Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in Changjiang River,China

Chinese sturgeon (Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon.     

Status of two <Emphasis Type="Italic">Coreius</Emphasis> species in the Three Gorges Reservoir,China

Dam construction alters natural flow regimes which, in turn, cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir, from impoundment of the Changjiang (Yangtze) River, China, may have affected native fish species. Thus, the status of two lotic freshwater fish species, Coreius heterodon and C. guichenoti, were monitored in the Three Gorges Reservoir, including fish abundance, individual composition, growth, condition, and mortality. Data on both species were gathered from upstream, midstream and downstream areas of the reservoir and, where available, from studies published before and after dam construction. Lower abundance, slower growth, a less diversified age structure, poorer fish condition (indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore, after final impoundment, individual Coreius species inhabiting the area changed, with young individuals becoming more abundant, while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment.     

Comparison of stem taper models for the four tropical tree species in Mount Makiling,Philippines

This study was conducted to evaluate the performance of six stem taper models on four tropical tree species, namely Celtis luzonica (Magabuyo), Diplodiscus paniculatus (Balobo), Parashorea malaanonan (Bagtikan), and Swietenia macrophylla (Mahogany) in Mount Makiling Forest Reserve (MMFR), Philippines using fit statistics and lack-of-fit statistics. Four statistical criteria were used in this study, including the standard error of estimate (SEE), coefficient of determination (R ²), mean bias \(( \bar E )\), and absolute mean difference (AMD). For the lack-offit statistics, SEE, \(\bar E\) and AMD were determined in different relative height classes. The results indicated that the Kozako2 stem taper model offered the best fit for the four tropical species in most statistics. The Kozako2 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE, \(\bar E\) and AMD in most of the relative height classes. These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height, merchantable stem volumes and total stem volumes of standing trees belonging to the four species of the tropical forest in MMFR.     

Characterization and in-vivo evaluation of potential probiotics of the bacterial flora within the water column of a healthy shrimp larviculture system

A thorough understanding of the normal bacterial flora associated with shrimp larviculture systems contributes to probiotic screening and disease control.The bacterial community of the water column over a commercial Litopenaeus vannamei larval rearing run was characterized with both culture-dependent and culture-independent methods.A total of 27 phylotypes at the species level were isolated and identified based on 16 S rDNA sequence analysis.Denaturing gradient gel electrophoresis(DGGE) analysis of the V3–V5 region of 16 S rRNA genes showed a dynamic bacterial community with major changes occurred from stages zoea to mysis during the rearing run.The sequences retrieved were affiliated to four phyla,Proteobacteria,Actinobacteria,Bacteroidetes,and Firmicutes,with the family Rhodobacteraceae being the most frequently recovered one.Subsequently,13 representative strains conferred higher larval survival than the control when evaluated in the in-vivo experiments;in particular,three candidates,assigned to Phaeobacter sp.,Arthrobacter sp.,and Microbacterium sp.,significantly improved larval survival( P 0.05).Therefore,the healthy shrimp larviculture system harbored a diverse and favorable bacterial flora,which contribute to larval development and are of great importance in exploiting novel probiotics.     

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.     

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.     

Distribution and quantitative zonation of unloading cracks at a proposed large hydropower station dam Site

Rock mass unloading is an important rock engineering problem because unloading may impact the stability of a rock mass slope. Based on hydroelectric engineering principles, this study focuses on the classification of unloading zones to reflect the rock mass structure characteristics. Geological background and slope structure of the study region were considered to investigate the distribution and deformation of the unloading process. Quantitative indices were classified according to the formation mechanisms and the geological exhibition of unloading zones. The P-wave velocity (V _P ), the ratio of the wave velocity (K _V , the ratio of the test P-wave velocity along the adit depth to the P-wave velocity of intact rock), the sum of joint openings every 2 meters (S _t ), and the density of open joints (D _t ) were calculated as quantitative indices for the rock mass unloading zone. The characteristics of the unloading zone of rock mass slopes at the dam site were successfully determined. The method of combining qualitative data with quantitative indices was found to be effective for the classification of slope unloading zones.     

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.     

Distribution of diatoms and silicoflagellates in surface sediments of the Yellow Sea and offshore from the Changjiang River,China

The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Changjiang (Yangtze) River, China. In total, 267 diatom taxa and two silicoflagellate species were identified from the sediments. The spatial variations in abundance and diversity were classified into three distinct geographic patterns using Q mode clustering: a south-north geographic pattern, a coastal-offshore pattern and a unique pattern in the Changjiang River mouth. The south-north geographic pattern was related to the spatial variations in sea temperature. Coscinodiscus oculatus, a warm-water species, indicated these variations by a gradual decrease in abundance from the south to the north. The coastal-offshore pattern was in response to the spatial variations in salinity. Cyclotella stylorum, Actinocyclus ehrenbergii and Dictyocha messanensis, the dominant brackish species in coastal waters, significantly decreased at the isobaths of approximately 30 m, where the salinity was higher than 31. Paralia sulcata and Podosira stelliger indicated the impact of the Yellow Sea Warm Current in the central Yellow Sea. The unique pattern in the Changjiang River mouth showed the highest species diversity but lower abundance, apparently because: freshwater input can significantly increase the proportion of brackish species; nutrients can supply the growth of phytoplankton; and high sedimentation rates can dilute the microfossil abundance in the sediments. Our results show that an integration of environmental factors (e.g., nutrient levels, sedimentation rate, sea temperature, salinity and water depth) determined the spatial characteristics of the siliceous microfossils in the surface sediments.     

Zooplankton Distribution in Coastal Water off Gopalpur,North-Western Bay of Bengal

An interannual study on zooplankton abundance, biomass, and species composition was carried out during different seasons in two local coastal water types off Gopalpur, north-western Bay of Bengal. Although, Type-1 was observed with higher zooplankton abundance in comparison to Type-2, pattern of variation followed similar seasonal trends in both water types during individual years. Well pronounced seasonality was observed in zooplankton distribution. Zooplankton community was composed of 217 holoplankton and 22 meroplankton. The holoplankton community was predominated by copepod in terms of species diversity and abundance followed by hydrozoa, tintinnida, malacostraca, gastropoda, chaetognatha and chordata. The meroplankton were represented by larval forms viz. bivalve veliger, brachyuran zoea larvae, caridean larvae, copepod nauplii, fish egg and gastropod veliger. Dominance of copepod species viz. Acrocalanus longicornis, Paracalanus aculeatus and Paracalanus parvus were observed frequently in both water types. The species richness was higher in Type-1 in comparison to Type-2 during both the years. Salinity regimes and availability of phytoplankton prey influenced the distribution and species composition of zooplankton assemblage.     

Temporal and spatial variations of abundance of phycocyanin- and phycoerythrin-rich <Emphasis Type="Italic">Synechococcus</Emphasis> in Pearl River Estuary and adjacent coastal area

Three surveys were carried out in Pearl River Estuary and adjacent coastal area in May, August, and November, 2013, to investigate the temporal and spatial variations of abundance of phycoerythrin-rich Synechococcus (PE-rich SYN) and phycocyanin-rich Synechococcus (PC-rich SYN). The effects of environmental factors on the alternation of the different Synechococcus groups were also elucidated. PE-rich SYN was detected in three surveys, whereas PC-rich SYN was detected in May and August, but not in November. The highest abundances of PE-rich SYN and PC-rich SYN were recorded in August and May, with mean values of 74.17×10³ and 189.92×10³ cells mL^?1, respectively. From May to November, the relative abundance of PE-rich SYN increased, whereas that of PC-rich SYN declined. PE-rich and PC-rich SYN presented similar horizontal distributions with high abundance in the southern estuary in May, and in the western estuary in August. The abundances of PE-rich and PC-rich SYN were high at 27–32°C and salinity of 10–20. PC-rich SYN was not detected at < 24°C, and PC:PE-rich SYN decreased in abundance with salinity increase. When less than 20 mg L^?1, suspended particulate matter (SPM) was helpful for Synechococcus growth. PE-rich SYN decreased in abundance when the concentration of dissolved inorganic nitrogen increased in May and November, and the concentration of phosphate increased in November. However, PC-rich SYN abundance and nutrients showed no correlation. Principal component analysis and regression analysis indicated that PE-rich SYN significantly correlated with the principal components that were affected by environmental factors.     

Distribution of dominant zooplankton species along a latitudinal gradient in China sea during spring

Dominant species of zooplankton community vary with latitude. Though China possesses a vast coastal area in northwestern Pacific, studies on the latitudinal dominant species gradient are rare. We collected zooplankton samples from Haizhou Bay(34.56?–35.19?N, 119.51?–120.30?E), Yueqing Bay(28.14?–28.38?N, 121.10?–121.21?E) and Dongshan Bay(23.65?–23.90?N, 117.45?–117.60?E) in May 2012 and May 2013 to preliminarily characterize the latitudinal dominant species distribution. All the samples were collected vertically using a 0.505 mm mesh plankton net with 0.8 m in mouth diameter from bottom to surface. Calanus sinicus, Aidanosagitta crassa, Labidocera euchaeta, Zonosagitta nagae, Acartia pacifica and Paracalanus parvus were found to be dominant. C. sinicus was the most dominant species and the unique one occurred in all three bays. With latitude decreasing, both the abundance and proportion of C. sinicus declined sharply. Cluster analysis showed that the 6 dominant species could be divided into 3 groups, based on their occurrences in the three bays. Our results suggested that the distribution of dominant species along the coast of China has a significant latitudinal gradient. C. sinicus which widely distributes in the coastal water of the northwestern Pacific can well adapt to the temperature at different latitudes. The high abundance in Haizhou Bay indicated that C. sinicus was an exemplary warm-temperate species, and more commonly occurs in the north of China seas. The ecological characteristics of dominant species change from warm-temperate type in high-latitudinal bays to warm water type in low-latitudinal bays.     

Niches of dominant fish in the waters surrounding the Taishan Islands,China

An index of relative importance (IRI) was employed to screen for dominant fish in the waters surrounding the Taishan Islands, China, using data from four seasonal trawl surveys undertaken between 2012 and 2013. Niche breadth and niche overlap were measured using the Feinsinger and Morisita-Horn indices, respectively, and the characteristics and seasonal variations in the niches of dominant fish were assessed via non-metric multidimensional scaling (NMDS) and cluster analysis. A total of 80 fish species, including 16 dominant species, were recorded. Only Amblychaeturichthys hexanema was dominant in all seasons. According to niche breadth values and NMDS, the 16 dominant species were grouped into the following three types: (1) wide niche breadth species, including Cynoglossus macrolepidotus, A. hexanema, and Trypauchen vagina, among others; (2) medium niche breadth species, including Setipinna taty and Johnius belangerii; and (3) narrow niche breadth species, including Atrobucca nibe and Coilia mystus. Most species with a wider niche breadth were demersal fish with a lower swimming capability and even distribution. The niche breadth of migrating fish was narrower than that of settled fish. At a given spatial scale, fish with stronger swimming capabilities had a narrower niche breadth. Niche overlap, which is associated with niche specialization, ranged from 0.000 to 0.886 and had an annual mean value of 0.314. In summer and autumn, niche overlap was relatively high within species of the Sciaenidae family and within species of the Gobiidae in autumn. Differences in thermophily, feeding habits, food organism abundance/distribution and predator-prey relationships affected the niche overlap of fish in this area. Cluster analysis revealed that species with the narrowest niche breadth and lowest niche overlap values usually displayed lower aggregation and greater distribution differences compared with other species.     

Karyotype analysis of four nemertean species

We performed a karyotype analysis on four species from Phylum Nemertea using regenerating somatic cells. Two palaeonemertean species, Cephalothrix hongkongiensis and Cephalothrix sp., had the same chromosome number (2n=28), but different karyotypes (16 m+10 sm+2 st, NF=54 and 22 m+4 sm+2 st, NF=54, respectively). The karyotypes of the two heteronemerteans, Notospermus geniculatus and Ramphogordius sanguineus were 2n=38, 30 m+6 sm+2 sm/st (NF=76/74) and 2n=56, 48 m+4 sm+4 sm/st (NF=112/108), respectively.     

Estimation of age,growth and maturation of purpleback flying squid, <Emphasis Type="Italic">Sthenoteuthis oualaniensis</Emphasis>, in Bashi Channel,central Pacific Ocean

The age, growth and maturation of Sthenoteuthis oualaniensis were determined with statolith data collected with a light purse seine from the Bashi Channel of central Pacific Ocean. The estimated longevity of the squid was no more than 6 months for females, and no more than 5 months for males. Growth in mantle length (ML) was best described by logistic models for both females and males, while growth in body weight (BW) was best fitted by power curves. The maximum absolute growth rate (AGR) and instantaneous growth rate (IGR) in ML or BW both occurred at 91–105 days for females and 76–90 days for males. Back calculated hatching dates were from October to January, with a peak in December, although the short duration of sampling date might have had an influence on the result. The lower percentage of mature females (37.2%) suggested that the study area during the sampling date was not a spawning ground for the species. Size and age at first maturity were 183 mm ML and 136 days for females, whereas they were 156 mm ML and 85 days for males.     

Early embryo and larval development of inviable intergeneric hybrids derived from <Emphasis Type="Italic">Crassostrea angulata</Emphasis> and <Emphasis Type="Italic">Saccostrea cucullata</Emphasis>

To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6–8 d after hatching, and those survived could not complete metamorphosis. C. angulata ♀× S. cucullata ♂ larvae had a growth rate similar to that of the maternal species, whereas S. cucullata ♀ × C. angulata ♂ larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata.     

Feeding broodstocks different starfish diets affect growth and survival of larvae of trumpet shell (<Emphasis Type="Italic">Charonia lampas sauliae</Emphasis> Reeve 1844)

Trumpet shell (Charonia lampas sauliae) (Mollusca, Heterogastropoda, Cymatidae) has extensive economic value. Studies on the artificial larval development of C. lampas sauliae for aquaculture utilization have become especially important due to the finite natural resources. In the present study, the growth and survival rate of the larvae of C. lampas sauliae broodstocks fed three types of starfish diets, Asterina pectinifera Müller & Troschel 1842, A. amurensis Lütken 1871 and their mixture were compared. The larval size increased gradually between day 10 and day 20 after hatching at 15°C and 20°C. No difference was found in body size and specific growth rate (SGR) (two-way ANOVA; P > 0.05). However, during transition from trochophore to veliger stage 20 days after hatching, significant increases in larval survival and growth rates were observed. The maximum survival rate was observed on day 10. The mean survival rate was 0.463, 0.730 and 0.515 at 15°C, and 0.369, 0.713 and 0.444 at 20°C when A. pectinifera, A. amurensis and their mixture were fed, respectively. The SGR and survival rate of the larvae were definitely influenced by the diets (P < 0.05), and the effect of A. amurensis alone was higher than that of A. pectinifera alone and their mixture.     

A review of interaction between neon flying squid (<Emphasis Type="Italic">Ommastrephes bartramii</Emphasis>) and oceanographic variability in the North Pacific Ocean

The neon flying squid (Ommastrephes bartramii) is a short-lived opportunistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic eggs to nektonic adults is closely linked to oceanographic conditions. The fluctuations in O. bartramii abundance and distribution tend to increase and widen continuously due to the heavy influences of ocean-climate events on various spatio-temporal scales. In this study, we reviewed the interaction between O. bartramii and oceanography variability in the North Pacific with respect to large-scale climatic-oceanic phenomena including El Niño, La Niña, Kuroshio, Oyashio and Pacific Decadal Oscillation (PDO), as well as regional environmental variables such as sea surface temperature (SST), sea surface height (SSH), sea surface salinity (SSS), chlorophyll-a (Chl-a) concentration, and plankton density. The population dynamics of O. bartramii is mediated mainly by meso- and large-scale climatic-oceanic events (e.g., Kuroshio and Oyashio Currents) rather than other local environmental conditions (e.g., SST and Chl-a concentration), because all of the oceanographic influences are imposed on the context of large-scale climate changes (e.g., PDO). An unstructured-grid finite-volume coastal ocean model coupled with an individual-based model is proposed to simulate relevant physical-biological oceanographic processes for identifying ocean-climate influence and predicting O. bartramii distribution and abundance in the North Pacific. Future research needs to be focused on improving the knowledge about early life history of O. bartramii and evaluating the relationship between marine physical environment and two separate passive drifting life stages of O. bartramii including free-floating eggs and planktonic paralarvae.     

The community structure and seasonal dynamics of plankton in Bange Lake,northern Tibet,China

The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at-2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identifi ed. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included H olophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and A rctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×10~7 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1–3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass(including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was signifi cantly negatively correlated with salinity.     

Component Analysis and Antifungal Activity of the Compounds Extracted from Four Brown Seaweeds with Different Solvents at Different Seasons

The polar and nonpolar extracts of Colpomenia sinuosa, Padina pavonia, Cystoseira barbata and Sargassum vulgare collected during spring, summer and autumn were evaluated for their antifungal activities. The phytochemicals of unexplored seaweeds were analyzed by gas chromatography and mass spectrometric (GC/MS). The algal extracts were tested for their antifungal activities against Aspergillus niger, A. flavus, Penicillium parasiticus, Candida utilis and Fusarium solani. Phytochemicals were extracted from the four seaweeds with various solvents including methanol, ethanol, acetone, chloroform and dimethyl ether. Among the various extracts, methanolic extract showed the highest inhibition activity on all fungal species. Seasonal variation in antifungal activity was studied, while methanol extracts showed the best antifungal activity in spring. Cystoseira barbata was the most effective seaweed, having antifungal activity throughout the whole year. The UV-Vis phytochemical procedure and GC-MS analysis of the methanol extracts from tested species indicated the existence of different constituents. In conclusions, the compounds with antifungal activity were identified as indoles, terpenes, acetogenins, phenols, and volatile halogenated hydrocarbons.