Green algal phylogeny

Studies on the fine structure of green algal cells in the 1970s fundamentally revised theories on the evolution of green algae (Division Chlorophyta) and their relation to higher and drier green plants (i.e. embryophytes or land plants). Recent molecular phylogenetic work has largely confirmed some rather unorthodox proposals about which of the green algae represent the closest living relatives of higher plants. Resolution of the most ancient divergences on the green algal-land plant lineage remains elusive because of the rapidity of these evolutionary radiations and because branch topology varies with the taxa and molecular sequences sampled (as well as method of analysis). Molecular analyses within green algal groups have reinforced the value of ultrastructural characters and challenged the use of vegetative form as on overriding feature in classification.     

Fungal farmers or algal escorts: lichen adaptation from the algal perspective

Domestication of algae by lichen‐forming fungi describes the symbiotic relationship between the photosynthetic (green alga or cyanobacterium; photobiont) and fungal (mycobiont) partnership in lichen associations ( Goward 1992 ). The algal domestication implies that the mycobiont cultivates the alga as a monoculture within its thallus, analogous to a farmer cultivating a food crop. However, the initial photobiont ‘selection’ by the mycobiont may be predetermined by the habitat rather than by the farmer. When the mycobiont selects a photobiont from the available photobionts within a habitat, the mycobiont may influence photobiont growth and reproduction ( Ahmadjian & Jacobs 1981 ) only after the interaction has been initiated. The theory of ecological guilds ( Rikkinen et al. 2002 ) proposes that habitat limits the variety of photobionts available to the fungal partner. While some studies provide evidence to support the theory of ecological guilds in cyanobacterial lichens ( Rikkinen et al. 2002 ), other studies propose models to explain variation in symbiont combinations in green algal lichens ( Ohmura et al. 2006 ; Piercey‐Normore 2006 ; Yahr et al. 2006 ) hypothesizing the existence of such guilds. In this issue of Molecular Ecology, Peksa & ?kaloud (2011) test the theory of ecological guilds and suggest a relationship between algal habitat requirements and lichen adaptation in green algal lichens of the genus Lepraria. The environmental parameters examined in this study, exposure to rainfall, altitude and substratum type, are integral to lichen biology. Lichens have a poikilohydric nature, relying on the availability of atmospheric moisture for metabolic processes. Having no known active mechanism to preserve metabolic thallus moisture in times of drought, one would expect a strong influence of the environment on symbiont adaptation to specific habitats. Adaptation to changes in substrata and its properties would be expected with the intimate contact between crustose lichens in the genus Lepraria. Altitude has been suggested to influence species distributions in a wide range of taxonomic groups. This is one of the first studies to illustrate an ecological guild, mainly for exposure to rainfall (ombrophiles and ombrophobes), with green algal lichens.     

Workshop on algal polysaccharides

Summary This workshop was an impromptu event, but the fact that a number of interesting problems were identified by the participants from the floor may indicate that it is worth repeating. If it is to be repeated, however, it is important that notice be given, and that the scope of the workshop be defined in advance, so that participants can be better informed and bring supporting data. The best approach would be to identify a convenor and define the scope of the workshop prior to the first circular for the next Seaweed Symposium; invitations could then be issued by the convenor for specific topics and data, and a very brief program could be issued with the third circular. Such a procedure may very well allow the identification of new areas for research.     

Electrophoresis of algal glucans

The ability of reactive dyes based on chloro-s-triazine to reactwith the primary and secondary hydroxyl groups of glucose, formingcovalent bonds, has been used to dye the storage polyglucosidesof the algae, Cytmidium caldarium, Oscillatoria princeps, Rhodymeniapertusa and Spirogyra setiformis, prior to electrophoresis oncellulose polyacetate strips in borate buffer. The techniqueresolves mixtures of glucans and defines some of the parametersof the internal structure of these glucans. The similarity ofthe glucans from Cyanidium caldarium and Oscillatoria princepsis evident using this method. The two components of the "starch"from Spirogyra setiformis have been studied and identified bytheir reactions with the dye and the mobilities of the dyedcomponents during electrophoresis. Inferences as to the biphyleticevolutionary pathways leading from the Cyanophyceae to the Rhodophyceaeand the Chlorophyceae can be made based on the data. (Received June 27, 1973; )     

Aspects of algal ecology

Bicosoeca accreta sp. nov. is described by light and electron microscopy. This species is so far unique in the genus in accreting extraneous fragments of mainly inorganic material on the outside of its amorphous undifferentiated lorica.     

Black Sea algal viruses

Monitoring of the Black Sea algal viruses in Sevastopol bays and Crimean water areas has been carried out since 2002. Based on the methods that were developed and patented by the author, more than 200 strains of algal viruses of five species of microalgae that are new to science were isolated: TvV (Tetraselmis viridis virus), DvV (Dunaliella viridis virus), PtV (Phaeodactylum tricornutum virus), PpV (Prorocentrum pusillum virus) and IgV (Isochrysis galbana virus). For the first time in the Black Sea, the Emiliania huxleyi virus (EhV) of microalgae was isolated. Using the method of electron microscopy, the Black Sea algal viruses were identified as icosahedral virions with respective sizes of 56–60, 45–48, 50–53, 88–92, and 128–132 nm, for the TvV, PtV, DvV, PpV and IgV viruses. The EhV size, as determined by the method of filtration, was within the range of 50–200 nm. In the IgV and EhV viruses we revealed a viral envelope. Based on their characters the isolated algal viruses were attributed to the Phycodnaeviridae. The maximum number of algal viruses was observed in the spring and autumn seasons, which is typical for their host phytoplankton species. The Black Sea algal viruses, TvV, PpV, IgV, and EhV, displayed no strict species specificity and have a wide range of available hosts.     

Some interesting algal flagellates

22 species or forms of flagellates, observed in nature in Czechoslovakia and Poland, are pictured and described in the present paper. They belong to four classes:Chrysophyceae (2),Chlorophyceae (1),Cryptophyceae (9), andDinophyceae (10). They were nearly all identified with the existing taxa; some names are suggested as synonyms, some new nomenclature combinations are put forward. One new species,Chilomonas bacillaris sp. n., has been established.     

Cyanophage and algal virus

<正>Cyanobacteria and eukaryotic algae are abundant in freshwater and marine environments,and are fundamentally important in global biogeochemical cycles and for primary productivity.Under certain conditions,such as an excess of nutrients due to human activities through fertilizers or sewage,     

Effects of live coral,epilithic algal communities and substrate type on algal recruitment

The recruitment of algae is a critical process during algal colonization and invasions, including coral-to-algal phase shifts. Although algae are widely assumed to colonize and kill corals, there is very little known about the recruitment dynamics of coral reef algae. This study tested the ability of two dominant macroalgae (Fucales including Sargassum spp. and Lobophora variegata) to settle and grow on healthy coral tissue. The study also explored the effects of interactions with prior occupants, and of abiotic substrate properties (texture, and ceramic and carbonate material). The results indicate that healthy corals were able to prevent attachment or survival of recruits of these macroalgae. This is a significant point, since it suggests that the replacement of corals by algae may often require prior stress or death in the coral tissue. Pre-conditioning of plates at different sites had some effects, but these were relatively minor, whereas there was considerable variation within sites. Some of this variation appeared to be related to the amount of turf algae or crustose coralline algae on the plates. Recruitment was generally, but not always, higher on plates with rougher texture. Overall, this preliminary exploration indicates considerable potential for variability in outcomes of algal colonization, with implications for the dynamics of algal invasions. In particular, the results do not support suggestions that planktonic algal propagules can directly settle on and colonize healthy coral tissue.Communicated by Topic Editor D. Barnes     

Microflotation performance for algal separation

The performance of microflotation, dispersed air flotation with microbubble clouds with bubble size about 50 μm, for algae separation using fluidic oscillation for microbubble generation is investigated. This fluidic oscillator converts continuous air supply into oscillatory flow with a regular frequency to generate bubbles of the scale of the exit pore. Bubble characterization results showed that average bubble size generated under oscillatory air flow state was 86 μm, approximately twice the size of the diffuser pore size of 38 μm. In contrast, continuous air flow at the same rate through the same diffusers yielded an average bubble size of 1,059 μm, 28 times larger than the pore size. Following microbubble generation, the separation of algal cells under fluidic oscillator generated microbubbles was investigated by varying metallic coagulant types, concentration and pH. Best performances were recorded at the highest coagulant dose (150 mg/L) applied under acidic conditions (pH 5). Amongst the three metallic coagulants studied, ferric chloride yielded the overall best result of 99.2% under the optimum conditions followed closely by ferric sulfate (98.1%) and aluminum sulfate with 95.2%. This compares well with conventional dissolved air flotation (DAF) benchmarks, but has a highly turbulent flow, whereas microflotation is laminar with several orders of magnitude lower energy density.     

The allometry of algal respiration

For 30 years, study after study has shown that respiration ratesincrease as {small tilde}0.75 of body size for organisms rangingfrom protozoans to mammals. However, a number of studies suggestedthat the respiration-size relationship for algae may be a rareexception to this general rule. Algal respiration may be almostproportional to cell size, such that the slope of the respiration-sizerelationship is closer to unity. The present study examinedthe effect of cell size and taxon on phytoplankton respiration,using data collected from the literature. To this end, we collecteda data set of 178 observations of algal respiration and cellsize representing six divisions-chlorophytes. chrysophytes,cyanophytes, euglenophytes, pyrrophytes and rhodophytes. Therelationship between respiration (R, in p1 O₂ cell^–1 h^–1)and cell carbon content (C, in pg C cell^–1) is describedas R = 0.030C^{0 93} and the exponent is significantly >3/4.When we expressed cell size in terms of volume, the exponentdecreased to 0.88 but this is still significantly >3/4. Amongthe six divisions studied, chlorophytes, euglenophytes and rhodophytesseemed to differ significantly in their respiration-size relationshipfrom other taxa. However, euglenophytes and rhodophytes havesuch small size ranges that no meaningful relationships canbe developed for those groups alone. The chlorophyte respiration-sizerelationship has obvious patterns in its residuals which mayindicate that significant sources of error were not controlledin these heterogeneous data. Thus, for the present, the generalmodel seems most appropriate for the prediction of respirationrates of phytoplankton.     

Chloroplast pigments and algal systematics

The chloroplast pigments of one typical representative (Pleurochloris magna) and two potential members (clone BSG Sticho and an isolate called Tunis) of the new class Eustigmatophyceae have been examined by modern methods including mass spectrometry. The three cultures all exhibited the same chloroplast pigments: Chlorophyll a, but no b or c, δ-carotene (I), canthaxanthin (II), violaxanthin (IIIa), and esterified vaucheriaxanthin (IVb) plus some free vaucheriaxanthin (IVa). Furanoid rearrangement of the epoxidic carotenoids complicated the analysis. The unique pigment complement hereby indicated for Eustigmatophyceae is clearly different from the pigment distribution patterns reported for Chlorophyceae and Xanthophyceae.