2006—2007年冬季长江口海域甲藻孢囊的分布及其与环境的关系

分析了2006—2007年冬季长江口海域(121°-127°E,30°-32.5°N)19个站位0-10cm沉积物中的甲藻孢囊,共检出27种甲藻孢囊类型,其中自养型10种,异养型17种,异养型孢囊数量比为0.70。各站位孢囊种数在1-15种之间,孢囊平均密度在干重0.7-89.0个/g之间。表层(0-3cm)、中层(3-5cm)和底层(5-10cm)之间孢囊组成差异不大,大多以原多甲藻类孢囊为主要优势种,孢囊密度表层大于中层,中层大于底层的分布趋势;在经度方向上,孢囊平均密度在近岸逐渐增高,到站位M4-13突然降到最低,然后再逐渐增高。与其它海湾相比,长江口属于孢囊密度较低的海域。亚历山大藻分布广泛但数量较低,最高密度为干重40.8个/g,其他种类如Polykrikos kofoidii、Gonyaulax spiniferacomplex(Spiniferites mirabilis)和G.spiniferacomplex(S.cf.ramosus)都在长江口海域有分布。沉积物类型是影响孢囊数量分布的重要因素,水深、温度、盐度与孢囊分布呈正相关性,溶解氧与孢囊分布呈负相关性。孢囊的分布格局对河口的富营养化与低氧区具有良好的指示意义。     

Identification of the harmful dinoflagellate Vulcanodinium rugosum recovered from a ballast tank of a globally traveled ship in Port Tampa Bay,Florida, USA

The transport of microalgae in the ballast tanks of shipping vessels is of global concern because many algal species can survive in ballast tanks as nonmotile or cyst stages increasing the likelihood of introductions into foreign ports. In 2004 a peridinoid dinoflagellate was collected and isolated from ballast residuals of the merchant vessel Southern Fighter in Port Tampa Bay, Florida, USA. Light and electron microscopy of the motile and nonmotile peridinoid cells indicated the dinoflagellate was Vulcanodinium rugosum. Bayesian and maximum-parsimony (MP) phylogenetic analyses of V. rugosum strain CCFWC516 showed that sequenced regions of its LSU and ITS matched those of V. rugosum strains from Japan but were divergent from those strains from New Zealand and France. LC–MS analyses indicated that strain CCFWC516 did not produce the neurotoxin pinnatoxin, an ability that has been reported for other strains of this species. Analyses did show, however, that strain CCFWC516 did produce portimine, a cyclic imine produced by all other strains of this species. The M/V Southern Fighter visited numerous ports along the coast of Japan and the North Sea before sailing to Florida. The phylogenetic match to Japanese strains, as well as the ship's ballast exchange history, suggests that strain CCFWC516 originated from Japan. In light of the increase in global shipping traffic, increases in vessel size and capacity, and the increased connectivity between the Pacific Ocean and the Caribbean and Gulf of Mexico that will result from the widening of the Panama Canal, the introduction of nonnative, harmful algal species is an area of heightened concern and calls for increased vigilance.     

Phytoplankton and bacterial assemblages in ballast water of U.S. military ships as a function of port of origin, voyage time, and ocean exchange practices

We characterized the physical/chemical conditions and the algal and bacterial assemblages in ballast water from 62 ballast tanks aboard 28 ships operated by the U.S. Military Sealift Command and the Maritime Administration, sampled at 9 ports on the U.S. West Coast and 4 ports on the U.S. East Coast. The ballast tank waters had been held for 2–176 days, and 90% of the tanks had undergone ballast exchange with open ocean waters. Phytoplankton abundance was highly variable (grand mean for all tanks, 3.21 × 10⁴ viable cells m⁻³; median, 7.9 × 10³ cells m⁻³) and was unrelated to physical/chemical parameters, except for a positive relationship between centric diatom abundance and nitrate concentration. A total of 100 phytoplankton species were identified from the ballast tanks, including 23 potentially harmful taxa (e.g. Chaetoceros concavicornis, Dinophysis acuminata, Gambierdiscus toxicus, Heterosigma akashiwo, Karlodinium veneficum, Prorocentrum minimum, Pseudo-nitzschia multiseries). Assemblages were dominated by chain-forming diatoms and dinoflagellates, and viable organisms comprised about half of the total cells. Species richness was higher in ballast tanks with coastal water, and in tanks containing Atlantic or Pacific Ocean source waters rather than Indian Ocean water. Total and viable phytoplankton numbers decreased with age of water in the tanks. Diversity also generally decreased with water age, and tanks with ballast water age >33 days did not produce culturable phytoplankton. Abundance was significantly higher in tanks with recently added coastal water than in tanks without coastal sources, but highly variable in waters held less than 30 days. Bacterial abundance was significantly lower in ballast tanks with Atlantic than Pacific Ocean source water, but otherwise was surprisingly consistent among ballast tanks (overall mean across all tanks, 3.13 ± 1.27 × 10¹¹ cells m⁻³; median, 2.79 × 10¹¹ cells m⁻³) and was unrelated to vessel type, exchange status, age of water, environmental conditions measured, or phytoplankton abundance. At least one of four pathogenic eubacteria (Listeria monocytogenes, Escherichia coli, Mycobacterium spp., Pseudomonas aeruginosa) was detected in 48% of the ballast tanks, but toxigenic strains of Vibrio cholerae were not detected. For ships with tanks of similar ballasting history, the largest source of variation in phytoplankton and bacteria abundance was among ships; for ships with tanks of differing ballasting histories, and for all ships/tanks considered collectively, the largest source of variation was within ships. Significant differences in phytoplankton abundance, but not bacterial abundance, sometimes occurred between paired tanks with similar ballasting history; hence, for regulatory purposes phytoplankton abundance cannot be estimated from single tanks only. Most tanks (94%) had adequate records to determine the source locations and age of the ballast water and, as mentioned, 90% had had ballast exchange with open-ocean waters. Although additional data are needed from sediments that can accumulate at the bottom of ballast tanks, the data from this water-column study indicate that in general, U.S. Department of Defense (DoD) ships are well managed to minimize the risk for introduction of harmful microbiota. Nevertheless, abundances of viable phytoplankton with maximum dimension >50 μm exceeded proposed International Maritime Organization standards in 47% of the ballast tanks sampled. The data suggest that further treatment technologies and/or alternative management strategies will be necessary to enable DoD vessels to comply with proposed standards.     

Temperature tolerances of toxic dinoflagellate cysts: application to the treatment of ships' ballast water

Using toxic dinoflagellates and their resistant resting cysts as model organisms, we demonstrate the potential of heat treatment as a method to minimise the transport of harmful aquatic organisms via ships' ballast water. Vegetative dinoflagellate cultures of Gymnodinium catenatum could be readily killed using temperatures as low as 35 °C and treatment times in the range 30 minutes to 5 h. The resistant resting cysts (hypnozygotes) of G. catenatum were killed after 2 h at 35 °C and the cysts of Alexandrium catenella were killed after 4.5 h at 38 °C . A careful assessment of various waste heat sources on the BHP bulk carrier Iron Whyalla has confirmed the practicability of this approach, and a successful pilot heat treatment plant was trialled on-board ship in April 1997.     

The efficiency of regional ballast water exchange: Changes in phytoplankton abundance and diversity

Ballast water was sampled on 12 occasions before and after an exchange process carried out in regional seas in order to assess the efficiency of this type of ballast water management at reducing the abundance and diversity of phytoplankton. Although there was an overall reduction in the average abundance and number of taxa after exchange this was not consistent between tanks and voyages. On some occasions there were changes in species composition after exchange and, in some cases, there were increases in potentially harmful species after the exchange process. Factors such as the depth of the water during the exchange process, the season and the method of exchange influenced the efficacy of the exchange process. The variability in the results after exchange mean that this is unlikely to be a ballast water management method that would give consistent results and careful consideration would have to be given to the suitability of using this method in regional seas as a means of reducing the risk of introducing non-native species.     

Critical review of the IMO international convention on the management of ships’ ballast water and sediments

The International Maritime Organization (IMO), the United Nations body which administers the international regulatory regime for shipping, noted the negative impact of non-indigenous organisms transported in the ballast water of ships already in the early 1970s. Consequently, measures were taken with the aim to minimize ballast water mediated species invasions through IMO Marine Environmental Protection Committee (MEPC) Resolutions. As a result of long-term IMO efforts, it was determined that an international convention would best meet the needs of the global community, hence the International Convention for the Control and Management of Ships’ Ballast Water and Sediments was adopted in a Diplomatic Conference in 2004 and is now open for signature by IMO Member States. This very complex (and by no means “simple”) Convention aims to reduce the transfer and subsequent impact of aquatic organisms in the ballast water and sediment of ships by acting to reduce the load of these organisms in discharged ballast water. A set of 15 guidelines provides technical guidance for the implementation of the Convention principles. This review considers critical aspects of this Convention and selected guidelines seen from perspectives of biological, shipping and regulatory concerns.     

Palaeoenvironmental distribution of the Rhaetian dinoflagellate cysts Dapcodinium priscum EVITT, 1961, emend. Below, 1987 and Rhaetogonyaulax rhaetica (SARJEANT) LOEBLICH and LOEBLICH, 1976, emend. Harland et al., 1975, emend. Below, 1987

In almost all Rhaetian marine assemblages of the Tethyan Realm, two dinoflagellate cyst species, Dapcodinium priscum EVITT, 1961, emend. Below, 1987, and Rhaetogonyaulax rhaetica (SARJEANT) LOEBLICH and LOEBLICH, 1976, emend. Harland et al., 1975, emend. Below 1987 are dominant. Thus, when one is relatively frequent the other scarce and vice versa. This paper considers the inverse relationship of the two species in 235 rock samples taken from Rhaetian strata well exposed along the western margin of the Mesozoic intracratonic basin of south-eastern France. The palynological variables recorded from the samples (seven types of phytoclasts and three marine taxa: D. priscum, R. rhaetica and micrhystridids) were submitted to principal components analysis, which shows that D. priscum occurs in deposits that reflect nearshore and restricted marine environments. R. rhaetica is indicative of more marine environments at greater water depth, as indicated by the relatively high proportions of buoyant needle-like phytoclasts. These observations suggest that D. priscum is the cyst of an opportunistic, euryhaline dinoflagellate taxon that occupied various ecological niches while R. rhaetica inhabited more normal open marine environments. The palaeoenvironmental distribution seems to have been influenced by the energy level of the water column. D. priscum is found in deposits that denote high to low energy while R. rhaetica is found in low energy sediments. Micrhystridid occurrences are similar to those of D. priscum; they are uncommon when the abundance of R. rhaetica increases.     

The efficacy of biocides and other chemical additives in cooling water systems in the control of amoebae

Aims:  In vitro experiments were undertaken to evaluate biocide formulations commonly used in cooling water systems against protozoa previously isolated from cooling towers. The investigations evaluated the efficacy of these formulations against amoebic cysts and trophozoites.
Methods and Results:  Laboratory challenges against protozoa isolated from cooling towers using chlorine, bromine and isothiazolinone biocides showed that all were effective after 4 h. The presence of molybdate and organic phosphates resulted in longer kill times for bromine and isothiazolinones. All treatments resulted in no detectable viable protozoa after 4 h of exposure.
Conclusions:  The chemical disinfection of planktonic protozoa in cooling water systems is strongly influenced by the residence time of the formulation and less so by its active constituent. Bromine and isothiazolinone formulations may require higher dosage of concentrations than currently practiced if used in conjunction with molybdate- and phosphate-based scale/corrosion inhibitors.
Significance and Impact of the Study:  Cooling water systems are complex microbial ecosystems in which predator–prey relationships play a key role in the dissemination of Legionella . This study demonstrated that at recommended dosing concentrations, biocides had species-specific effects on environmental isolates of amoebae that may act as reservoirs for Legionella multiplication in cooling water systems.     

Antagonistic activity of Staphylococcus siderophores and chemical biocides against Bacillus subtilis in a paper-machine environment

The antagonistic potential of nonpathogenic Staphylococcus strains against Bacillus subtilis wild and type strains were studied under conditions simulating a paper- and board-machine environment. The antimicrobial activity was measured by growth inhibition in an automated turbidimeter. The antagonistic potential was compared with that of generally used chemical biocides in a paper- and board-machine environment. The siderophore-containing extracts of Staphylococcus strains significantly inhibited vegetative growth of B. subtilis and delayed the germination of spores both in synthetic and in white-water media. The mill strains were more resistant than type strain against Staphylococcus siderophores and against chemical biocides. The Staphylococcus siderophore-containing extracts did not interfere with the bacteriostatic effect of chemical biocides, but no synergy was detected. The results indicate the potential for application of Staphylococcus siderophore-containing extracts as biocontrol agents in paper- and boardmachine environment. Received 2 January 1998/ Accepted in revised form 4 December 1998     

Late Aptian to early Cenomanian dinoflagellate cysts from Agadir Basin,southwestern Morocco: Biostratigraphy and palaeoenvironment

The Agadir Basin (Moroccan Atlantic margin) is characterized by its fossil richness, including organic-walled microfossils. The palynological analysis of the middle Cretaceous succession from the Tamzargout section and EGA.1 well reveals the presence of well-preserved and diverse assemblage, rich in dinoflagellate cysts. The assemblages contain stratigraphic marker taxa and show significant chronostratigraphic events. Based on these bioevents and on the comparison with different palaeogeographic domains, a determination of age was proposed. The biogeographic characteristics of most cosmopolitan taxa in this study confirm the establishment of new oceanic communication related to the opening of the equatorial Atlantic. The Albian-Cenomanian transition has been recognized only in EGA.1 well, whereas the Aptian-Albian transition, the early-mid Albian and the mid-late Albian have been defined in both the section and the well. The recorded associations are comparable to those of neighboring deposits and those of the Tethyian and Atlantic domains. The vertical distribution of the organic matter in the sediments of the Agadir Basin and the compilation of all palaeoenvironmental proxies allowed identifying an Albian transgression with specific palaeoenvironments in each interval. Neritic marine environments alternated with short phases of continental and oceanic influence is deduced for the late Aptian-early Cenomanian in this basin. The late Aptian-early to mid Albian recorded an outer neritic palaeoenvironment under oceanic influence; the mid to late Albian showed littoral conditions during a regressive phase fluctuating to middle to outer neritic environment; finally the late Albian-early Cenomanian transition was characterized by a middle neritic palaeoenvironment under coastal influence.     

光催化与纯紫外工艺对船舶压载水微藻的处理效果比较

分析光催化和纯紫外工艺对控制处理压载水中10～50μm藻类的影响,比较了压载水中10～50μm藻类的去除率、种类变化、绿藻和硅藻去除率以及硅藻种类数的变化,结果显示光催化工艺对10～50μm藻类的去除效果要好于纯紫外工艺。两种工艺对10～50μm藻类的即时去除率均可以达到96.0%以上,压载数日后排放则效果更佳。研究发现两种工艺对硅藻的处理效果不如绿藻。并且压载水盐度会影响压载水处理工艺的效果。     

Molecular detection of native and invasive marine invertebrate larvae present in ballast and open water environmental samples collected in Puget Sound

Non-native marine species have been and continue to be introduced into Puget Sound via several vectors including ship's ballast water. Some non-native species become invasive and negatively impact native species or near shore habitats. We present a new methodology for the development and testing of taxon specific PCR primers designed to assess environmental samples of ocean water for the presence of native and non-native bivalves, crustaceans and algae. The intergenic spacer regions (IGS; ITS1, ITS2 and 5.8S) of the ribosomal DNA were sequenced for adult samples of each taxon studied. We used these data along with those available in Genbank to design taxon and group specific primers and tested their stringency against artificial populations of plasmid constructs containing the entire IGS region for each of the 25 taxa in our study, respectively. Taxon and group specific primer sets were then used to detect the presence or absence of native and non-native planktonic life-history stages (propagules) from environmental samples of ballast water and plankton tow net samples collected in Puget Sound. This methodology provides an inexpensive and efficient way to test the discriminatory ability of taxon specific oligonucleotides (PCR primers) before creating molecular probes or beacons for use in molecular ecological applications such as probe hybridizations or microarray analyses. This work addresses the current need to develop molecular tools capable of diagnosing the presence of planktonic life-history stages from non-native marine species (potential invaders) in ballast water and other environmental samples.     

Batch solar disinfection inactivates oocysts of Cryptosporidium parvum and cysts of Giardia muris in drinking water

AIM: To determine whether batch solar disinfection (SODIS) can be used to inactivate oocysts of Cryptosporidium parvum and cysts of Giardia muris in experimentally contaminated water. METHODS AND RESULTS: Suspensions of oocysts and cysts were exposed to simulated global solar irradiation of 830 W m(-2) for different exposure times at a constant temperature of 40 degrees C. Infectivity tests were carried out using CD-1 suckling mice in the Cryptosporidium experiments and newly weaned CD-1 mice in the Giardia experiments. Exposure times of > or =10 h (total optical dose c. 30 kJ) rendered C. parvum oocysts noninfective. Giardia muris cysts were rendered completely noninfective within 4 h (total optical dose >12 kJ). Scanning electron microscopy and viability (4',6-diamidino-2-phenylindole/propidium iodide fluorogenic dyes and excystation) studies on oocysts of C. parvum suggest that inactivation is caused by damage to the oocyst wall. CONCLUSIONS: Results show that cysts of G. muris and oocysts of C. parvum are rendered completely noninfective after batch SODIS exposures of 4 and 10 h (respectively) and is also likely to be effective against waterborne cysts of Giardia lamblia. SIGNIFICANCE AND IMPACT OF THE STUDY: These results demonstrate that SODIS is an appropriate household water treatment technology for use as an emergency intervention in aftermath of natural or man-made disasters against not only bacterial but also protozoan pathogens.     

Experimental study on the influence of bioturbation performed by Nephtys caeca (Fabricius) and Nereis virens (Sars) annelidae on the distribution of dinoflagellate cysts in the sediment

Dinoflagellates include noxious microalgae responsible for the formation of toxic red tides and the poisoning of molluscs and crustaceans, resulting in important economic losses. As a consequence, the life cycle of these algae has been extensively studied, but the dormancy phase (cyst) in the sediment record is little known. In the intertidal zone, bioturbation, an important biological process resulting from the activities of benthic fauna, significantly influences the movement of particles in the sediments. Laboratory experiments have allowed comparing and quantifying the movements of fluorescent microspheres resulting from the activity of two polychaetes annelidae, Nereis virens and Nephtys caeca. The particles, which simulate 45 µm diameter dinoflagellate cysts, are deposited in flat aquaria at the surface or deep in the sediment. Photographs of the aquaria were taken at regular intervals, to observe, in a non-destructive manner, the movement of the particles and to calculate, using adapted software, the optical reworking coefficient (ORC) over time. A difference appears between the movements of the particles generated by both species of polychaetes. Nereis virens create “permanent” galleries that carry the microspheres deeply in the sediment during the digging, bioirrigation and feeding, and Nephtys caeca homogenize the particles in the first centimetres of sediment during its erratic movements. The study shows that the bioturbation generated by these organisms can modify the distribution of the 45 µm diameter dinoflagellate cysts in the sedimentary column, burying them or raising them back to the water-sediment interface.     

Late Holocene variability in pelagic fish scales and dinoflagellate cysts along the west coast of Vancouver Island, NE Pacific Ocean

Fish stocks and dinoflagellates are essential components of the marine food chain. Sediment cores from a predominantly anoxic basin in Effingham Inlet, Vancouver Island, British Columbia, archive a late Holocene (500–5300 years BP) record of paleoproductivity in the North American Coastal Upwelling Domain (CUD). We present evidence that late Holocene changes in the dinoflagellate cyst assemblages, sedimentary record, and fish stocks in the northeastern Pacific Ocean fluctuated, at least partially, in accordance with regional and global climate cycles.Principal components analysis (PCA), and trend, wavelet and spectral analyses were used to identify relationships, cycles and trends in sediment grey-scale values, and the abundances of fish scales and dinoflagellate cysts on centennial to millennial time scales. Most observed cycles fluctuated in intensity over time, particularly following transition of the regional climate to a higher rainfall phase that impacted coastal oceanic dynamics 3400 ± 150 years ago. Correlation of the marine paleoproductivity records observed in Effingham Inlet with solar influenced climate proxy cycles observed in the North Atlantic region indicates that solar forcing at different scales might have influenced the climate in the northeast Pacific as well. In particular an 1100- to 1400-year cycle in regional climate is well represented in the fish productivity proxy and sedimentological record. It was also observed that colder water, high-productivity, Selenopemphix nephroides and anchovy-dominated “Anchovy Regime” ecosystems alternate with warmer water, herring-dominated “Herring Regime” ecosystems at millennial time scales. The fish scale record preserved in Effingham Inlet indicates that the NE Pacific is now in transition from an ‘anchovy-’ to a ‘herring’-dominated regime.     

Efficacy of commercially available predators,nematodes and fungal entomopathogens for augmentative control of Drosophila suzukii

The recent arrival of Drosophila suzukii, an invasive pest of soft‐skinned fruit with a wide host range, has resulted in increased production costs for growers and the need for additional insecticide applications each growing season. There are few effective organic insecticides for D. suzukii, and insecticide use in conventional farms may be disruptive to natural enemies, suggesting a need for effective biological control to combat D. suzukii. Commercially available natural enemies were evaluated for their potential use in augmentative releases, including: the predators Orius insidiosus and Dalotia coriaria; the entomopathogenic fungi Metarhizium anisopliae, Beauveria bassiana and Paecilomyces fumosoroseus; and the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema feltiae and S. carpocapsae. This suite of natural enemies was chosen to target D. suzukii adults as well as larvae in hanging or dropped fruit. Of the cultured fungal strains tested, only M. anisopliae significantly decreased D. suzukii survival, but it had low residual activity and no effect on D. suzukii fecundity. O. insidiosus decreased D. suzukii survival in simple laboratory arenas but not on potted blueberries or bagged blueberry branches outdoors. D. coriaria did not decrease D. suzukii survival in infested blueberries in simple laboratory arenas. The nematodes tested showed low infection rates and were not able to affect D. suzukii survival. Although this suite of natural enemies showed limited ability to suppress D. suzukii under the tested conditions, these and related natural enemies are present as part of the endemic natural enemy community in agricultural fields, where they may contribute to D. suzukii suppression.     

A review of the molecular evidence for ballast water introduction of the toxic dinoflagellates Gymnodinium catenatum and the Alexandrium “tamarensis complex” to Australasia

The potential of ballast water to act as a major introduction vector for toxic dinoflagellates and other phytoplankton is beyond doubt; however, evidence that links the suspected introduced species with a source population is less convincing, especially without supporting historical and biochemical data, or consideration of palaeobiogeographical scenarios that may explain current species distributions. This paper presents new molecular data based on LSU-rDNA and rDNA-ITS sequences that demonstrate an unequivocal and recent link between Temperate Asian and Australasian populations of the toxic dinoflagellates Gymnodinium catenatum and toxic strains of the Alexandrium “tamarensis complex”. We integrate our data with supporting evidence from historical distribution records, sediment dating studies, toxin profiles, mating studies and previous molecular studies. We contrast the observed patterns of genetic and biochemical variation with those expected from various palaeobiogeographical scenarios explaining the evolution and natural dispersal of both species. While definitive proof is impossible, the total evidence indicates that these toxic dinoflagellates were introduced to Australasia during the past 100 years, most probably via ballast water from bulk-cargo shipping from Japan and/or south-east Asia.     

Relative importance of bacteria, microalgae and yeast for growth of the sponge Halichondria melanadocia (De Laubenfels, 1936): A laboratory study

Bacteria, microalgae and yeast less than 10 μm in size are the primary food source of sponges but their relative contribution to somatic growth is poorly understood. In a laboratory study, the sponge Halichondria melanadocia was fed for 6 weeks a diet consisting solely of four bacterial strains, or a mixed diet consisting of bacteria, microalgae and yeast. Both diets were fed at three concentrations, based on the natural concentration (NC) of particles available to sponges: 1/5, 1 and 5NC. Mean final size of H. melanadocia was 40% greater on a mixed diet than on the bacteria diet, probably because of the greater supply of carbon and other essential nutrients in microalgae and yeast. Cell concentration also significantly affected the growth of H. melanadocia, with greatest growth for sponges fed at the highest cell concentration. The estimated carbon requirement for H. melanadocia to meet metabolic costs was 0.356 mg C l^− 1 or 103 μg C h^− 1 gDW^− 1. Many H. melanadocia appeared to be optimizing their surface area for food uptake.