A survey for paralytic shellfish poisoning (PSP) in Vancouver Harbour

Shellfish samples were collected from seven inter-tidal and two sub-tidal sites between 23 May and 8 June 1999 in Vancouver Harbour and were analysed for paralytic shellfish poisoning (PSP) using a mouse bioassay. PSP was detected in mussels collected at four sampling sites in English Bay and Burrard Inlet, at a concentration below 20 mug saxitoxin equivalents (STXeq)/100 g wet weight. (C) 2003 Elsevier Ltd. All rights reserved.

Application of Neomysis awatschensis as a standard marine toxicity test organism in China

The small mysid crustacean Neomysis awatschensis was collected in the west coast of Jiaozhou Bay, Qingdao, China in 1992 and acclimated and cultured in laboratory conditions since then. Standard acute toxicity tests using 4-6 d juvenile mysids of this species were conducted and the results were compared with Mysidopsis bahia, a standard toxicity test organism used in the US in terms of their sensitivities to reference toxins, as well as their taxonomy, morphology and geographic distributions. Because of its wide distribution along the Chinese coast, similar sensitivity to pollutants as M. bahia, short life history, small size and the case of handling, this study intended to use N. awatschensis as one of the standard marine organisms for toxicity testing in China. The species were applied to acute toxicity evaluations of drilling fluid and its additives I organotin TPT and toxic algae, and to chronic ( life cycle) toxicity assays of organotin TPT and a toxic dinofalgellate Alexandrium tamarense, respectively. Using N, awatschensis as a standard toxicity testing organism in marine pollution assessment in China is suggested.

Effects of the dinoflagellate Alexandrium tamarense on early development of the scallop Argopecten irradians concentricus

The effects of Alexandrium tamarense (strain ATHK) on early development of the bay scallop Argopecten irradians concentricus were studied under laboratory conditions. The algal culture was verified by HPLC to produce paralytic shellfish poisoning (PSP) at a level of 37.48 fmol/cell. Survival of the scallop larvae was not affected when they were grown with A. tamarense at concentrations of 500-10,000 cells/ml for 48 h. However, the activity of D-shape larvae was inhibited after 48-h exposure to A. tamarense at the algal cell density of 10,000 cells/ml. Scallop growth was inhibited significantly by A. tantarense during a 14-day exposure starting at the eye-spot larval stage. The size of juvenile scallops in the group of 10,000 cells/ml was only about 32% of that of the controls, although no obvious effect of A. tamarense was found on the rate of larval metamorphosis. All juvenile scallops survived in algal concentrations of 600-2400 cells/ml, however, attachment rates were significantly lower than control values after a 5-h exposure to A. tamarense at concentrations >600 cells/ml, while they were not obviously reduced after only 1 h of exposure. At concentrations >600 cells/ml, the climbing ability of juveniles was clearly reduced by exposure to A. tamarense after only 1 h. The climbing rate and height were only 55% and 45%, respectively, of those of the controls, when exposed to A. tantarense at a concentration of 600 cells/ml. The results indicated that A. tamarense blooms may have detrimental impacts on shellfish at early life stages, therefore, special attention should be paid to the toxic algal blooms in shellfish breeding area. (C) 2003 Elsevier Science B.V. All rights reserved.

Inhibition of egg hatching success and larvae survival of the scallop, Chlamys farreri, associated with exposure to cells and cell fragments of the dinoflagellate Alexandrium tamarense

We report an apparently novel toxic effect of the dinoflagellate Alexandrium tamarense, manifested by inhibition of the egg hatching success of the scallop, Chlamys farreri. The hatching rate of C. farreri approached only 30% of controls when its fertilised eggs were exposed for 36 h to A. tamarense cells or cellular fragments at a concentration of 100 cells/ml, and the hatching rate was just 5% after exposure to A. tamarense of 500 cells/ml. Similar exposures of the fertilised scallop eggs to two other algal species, the diatom Phaeodactylum tricornutum and the raphidophyte Heterosigma carterae, resulted in no such toxicity or inhibitory effects.. Likewise, exposure of eggs to standard STX toxin. as well as to A. tamarense cell contents (supernant of re-suspended algal cells following ultrasonication and centrifugation), did not elicit this inhibitory response. However, exposure of the scallop eggs to cell cultures, intact algal cells, or cell fragments of A. tamarense produced marked toxicity. The alga also influenced larvae at early D-shape stage of scallop. The survival rates began to decrease significantly after exposed for 6 days at concentration of 3000 cells/ml and above: no larvae could survive after 14-day exposure to A. tamarense at 10,000 cells/ml or 20-day at 5000 cells/ml. The results indicated the production of novel substances from A. tamarense which can cause adverse effects on egg hatching and survival of the scallop larvae, The experiment also found that the developmental stages before blastula was the developmental period most sensitive to the A. tamarense toxin(s) and the alga at early exponential stage had the strongest effect on egg hatching comparing with other growth phases. The adverse effect of A. tamarense on early development of scallops may cause decline of shellfish population and may have further impact on marine ecosystem. (C) 2001 Elsevier Science Ltd. All rights reserved.

A recent shellfish toxin investigation in China

A shellfish toxin investigation along the Chinese coast has recently been conducted using both HPLC and mouse assay methods. The results showed that DSP was widely distributed in different shellfish species in China. 26 out of 89 samples had DTX1 (dinophysistoxin-1) or OA (okadaic acid) but the DSP content in most shellfish samples did not reach the regulatory limit for human consumption adopted in many countries (20 mu g/100 g soft tissue). PSP was also found in 5 out of 96 samples along the coast. One sample, Chlamys nobilis from Hong Kong contained high levels of PSP (320 mu g STX equivalent/100 g soft tissue), compared to the regulatory limit (80 mu g STX equivalent/100 g soft tissue). After the recent outbreak of red tide in Hong Kong waters, three further shellfish samples were collected within 40 days to investigate the impacts of this event, It was shown that high levels of PSP continued to exist in Hong Kong waters. This report provides the first report of DSP and PSP distribution along the Chinese coast. (C) 1999 Elsevier Science Ltd, All rights reserved.

A modified HPLC method for analysis of PSP toxins in algae and shellfish from China

Improvements to an established HPLC method are introduced. The modified method is more efficient for separation and detection of the toxins responsible for paralytic shellfish poisoning (PSP). The PSP toxin content of two strains of Alexandrium tamarense and approximately forty shellfish samples collected from different locations in China have been analyzed with this HPLC method. Only one shellfish sample, collected from Lianyungang, China, contained PSP toxins.

Protein phosphatase inhibition assay for detection of diarrhetic shellfish poison in oyster

A method based on protein phosphatase enzyme activity inhibition for the detection of diarrhetic shellfish poison (DSP) was used to analyze the DSP toxicity in three oyster samples. Based on the standard dose-effect curve developed with a series of okadaic acid (OA) standard solutions, the DSP toxicity of the three oyster samples collected were screened, and the results showed that there were no OA and dinophysis toxins ( DTXs) in the samples without hydrolization. However, the OA toxicity could be detected in two of the hydrolyzed samples, and the OA toxicity of the two samples were 1.81 and 1.21 mu g OA eq./kg oyster, respectively.

Restructuring of a zooplankton community by perturbation from a wind-forced coastal jet

The impact of transient wind events on an established zooplankton community was observed during a, field survey in a, coastal region off northern Norway in May 2002. A transient wind event induced a coastal jet/filament intrusion of warm, saline water into our survey area where a semi-permanent eddy was present. There was an abrupt change in zooplankton community structure within 4-7 days of the wind event, with a change in the size structure, an increase in lower size classes less than 1 mm in equivalent spherical diameter (ESD) and a decrease in larger size classes greater than 1.5 mm in ESD. The slope of zooplankton biovolume spectra changed from -0.6 to -0.8, consistent with the size shifting towards smaller size classes. This study shows that even well established zooplankton communities are susceptible to restructuring during transient wind events, and in particular when wind forcing induces horizontal currents or filaments.

Temporal and spatial variability in nitrogen uptake kinetics during harmful dinoflagellate blooms in the East China Sea

Temporal and spatial variability in the kinetic parameters of uptake of nitrate (NO3-), ammonium (NH4+), urea, and glycine was measured during dinoflagellate blooms in Changjiang River estuary and East China Sea coast, 2005. Karenia mikimotoi was the dominant species in the early stage of the blooms and was succeeded by Prorocentrum donghaiense. The uptake of nitrogen (N) was determined using N-15 tracer techniques. The results of comparison kinetic parameters with ambient nutrients confirmed that different N forms were preferentially taken up during different stages of the bloom. NO3- (V-max 0.044 h(-1); K-s 60.8 mu M-N) was an important N source before it was depleted. NH4+ (V-max 0.049 h(-1); K-s 2.15 mu M-N) was generally the preferred N. Between the 2 organic N sources, urea was more preferred when K. mikimotoi dominated the bloom (V-max 0.020 h(-1); K-s 1.35 mu M-N) and glycine, considered as a dominant amino acid, was more preferred when P. donghaiense dominated the bloom (V-max 0.025 h(-1); K-s 1.76 mu M-N). The change of N uptake preference by the bloom-forming algae was also related to the variation in ambient N concentrations. Published by Elsevier B.V.

Metabolic characteristics of sea cucumber Apostichopus japonicus (Selenka) during aestivation

Metabolic characteristics of the sea cucumber Aposticholpus japonicus (Selenka) during aestivation were studied in the laboratory. The effects of water temperature on oxygen consumption rate (OCR) and ammonia-N excretion rate (AER) in A. japonicus were determined by the Winkler and Hypobromite methods, respectively. Mature (large, 148.5 +/- 15.4 g, medium 69.3 +/- 6.9 g) and immature (small, 21.2 +/- 4.7 g) individuals aestivated at water temperatures of 20 and 25 degrees C, respectively. The metabolic characteristics of mature individuals were different from immature individuals during this period. The OCR of mature sea cucumbers peaked at 20 degrees C, and then dropped significantly at higher temperatures, whereas the OCR of the immature animals continued to increase slightly, even beyond the aestivation temperature. The AER of mature individuals peaked at 20 T, while that of the immature animals peaked at 25 degrees C. The relationships between dry weight (DW) and absolute oxygen consumption (R) and absolute ammonia-N excretion (N) could be described by the regression equation R or N=aW(b). With the exception of 15 degrees C, the O/N ratios (calculated in atomic equivalents) of large size sea cucumbers was close to 20 across the temperatures used in this study, indicating that their energy Source was a combination of lipid and protein. Oil the other hand, apart from small individuals maintained at 10 degrees C, the O/N ratios of the medium and small sea Cucumbers were close to 10, indicating that protein was their major energy source. The O/N ratios in all size groups remained unchanged after aestivation was initiated. (c) 2005 Elsevier B.V. All rights reserved.

Isolation and characterization of a marine magnetotactic spirillum axenic culture QH-2 from an intertidal zone of the China Sea

Magnetotactic bacteria (MTB) are ubiquitous in aquatic habitats. Because of their fastidious requirements for growth conditions, only very few axenic MTB cultures have been obtained worldwide. In this study, we report a novel marine magnetotactic spirillum axenic culture, designated as QH-2, isolated from the China Sea. It was able to grow in semi-solid or liquid chemically defined medium. The cells were amphitrichously flagellated and contained one single magnetosome chain with an average number of 16 magnetosomes per cell. Phosphate and lipid granules were also observed in the cells. Both rock magnetism and energy-dispersive X-ray spectroscopy characterizations indicated that the magnetosomes in QH-2 were single-domain magnetites (Fe3O4). QH-2 cells swam mostly in a straight line at a velocity of 20-50 mu m/s and occasionally changed to a helical motion. Unlike other magnetotactic spirilla. QH-2 cells responded to light illumination. As a consequence of illumination, the cells changed the direction in which they swam from parallel to the magnetic field to antiparallel. This response appears to be similar to the effect of an increase in [O-2]. Analysis of the QH-2 16S rRNA sequence showed that it had greater than 11% sequence divergence from freshwater magnetotactic spirilla. Thus, the marine QH-2 strain seems to be both phylogenetically and magnetotactically distinct from the freshwater Magnetospirillum spp. studied previously. (C) 2010 Elsevier Masson SAS. All rights reserved.

Determination of tetrodotoxin by liquid chromatography coupled with electrospray ion-trap mass spectrometry

Two methods for tetrodotoxin analysis using liquid chromatography coupled with electrospray iontrap mass spectrometry (LC-ESI-MS) have been established with C,, reversed phase column and hydrophilic interaction liquid chromatography (HILIC) column, respectively. Sensitivity and reproducibility of the methods were compared. The method using C-18 column in selected ion monitoring (SIM) mode had a detection limit (S/N = 3) of 120 pg, and a good linearity of the calibration curve was obtained for tetrodotoxin (r = 0. 9992). High reproducibility of the method was observed, with a relative standard deviation (RSD) below 10%. The method using HILIC column in SIM mode and selected reaction monitoring (SRM) mode had detection limits (S/N = 3) of 15 and 3.75 pg, respectively. Good linearity of the calibration curves was obtained for tetrodotoxin (r = 0. 9996 and 0. 9998 in SIM and SRM mode, respectively). T he reproducibility was high in SIM mode but relatively poor in SRM mode. Based on the results, the method using HILIC column in SIM mode was suggested for the analysis of tetrodotoxin with LC-MS system.

Community structure of macrobenthos in coastal water off Rushan, southern Shandong Peninsula, and the relationships with environmental factors

To understand the present actuality of the marine ecosystem in the southern coastal water region of the Shandong Peninsula and the impact of the global change and the human activities to the marine ecosystem of the region, the macrobenthic community structure was researched based on data from 26 sampling stations carried out on four seasonal cruises from December 2006 to November 2007. The data was analyzed using PRIMER 6.0 and SPSS 15.0 software packages. The results showed that 236 macrobenthic species in total were collected from the research region by the field works. Most of the species belong to Polychaeta (76 species), Mollusca (75) and Crustacea (60). Of which, 33 species were common species by the four cruises. The dominant species were different among the four seasons, however, the polychaete species Nephtys oligobranchia and Sternaspis scutata were always dominant in the four seasons. The abundances and biomasses of the macrobenthos from the research region were variable in tire four seasons. The results of CLUSTER and MDS analysis showed that the similarities of macrobenthic structures among the stations were low, most of the similarities were at about 40% of similarity values, only that of two stations were up to 60%. In accordance with the similarity values of the macrobenthic structures, the 26 stations were clustered as six groups at arbitrary similarity level of 30%. The ABC curve indicated that the marcofauna communities in the research region had riot been disturbed distinctly. The results of BIOENV and BVSTEP (Spearman) analysis implied that the concentrations of organic matter in bottom water and heavy metal copper in sediment, water depth and temperature of bottom were the most significant environmental factors to affect the macrobentic community.

A new species of Scolelepis (Polychaeta: Spionidae) from sandy beaches in China, with a review of Chinese Scolelepis species

A new species of Spionidae, Scolelepis (Scolelepis) daphoinos sp. nov., is described and illustrated from northern China seas. The species was frequently encountered and highly abundant on sand beaches, but rarely found in subtidal areas. It was formerly misidentified as S. (S.) squamata (Muller, 1806) in China but differed from the latter species in several details in morphology, including the presence of obvious reddish pigmentation patches and the absence of unidentate hooded hooks. Another two Scolelepis species, S. (S.) lingulata Imajima, 1992 and S. (S.) variegata Imajima, 1992, are reported for the first time from Chinese waters. Two species of Scolelepis, S. (S.) globosa Wu & Chen, 1964 and S. (S.) lefebvrei (Gravier, 1905), were reported previously; therefore, five species in this genus are known from China in total. A key to all Scolelepis species from Chinese waters is provided.

First record of Paraonella platybranchia (Hartman, 1961) (Polychaeta: Paraonidae) from the Yellow Sea

This paper reports for the first time a species of polychaetous family Paraonidae, Paraonella platybranchia (Hartman, 1961), a rare species found previously only in the coast near the boundary between the United States and Mexico, and it was recently discovered in the samples collected in 1982 from Chinese side of the Yellow Sea. This is the first record of the species in China as well as in the Northwest Pacific.