Are some bacteria toxic for marine algae?

It was observed in vitro that some bacteria from different origins, including the sea, are capable of inhibiting the growth of several marine algae. However, there is too much difference between in vitro experiments and in situ environmental conditions to assume that bacterial poisons may rule a great deal of algac-bacteria relationships in the sea as a whole. In the author's opinion the importance of bacterial poison is limited to special and rare instances.     

Lysozyme,chitinase and exo-N-acetyl-β-D-glucosaminidase (NAGase) in lymphomyeloid tissue of marine fishes

Lymphomyeloid (haemopoietic) tissues produce or store blood cells — among these leucocytes rich in lysosomal enzymes. The thymus, unlike the other lymphomyeloid tissues found in fish, produces exclusively lymphocytes. The carbohydrate-hydrolysing enzymes lysozyme (EC 3.2.1.17), chitinase (EC 3.2.1.14) and exo-N-acetyl--D-glucosaminidase (NAGase; EC 3.2.1.30) were assayed in various lymphomyeloid tissues of the cartilaginous fish Chimaera monstrosa, Squalus acanthias, Etmopterus spinax and Raja radiata, and in the thymus of the marine teleost Lophius piscatorius. Lysozyme activity was high in the cranial lymphomyeloid tissue of C. monstrosa; in Leydig's organ (oesophageal lymphomyeloid tissue) and the spleen from E. spinax; and in Leydig's organ, the epigonal organ and the spleen from R. radiata. Little or no lysozyme activity was found in Leydig's organ and the epigonal organ of S. acanthias, or in the thymus of C. monstrosa, R. radiata and L. piscatorius. The pH optima for lysozyme activities lay between 4.8 and 5.4 when assayed photometrically. Chitinase was most active at pH 1 in Leydig's organ from R. radiata, and at pH 2.7 in the epigonal organ from S. acanthias. The chitinolytic activity in Leydig's organ of E. spinax may be due to lysozyme. The optimum for NAGase activity in Leydig's organ from R. radiata lay at pH 4.0, that from S. acanthias and E. spinax at pH 4.5. The role of the enzymes in the defense against microorganisms and parasites is discussed.     

Interoperable web GIS services for marine pollution monitoring and forecasting

This paper presents services and systems developed in the FP6 InterRisk (Interoperable GMES Services for Environmental Risk Management in Marine and Coastal Areas of Europe) project, which addresses the need for better access to information for risk management in Europe, both in cases of natural hazards and industrial accidents. The overall objective of the project is to develop a pilot system for interoperable GMES monitoring and forecasting services for environmental management in marine and coastal areas. This pilot system is based on established and widely adopted web-GIS standards, in line with INSPIRE recommendations. The pilot is comprised of, among other things, a portal and a web-GIS map viewer, both developed using open source tools. Providers using commercial tools adhering to the adopted standards, however, can also deliver products to the InterRisk pilot. The InterRisk services and system are based on a combination of free and commercial software, and have been demonstrated to end-users in three European areas: Norwegian, UK and Irish waters, and German and Polish waters. Products and services offered in these areas are presented, along with an outline of the technical development of web-GIS clients and portals.

Use of seaweeds for monitoring trace elements in coastal waters

Concentrations of a wide range of trace elements: arsenic, cadmium, cobalt, chromium, hafnium, nickel, thorium, uranium, zinc and the rare earth elements, cerium, europium, samarium, terbium and ytterbium were determined by instrumental neutron activation analysis in the brown alga,Fucus vesiculosus from Eckwarder Hörne, North Sea and from Rügen, Baltic Sea. Another brown alga,Sargassum filipendula from Sri Lanka, Indian ocean (representing an unpolluted control station) was similarly investigated. Cobalt, chromium and nickel concentrations were highest inF. vesiculosus from the North Sea while zinc was highest in samples from the Baltic Sea, reflecting high levels of these elements in coastal waters of the North and the Baltic sea. Cadmium, cobalt, nickel and zinc levels were lowest inS. filipendula from Sri Lanka, probably demonstrating lower levels of those elements in coastal waters. Concentration levels of hafnium, thorium, uranium, and the rare earth elements were highest inS. filipendula. Two years later in 1994,S. filipendula along withUlva sp. (green alga) was resampled from the same sampling site, and in addition to the above elements, six other trace elements (Ag, Ba, Br, Rb, Se and Sr) were determined.Sargassium filipendula showed a particular affinity for Ag, As, Br and Sr. For the other elements, marginal concentration differences were observed betweenS. filipendula andUlva sp., probably reflecting the regional background levels. Substantially higher concentrations of Hf, Th, U, and the rare earths were found again in the 1994Sargassum andUlva samples, reflecting the effect of a substrate rich in rare earth elements. The brown algae used in this study may be used to monitor trace elements in coastal waters.     

Dynamics of heavy-metal transfer between biotic (Cytheria chione and Cerastoderma edule) and abiotic (water and sediment) components in marine environment (Bay of Martil, Moroccan Mediterranean coast)

This study deals with the transfer of heavy metals (Hg, Cd, Pb, Cr, Ni, Ti, Zn, and Cu) between abiotic and biotic components (Cytheria chione and Cerastoderma edule) in the inshore intertidal zones of Tetouan/Martil over 2 yr of investigation (1992-1994). Analysis of the heavy-metal accumulation kinetics in Cytheria chione and Cerastoderma edule shows that their highest contents occur during the spring-summer period when an important proliferation of the plankton biomass occurs. However, the accumulation of Cd is higher during the period between winter and spring. In general, heavy-metal concentrations are higher at Cytheria chione than at Cerastoderma edule. These results, according to previous studies, suggest the presence of significant correlations and dynamic reciprocal transfer of heavy metals among seawater, sediment, and molluscs. They also suggest that the level of contamination of decreasing heavy metals follows the sequence: sediment, organisms, and water. Among the molluscs investigated, the variability of the thallium (Tl) contents is difficult to detect due to the very weak presence of this metal in the analysed tissues.     

Evaluation of the copepod Tigriopus californicus as a bioassay organism for the detection of chemical feeding deterrents produced by marine phytoplankton

Marine phytoplankton have been shown to use chemical feeding deterrents to reduce or inhibit zooplankton grazing. In order to screen phytoplankton species for feeding deterrent production and to isolate and identify feeding deterrent compounds, a new, rapid, and reliable laboratory bioassay was developed. This bioassay used the laboratory-reared harpacticoid copepod Tigriopus californicus and measured inhibition of feeding by measuring the fecal pellet production rate. The bioassay was capable of detecting deterrent compounds: (1) adsorbed onto ground fish food (a normally palatable food); (2) dissolved in a mixture of seawater and live Thalassiosira pseudonana cells (a species of diatom which had no feeding deterrent activity); and (3) present in live cell cultures. Method (2) was recommended for use in bioassay-guided fractionation (isolation of chemical compounds), as it was reliable, rapid, accurate, and easy to perform with large numbers of samples. The total bioassay time was < 48 h, and data collection required only a microscope. Methanolic cell extracts of several phytoplankton species were screened for feeding deterrent activity. Extracts from the diatom Phaeodactylum tricornutum and the dinoflagellate Gonyaulax grindleyi gave feeding deterrent responses, while extracts from the diatom Thalassiosira pseudonana gave no feeding deterrent responses. Live P. tricornutum cells deterred feeding at densities of 6x10⁵ cells ml^-1. This bioassay should provide a valuable tool in screening phytoplankton for feeding deterrent compounds and determining the chemical nature of these compounds.     

Polychlorinated biphenyl (PCB) uptake by marine phytoplankton

The time-courses of uptake for 2,4,5,2,5-pentachlorobiphenyl (PCB) by 11 marine phytoplankton species were measured and found to be rapid, with equilibration occurring within 0.5 to 2.0 h. These data were described with the empirical Freundlich adsorption isotherm. The relationship between cell density and accumulation of PCBs was also investigated. Concentration factors on a volume per volume basis ranged from 1.23x10⁴ to 2.41x10⁶ for the 11 algal species examined. These values are comparable in magnitude to factors reported previously for phytoplankton in natural marine systems.     

Shell growth response of mussels (Mytilus edulis) exposed to toxic microalgae

Mussels (Mytilus edulis) were exposed to the algaeAlexandrium ostenfeldii, Chrysochromulina polylepis, Gyrodinium aureolum, Gymnodinium galatheanum andHeterosigma akashiwo for 24 h; significant reductions in growth rate, as compared to the control, were observed after exposure toA. ostenfeldii, C. polylepis, G. aureolum andG. galatheanum at initial concentrations of 4.5 × 10⁶, 110 × 10⁶, 9 × 10⁶ and 120 × 10⁶ cells l^–1, respectively. Exposure to high initial concentrations of the non-toxic algaeTetraselmis suecica (174 × 10⁶ cells l^–1) andIsochrysis galbana (610 × 10⁶ cells l^–1) showed no adverse effect on growth rate. When mussels with reduced growth were transferred to clean seawater, they recovered to > 90% of control growth within 2 to 4 d. Exposure to algal filtrates of the toxic algal cultures produced no reduction in growth rate.     

Preparation,characterization and toxic activity of oxovanadium(IV) mixed-ligand complexes

New oxovanadium(IV) mixed-ligand complexes of the general composition [VO(L)(A)], where KHL?=?potassium salt of salicylideneglycine, A¹?=?bis(benzylidene)ethylenediamine, A²?=?bis (acetophenone)ethylenediamine, A³?=?di(2-pyridyl)amine, A⁴?=?bis(benzylidene)-1,8-diaminonaphthalene, A⁵?=?thiophene-o-carboxaldene-aniline, A⁶?=?thiophene-o-carboxaldene-p-anisidine, have been synthesized by the interaction of these ligands with vanadyl sulphate. The mixed-ligand complexes have been characterized on the basis of elemental analysis, magnetic measurements, electronic and infrared spectra. An octahedral structure has tentatively been assigned to all of the mixed-ligand complexes. The mixed-ligand complexes show higher toxic activity against the Salmonella typhi, Escherichia coli and Serratia mercescen as compared to the ligands, vanadyl sulphate and control (dimethyl sulphoxide). The mixed-ligand complexes were also tested against a standard drug (tetracycline).     

三丁基锡对中国近海常见海洋微藻的毒性效应

研究三丁基氯化锡(TBT)对中国近海常见5种硅藻和甲藻(硅藻中丹麦细柱藻(Leptocylindrus danicus)、派格棍形藻(Bacilaria paxillifera)、聚生角毛藻(Chaetoceros socialis),甲藻中微型原甲藻(Prorocentrum minimum)、简裸甲藻(Gymnodinium simplex))的毒性效应,考察了有机锡对浮游藻光合活性(Fv/Fm)、粒径、生长的影响。结果表明:派格棍形藻、聚生角毛藻、简裸甲藻的光合活性(Fv/Fm)受TBT影响较显著;微型原甲藻、丹麦细柱藻的光合活性受TBT影响较小。高质量浓度TBT胁迫下海洋微藻峰值粒径显著减小,低质量浓度TBT对峰值粒径影响不显著。低质量浓度TBT对派格棍形藻、聚生角毛藻、简裸甲藻、微型原甲藻均有较强的毒性作用,非检测毒性浓度(NDEC)分别为1.17、1.07、0.23、3.73μg.L-1,丹麦细柱藻对TBT具有很强耐受性,NDEC为112.62μg.L-1。     

The composition of natrophosphate (sodium fluoride phosphate hydrate)

Natrophosphate is a common trace mineral in alkaline rocks and a major salt in alkaline nuclear waste that complicates waste processing. Natrophosphate has historically been assigned the composition Na₇F(PO₄)₂·19H₂O, but this conflicts with a more recent solubility study that claimed natrophosphate is a solid solution of NaF and Na₃PO₄. It is not possible to model the solubility of natrophosphate in nuclear waste until this controversy is resolved. The present study mixed stock solutions of 0.9 M NaF and Na₃PO₄ at different ratios at 8 °C. The compositions of the liquid phase and wet natrophosphate sample were measured by ion chromatography. Plotting the tie-lines between the solid and liquid phase composition showed convergence on a single composition, indicating that natrophosphate is not a solid solution. The resulting composition is approximately the same as the composition first reported more than 140 years ago. Thus, this study resolves the long-standing controversy in the literature concerning the composition of natrophosphate.     

Faster phototransformation of the formate (terrestrial) versus methanesulphonate (marine) markers of airborne particles: implications for modelling climate change

Atmospheric particulate matter is altering climate. For instance marine biogenic particles are cooling climate. Organic markers are major tools to elucidate the sources of atmospheric particulate matter. Formate is commonly used as a marker of continental aerosols, whereas methanesulphonate is used as tracer of biogenic marine aerosols. However, transformation processes during aerosol transport may modify their relative concentrations and, in turn, introduce a bias in the assessment of particle sources. Actually very little is known about the transformation of formate and methanesulphonate in aerosols. Therefore, we irradiated formate and methanesulphonate in the presence of nitrate and haematite. Nitrate and haematite are aerosol photosensitisers, producing reactive species that degrade organic compounds. The time evolution of formate and methanesulphonate was monitored by ion chromatography. Our results show that formate is transformed from 1.6 to 4.1 times faster than methanesulphonate. This trend is partly due to higher reactivity with the hydroxyl radical and partly due to additional reaction with other transients such as nitrogen dioxide. Such results strongly suggest faster formate transformation during particle transport. Therefore, when formate and methanesulphonate are used as particle tracers, an overestimation of marine biogenic versus continental particle sources is expected. This bias has major implications for climate prediction models, because marine biogenic particles have a cooling effect on climate.     

Apoptosis in marine sponges: a biomarker for environmental stress (cadmium and bacteria)

The marine demosponge Suberites domuncula is abundantly present on muddy sand bottoms, both in the open sea and in harbors. In the present study it is shown that exposure of S. domuncula to cadmium (CdCl₂) in concentrations ranging from 0.01 to 5.0 g ml⁻¹ for up to 5 d results in apoptotic fragmentation of DNA. Kinetics experiments revealed that after 24 h a significant increase of DNA fragmentation already occurred. Besides cadmium a second stimulus was identified to also cause apoptosis in this species, namely exposure to heat-treated Escherichia coli. In order to support the finding that both cadmium and E. coli induce apoptosis in the sponge, expression of the apoptotic gene MA-3 was studied. The cDNA, SDMA3, was isolated and found to be 2247 nucleotides long. The deduced amino acid sequence (M_r 50 765) shares high similarity with the corresponding mouse molecule. Like the mouse gene, the sponge MA-3 gene undergoes increased expression in response to apoptotic stimuli. While the specimens remained alive after treatment with cadmium, the sponges treated with E. coli died after approximately 12 d. The E. coli-treated animals started to form gemmules 10 to 12 d after addition of the bacteria. Hence, the process of apoptosis in sponges is triggered by two different pathways, one which is initiated by exogenous factors, e.g. heavy metals, and a second one, caused by endogenous factors, which leads to gemmule formation and a shift of the presumably immortal cells to mortal cells. The latter assumption is supported by the finding that during the process of bacteria-induced apoptosis, which results in the death of the specimens, the activity of the telomerase drops. It is concluded that the cells which appear to be immortal and telomerase-positive undergo apoptosis during the process of gemmule formation. In consequence cells not involved in the production of gemmules become mortal. Based on these data, it is proposed that apoptosis is a suitable biomarker in the bioindicator organism S. domuncula to monitor unfavorable environmental conditions, at least in this animal phylum. Received: 10 November 1997 / Accepted: 6 March 1998     

Evolutionary genetics of marine Mysis spp. (Crustacea: Mysidacea)

Inter-and intraspecific allozyme differentiation in the mysid crustacean genus Mysis in the North Atlantic region was studied in order to evaluate earlier concepts of evolutionary and systematic relationships and to assess patterns of subdivision within widespread taxa. The results support a relatively ancient divergence of the marine and non-marine species of the genus, and are generally in line with the current subgeneric tridivision into Mysis s.str., Michteimysis and Auricomysis. However, the North American littoral species M. gaspensis should be returned to subgenus Mysis s.str. from its present position in Michteimysis with M. mixta. The closest observed affinities within Mysis s.str. were between M. gaspensis and the freshwater M. relicta group, and between M. oculata and M. litoralis. Intraspecific differentiation among North European coastal populations of M. oculata and M. litoralis was moderately strong (F _ST0.1), suggesting population bottlenecks and limited dispersal in the post-glacial time. On the other hand, ransoceanic differences were not essentially greater, indicating the systematic homogeneity and long-term dispersal capacity in the marine species. This contrasts with the strong genetic and systematic fragmentation earlier found within the circumboreal M. relicta species group.     

Mating system of the commensal marine isopod Jaera hopeana (Crustacea)

The commensal marine isopod Jaera hopeana Costa, 1853 was reared in the laboratory through 30 generations in the absence of its host, Sphaeroma serratum, to study its development and reproductive behaviour. It was found that adult males take virtually any opportunity to associate with a young conspecific in manca-I stage (first free-living stage) and carry it around in a characteristic position. This male-manca(I) amplexus ends during the manca's first postmarsupial molt (manca-I to manca-II) at an average age of about 9 d after hatching from the marsupium. Entry into amplexus does not alter a manca's molt timing, the duration of the amplexus thus depending exclusively on the manca's age when it joined by a male. Given a choice, males do not prefer manca-I close to molting over those just hatched. With the first postmarsupial molt, long before sexual maturity, female J. hopeana become receptive to mating. Before a female manca is released from amplexus, it is inseminated by its male partner. Sperm transferred to young immature females are stored within special sperm stores until they are needed for fertilization. The male-manca(I) amplexus seems to be a precopula, wherein males wait for their partners to molt and become sexually receptive. Nevertheless, it is inevitable that every second amplexus on average ends unsuccessfully: although manca-I have already been determined irreversibly (and probably genetically) as males and females in equal numbers, adult males are unable to predict which manca-I are potential mates and which are not. Males accept any manca-I as a precopula partner, and even when given a choice they do not prefer female over male manca-I. From the manca-II stage onward, females are continuously receptive to mating for the rest of their life, and mating can occur immediately upon contact of the partners without any significant investment in energy and time (en passant copulation).     

A flume study of drift in marine infaunal amphipods (Haustoriidae)

Amphipods of the infaunal family Haustoriidae are characteristic of high-energy marine sands and occur both in the sediment and the overlying water column. Sediments in this habitat are subject to constant reworking by tidal currents, suggesting that resident amphipod populations are affected by this disturbance in a phenomenon similar to freshwater invertebrate drift. A controlled-velocity laboratory flume was used to examine the effect of haustoriid density, current velocity, illumination, and food availability on drift rates to determine a causal basis for drift. Drift is densityindependent and greatest at night and during high current flow; it is also greater at night from sterile sediment than from untreated sand. Flume transport was usually less than 10% of amphipods present in the sediment. Haustoriids captured downstream were mostly adults occurring in a 1:1 sex ratio, suggesting no obvious function of drift in reproduction. Current-induced displacement of haustoriids may produce the patchiness in distribution observed in nature. Disturbance of the bed could also function to keep amphipod densities below the carrying capacity of the local environment. In certain cases, food limitation may cause amphipods to actively leave the substrate. Under all conditions, greater drift rates in darkness are probably adaptive in avoidance of predators. Despite the nature of sediment movement in a high-energy environment, haustoriid drift may have an active as well as passive component.     

Use made in marine ecology of methods for estimating demographic parameters from size/frequency data

Macdonald and Pitcher's method of decomposing a sizefrequency histogram into cohorts (mathematical optimization of the fit of the distribution function to the histogram) has been used to estimate the composition of random samples drawn from populations with known cohort structure. The large-sample behaviour of the method is in accordance with the results of asymptotic theory. With sample sizes typical of those used in many ecological studies, good estimates often could not be obtained without imposing constraints upon the estimation procedure, even when the number of age classes in the population was known. If the number of age classes was not known, it was frequently difficult to determine from small samples. When unconstrained solutions were obtainable, confidence limits about estimates were often very wide. Our results and information in the theoretical literature indicate that if the Petersen method (whereby several modes on a size-frequency histogram are taken to represent single age classes and all age classes to be present) does not work, accurate estimates of demographic parameters are unlikely to be obtainable using more rigorous methods. In view of these difficulties, we recommend that an iptimization method, such as that described by Macdonald and Pitcher, be used to estimate demographic parameters. Standard errors of estimates should be reported. Optimization methods give an indication when the data is inadequate to obtain accurate parameter estimates, either by failing to converge or by placing large standard errors about the estimates. Graphical methods do not give a clear warning of this, and should be avoided except where the modes on the size-frequency histogram are very well separated and sample sizes are large. Often, assumptions must be made about population parameters to enable their estimation. This may involve constraining some parameters to particular values, assuming a fixed relationship between cohort mean sizes and their standard deviations, or by assuming that individuals grow according to a von Bertalanffy curve. Any such assumptions need detailed justification in each case.     

Use of kappa-carrageenan microbound diet (C-MBD) as feed for Penaeus monodon larvae

The performance of an artificial practical diet, kappacarrageenan microbound diet (C-MBD) was assessed on Penaeus monodon larvae at the SEAFDEC Broodstock and Maturation Experimental Laboratory in March 1986. Shrimps were reared from zoea₁ to post-larvae₁ using five dietary treatments: (a) natural food — Chaetoceros calicitrans and Artemia salina (b) C-MBD; (c) combination of natural food and C-MBD; (d) commercial diet (microencapsulated, MED); (e) combination of natural food and commercial diet. Results showed slow development with larvae fed the commercial diet. Feeding with C-MBD in combination with natural food resulted in the highest % survival among treatments (69.6), but this was not significantly different (P>0.05) from those obtained with larvae fed natural food alone, C-MBD alone or their combination. While mean values for survival of larvae fed the commercial diet, either alone or in combination, was significantly lower (p<0.05) than all other treatments, their mean growth indices were comparable with larvae fed C-MBD alone or in combination. The low levels of protein, lipid and essentially fatty acids (which are considered important nutrients during larval development) contained in the commercial diet may well justify the results on metamorphosis, survival and growth of the larvae fed this diet. The good performance of C-MBD in this experiment suggests that this kind of diet can be used as partial or total replacement to the traditional algal food.     

Acute toxic effects of organic effluents on Chironomus travalensis Kieffer (Chironomidae: Diptera)

The acute toxicity of abattoir and sewage effluents on Chironomus travalensis was determined in a 96?h static bioassay. The toxicity was undertaken in replicates using effluent concentrations between 5% and 100%. Determination of the physical and chemical parameters of both effluents was carried out. The abattoir effluent was toxic to the test organisms at different concentrations while the sewage effluent did not produce lethality. The 96?h LC₅₀ value of the abattoir effluent was 23%. The acute toxicity unit at 96?h was 4.3. To avoid the adverse effect of effluent waste to aquatic life, it is recommended that effluent waste needs to be channelled through normal treatment procedures in industrial and residential areas.