large wood(LW) filtration effect in this structure. This paper presents preliminary research on the wood filtration effect of the herringbone structure based on physical model tests.The results show that the herringbone structure exhibited effective performance in large wood size segregation, with a 100% component filtration rate for LW that diameter(D) larger than ribbed beam opening width(a). The total filtration rate also exceeded 80% when the Fraud number(Fr) is larger than 2.64 and increased with the increase of Fr. After exceeding Frmax, total filtration rate would be decreased due to overflow. Beside flow condition,structure parameters influence significantly on LW filtration rate. We attempt to explain the filtration process via particle contact trajectory and particle movement trajectory. The inclined angle of ribbed beam(γ) contributed the most variation to the filtration rate via influencing the coincidence with particle contact trajectory and particle movement trajectory. The high sensitivity coefficient of ribbed beam(θ) under relatively low Fr conditions implies remarkable influences on LW filtration effects by causing clogging problem. The ribbed beam opening width(a) together with LW diameter(D) influenced the size segregation performance.     

Impact of <Emphasis Type="Italic">Vibrio parahaemolyticus</Emphasis> and white spot syndrome virus (WSSV) co-infection on survival of penaeid shrimp <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

White spot syndrome virus (WSSV) is an important viral pathogen that infects farmed penaeid shrimp, and the threat of Vibrio parahaemolyticus infection to shrimp farming has become increasingly severe. Viral and bacterial cross or superimposed infections may induce higher shrimp mortality. We used a feeding method to infect Litopenaeus vannamei with WSSV and then injected a low dose of V. parahaemolyticus (WSSV+Vp), or we first infected L. vannamei with a low-dose injection of V. parahaemolyticus and then fed the shrimp WSSV to achieve viral infection (Vp+WSSV). The eff ect of V. parahaemolyticus and WSSV co-infection on survival of L. vannamei was evaluated by comparing cumulative mortality rates between experimental and control groups. We also spread L. vannamei hemolymph on thiosulfate citrate bile salt sucrose agar plates to determine the number of Vibrio, and the WSSV copy number in L. vannamei gills was determined using an absolute quantitative polymerase chain reaction (PCR) method. LvMyD88 and Lvakt gene expression levels were detected in gills of L. vannamei by real-time PCR to determine the cause of the diff erent mortality rates. Our results show that (1) the cumulative mortality rate of L. vannamei in the WSSV+Vp group reached 100% on day 10 after WSSV infection, whereas the cumulative mortality rate of L. vannamei in the Vp+WSSV group and the WSSV-alone control group approached 100% on days 11 and 13 of infection; (2) the number of Vibrio in the L. vannamei group infected with V. parahaemolyticus alone declined gradually, whereas the other groups showed significant increases in the numbers of Vibrio (P<0.05); (3) the WSSV copy numbers in the gills of the WSSV+Vp, Vp+WSSV, and the WSSV-alone groups increased from 10⁵ to 10⁷ /mg tissue 72, 96, and 144 h after infection, respectively. These results suggest that V. parahaemolyticus infection accelerated proliferation of WSSV in L. vannamei and vice versa. The combined accelerated proliferation of both V. parahaemolyticus and WSSV led to massive death of L. vannamei.     

Leaf stable carbon isotope composition in <Emphasis Type="Italic">Picea schrenkiana</Emphasis> var. <Emphasis Type="Italic">tianschanica</Emphasis> in relation to leaf physiological and morphological characteristics along an altitudinal gradient

To understand the effects of leaf physiological and morphological characteristics on δ ¹³C of alpine trees, we examined leaf δ ¹³C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and N_area in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient (P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ ¹³C, LNC, Chla+b, LDMC, LMA and N_area varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ ¹³C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ ¹³C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ ¹³C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation.     

Effects of ocean acidification driven by elevated CO<Subscript>2</Subscript> on larval shell growth and abnormal rates of the venerid clam, <Emphasis Type="Italic">Mactra veneriformis</Emphasis>

The venerid clam (Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO₂. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO₂-enriched air at (400±25)×10^-6 (ambient control), (800±25)×10^-6 (high pCO₂), or (1 200±28)×10^-6 (extremely high pCO₂), the atmospheric CO₂ concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO₂ groups compared with the ambient control groups. Furthermore, under high and extremely high pCO₂ conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO₂ exerts an additional burden on the health of M. veneriformis larvae by impairing early development.     

Fatty acid composition of <Emphasis Type="Italic">Euphausia superba</Emphasis>, <Emphasis Type="Italic">Thysanoessa macrura</Emphasis> and <Emphasis Type="Italic">Euphausia crystallorophias</Emphasis> collected from Prydz Bay,Antarctica

The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C14:0, C16:0, EPA (eicosapentenoic acid) and DHA (decosahexenoic acid) while E. crystallorophias showed higher contents of C18:1(n-9), C18:1(n-7), DHA and EPA than the former two. Higher fatty acid ratios of C18:1(n-9)/18:1(n-7), PUFA (polyunsaturated fatty acid)/SFA (saturated fatty acid), and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical omnivore with a higher trophic position compared with E. superba and T. macrura.