Bacteriolytic Bacillus species isolated from brackish waters of the Southern Baltic Sea

The present study examines antagonistic relationships between different microorganisms inhabiting brackish water and includes a systematic screening for bacteriolytic prokaryotes in the brackish waters of the Southern Baltic Sea (Nordruegenscher Bodden) sampled in July/August 2009. Ten of the 35 marine bacteriolytic isolates belong to the genus Bacillus. Five isolates (B. pumilus, B. subtilis, B. megaterium, B. licheniformis) lysed living microbial cells such as the bacteria Arthrobacter citreus, Arthrobacter protophormiae, Micrococcus luteus, Pseudomonas putida and the yeast Trichosporon mucoides. These and other bacteria (Aeromonas sp., Bacillus subtilis, Chromobacterium violaceum, Citrobacter freundii, Enterobacter aerogenes, Proteus mirabilis, Pseudomonas aeruginosa and Serratia marcescens) were also lysed as autoclaved and pasteurized cells on agar plates. One isolate of Bacillus pumilus showed a distinct bacteriolysis activity against pasteurized cells of A. citreus in liquid culture. Our results suggest that Bacillus species may play a role as opportunistic predators in the marine microbial food web.     

Occurrence and biological role of light-induced chromatophore displacements in seaweeds

The occurrence of light-induced chromatophore displacements and concomitant transmittance changes in marine algae was investigated by microscope and photometrically with an automated recording microphotometer system; 16 brown, 6 green and 20 red algae were studied. In most of the brown algae, both phaeoplast displacements and transmittance changes were found. In some red algae which are frequently exposed to direct sun light during emergence at low tide, light-induced transmittance changes were measured, but they could not unequivocally be correlated with changes in the position of rhodoplasts. Among green algae, only Ulva lactuca shows chloroplast displacements which, however, follow circadian rhythms and are consequently not light-induced in the strict sense. The dose-response curves of light-induced chromatophore displacements were measured in the following Fucus and Laminaria species: F. spiralis, F. vesiculosus, F. serratus, L. digitata, L. saccharina and L. hyperborea. While in Fucus species correlations between light-induced transmittance changes and zonation of the intertidal area seem to exist, no significant differences have been found in the Laminaria species. The physiological role and ecological importance of light-induced chromatophore displacements for seaweeds living in the intertidal belt are discussed.     

Arctic-Antarctic disjunctions in the benthic seaweeds Acrosiphonia arcta (Chlorophyta) and Desmarestia viridis/willii (Phaeophyta) are of recent origin

Two examples of the most extreme biogeographic disjunctions in benthic marine algae are found in Acrosiphonia arcta (Chlorophyta) and Desmarestia viridis/willii (Phaeophyta). Both species are members of the Arctic and Antarctic boreal and subboreal marine floras. Although both genera have temperate species, neither genus has subtropical or tropical representative. Comparisons of the fast-evolving ribosomal DNA internal transcribed spacer regions among isolates in each of the two species collected from both hemispheres showed an unexpected near sequence identity suggesting that these biogeographic disjunctions are of recent origin, possibly as recent as the last Pleistocene glacial maximum (18000 yr ago). Paleoclimatic explanations that rely on a much earlier transequatorial passage of cold-adapted species through a narrowed and cooler tropical belt during the Oligocene/Miocene (38 to 7 Ma ago) are unlikely. We hypothesize that despite the separated evolutionary histories of the northern and southern hemisphere coldwater marine floras, deep-water dispersal of microthalli has occurred and probably occurs on a regular basis.     

Nutritional quality of macrophytes eaten and not eaten by two temperatezone herbivorous fishes: A multivariate comparison

The mean annual chemical compositions (ash, lipid, carbohydrate, protein, nitrogen and carbon) of 23 species of macrophytes (22 seaweeds and 1 seagrass) from a rocky intertidal habitat on the central California coast were determined from December 1981 through December 1982. These data were used to test the hypothesis that the 13 red and green seaweeds eaten by the two principal herbivorous fishes (Cebidichthys violaceus andXiphister mucosus) at the site are higher in nutritional quality than the 9 red and brown seaweeds and the seagrass not consumed by these fishes. A MANOVA using the ash, lipid, carbohydrate and nitrogen data showed that the centroids of the dietary and nondietary species groups were significantly different. In a two-group discriminant analysis that followed, only two species were misclassified as members of the opposite group. Multigroup discriminant analysis of the 23 macrophytes resulted in some overlap among dietary and nondietary species. Species were discriminated on the first canonical axis by ash content and on the second and third axes by lipid and carbohydrate contents. Nitrogen contributed little to the overall discrimination of species in the analysis. The nondietary red algaCorallina vancouveriensis, with its high ash content and therefore relatively low nutritional quality, was clearly separated from all other species in the analysis. Brown algae were of higher nutritional quality, but are not eaten by the two fishes, possibly because these seaweeds produce indigestible carbohydrates and secondary compounds. However, the exclusion from the diets of several red algal species that were virtually indistinguishable from the dietary red algae remains unexplained.Contribution No. 64 from the Ocean Studies InstitutePlease address all correspondence and requests for reprints to Dr. Horn at Fullerton     

Yeasts from the North Sea

Yeasts were isolated from twelve established sites in the North Sea from 1964 to 1966. A percentage frequency of 99% with populations varying from <10 to >3000 viable cells/L was observed. This mycota was characterized by considerable spatial and temporal fluctuation, with the dominant yeast present being the ascosporogenous species, Debaryomyces hansenii. This taxon, as well as other common North Sea yeasts, e.g., Rhodotorula rubra and Candida diddensii, have been reported frequently from other marine locales. Noteworthy concentrations of yeasts, especially D. hansenii, were observed during summer months, often in association with various stages of development of the dinoflagellate, Noctiluca miliaris. The population dynamics of the North Sea yeasts are discussed in relation to similar studies of other marine environments.     

Etude des bactéries associées aux Algues marines en culture

Some bacteria strains have been isolated from marine algae cultures and assigned tentative genera and species. Observations and tests were conducted using Bergey's manual and specific papers on marine bacteria as taxonomic keys. The genera Pseudomonas, Flavobacterium and Achromobacter appear to be the most important, as far as the number of species is concerned.     

Growth response of an early successional assemblage of coralline algae and benthic diatoms to ocean acidification

The sustained absorption of anthropogenically released atmospheric CO₂ by the oceans is modifying seawater carbonate chemistry, a process termed ocean acidification (OA). By the year 2100, the worst case scenario is a decline in the average oceanic surface seawater pH by 0.3 units to 7.75. The changing seawater carbonate chemistry is predicted to negatively affect many marine species, particularly calcifying organisms such as coralline algae, while species such as diatoms and fleshy seaweed are predicted to be little affected or may even benefit from OA. It has been hypothesized in previous work that the direct negative effects imposed on coralline algae, and the direct positive effects on fleshy seaweeds and diatoms under a future high CO₂ ocean could result in a reduced ability of corallines to compete with diatoms and fleshy seaweed for space in the future. In a 6-week laboratory experiment, we examined the effect of pH 7.60 (pH predicted to occur due to ocean acidification just beyond the year 2100) compared to pH 8.05 (present day) on the lateral growth rates of an early successional, cold-temperate species assemblage dominated by crustose coralline algae and benthic diatoms. Crustose coralline algae and benthic diatoms maintained positive growth rates in both pH treatments. The growth rates of coralline algae were three times lower at pH 7.60, and a non-significant decline in diatom growth meant that proportions of the two functional groups remained similar over the course of the experiment. Our results do not support our hypothesis that benthic diatoms will outcompete crustose coralline algae under future pH conditions. However, while crustose coralline algae were able to maintain their presence in this benthic rocky reef species assemblage, the reduced growth rates suggest that they will be less capable of recolonizing after disturbance events, which could result in reduced coralline cover under OA conditions.     

Chemical composition of dietary species of marine unicellular algae and rotifers with emphasis on fatty acids

The lipid profiles of a few species of marine unicellular algae and yeast were studied with emphasis on fatty acids as part of a search for the nutritional value of plankton to the diet of marine fish larvae commonly used in marine hatcheries. The general proximate chemistry of rotifers was closely related to the proximate chemistry of the diet organism, exhibiting a higher content of protein and carbohydrate and a lower content of lipid. Major lipids in all algae, yeast and rotifers comprised mono-, di- and tri-glycerides and polar lipids. The algae Chaetoceros gracilis Schutt, Isochrysis galbana Parke and their respective algaefed rotifers exhibited higher amounts of neutral lipids, consisting mainly of cyclic and branched polyunsaturated components. Fatty acid composition of the algae was species-specific, with the highest ratio of polyethylenic to saturated and monoethylenic acid in I. galbana and Phaeodactylum tricornutum Bohlin, and the highest content (15%) of n-3 highly unsaturated fatty acids in Nannochloropsis salina and P. tricornutum. A closely mirrored distribution of the fatty acids, but with a lower amount of n-3 highly unsaturated fatty acids, was present in the respective algae-fed rotifers. Comparison of the fatty acid spectrum of Artemia sp. and Euterpina acutifrons grown in the laboratory on I. galbana with zooplankton samples of E. acutifrons and Oitona nana collected from the sea showed a higher concentration of docosahexaenoic acid (22:6 n-3) in the naturally collected sample. The results indicate that the efficacy of the food algae C. gracilis and I. galbana in increasing the survival of fish larvae in marine hatcheries is not obvious on the sole basis of fatty acid composition.     

Descriptive ecology of offshore,deep-water,benthic algae in the temperate western North Atlantic Ocean

The vertical distribution, floristic composition and habitat ecology of sublittoral, benthic algae are described for two deep water, offshore stations in the Gulf of Maine, based on in situ observations and collections to 47 m depth during SCUBA and submarine dives. Twenty species of macroscopic algae were collected between 29 and 45 m. These occurred in two benthic algal associations: a Ptilota serrata association of fleshy, almost exclusively red algae from 29 to 37 m; and a deeper Lithothamnium glaciale association dominated by encrusting corallines and extended from ca 38 m to the lowest limit of macroscopic vegetation at 44 to 45 m. Below 45 m only endozoic and epizoic diatoms associated with sponges were observed. Owing to the seasonal stability, homogeneous composition and clear extinction depths of the two associations, we propose that the extinction depth of benthic seaweeds may provide a useful bioassay for making temporal comparison of water conditions at a single geographic region and, where substrata are similar, spatially among different geographic regions. Data obtained during the Jeffreys Ledge study are discussed in relation to this hypothesis.     

Herbivory in the gammarid amphipod Aora typica: relationships between consumption rates, performance and abundance across ten seaweed species

This paper reveals a substantial capacity for herbivory of seaweeds in the gammarid amphipod Aora typica, adults eating seven of ten taxonomically and morphologically diverse seaweed species offered to them in a no-choice assay. The green algae Ulva spathulata and Enteromorpha intestinalis were consumed at the highest rates in both no-choice (2.3–2.5 mg blotted weight individual⁻¹ day⁻¹) and multiple-choice assays (0.5–1.3 mg blotted weight individual⁻¹ day⁻¹). Adult A. typica collected from two different species of brown seaweeds had very similar feeding preferences to each other. Juvenile A. typica grew to reproductive maturity on the green algae E. intestinalis and U. spathulata, and the brown algae Carpophyllum maschalocarpum and Ecklonia radiata. In common with previous studies on members of other amphipod families, survivorship of juvenile amphipods was positively correlated with feeding preferences of adults across seaweed species (r ²=0.43, P=0.04). However, densities of A. typica on seaweeds in the field (excluding the intertidal E. intestinalis and U. spathulata) were not significantly correlated with feeding preferences of adults (r ²=0.07, P=0.5) or survivorship of juveniles (r ²=0.17, P=0.31). This suggests that either host seaweeds are not a major dietary component of these amphipods in nature, or that the host’s value as a food source is overridden by other properties such as the degree of shelter it affords from larger consumers. This study provides the first demonstration that a member of the cosmopolitan amphipod family Aoridae is capable of consuming a diverse range of seaweeds.     

Kinetic evidence for common photosynthetic step in diverse seaweeds

The turnover time of photosynthetic oxygen production was the same, near 0.5 msec, for the seaweeds Ulva lactuca, Codium fragile, Porphyryaumbilicalis, Chondrus crispus, Champia parvula and Fucus vesiculosis. This turnover time did not change for sun- and shade-adapted U. lactuca and P. umbilicalis. The similarity of these turnover times to those of other algae, higher plants, and cyanobacteria is strong evidence for similarity in the kinetics, and thus for a universal mechanism of photosynthesis. Evolution in the light-gathering apparatus responsible for the color of seaweeds has occurred without variation in the mechanism of photosynthesis. The size of the Emerson-Arnold photosynthetic unit (the ratio of chlorophyll to oxygen formed in a single tumover light flash) in the green seaweeds is about the same as that in algae, i.e., 2000. It is about half this number for the red and brown seaweeds. The different accessory pigments in the latter two groups compensate for the smaller amount of chlorophyll. The size of the unit was independent of sun- and shade-adaptation in U. lactuca, but did increase in shade-adapted P. umbilicalis.     

Atypical plant–herbivore association of algal food and a kleptoplastic sea slug (Elysia clarki) revealed by DNA barcoding and field surveys

The identity of food sources and feeding preferences of specialist herbivores have been commonly inferred from spatial associations between consumer and food items. However, such basic information for well-known marine herbivores, sacoglossans (sea slugs), and their algal diets remains disappointingly lacking, especially from field studies. The sacoglossan, Elysia clarki (Pierce et al. in Molluscan Res 26:23–38, 2006), is kleptoplastic and sequesters chloroplasts from algal food to photosynthesize, so DNA identification of sequestered chloroplasts was employed to verify the algal species fed upon by the slug across its geographic range. The molecular information on the algae consumed by E. clarki was combined with field surveys of slugs and algae in slug habitats in the Florida Keys in July and August of 2008 in order to evaluate whether the diet of this herbivore could be predicted based on its spatial association with algae in the field. A considerable mismatch between food availability and kleptoplast identity was recorded. E. clarki commonly occupied areas devoid of potential food and often contained symbiotic plastids from algal species different from those most frequently found in the surveyed habitats. In three of the four study sites, algal species present were poor predictors of slug diet. These findings suggest that the photosynthetic capability of E. clarki may release the slug from the constraint of requiring proximity to its food sources and may allow for the potential lack of spatial coupling between this herbivore and its algal food. This combination of field surveys and DNA barcoding provided critical and previously unavailable information on herbivore feeding in this marine system.     

Changes in photosynthetic pigment concentration in seaweeds as a function of water depth

We conducted a study of the relationship between changes in photosynthetic pigment content and water depth in Great Harbor near Woods Hole, Massachusetts, USA, on the green algae Ulva lactuca and Codium fragile and the red algae Porphyra umbilicalis and Chondrus crispus. A calibrated underwater photometer equipped with spectral band filters measured light attenuation by the water column. The depth required for a 10-fold diminution of photon flux was 3.6, 5.3, 6.0 and 6.0 m for red, blue, yellow and green light, respectively. Seaweeds were attached to vertically buoyed lines and left to adapt for 7 days; then, with their positions reversed, they were allowed to readapt for 7 days. All species showed greater photosynthetic pigment content with increased depth. Further, the ratio of phycobiliproteins and chlorophyll b to chlorophyll a increased with depth. Changes in pigment content were reversible and occurred in the absence of cell division. There was a net loss of pigments near the surface (high irradiance), and subsequent synthesis when seaweeds were transferred to a position deep in the water column (low irradiance). In contrast, seaweeds which were found in intertidal habitats changed only their pigment concentration, and not pigment ratio, a phenomena analogous to higher plant sun and shade adaptation. Therefore, seaweeds modify their photon-gathering photosynthetic antennae to ambient light fields in the water column by both intensity adaptation and complementary chromatic adaptation.     

三种海藻凝集素细胞凝集活性的比较

比较了3种经纯化的海藻凝集素即铁钉菜凝集素（IOL），鹿角沙菜凝集素（HCL0和脆江蓠凝集素（GBL）对红细胞，微藻，细菌，酵母及肿瘤细胞的凝集活性，IOL对供试的动物红细胞均有凝集作用，而HCL和GBL只对部分红细胞产生凝集作用，3种凝集素都不能凝集人的A，O，B型血红细胞。在12种供试的微藻中，有6种单细胞藻类分别被海藻凝集素所凝集，海洋微藻比淡水微藻敏感，盐生杜氏藻均可被3种海藻凝集素所凝集，3种海藻凝集素都能凝集枯草杆菌，但不能凝集胃癌细胞，3种凝集素中，IOL对细胞的凝集作用最好，表3参13     

Culturable actinobacteria isolated from marine sponge <Emphasis Type="Italic">Iotrochota</Emphasis> sp.

The study describes the diversity of actinobacteria isolated from the marine sponge Iotrochota sp. collected in the South China Sea. Species and natural product diversity of isolates were analyzed, including screening for genes encoding polyketide synthases (PKS) and nonribosomal peptide synthetase (NRPS), and 16S rRNA gene restriction fragment length polymorphism (RFLP). PKS and NRPS sequences were detected in more than half of the isolates and the different “PKS-I–PKS-II–NRPS” combinations in different isolates belonging to the same species indicated a potential natural product diversity and divergent genetic evolution. The phylogenetic analysis based on 16S rRNA gene sequencing showed that the isolates belonged to genera Streptomyces, Cellulosimicrobium, and Nocardiopsis. The majority of the strains tested belonged to the genus Streptomyces and one of them may be a new species. To our knowledge, this is the first report of a bacterium classified as Cellulosimicrobium sp. isolated from a marine sponge. Key Laboratory of Marine Bio-recourses Sustainable Utilization (LMB-CAS), Guangdong Key Laboratory of Marine Materia Medica (LMMM-GD), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, People’s Republic of China.     

Hexabathynella halophila gen. n., sp. n. und die Frage nach der marinen Abkunft der Bathynellacea (Crustacea: Malacostraca)

All species of Bathynellacea, known to occur in the immediate vicinity of the sea, belong to the same genus, Hexabathynella gen. n. The species are: H. pauliani, H. knoepffleri, H. tenera. Also included into the new genus are the fresh-water species H. hebrica, H. szidati, H. minuta. To these, a new species, H. halophila sp. n., is added; it was found at a salinity of 27‰ and is the first representative of the Bathynellacea recorded from polyhaline waters. A simple experiment revealed that the new species is likely to be extremely euryhaline. Current opinion as to the marine origin of the Bathynellacea is criticized in the light of new evidence resulting from recent studies on the evolution and systematic relationships within this order. Contrary to common belief, the Bathynellacea did not colonize the fresh-water mesopsammal via the mesopsammal of marine sandy beaches. The extant Bathynellacea most likely derived from ancestors which lived in fresh-water lakes or running surface waters. They became distributed in their mesopsammal habitat. The occurrence of some species of Hexabathynella gen. n. in oligohalime to polyhaline waters is secondary.     

Cu（Ⅱ）对海洋浮游植物生长影响的初步研究

选择赤潮异弯藻(Heterosigma akashiwo Hada)、三角褐指藻(Pheodactylum tricornutum Bohlin)、海洋原甲藻(Prorocentrum micans Ehrenber)、裸甲藻(Gymnodinim sp.)、亚心型扁藻(Platymonas subcordiforus)、旋链角毛藻(Chaetoceros curvisetus Cleve)、中肋骨条藻(Skeletonema costatum(Greville)Cleve)、青岛大扁藻(Platymonashelgolanidica)8种浮游植物,采用一次培养实验方法,研究了重金属Cu(Ⅱ)对海洋浮游植物生长的影响,并在Logistic生长模型的基础上结合Lorentz方程和GaussAmp方程,引入Cu(Ⅱ)浓度项,建立了Cu(Ⅱ)胁迫下海洋浮游植物生长动力学模型——Logistic-W模型,描述了Cu(Ⅱ)存在条件下海洋浮游植物的生长过程.结果表明,较高浓度Cu(Ⅱ)对8种浮游植物的生长普遍具有抑制作用,而较低浓度Cu(Ⅱ)则可促进旋链角毛藻、中肋骨条藻、青岛大扁藻的生长;Lorentz方程可以描述Cu(Ⅱ)浓度对浮游植物生长速率参数的影响,而GaussAmp方程可以描述Cu(Ⅱ)浓度对浮游植物生物量的影响;Cu(Ⅱ)胁迫下浮游植物的生长可用动力学方程Logistic-W描述,实验验证该模型合理,其拟合相关系数R2为0.817～0.993,平均为0.916.论文提出的生长模型可以预测不同浓度Cu(Ⅱ)胁迫下海洋浮游植物的生长情况,也可根据浮游植物的生长情况推测相应海区的Cu(Ⅱ)浓度.     

Pyrolysis mass spectrometry: a fresh approach to old problems in brown algal systematics?

Pyrolysis mass spectrometry (PyMS) has been tested on five freeze-dried cultures of ectocarpoid algae and on live tissue from three field populations of Fucus species. The technique enabled discrimination of Baltic and Irish Sea isolates of Pilayella littoralis. The results were in agreement with the view that P. littoralis and Hincksia ovata may be considered members of a single family (Ectocarpaceae) and support the location of Elachista fucicola in the Elachistaceae. Microspongium globosum was least similar to the other isolates and, on present evidence, should be located in another higher taxon (Myrionemataceae?). Baltic F. vesiculosus could be distinguished from conspecific plants from the Irish Sea, but the technique failed to separate clearly Irish Sea F. serratus and F. vesiculosus. This anomalous result is considered a probable consequence of introgression occurring at a shore level where the two species coexist. It is concluded that PyMS has considerable potential in the study of brown algal systematics.     

Nutrient enrichment of seagrass beds in a rhode island coastal lagoon

Seagrass and algal beds showed a variety of reponses when the water column was treated with low level additions of ammonium, nitrate and phosphate. The nutrients were added separately to 3 uniform seagrass beds of a temperature coastal lagoon during 1979 and 1980. (1) Ammonium caused the production of dense mats of free-floating green algae Enteromorpha plumosa and Ulva lactuca. It also stimulated growth in both the leaf and root-rhizome fractions of Zostera marina. This growth response in Z. marina was greater in the area where current reached 12 cm · s^-1 than in the area with little or no current. The concentration of nitrogen in the tissue did not change. In contrast, where current was lacking, Z. marina growth increase with ammonium was small, but the concentration of nitrogen in the tissue doubled over that in control plots. The growth of Ruppia maritima was inversely related to the growth of green algae in the same plots. The red alga Gracilaria tikvahiae did not grow better in ammonium, but its tissue reddened. (2) Nitrate additions enhanced the growth of the green seaweeds Enteromorpha spp. and U. lactuca, but not Z. marina or R. maritima. G. tikvahiae, when fertilized in isolation from other plants, showed a marginal response to this nutrient, and the tissue always reddened. (3) Phosphate enhanced growth in Z. marina and R. maritima exposed to moderate current. G. tikvahiae growing alone showed a small growth response to phosphate. The phosphate made no difference in the growth of the green seaweeds. (4) None of the nutrient supplements noticeably altered the species composition of either epiphytic or planktonic algae associated with the beds, although we did detect small increases in their numbers. The rapid and dense growth of green algae in nitrogen-enriched water probably limited growth of adjacent seagrasses and red algae. Because these seaweeds did not use the phosphate, it became available to other plant components. The overall floral response to nutrient addition in seagrass communities depends, therefore, upon the particular nutrient supplied, the ability of alternate species in the area to compete for that nutrient and the velocity of current in the specific area.