Phlorotannine als UV-Schutzsubstanzen in frühen Entwicklungsstadien von Braunalgen

Communities of macro- and microalgae present a dominant group of coastal benthic ecosystems. Macroalgae exhibit a complex developmental cycle involving microscopic life stages which are fully exposed to environmental factors such as UV radiation (UV) and water temperatures displaying the most sensitive stage of the entire macroalgal life-cycle. In the last 50 years, the ozone content in the atmosphere has significantly diminished due to growing emissions of synthetic chlorofluorocarbon molecules. At the same time, global mean temperature increased due to the so-called green house effect. These global environmental changes may affect ecosystems to a hitherto unknown extent. The aims of the present study therefore involve the depiction of acclimation to UVR and PAR in the protective and metabolic mechanisms of brown algal juvenile life stages of the species Alaria esculenta, Laminaria digitata, Saccharina latissima and Saccorhiza dermatodea as well as the species' adaptive potential to enhanced temperatures. Including a comparative approach of field and laboratory experiments, the present study integrates various radiation regimes and intensities, temperature experiments and exposure times. For a broader understanding of effects, a variety of methods investigating e.g. intra- and extracellular levels of phlorotannins by the Folin-Ciocalteu method, fatty acid determination by gas chromatography, determination of reactive oxygen species and electron microscopy was applied to several juveniles of various Arctic macroalgae from Spitsbergen (Kongsfjorden). Results reveal that the sensitivity to visible and UVR of various macroalgal species is determined by their radiation tolerance and the protective potential of their parental tissue. As still only few data are available on interactive effects of PAR, enhanced UVR and temperatures, predictions of future consequences for algal recruitment and survival as well as on the community level remain difficult. While enhanced UVR in combination with low PAR in the laboratory was not affecting algal propagules, field experiments under high PAR showed detrimental effects leading to a decrease of spore germination. Most studies conducted in the past have focused on UVR effects while the present study reveals that high PAR was always underestimated and might play a more pronounced role than usually expected. Ozone depletion might be of greater importance for smaller organisms such as spores and bacteria which are physically less protected from UVR damage, especially in marine environments where concentrations of chromophoric dissolved organic matter are low and UVR transparency is high. Stratospheric ozone depletion over the Arctic in combination with rising temperatures is therefore expected to have a strong impact on the survival of macroalgal zoospores and finally the vertical zonation of Arctic and cold temperate macroalgal species around Spitsbergen

Cyanobacteria in Scandinavian coastal waters — A potential source for biofuels and fatty acids?

Since land-based biofuel production competes with conventional food production, a water-based biomass and biofuel production from cyanobacteria offers large potential. This study investigates the application potential of cyanobacteria for fuel production and by-products by mimicking nutrient depleted environmental conditions. Three Baltic cyanobacteria strains (Aphanizomenon flos-aquae, Dolichospermum lemmermannii and Nodularia spumigena) were inoculated in full nutrient levels, as well as phosphorus and nitrogen depleted medium, before being monitored for 14 days. For screening reasons, multiple parameters such as fatty acids, photosynthetic pigments including phycobilins, biovolume, photosynthetic activity, inorganic nutrients, particulate organic carbon, nitrogen and phosphorous were investigated every seven days. We observed a strong negative relationship between lipid content, growth and nutrient availability, resulting in high lipid and pigment production in combination with a limited growth rate in nutrient depleted treatments. Our results suggest that cultivation and harvest of bloom-forming cyanobacteria for fuel and by-product production are feasible in Scandinavia, but strongly depends on the desired compounds and biomass. Each cyanobacteria species originally has a species-specific chemical fingerprint that may be modified by rearing conditions and harvesting period to meet the needs of the consumer. This leads to important conclusions regarding future culturing conditions and biomass production of the desired compounds

Health effects of feed dilution and roughage in Ross 308 broiler breeder cockerels

ABSTRACT: To ensure reproductivity and prevent obesity, broiler breeder's growth rate is controlled by quantitative feed restriction. However, feed restriction is associated with chronic hunger, frustration, and abnormal behaviors, thus representing a welfare problem. Feed diluted with insoluble fiber is an alternative, allowing larger amounts of feed and more gut filling, increasing satiety without increasing the caloric intake. Previous research on feed dilution has focused on pullets not cockerels. In addition, the health effects of diluted feed are less explored. The aim of this study was to investigate the effects of feed dilution and roughage on health indicators in broiler breeder cockerels, 5 to 10 wk of age (WOA), a very feed restricted period. In total, 200 Ross 308 broiler breeder cockerels were housed in 12 pens (6 pens/treatment), 16 to 17 birds per pen. The treatments were standard feed (Control) and feed diluted with (20%) insoluble oat hulls and 150 g of roughage (lucerne/alfalfa) daily per pen (D + R). The D + R birds received 20% more feed per day. Body weight, pecking injuries, footpad dermatitis (FPD), and litter quality were recorded weekly between 5 and 9 WOA. At 10 WOA all birds were euthanized and subjected to postmortem assessment. D + R birds tended to weigh more than controls (P = 0.055), but diet did not affect flock uniformity (P = 0.57). The weekly assessment showed no effect of treatment on foot pad lesion scores (P = 0.31). However, an effect on FPD was observed postmortem (P = 0.04), where Control had slightly better footpad condition compared to the D + R group. Litter had to be completely changed in 2 control pens during the trial, due to quality deterioration. There was no effect of treatment on the weight of specific organs, the length of the gut, the intestinal mucosa, nor on the incidence of wounds on the head (P = 0.15). Overall, these results indicate that feed dilution and roughage have neither adverse nor beneficial health effects on Ross 308 broiler breeder cockerels

Carbon Emissions of Infrastructure Development

Identifying strategies for reconciling human development and climate change mitigation requires an adequate understanding of how infrastructures contribute to well-being and greenhouse gas emissions. While direct emissions from infrastructure use are well-known, information about indirect emissions from their construction is highly fragmented. Here, we estimated the carbon footprint of the existing global infrastructure stock in 2008, assuming current technologies, to be 122 (−20/+15) Gt CO₂. The average per-capita carbon footprint of infrastructures in industrialized countries (53 (±6) t CO₂) was approximately 5 times larger that that of developing countries (10 (±1) t CO₂). A globalization of Western infrastructure stocks using current technologies would cause approximately 350 Gt CO₂ from materials production, which corresponds to about 35–60% of the remaining carbon budget available until 2050 if the average temperature increase is to be limited to 2 °C, and could thus compromise the 2 °C target. A promising but poorly explored mitigation option is to build new settlements using less emissions-intensive materials, for example by urban design; however, this strategy is constrained by a lack of bottom-up data on material stocks in infrastructures. Infrastructure development must be considered in post-Kyoto climate change agreements if developing countries are to participate on a fair basis

Ocean acidification and desalination : climate-driven change in a Baltic Sea summer microplanktonic community

Helcom scenario modelling suggests that the Baltic Sea, one of the largest brackish-water bodies in the world, could expect increased precipitation (decreased salinity) and increased concentration of atmospheric CO2 over the next 100 years. These changes are expected to affect the microplanktonic food web, and thereby nutrient and carbon cycling, in a complex and possibly synergistic manner. In the Baltic Proper, the extensive summer blooms dominated by the filamentous cyanobacteria Aphanizomenon sp., Dolichospermum spp. and the toxic Nodularia spumigena contribute up to 30% of the yearly new nitrogen and carbon exported to the sediment. In a 12 days outdoor microcosm experiment, we tested the combined effects of decreased salinity (from 6 to 3) and elevated CO2 concentrations (380 and 960 µatm) on a natural summer microplanktonic community, focusing on diazotrophic filamentous cyanobacteria. Elevated pCO2 had no significant effects on the natural microplanktonic community except for higher biovolume of Dolichospermum spp. and lower biomass of heterotrophic bacteria. At the end of the experimental period, heterotrophic bacterial abundance was correlated to the biovolume of N. spumigena. Lower salinity significantly affected cyanobacteria together with biovolumes of dinoflagellates, diatoms, ciliates and heterotrophic bacteria, with higher biovolume of Dolichospermum spp. and lower biovolume of N. spumigena, dinoflagellates, diatoms, ciliates and heterotrophic bacteria in reduced salinity. Although the salinity effects on diatoms were apparent, they could not clearly be separated from the influence of inorganic nutrients. We found a clear diurnal cycle in photosynthetic activity and pH, but without significant treatment effects. The same diurnal pattern was also observed in situ (pCO2, pH). Thus, considering the Baltic Proper, we do not expect any dramatic effects of increased pCO2 in combination with decreased salinity on the microplanktonic food web. However, long-term effects of the experimental treatments need to be further studied, and indirect effects of the lower salinity treatments could not be ruled out. Our study adds one piece to the complicated puzzle to reveal the combined effects of increased pCO2 and reduced salinity levels on the Baltic microplanktonic community.publishedVersio