Seasonal changes in antibacterial activity of North Sea water

During 1969 and 1970, the antibacterial activity of North Sea water was investigated at Helgoland (southern North Sea). Tests were performed with resting cells of Escherichia coli, Staphylococous aureus and Serratia marinorubra, inoculated in freshly sampled sea water used raw or after filter sterilization. Simultaneously, growth of indigenous bacterial populations which occurred in the presence, as well as in the absence (only 1970), of test bacteria was controlled. Seasonal changes in inactivation of test cells and multiplication of marine bacteria were correlated with the life cycles of several diatom species. Breakdown of phytoplankton flowerings produced the most pronounced influence on antibacterial activity of sea water. Sometimes, enhancement of kill rate could be established during growth periods of various algal species, too. From the results obtained, it is concluded that the inactivation capacity of sea water depends, to a considerable degree, on the availability of nutritive organic matter, the concentration of which changes according to phytoplankton development. Strain-specific differences in resistance to inimical action of sea water are, in part, correlated with the ability of test cells to use, and to compete with, marine bacteria for nutrients from the sea. A somewhat modified interpretation of antibacterial activity of sea water is presented.     

Interactions of 233Pa with tissues of Mytilus galloprovincialis and Carcinus mediterraneus

Uptake of ²³³Pa from sea water by mussels Mytilus galloprovincialis L. and shore crabs Carcinus mediterraneus Csrn. was studied. Results indicate a high contamination factor in digestive tract, gills and skeleton of both investigated species and an increment of the contamination factor in mussel byssus. In spite of this, reproductive system, muscle and hemolymph were only negligibly contaminated. The presence of complexone EDTA in sea water has no effect on uptake of ²³³Pa in the animal tissues tested.     

Antibacterial activity of the marine blue-green alga Trichodesmium erythraeum in the gastro-intestinal contents of the sea gull Laurus brunicephalus

The gastro-intestinal contents of the sea gull Laurus brunicephalus Jerdon were found to possess antibacterial activity. This activity could be traced to heavy accumulations of the marine blue-green alga Trichodesmium erythraeum in the gut. During 1969, a bloom of T. erythraeum began in Porto Novo waters about the middle of February, and attained a peak during the second week of March. It has been reported previously by the author that antibacterial properties are exhibited by T. erythraeum maintained in laboratory cultures, as well as in water samples collected from a red tide area. It was also reported (Ramamurthy, 1970) that the gut contents in 2 pelagic fishes, Hilsa kanagurta and Rastrelliger kanagurta, collected during the same red tide bloom period, possessed antibacterial properties. During this period large numbers of these fishes were consumed by sea gulls L. brunicephalus. In view of this finding, experimental procedures were adopted to determine whether extracts of T. erythraeum occurring in the gut of the sea gulls might exhibit antibacterial activity. It was found that T. erythraeum collected from the gut of L. brunicephalus could inhibit both gram positive and gram negative bacteria. Gastro-intestinal extracts from L. brunicephalus collected during the non-bloom period of T. erythraeum showed heavy microbial growth of bacteria and fungi. Evidently, antibacterial or sterile conditions prevail in the gut of these tropical sea gulls in a manner similar to that observed in Polar penguins by Sieburth (1959, 1961).     

The influence of storage on antibacterial activity of sea water. I. Experiments with sea water stored at 18°C

Three sea-water samples of about 25 l each, stored at 18°C in the dark, were examined for antibacterial activity and bacterial content. Serratia marinorubra mainly was used as test bacterium. During storage for 197 to 454 days, bactericidal capacity varied considerably. In raw sea water, extreme log (N ₃–N ₀) values (N: number of colony-forming test bacteria/ml after 0 and 3 days of any test) were higher than-1 and lower than-4. Antibacterial activity of filtersterilized and autoclaved, stored, sea water likewise varied, but to a lesser degree. The number of colony-forming marine bacteria fluctuated about 3 orders of magnitude. Variations in bacterial content and in bactericidal action of stored sea water were positively correlated during the first months of storage; later, this correlation became negative. From these results it is concluded that variations in nutrient concentration — due to successive periods of growth and autolysis of marine bacteria — were the primary reason for the changes observed in antibacterial activity of stored sea-water samples.     

Microbial transformation of metazoan (Idotea granulosa) faeces

Freshly collected faecal pellets of the common intertidal isopodIdotea granulosa Rathke, 1843, were exposed to natural communities of bacteria + protozoa, and bacteria + protozoa + metazoa for 16 d in running North Sea nearshore water during September 1989. All treatments showed quite identical changes in chlorophylla, phaeopigments, carbon (C) to nitrogen (N) ratio, heterotrophic bacteria and protozoa. Plant pigment, C and N content of faeces decreased by about half in 94 h. Interestingly, although the C/N ratio changed considerably during the study, the values at the end of 16 d were similar to ones at the beginning, suggesting that the C/N value per se of particles in the sea may not reflect their age or nutritive value to consumers. Further, dry weight of pellets which remained unchanged in appearance, decreased by half in 4 d and by two thirds in 16 d, indicating loss of substance but not bulk. The development and abundance of free bacteria in the water closely matched that in pellets, supporting the idea that faeces export bacteria or stimulate bacterial growth in the water through release of dissolved nutrients. There were 10³ times more bacteria on faeces than free in the water of the same volume. However, given the relative volumes of the pellet (ca 0.1 mm³) and the free water in the microcosms (ca 10⁷ × pellet volume), the degradation of faecal matter may support the production of the bulk of free-living bacteria in water. When organisms of larger sizes were allowed access to the pellets, several metazoans (e.g. nematodes ca 4 per pellet) were observed, but did not significantly accelerate faeces degradation. It appears that the combined activities of microbes (bacteria and protozoa) is mostly responsible for the rapid transformation ofI. granulosa faeces containing fucoid macroalgal tissue in the nearshore ecosystem.Contribution No. 308 from the Alfred-Wegener Institut, BremerhavenPlease address all correspondence and requests for reprints to Dr Biddanda at the Alfred-Wegener Institut, Bremerhaven     

Fertilization and early developmental stages of eggs of Clupea harengus pallasi n. maris-albi under fresh-water conditions

Eggs of the White Sea herring Clupea harengus pallasi Val. are laid in the intertidal zone, where they are liable to come under the influence of fresh water. The present paper deals with the effect of fresh-water influence on the egg of the White Sea herring, under experimental conditions. In fresh water, egg and sperm are in an unactivated state and, after transfer into sea water, are capable of re-activation, even after 212/ h exposure. The treated eggs develop until the hatching of normal and viable larvae. The number of eggs which are able to complete development depends upon the period of freshwater exposure, although the correlation between the length of that period and survival rates is not very close. Apparently, this is due both to the ability of C. harengus pallasi eggs to develop parthenogenetically and different qualities of eggs (which were obtained from different females). The morphological features of White Sea herring eggs, induced by experimental fresh-water influence, are very similar to those typical for herring eggs of the genus Ilisha, obtained from natural brackish waters. However, such changes are not characteristic of the eggs of forms from natural fresh and brackish-waters.     

Biological production of nitrite in seawater

The relative importance of 3 different sources for biological production of nitrite in seawater was studied. Decomposition of fecal pellets of the copepod Calanus helgolandicus (at a concentration of approximately 12 g-at N/l), in seawater medium, released small amounts of ammonia over a 6 week period. It nitrifying bacteria were added to the fecal pellets nitrite was barely detectable over the same period. Decomposition of phytoplankton (present at a concentration of about 8 g-at particulate plant N/l) with added heterotrophic bacteria, released moderate amounts of ammonia over a 12 week period. If the ammonia-oxidizing bacterium Nitrosocystis oceanus was added to the decomposing algae, nitrite was produced at a rate of 0.2 g-at N/l/week. Heterotrophic nitrification was not observed when 7 open-ocean bacteria were tested for their ability to oxidize ammonia. The diatom Skeletonema costatum, either non-starved or starved of nitrogen, produced nitrite when growing with 150 or 50 g-at NO ₂ ^- -N/l at a light intensity of about 0.01 ly/min. When nitrate in the medium was exhausted, S. costatum assimilated nitrite. If starved of vitamin B₁₂, both non-N-starved and N-starved cells of S. costatum produced nitrite in the medium with 150 g-at NO ₃ ^- -N/l. Nitrate was not exhausted and cell densities reached 2x10⁵/ml due to vitamin B₁₂ deficiency. If light intensity was reduced to 0.003 ly/min under otherwise similar conditions, cells did not grow due to insufficient light, and nitrite was not produced. In the sea, it appears that, in certain micro-environments, decomposition of particulate matter releases ammonia with its subsequent oxidation to nitrite. The amounts of these nutrients and the rate at which they are produced are dependent upon the nature of the materials undergoing decomposition and the associated bacteria. In certain other areas of the sea, where phytoplankton standing stock is high and nitrate is non-limiting, excretion by these organisms is a major source of nitrite.     

Induction of metamorphosis of two species of sea urchin from Sea of Japan

The induction of metamorphosis in mature larvae by selected chemical compounds and natural substrata was investigated in two species of sea urchins from the Sea of Japan, Strongylocentrotus intermedius and Scaphechinus mirabilis. Glutamine in crystalline form was added directly to water containing mature larvae, and this compound, at a final concentration of 10 g ml^-1, was an inducer of metamorphosis in S. intermedius (100% activity) and S. mirabilis (50% activity). Gutamine, or its natural mimetic molecules, may be an active component of the exogenous cue that induces metamorphosis of S. intermedius larvae. This exogenous cue was produced by the epiphytic calcareous algae, Melobesia spp. that colonized the older sea grass Zostera marina. Glutamic acid was also used as an inducer of metamorphosis for S. intermedius and S. mirabilis larvae (50 to 60% activity), but it was toxic to the larvae.     

Comparative study of vanadium biokinetics in three species of echinoderms

Vanadium-48 (as vanadate) was used to study the uptake, tissue distribution, depuration and food-chain transfer of vanadium through 3 species of echinoderms: the seastar Marthasterias glacialis L., the sea urchin Paracentrotus lividus Lmk. and the holothurian Holothuria forskali D.Ch.; all were collected from the littoral zone near Monaco. Uptake by all species was relativelyslow; after 3 wk exposure, isotopic equilibrium had not been reached and whole-body concentration factors ranged from 5 and 7 in the holothurian and sea urchin, respectively, to 18 in the seastar. Sixty-three to 77% of the incorporated radiotracer was associated with the body wall or test, suggesting surface sorption as the principal mechanism governing uptake from water. Stable vanadium measurements confirmed the preponderance of this element in the external hard parts of the echinoderms; however, concentration factors based on stable vanadium levels were significantly higher than those measured experimentally. Subsequent vanadium depuration rates were also species-dependent, with biological half-times for loss ranging from approximately 50 d in the sea urchin and holothurian to 123 d in the seastar. Food-chain transfer experiments indicated that seastars can assimilate and retain a large fraction of the vanadium ingested with food whereas sea urchins appear to lack this capability. The relative importance of the water and food input pathway in achieving vanadium levels in echinoderms is discussed in light of results of ⁴⁸V distribution in experimental individuals and stable vanadium distribution in samples from the natural environment.     

不同补给水源的城市人工湖中异养菌耐药性及耐药菌种属分布研究

为了阐明不同补给水源的城市人工湖中异养菌耐药状况和耐药菌种属分布特征,选取分别以地表水和再生水为补水来源的XQ湖和FQ湖为代表进行研究。从2018年4—11月逐月采集水样,考察了各水样中对氨苄西林(AMP)、磺胺甲恶唑(SMZ)和四环素(TET)这3种不同种类抗生素具有耐药性的异养菌含量,并对分离菌株的耐药表型、耐药菌株的种属分布以及水质理化指标进行了分析。结果表明,2处人工湖中的AMP耐药菌和SMZ耐药菌含量约为10~2～10~4CFU·(100 m L)~(-1),而TET耐药菌含量则约10~1～10~3CFU·(100 m L)~(-1)。分离出的84株耐药菌归属于19个种,其中蜡状芽孢杆菌、大肠埃希氏菌、维氏气单胞菌、豚鼠气单胞菌和鸟氨酸拉乌尔菌为2个湖共有耐药菌。71.4%的耐药菌都是对AMP单一耐药,以蜡状芽孢杆菌为主。由于具有固有耐药性的细菌在分离出的耐药菌中占比很低,获得性耐药很可能在城市人工湖中异养菌耐药性的发展上发挥了主要贡献作用。地表水补水的XQ湖和再生水补水的FQ湖在总异养菌含量、耐药菌含量和检出率上均无显著差异。分离来源对16株耐药性气单胞菌的聚类无明显影响。     

Natural chelators — an indication of activity with the calanoid copepod Euchaeta japonica

Survival of Euchaeta japonica Marukawa prefeeding stages in natural seawater is increased by the addition of a synthetic chelating agent. This increase occurs periodically in inshore waters and more frequently in near-oceanic water. The periodicity is associated with changes in chelator-like characteristics of the seawater. Changes in these characteristics are associated with changes in biological activity in the water.     

The water economy of the sea grass Thalassia testudinum

The osmotic values in the leaves of Thalassia testudinum Banks ex König, collected from the natural habitat, were found to be 32 atm; the relative transpiration was 100%. Electronmicroscopical analysis of the cuticle reveals many perforations. The critical sublethal water deficit lies near 65%. In dense meadows the green surface area of the plants amounts to 18.56 m²/m² bottom area.     

The effect of Kuwait crude oil and a solvent emulsifier on the metabolism of the marine lichen Lichina pygmaea

As lichens are sensitive monitors of environmental pollution and are known to be affected by marine pollutants, a study was made of the effect of Kuwait crude oil and a solvent emulsifier (BP 1002) on the metabolism of the marine lichen Lichina pygmaea (Lightf.) C. Ag. Photosynthesis in the presence of NaH¹⁴CO₃ enabled an investigation to be made of the effect of these pollutants on the total ¹⁴C-fixation and the pattern of ¹⁴C-fixation. Oil was shown to be substantially less inhibitory than the emulsifier to the total ¹⁴C fixed. The emulsifier, but not the oil, induced loss of labelled material from the lichen. No change was observed in the influence of oil or undiluted emulsifier after ageing. Combination of the emulsifier with either oil or sea water resulted in a decreased inhibitory effect, which was further reduced on ageing the mixture. It was concluded that the inhibitory component of the emulsifier was the surfactant and not the solvent.     

Demonstration,using Desulfobacter sp., of two pools of acetate with different biological availabilities in marine pore water

Desulfobacter sp. (Strain 3ac10), an acetate-utilizing sulphatereducing bacteria, was added to sterile marine pore water spiked with ¹⁴C-acetate, and changes in both the natural acetate pool and the added ¹⁴C-acetate were measured over time. Initially, both the added ¹⁴C-acetate and the chemically measured acetate were rapidly mineralized, but then the rate of removal decreased and a significant amount (approximately 20%) of both ¹⁴C-acetate and chemically measured acetate remained unmetabolised. In a replicate experiment, approximately 50% of the acetate was not metabolised. Kinetic analysis of the data indicated that there were two pools of acetate in the original pore water, a biologically available pool (which is rapidly metabolised) and a recalcitrant pool (which is only very slowly metabolised). Addition of ¹⁴C-acetate after the biologically available acetate had been removed resulted in rapid removal of the added acetate but no change in the recalcitrant acetate pool. The implications of this data to radiolabelled techniques of measuring in situ acetate turnover are discussed.     

Impact of conditions of cultivation and adsorption on antimicrobial activity of marine bacteria

The potency of free-living and animal-associated marine bacteria to produce antimicrobial substances has been studied in 491 strains isolated from northern and southern parts of the Pacific Ocean. A total of 26% (126 out of 491) of the strains examined produced antimicrobial compounds against 11 test bacterial strains (TBS) including the fish pathogens Aeromonas hydrophila and Vibrio anquillarum. Antimicrobial substances (AS) produced by marine bacteria were especially active against Staphylococcus epidermidis, Proteus vulgaris, Enterococcus faecalis, and Candida albicans. Twelve strains, isolated from different sources, were chosen as promising candidates, producing a number of AS. Production of AS varied within 24 to 72 h, increasing in a culture medium based on natural sea water with Br-ions, and after attachment to polymeric surfaces. In order to study the influence of adsorption, selected strains with a high potential for antimicrobial production were cultivated on polymeric surfaces with different hydrophobicities and chemical functionalities. These parameters of the surface hydrophobicity (measured by means of water contact angles) and chemical functionality of the surfaces were manipulated using the photo- and thermochemistry of a polymeric system (diazo-naphto-quinone/novolak) commonly used as a photoresistant material in semiconducto-manufacturing. The highest antimicrobial activities occurred on hydrophilic surfaces (standard exposed photoresistant films), whereas the number of attached cells was greater on hydrophobic surfaces, characterized as unexposed resistant films. These results suggest that the chemical nature of induced hydrophilicity may also be a major factor in controlling antimicrobial activity of adsorbed bacteria. Received: 5 March 1997 / Accepted: 24 August 1997     

Expansive covers of turf-forming algae on human-dominated coast: the relative effects of increasing nutrient and sediment loads

Turf-forming algae form more extensive habitat on subtidal rock adjacent to urban than non-urban coast of South Australia. This pattern is frequently observed on the worlds temperate coasts and is variously considered to be a result of enhanced concentration of nutrients or rates of sediment deposition on urban coasts. We experimentally tested which of three components of environmental change (increased nutrients in water, increased nutrients in sediments and increased sediment deposition) best explain the expansive covers of turf-forming algae on urban coasts. All three treatments had independent and positive effects on the percentage cover of turf-forming algae. The addition of nutrients from the water column had the largest influence (²=0.55), which was more than six times greater than the effect of nutrients added to sediments (²=0.08). An increase in rate of deposition of sediments had substantial effects (²=0.35), which were about one third less than those of water-borne nutrients. Importantly, the combined effect of all three treatments caused a 77% increase in percentage cover of turf-forming algae, which is comparable to the observed difference in covers between urban and non-urban coast in South Australia (93%). These results suggest that human activities that reduce water quality in both nutrient and sediment loads account for major change observed on human-dominated coasts. Despite this knowledge, we still lack complete information on the mechanisms that switch the primary subtidal habitat from canopy-forming algae to turf-forming algae on human-dominated coasts.Communicated by M.S. Johnson, Crawley     

南方某铀矿山废水对生物的急性毒性研究

为探明铀矿山对周围环境的联合毒性机制,本研究以常用生物毒性测试菌种——发光细菌青海弧菌Q67和费氏弧菌以及禾花鲤为受试生物代表,实地采集的铀矿山废水为目标废水,研究铀矿山废水对发光细菌和禾花鲤的急性毒性。实验结果表明,矿山废水对3种生物的急性毒性存在显著的剂量-效应关系,毒性效应浓度EC_(50)(LC50)的大小顺序为禾花鲤幼鱼费氏弧菌青海弧菌Q67,Pb~(2+)/U~(6+)浓度分别为6.052/3.026 mg·L~(-1)、2.284/1.142 mg·L~(-1)、1.339/0.669 mg·L~(-1),均可有效指示矿山废水的毒性水平,其中发光细菌更为灵敏、快速;且青海弧菌Q67的EC_(50)值最小,灵敏度最高,可作为表征矿山废水毒性风险的首选指示物。研究结果能够为放射性矿区废水生态风险预警、安全处理处置、水质基准制定及流域水环境管理提供依据。     

Photosynthesis and ion loss in the brown algae Dictyopteris membranacea and Fucus virsoides

The sublittoral brown alga Dictyopteris membranacea (Stackhouse) Batters is very sensitive to low salinities. A one minute exposure to distilled water causes total breakdown of photosynthesis and respiration. The breakdown phenomena were studied as after-effects following re-exposure to sea water. Since rate of ion loss is highest during the first minute of osmotic stress, the irreversible metabolic depression appears to be due to fast ion loss. Photosynthesis of Fucus virsoides J.Ag is not affected by distilled water, even over very long periods of time.     

Eutrophication Phenomenon with Special Reference to the Kasštela Bay

Abstract

The paper discusses the eutrophication phenomenon as a result of pollution from land-based sources with special reference to the experience gained in the Kas?tela Bay Project.

The Bay of Kas?tela is a semi-enclosed bay of a total volume of 1.4 km³. It receives a great amount of untreated waste water, both domestic and industrial.

Results of the analyses of long-term data series of dissolved oxygen, nutrients, transparency and phytoplankton have shown a continuous increase of eutrophication in the Bay. While the concentration of oxygen in the euphotic layer increases due to a higher phytoplankton productivity, in the bottom layer it decreases as a result of the activity of heterotrophic bacteria. the nitrogen/phosphorus ratio in sea water has decreased, and today is much lower than in the open sea. From the Secchi-disc data it is clear that transparency has also decreased for the last three decades. Primary production as well as phytoplankton biomass has also increased. the structure of phytoplankton community has been changed and dinoflagellate species have become dominant rather than diatoms.     

Acute toxicity of industrial endocrine-disrupting chemicals,natural and synthetic sex hormones to the freshwater planarian,Dugesia japonica

Many chemicals commonly occurring in surface water are found to be hormonally active. Fourteen compounds including four sex hormones, three synthetic hormones, one non-steroidal anti-androgen, and six industrial endocrine-disrupting chemicals were selected to examine their acute toxicities on the freshwater planarian, Dugesia japonica. Among all test chemicals, diethylstilbestrol had the highest toxicity. Relatively, the toxicities of the synthetic hormones were higher than the natural ones. Among the six industrial endocrine-disrupting chemicals tested, bisphenol A was the most toxic, with a 48-h LC₅₀ of 8.3 mg L^?1. Overall, the natural or synthetic hormones, other than estrone and estriol, were more acutely toxic to planarians than the industrial endocrine disruptors tested. The acute toxicities of the test chemicals to Dugesia japonica were in the same order of magnitude as those to Daphnia magna based on available published data. Despite this study used non-environmentally relevant levels, such kinds of chemicals do not exist singly in the aquatic environment, but typically act in synergistic and/or additive ways in the complex environmental mixtures, and the total estrogen equivalents are much higher than a single chemical. This study stands as a starting point for other acute and chronic assays, namely using mixtures.