UNUSUAL CHROMOSOME-NUMBER OF GRACILARIA-VERRUCOSA (GRACILARIALES, RHODOPHYTA) IN THE CAPE-GRIS-NEZ AREA, NORTHERN FRANCE

The chromosome number of Gracilaria verrucosa (Hudson) Papenfuss was estimated in numerous individuals from different populations of the Cape Gris-Nez area of Northern France. To optimize estimates and to minimize counting errors, several counts were made on the same nucleus and in different nuclei of the same individual. The haploid chromosome number was estimated in vegetative gametophytic cells and tetrasporocytic cells; the diploid number was estimated from tetrasporophytic vegetative cells. The basic haploid number was n = 17 +/- 1, whereas all other Gracilaria species for which chromosome numbers are available are reported to have n = 24. These include populations of G. verrucosa from Norway and Wales that have previously been shown to be conspecific with the Cape Gris-Nez populations by comparison of plastid DNA data. G. verrucosa is therefore one of the few red algae for which populations with different chromosome numbers are known.

A NOVEL LIFE-HISTORY IN AGLAOTHAMNION-DIAPHANUM-SP NOV (CERAMIACEAE, RHODOPHYTA) FROM BRITTANY AND THE BRITISH-ISLES

A diminutive species of Aglaothamnion (Ceramiaceae, Rhodophyta), A. diaphanum sp. nov., is described from Brittany (Atlantic France), the Isles of Scilly (off S.W. England) and western Ireland. Aglaothamnion diaphanum is confined to the sublittoral zone, where it grows almost exclusively on algae and sessile animals attached to hard substrata. Thalli are delicate, and branched distichously in one plane. The main axes are ecorticate but may form loose non-corticating rhizoidal filaments. The lateral branches bear a characteristic, regularly alternate distichous series of branchlets, the first of which is always adaxial. All vegetative cells are uninucleate. The majority of field-collected plants bear only bisporangia, but a few bisporangial plants also form spermatangia; some male plants and a single female specimen have been collected. The spermatangial branchlets consist of 3-5 spermatangial mother cells each bearing 2-4 spermatangia, which are constricted around a central nucleus. None of the U-shaped carpogonial branches showed any sign of fertilization, and the gametangia appear to be non-functional. The bisporangia are ovoid and contain two uninucleate spores separated by an oblique curved wall. The occurrence of bisporangia and the lack of adherent cortication distinguish A. diaphanum from two similar species, Aglaothamnion bipinnatum (P. Crouan et H. Crouan) Feldmann-Mazoyer and Aglaothamnion decompositum (J. Agardh) Halos. The life history in culture of French and Irish isolates of A. diaphanum consists of a series of bisporangial generations, a single plant of which also formed spermatangia. Apical cells of bisporophytes are haploid (n = c. 32), but the first division of meiosis, with chromosome pairing and crossing over, occurs in dividing bisporocytes. The germinating bispores are haploid. Endodiploidization may occur in the early stages of sporangium development, as in some phycomycete fungi, or in vegetative cells that subsequently give rise to bisporocytes. This is the first demonstration in the red algae of meiotic bisporangia on plants of which the apical cells, at least, are haploid.

Bio-port Free Energy City

In an age of depleting oil reserves and increasing energy demand, humanity faces a stalemate between environmentalism and politics, where crude oil is traded at record highs yet the spotlight on being ‘green’ and sustainable is stronger than ever. A key theme on today’s political agenda is energy independence from foreign nations, and the United Kingdom is bracing itself for nuclear renaissance which is hoped will feed the rapacious centralised system that the UK is structured upon. But what if this centralised system was dissembled, and in its place stood dozens of cities which grow and monopolise from their own energy? Rather than one dominant network, would a series of autonomous city-based energy systems not offer a mutually profitable alternative? Bio-Port is a utopian vision of a ‘Free Energy City’ set in Liverpool, where the old dockyards, redundant space, and the Mersey Estuary have been transformed into bio-productive algae farms. Bio-Port Free Energy City is a utopian ideal, where energy is superfluous; in fact so abundant that meters are obsolete. The city functions as an energy generator and thrives from its own product with minimal impact upon the planet it inhabits. Algaculture is the fundamental energy source, where a matrix of algae reactors swamp the abandoned dockyards; which themselves have been further expanded and reclaimed from the River Mersey. Each year, the algae farm is capable of producing over 200 million gallons of bio-fuel, which in-turn can produce enough electricity to power almost 2 million homes. The metabolism of Free-Energy City is circular and holistic, where the waste products of one process are simply the inputs of a new one. Livestock farming – once traditionally a high-carbon countryside exercise has become urbanised. Cattle are located alongside the algae matrix, and waste gases emitted by farmyards and livestock are largely sequestered by algal blooms or anaerobically converted to natural gas. Bio-Port Free Energy City mitigates the imbalances between ecology and urbanity, and exemplifies an environment where nature and the human machine can function productively and in harmony with one another. According to James Lovelock, our population has grown in number to the point where our presence is perceptibly disabling the planet, but in order to reverse the effects of our humanist flaws, it is vital that new eco-urban utopias are realised.

Environmental context determines multi-trophic effects of consumer species loss

Loss of biodiversity and nutrient enrichment are two of the main human impacts on ecosystems globally, yet we understand very little about the interactive effects of multiple stressors on natural communities and how this relates to biodiversity and ecosystem functioning. Advancing our understanding requires the following: (1) incorporation of processes occurring within and among trophic levels in natural ecosystems and (2) tests of context-dependency of species loss effects. We examined the effects of loss of a key predator and two groups of its prey on algal assemblages at both ambient and enriched nutrient conditions in a marine benthic system and tested for interactions between the loss of functional diversity and nutrient enrichment on ecosystem functioning. We found that enrichment interacted with food web structure to alter the effects of species loss in natural communities. At ambient conditions, the loss of primary consumers led to an increase in biomass of algae, whereas predator loss caused a reduction in algal biomass (i.e. a trophic cascade). However, contrary to expectations, we found that nutrient enrichment negated the cascading effect of predators on algae. Moreover, algal assemblage structure varied in distinct ways in response to mussel loss, grazer loss, predator loss and with nutrient enrichment, with compensatory shifts in algal abundance driven by variation in responses of different algal species to different environmental conditions and the presence of different consumers. We identified and characterized several context-dependent mechanisms driving direct and indirect effects of consumers. Our findings highlight the need to consider environmental context when examining potential species redundancies in particular with regard to changing environmental conditions. Furthermore, non-trophic interactions based on empirical evidence must be incorporated into food web-based ecological models to improve understanding of community responses to global change.

Impacts of sewage outfalls on rocky shores: incorporating scale, biotic assemblage structure and variability into monitoring tools.

Coastal systems, such as rocky shores, are among the most heavily anthropogenically-impacted marine ecosystems and are also among the most productive in terms of ecosystem functioning. One of the greatest impacts on coastal ecosystems is nutrient enrichment from human activities such as agricultural run-off and discharge of sewage. The aim of this study was to identify and characterise potential effects of sewage discharges on the biotic diversity of rocky shores and to test current tools for assessing the ecological status of rocky shores in line with the EU Water Framework Directive (WFD). A sampling strategy was designed to test for effects of sewage outfalls on rocky shore assemblages on the east coast of Ireland and to identify the scale of the putative impact. In addition, a separate sampling programme based on the Reduced algal Species List (RSL), the current WFD monitoring tool for rocky shores in Ireland and the UK, was also completed by identifying algae and measuring percent cover in replicate samples on rocky shores during Summer. There was no detectable effect of sewage outfalls on benthic taxon diversity or assemblage structure. However, spatial variability of assemblages was greater at sites proximal or adjacent to sewage outfalls compared to shores without sewage outfalls present. Results based on the RSL, show that algal assemblages were not affected by the presence of sewage outfalls, except when classed into functional groups when variability was greater at the sites with sewage outfalls. A key finding of both surveys, was the prevalence of spatial and temporal variation of assemblages. It is recommended that future metrics of ecological status are based on quantified sampling designs, incorporate changes in variability of assemblages (indicative of community stability), consider shifts in assemblage structure and include both benthic fauna and flora to assess the status of rocky shores.

The Influence of Aspect on the Biological Colonization of Stone in Northern Ireland.

The rate and type of biological colonization of stone is influenced by a wide array of environmental factors in addition to substrate characteristics. A series of experiments was designed to compare the rate and type of biological colonization of stone at varying locations over a 21-month time period. Exposure
trials were set up at nine different sites across Northern Ireland that covered a wide variety of environmental conditions. To determine aspect-related differences in colonization, blocks of Peakmoor sandstone and Portland limestone were placed on the north- and south-facing sides of purpose-designed exposure racks. Colorimetry and visual analysis were carried out on collected samples at increasing time intervals. Results showed significantly different rates of darkening and greening over time between north-facing and south-facing blocks, for both sandstone and limestone. This difference is likely to be representative of the fact that in Northern Ireland’s wet climate and northern-latitude position, the north face of a building will receive less direct sunlight. Therefore north-facing blocks, once wet, will remain damp for much longer than blocks on other façades. This slow-drying phenomenon is much more hospitable for biological colonization and continued growth than the hostile environment of rapid wetting and drying cycles experienced on the south face.

The colonization of macroalgal rafts by the genus Idotea (sub-phylum Crustacea; Order Isopoda):An active or passive process?

The association of invertebrate communities with macroalgae rafts has received much attention over recent decades, yet significant gaps in our knowledge remain with respect to the colonization process. Using laboratory-based experiments and in situ field trials in Strangford Lough, Northern Ireland, this study investigated whether members of the known rafting genus Idotea (sub-phylum Crustacea; order Isopoda) could effectively colonize rafts after shore seaweed detachment, or if their presence merely reflected a passive marooning process. Test tank arenas were used to identify traits that may influence the rafting potential of the dominant shore species Idotea granulosa and the well known rafter Idotea baltica. When released mid-water, I. granulosa initially ascended and associated with floating seaweed whereas I. baltica tended to descend with no clear habitat association. These findings conflict with the differential distribution of these Idotea species among rafts and shore algae, thus highlighting the complex nature of the potential of organisms to raft. In the field we considered the relative ability of different Idotea species to colonize tethered rafts composed of Ascophyllum nodosum and Fucus vesiculosus, cleaned of all vagile organisms and deployed at locations adjacent to established intertidal Idotea species populations. At the end of the experiment (after 44 days) rafts were inhabited by known rafting and shoreline species, confirming that colonization can occur after algal detachment. Previously considered shoreline species on occasion outnumbered well known rafters suggesting that a wide range of Idotea species can readily avail of macroalgal rafts as a potential dispersal mechanism or alternative habitat. © 2012 Marine Biological Association of the United Kingdom.

Photosynthetic pigments in soils from northern Victoria Land (continental Antarctica) as proxies for soil algal community structure and function

Although soil algae are among the main primary producers in most terrestrial ecosystems of continental Antarctica, there are very few quantitative studies on their relative proportion in the main algal groups and on how their distribution is affected by biotic and abiotic factors. Such knowledge is essential for understanding the functioning of Antarctic terrestrial ecosystems. We therefore analyzed biological soil crusts from northern Victoria Land to determine their pH, electrical conductivity (EC) water content (W), total and organic C (TC and TOC) and total N (TN) contents, and the presence and abundance of photosynthetic pigments. In particular, the latter were tested as proxies for biomass and coarse-resolution community structure. Soil samples were collected from five sites with known soil algal communities and the distribution of pigments was shown to reflect differences in the relative proportions of Chlorophyta, Cyanophyta and Bacillariophyta in these sites. Multivariate and univariate models strongly indicated that almost all soil variables (EC, W, TOC and TN) were important environmental correlates of pigment distribution. However, a significant amount of variation is independent of these soil variables and may be ascribed to local variability such as changes in microclimate at varying spatial and temporal scales. There are at least five possible sources of local variation: pigment preservation, temporal variations in water availability, temporal and spatial interactions among environmental and biological components, the local-scale patchiness of organism distribution, and biotic interactions. (C) 2009 Elsevier Ltd. All rights reserved.

Multiplex biotoxin surface plasmon resonance method for marine biotoxins in algal and seawater samples

A multiplex surface plasmon resonance (SPR) biosensor method for the detection of paralytic shellfish poisoning (PSP) toxins, okadaic acid (and analogues) and domoic acid was developed. This method was compared to enzyme-linked immunosorbent assay (ELISA) methods. Seawater samples (n?=?256) from around Europe were collected by the consortia of an EU project MIcroarrays for the Detection of Toxic Algae (MIDTAL) and evaluated using each method. A simple sample preparation procedure was developed which involved lysing and releasing the toxins from the algal cells with glass beads followed by centrifugation and filtering the extract before testing for marine biotoxins by both multi-SPR and ELISA. Method detection limits based on IC20 values for PSP, okadaic acid and domoic acid toxins were 0.82, 0.36 and 1.66 ng/ml, respectively, for the prototype multiplex SPR biosensor. Evaluation by SPR for seawater samples has shown that 47, 59 and 61 % of total seawater samples tested positive (result greater than the IC20) for PSP, okadaic acid (and analogues) and domoic acid toxins, respectively. Toxic samples were received mainly from Spain and Ireland. This work has demonstrated the potential of multiplex analysis for marine biotoxins in algal and seawater samples with results available for 24 samples within a 7 h period for three groups of key marine biotoxins. Multiplex immunological methods could therefore be used as early warning monitoring tools for a variety of marine biotoxins in seawater samples.

Novel hydrolysis-probe based qPCR assay to detect saxitoxin transcripts of dinoflagellates in environmental samples

Paralytic Shellfish Poisoning (PSP) is a serious human illness caused by ingestion of seafood enriched with paralytic shellfish toxins (PSTs). PSTs are neurotoxic compounds produced by marine dinoflagellates, specifically by Alexandrium spp., Gymnodinium catenatum and Pyrodinium bahamense. Every year, massive monitoring of PSTs and their producers is undertaken worldwide to avoid PSP incidences. Here we developed a sensitive, hydrolysis probe-based quantitative PCR (qPCR) assay to detect a gene essential for PST synthesis across different dinoflagellate species and genera and tested it on cDNA generated from environmental samples spiked with Alexandrium minutum or Alexandrium fundyense cells. The assay was then applied to two environmental sample series from Norway and Spain and the results were complemented with cell counts, LSU-based microarray data and toxin measurements (enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) biosensor method). The overall agreement between the results of the qPCR assay and the complementary data was good. The assay reliably detected sxtA transcripts from Alexandrium spp. and G. catenatum, even though Alexandrium spp. cell concentrations were mostly so low that they could not be quantified microscopically. Agreement between the novel assay and toxin measurements or cell counts was generally good; the few inconsistencies observed were most likely due to disparate residence times of sxtA transcripts and PSTs in seawater, or, in the case of cell counts, to dissimilar sxtA4 transcript numbers per cell in different dinoflagellate strains or species. © 2013 Elsevier B.V.

First development and characterisation of polyclonal and monoclonal antibodies to the emerging fresh water toxin cylindrospermopsin

As increasing incidences in the occurrence of cylindrospermopsin (CYN) appear, in addition to further research on its toxicological nature, improved rapid methods to detect this toxin are required. Antibody based assays are renowned for their ability to provide rapid, portable, simple to use tests. As yet however there are no publications outlining how an antibody to CYN can be produced. A range of chemical approaches was investigated to synthesise CYN immunogens for antibody production but failed to generate a response. Finally, a modified Mannich reaction for immunogen synthesis was employed to couple the toxin to two carrier proteins. Both protein conjugates were successfully used to raise both polyclonal and monoclonal antibodies of high sensitivity to CYN. These antibodies were characterised employing competitive indirect ELISA and an optical biosensor assay. By ELISA the sensitivity achieved ranged from 27 to 131. pg/mL and by SPR 4.4 to 11.1. ng/mL thus demonstrating that the selection of immunoassay platform is important for the detection level required by the end user for their application. Low cross-reactivity to the much less toxic metabolite deoxyCYN was observed. This is the first reported production of antibodies to this toxin. © 2013 Elsevier B.V.

Effects of Undaria pinnatifida, Himanthalia elongata and Porphyra umbilicalis extracts on in vitro α-glucosidase activity and glucose diffusion

Background: Seaweeds are good sources of dietary fibre, which can influence glucose uptake and glycemic control.Objective: To investigate and compare the in vitro inhibitory activity of different extracts from Undaria pinnatifida (Wakame), Himanthalia elongata (Sea spaghetti) and Porphyra umbilicalis (Nori) on α-glucosidase activity and glucose diffusion.Methods: The in vitro effects chloroform-, ethanol- and water-soluble extracts of the three algae were assayed on α- glucosidase activity and glucose diffusion through membrane. Principal Components Analysis (PCA) was applied to identify patterns in the data and to discriminate which extract will show the most proper effect.Results: Only water extracts of Sea spaghetti possessed significant in vitro inhibitory effects on α-glucosidase activity (26.2% less mmol/L glucose production than control, p < 0.05) at 75 min. PCA distinguished Sea spaghetti effects, supporting that soluble fibre and polyphenols were involved. After 6 h, Ethanol-Sea spaghetti and water-Wakame extracts exerted the highest inhibitory effects on glucose diffusion (65.0% and 60.2% vs control, respectively). This extracts displayed the lowest slopes for glucose diffusion-time lineal adjustments (68.2% and 62.8% vs control, respectively).Conclusions: The seaweed hypoglycemic effects appear multi-faceted and not necessarily concatenated. According to present results, ethanol and water extracts of Sea spaghetti, and water extracts of Wakame could be useful for the development of functional foods with specific hypoglycemic properties.

Monitoring a toxic bloom of Alexandrium minutum using novel microarray and multiplex surface plasmon resonance biosensor technology

Blooms of Alexandrium occur annually during the summer months in the North Channel of Cork Harbour on the south coast of Ireland. This study monitored an extensive bloom of the toxin producing Alexandrium minutum during the summer of 2011 with the use of the MIDTAL (Microarrays for the Detection of Toxic Algae) microarray and a prototype multiplex surface plasmon resonance (multi SPR) biosensor. Microarray signal intensities and toxin results from three testing platforms of the prototype multi SPR biosensor, commercial (CER) enzyme-linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC) were compared against light microscopy counts. The main aim was to demonstrate the use of these methodologies to support national monitoring agencies by providing a faster and more accurate means of identifying and quantifying the harmful phytoplankton community and their toxins in natural water samples. Both the microarray signals and multi SPR biosensor results followed a significant trend with light microscopy results and both techniques indicated detection limits of <4000 cells of A. minutum in natural seawater samples.

Productive Synergies in the City

The chapter focuses on the development of sustainable growing infrastructure in the city at two scales. Firstly the development of a large-scale city wide fuel productive landscape through the development of algae arrays in Liverpool and their connection through urban agriculture systems to develop a closed-cycle food and energy system where waste is food and secondly a hyper-localised neighbourhood food production system in Salford UK that utilises a closed cycle aquaponic system to re-invigorate an urban food desert.

The author develops a three-part model for the implementation of urban agriculture based on hardware (the technological system), software (the biological components) and interface (the links to food and other social networks). The conclusion being that it is possible to develop urban agriculture in cities if their implementation is seen as a process, rather than a static design. Also that as the benefits of such systems are wider than purely the physical outputs of the system in terms of energy and food, and thus we should re-evaluate the purely economic model of appraisal to include these.

Stressor intensity determines antagonistic interactions between species invasion and multiple stressor effects on ecosystem functioning

Biological invasions, nutrient enrichment and ocean warming are known to threaten biodiversity and ecosystem functioning. The independent effects of these ecological stressors are well studied, however, we lack understanding of their cumulative effects, which may be additive, antagonistic or synergistic. For example, the impacts of biological invasions are often determined by environmental context, which suggests that the effects of invasive species may vary with other stressors such as pollution or climate change. This study examined the effects of an invasive seaweed (Sargassum muticum) on the structure and functioning of a benthic marine assemblage and tested explicitly whether these effects varied with nutrient enrichment and ocean warming. Overall, the presence of Sargassum muticum increased assemblage productivity rates and warming altered algal assemblage structure, which was characterised by a decrease in kelp and an increase in ephemeral green algae. The effects of Sargassum muticum on total algal biomass accumulation, however, varied with nutrient enrichment and warming producing antagonistic cumulative effects on total algal biomass accumulation. These findings show that the nature of stressor interactions may vary with stressor intensity and among response variables, which leads to less predictable consequences for the structure and functioning of communities.