WorldWideScience

Sample records for antarctic macroalgae effects

  1. Effects of Drifting Macroalgae in Eelgrass Ecosystems

    DEFF Research Database (Denmark)

    Canal Vergés, Paula; Valdemarsen, Thomas Bruun; Kristensen, Erik;

    2010-01-01

    physical damage on eelgrass can occur when macroalgae are drifting as bedload. The ballistic effect of moving macroalgae on surface sediment was tested in the field as well as in a series of annular flume experiments, where simultaneous measurements of macroalgae transport and turbidity were measured at...

  2. Ecophysiology of Antarctic macroalgae: effects of environmental light conditions on photosynthetic metabolism Ecofisiología de macroalgas marinas antárticas: efectos de las condiciones de luz sobre el metabolismo fotosintético

    Directory of Open Access Journals (Sweden)

    I. GÓMEZ

    2001-06-01

    Full Text Available Daylength is the major environmental factor affecting the seasonal photosynthetic performance of Antarctic macroalgae. For example, the "season anticipation" strategy of large brown algae such as Ascoseira mirabilis and Desmarestia menziesii are based on the ability of their photosynthetic apparatus to make use of the available irradiance at increasing daylengths in late winter-spring. The seasonal development and allocation of biomass along the lamina of A. mirabilis are related to a differential physiological activity in the plant. Thus, intra-thallus differentiation in O2-based photosynthesis and carbon fixation represents a morpho-functional adaptation that optimizes conversion of radiant energy to primary productivity. In Desmarestia menziesii, reproductive phases show different photosynthetic characteristics. Small gametophytes and early stages of sporophytes, by virtue of their fine morphology, have a high content of pigments per weight unit, a high photosynthetic efficiency, very low light requirements for photosynthesis, and they are better suited to dim light conditions than adult sporophytes. This strategy ensures the completion of the life-cycle under seasonally changing light conditions. Low light requirements for growing and photosynthesizing are developed to cope with Antarctic seasonality and constitute adaptations to expand depth zonation of macroalgae. No differences in net Pmax and photosynthetic efficiency (a among algae growing at depths between 10 and 30 m, suggest a low potential for photoacclimation enabling algae to grow over a wide range of prevailing light conditions. However, shortenings in the daily period during which plants are exposed to saturation irradiances for photosynthesis (Hsat and low carbon balance (daily P/R ratios at depths close to or larger than 30 m negatively affect primary productivity. In general, photosynthetic rates of Antarctic macroalgae at 0 °C are comparable to those measured in species

  3. The potential macroalgae habitat shifts in an Antarctic Peninsula fjord due to climate change

    Science.gov (United States)

    Jerosch, Kerstin; Scharf, Frauke; Deregibus, Dolores; Campana, Gabriela; Zacher, Katharina; Hass, Christian; Quartino, Liliana; Abele, Doris

    2016-04-01

    The Western Antarctic Peninsula (WAP) region is one of the most rapidly warming on earth since the last 50 yr. The WAP glaciers currently contribute one third of the melt water to global sea level rise. Climate warming is supposed to induce important changes in polar ecosystems, from microbial communities to apex predators' levels. Macroalgae are the main biomass producers in Potter Cove located at King George Island, the biggest island of the South Shetland Arc. They are sensitive to climate change factors such as suspended particulate matter (SPM). Macroalgae presence and absence data were used to test SDMs suitability and, simultaneously, to assess the environmental response of macroalgae as well as to model four scenarios of distribution shifts by varying SPM conditions due to climate change. Species distribution models (SDM) predict species occurrence based on statistical relationships with environmental conditions. The R-package 'biomod2' which includes 10 different SDM techniques and 10 different evaluation methods was used in this study. According to the averaged evaluation scores of Relative Operating Characteristics (ROC) and True scale statistics (TSS) by models, those methods based on a multitude of decision trees such as Random Forest and Classification Tree Analysis, reached the highest predictive power followed by generalized boosted models (GBM) and maximum-entropy approaches (Maxent). The final ensemble model (EM) used 135 of 200 calculated models (TSS > 0.7) and identified hard substrate and SPM as the most influencing parameters followed by distance to glacier, total organic carbon (TOC), bathymetry and slope. The modeled current status of macroalgae distribution results in only 18.25% of earlier estimated areas populated by macroalgae in Potter Cove. The climate change scenarios show an invasive reaction of the macroalgae in case of less SPM and a retreat of the macroalgae in case of higher assumed SPM values.

  4. Effects of Ocean Acidification and Temperature Increases on the Photosynthesis of Tropical Reef Calcified Macroalgae

    Science.gov (United States)

    Pereira, Cristiano Macedo; Duarte, Gustavo; Horta, Paulo Antunes; e Castro, Clovis Barreira; Barufi, José Bonomi; Pereira, Sonia Maria Barreto

    2016-01-01

    Climate change is a global phenomenon that is considered an important threat to marine ecosystems. Ocean acidification and increased seawater temperatures are among the consequences of this phenomenon. The comprehension of the effects of these alterations on marine organisms, in particular on calcified macroalgae, is still modest despite its great importance. There are evidences that macroalgae inhabiting highly variable environments are relatively resilient to such changes. Thus, the aim of this study was to evaluate experimentally the effects of CO2-driven ocean acidification and temperature rises on the photosynthesis of calcified macroalgae inhabiting the intertidal region, a highly variable environment. The experiments were performed in a reef mesocosm in a tropical region on the Brazilian coast, using three species of frondose calcifying macroalgae (Halimeda cuneata, Padina gymnospora, and Tricleocarpa cylindrica) and crustose coralline algae. The acidification experiment consisted of three treatments with pH levels below those occurring in the region (-0.3, -0.6, -0.9). For the temperature experiment, three temperature levels above those occurring naturally in the region (+1, +2, +4°C) were determined. The results of the acidification experiment indicate an increase on the optimum quantum yield by T. cylindrica and a decline of this parameter by coralline algae, although both only occurred at the extreme acidification treatment (-0.9). The energy dissipation mechanisms of these algae were also altered at this extreme condition. Significant effects of the temperature experiment were limited to an enhancement of the photosynthetic performance by H. cuneata although only at a modest temperature increase (+1°C). In general, the results indicate a possible photosynthetic adaptation and/or acclimation of the studied macroalgae to the expected future ocean acidification and temperature rises, as separate factors. Such relative resilience may be a result of the

  5. Effects of Ocean Acidification and Temperature Increases on the Photosynthesis of Tropical Reef Calcified Macroalgae.

    Directory of Open Access Journals (Sweden)

    Fernando Scherner

    Full Text Available Climate change is a global phenomenon that is considered an important threat to marine ecosystems. Ocean acidification and increased seawater temperatures are among the consequences of this phenomenon. The comprehension of the effects of these alterations on marine organisms, in particular on calcified macroalgae, is still modest despite its great importance. There are evidences that macroalgae inhabiting highly variable environments are relatively resilient to such changes. Thus, the aim of this study was to evaluate experimentally the effects of CO2-driven ocean acidification and temperature rises on the photosynthesis of calcified macroalgae inhabiting the intertidal region, a highly variable environment. The experiments were performed in a reef mesocosm in a tropical region on the Brazilian coast, using three species of frondose calcifying macroalgae (Halimeda cuneata, Padina gymnospora, and Tricleocarpa cylindrica and crustose coralline algae. The acidification experiment consisted of three treatments with pH levels below those occurring in the region (-0.3, -0.6, -0.9. For the temperature experiment, three temperature levels above those occurring naturally in the region (+1, +2, +4°C were determined. The results of the acidification experiment indicate an increase on the optimum quantum yield by T. cylindrica and a decline of this parameter by coralline algae, although both only occurred at the extreme acidification treatment (-0.9. The energy dissipation mechanisms of these algae were also altered at this extreme condition. Significant effects of the temperature experiment were limited to an enhancement of the photosynthetic performance by H. cuneata although only at a modest temperature increase (+1°C. In general, the results indicate a possible photosynthetic adaptation and/or acclimation of the studied macroalgae to the expected future ocean acidification and temperature rises, as separate factors. Such relative resilience may be a

  6. THE EFFECT OF LITOPENAEUS STYLIROSTRIS AQUACULTURE ON MACROALGAE GROWTH IN OPUNOHU BAY, MOOREA, FRENCH POLYNESIA

    OpenAIRE

    Horn, Rachel A

    2012-01-01

    Aquaculture has many effects on the surrounding landscape. In Mo’orea, the only aquaculture operation is a shrimp farm in Opunohu Bay. To test the effect of shrimp farm runoff into the bay, a macroalgae field survey was conducted at different distances from the Opunohu River, where the effluent outlets. Algae cover was used to indicate nutrient concentration. I found that there is no significant relationship between distance from the shrimp farm outlet and algae cover. The red algae Acanthoph...

  7. Some observations on endemic macroalgae of the Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Abidi, S.A.H.

    The paper summarises current level of knowledge on the endemic Antarctic macroalgae. The macroalgal adaptation to low temperature, response to different photoperiod during the season, animal-macroalgal interaction and reproductive strategies...

  8. Macroalgae Has No Effect on the Severity and Dynamics of Caribbean Yellow Band Disease

    OpenAIRE

    Ivana Vu; Gillian Smelick; Sam Harris; Lee, Sarah C.; Ernesto Weil; Whitehead, Robert F.; John F Bruno

    2009-01-01

    By removing herbivores and promoting increases in macroalgae, overfishing is thought to indirectly cause coral disease and mortality. We performed three field manipulations to test the general hypothesis that overfishing and the subsequent alteration of coral reef trophic dynamics are a cause of coral epizootics. Specifically, we asked whether the presence of macroalgae can influence within- and among-colony spread rates of Caribbean Yellow Band Disease in Montastraea faveolata. Macroalgae we...

  9. Effect of Antarctic solar radiation on sewage bacteria viability

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, K.A. [National Environment Research Council, Cambridge (United Kingdom). British Antarctic Survey

    2005-06-01

    The majority of coastal Antarctic research stations discard untreated sewage waste into the near-shore marine environment. However, Antarctic solar conditions are unique, with ozone depletion increasing the proportion of potentially damaging ultraviolet-B (UV-B) radiation reaching the marine environment. This study assessed the influence of Antarctic solar radiation on the viability of Escherichia coli and sewage microorganisms at Rothera Research Station, Adelaide Island, Antarctic Peninsula. Cell viability decreased with increased exposure time and with exposure to shorter wavelengths of solar radiation. Cell survival also declined with decreasing cloud cover, solar zenith angle and ozone column depth. However, particulates in sewage increased the persistence of viable bacteria. Ultraviolet radiation doses over Rothera Point were highest during the austral summer. During this time, solar radiation may act to partially reduce the number of viable sewage-derived microorganisms in the surface seawater around Antarctic outfalls. Nevertheless, this effect is not reliable and every effort should be made to fully treat sewage before release into the Antarctic marine environment. (author)

  10. Effect of different temperature regimes on the chlorophyll a concentration in four species of Antarctic macroalgae

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.

    from beneath the sea-ice from the coast of the Vestfold Hills, Antarctica were cultured under different temperature regimes (- 4, -1.8, +4, +12, +20°C). The algae were cultured at each of these temperatures and Chlorophyll a concentrations of the algae...

  11. Disentangling the effects of solar radiation, wrack macroalgae and beach macrofauna on associated bacterial assemblages.

    Science.gov (United States)

    Rodil, Iván F; Fernandes, Joana P; Mucha, Ana P

    2015-12-01

    Wrack detritus plays a significant role in shaping community dynamics and food-webs on sandy beaches. Macroalgae is the most abundant beach wrack, and it is broken down by the combination of environmental processes, macrofauna grazing, and microbial degradation before returning to the sea as nutrients. The role of solar radiation, algal species and beach macrofauna as ecological drivers for bacterial assemblages associated to wrack was investigated by experimental manipulation of Laminaria ochroleuca and Sargassum muticum. We examined the effects of changes in solar radiation on wrack-associated bacterial assemblages by using cut-off filters: PAR + UVA + UVB (280-700 nm; PAB), PAR + UVA (320-700 nm; PA), PAR (400-700 nm; P), and a control with no filter (C). Results showed that moderate changes in UVR are capable to promote substantial differences on bacterial assemblages so that wrack patches exposed to full sunlight treatments (C and PAB) showed more similar assemblages among them than compared to patches exposed to treatments that blocked part of the solar radiation (P and PA). Our findings also suggested that specific algal nutrient quality-related variables (i.e. nitrogen, C:N ratio and phlorotannins) are main determinants of bacterial dynamics on wrack deposits. We showed a positive relationship between beach macrofauna, especially the most abundant and active wrack-users, the amphipod Talitrus saltator and the coleopteran Phaleria cadaverina, and both bacterial abundance and richness. Moderate variations in natural solar radiation and shifts in the algal species entering beach ecosystems can modify the role of wrack in the energy-flow of nearshore environments with unknown ecological implications for coastal ecosystems. PMID:26498844

  12. Sewage pollution in Negril, Jamaica: effects on nutrition and ecology of coral reef macroalgae

    Science.gov (United States)

    Lapointe, B. E.; Thacker, K.; Hanson, C.; Getten, L.

    2011-07-01

    Coral reefs in the Negril Marine Park (NMP), Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C:N:P and stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on shallow and deep reefs of the NMP in 1998 showed strong P-limitation and evidence of increasing sewage pollution. In 1999, a sewage collection and treatment project began diverting wastewater from the resort and urban areas to a pond system that discharged partially-treated effluent into the South Negril River (SNR). These sewage discharges significantly increased concentrations of NH{4/+} and SRP (N:P ˜13) in the SNR, which flows into Long Bay and around Negril's "West End". Concentrations of SRP, the primary limiting nutrient, were higher on shallow reefs of the West End in 2001 compared to 1998. Stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on both shallow and deep reefs of the West End in 2002 were significantly higher than baseline values in 1998, indicating an escalating impact of sewage nitrogen pollution over this timeframe. The increased nutrient concentrations and δ15N enrichment of reef macroalgae correlated with blooms of the chlorophyte Chaetomorpha linum in shallow waters of Long Bay and Codium isthmocladum and Caulerpa cupressoides on deep reefs of the West End. Sewage treatment systems adjacent to coral reefs must include nutrient removal to ensure that DIN and SRP concentrations, after dilution, are below the low thresholds noted for these oligotrophic ecosystems.

  13. The effect of desiccation on the emission of volatile bromocarbons from two common temperate macroalgae

    Directory of Open Access Journals (Sweden)

    E. C. Leedham Elvidge

    2014-07-01

    Full Text Available Exposure of intertidal macroalgae during low tide has been linked to the emission of a variety of atmospherically-important trace gases into the coastal atmosphere. In recent years, several studies have investigated the role of inorganic iodine and organoiodides as antioxidants and their emission during exposure to combat oxidative stress, yet the role of organic bromine species during desiccation is less well understood. In this study the emission of dibromomethane (CH2Br2 and bromoform (CHBr3 during exposure and desiccation of two common temperate macroalgae, Fucus vesiculosus and Ulva intestinalis, is reported. Determination of the impact exposure may have on algal physiological processes is difficult as intertidal species are adapted to desiccation and may undergo varying degrees of desiccation before their physiology is affected. For this reason we include comparisons between photosynthetic capacity (Fv / Fm and halocarbon emissions during a desiccation time series. In addition, the role of rewetting with freshwater to simulate exposure to rain was also investigated. Our results show that an immediate flux of bromocarbons occurs upon exposure, followed by a decline in bromocarbon emissions. We suggest that this immediate bromocarbon pulse may be linked to volatilisation or emissions of existing bromocarbon stores from the algal surface rather than the production of bromocarbons as an antioxidant response.

  14. Facilitative effects of introduced Pacific oysters on native macroalgae are limited by a secondary invader, the seaweed Sargassum muticum

    Science.gov (United States)

    Lang, Anne C.; Buschbaum, Christian

    2010-02-01

    Introduced habitat-providing organisms such as epibenthic bivalves may facilitate the invasion and expansion of further non-native species which may modify the effects of the primary invader on the native system. In the sedimentary intertidal Wadden Sea (south-eastern North Sea) introduced Pacific oysters ( Crassostrea gigas) have overgrown native blue mussel beds ( Mytilus edulis). These oyster beds are now providing the major attachment substratum for macroalgae. Recently, oysters have expanded their distribution into the shallow subtidal zone of the Wadden Sea, and there support a rich associated species community including the Japanese seaweed Sargassum muticum, which has been presumably introduced together with the oysters. With a block designed field experiment, we explored the effects of S. muticum on the associated community of soft-bottom C. gigas beds in the shallow subtidal. Replicated oyster plots of 1 m 2 were arranged with a density of 0, 7, 15 or 45 S. muticum m - 2 , respectively. We found no effects of different S. muticum densities on associated epi- and endobenthic community compositions associated to the oyster plots. However, the overall coverage of sessile organisms settling on the oyster shells was significantly reduced at high S. muticum densities. The occurrence of abundant native macro-algal species such as Polysiphonia nigrescens, Antithamnion plumula and Elachista fucicola decreased with increasing S. muticum densities. Sessile invertebrates, by contrast, were only marginally affected and we found no effects of S. muticum canopy on diversity and abundance of endofauna organisms. We conclude that increasing densities of S. muticum on C. gigas beds in the shallow subtidal zone of the Wadden Sea limit the occurrence of native macroalgae which otherwise would benefit from the additional hard substratum provided by the oysters. Thus, a secondary invader may abolish the effects of the primary invader for native species by occupying the new

  15. Allelopathic effects of macroalga Corallina pilulifera on the red-tide forming alga Heterosigma akashiwo under laboratory conditions

    Science.gov (United States)

    Wang, Renjun; Tang, Xuexi

    2016-03-01

    Over the past few years, harmful algal blooms (HABs), such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can alter the structure and succession of aquatic ecosystems. We investigated the influence of four environmental factors (temperature, salinity, light, and pH) on the allelopathic effects of the macroalgae Corallina pilulifera on red-tide forming Heterosigma akashiwo under laboratory conditions. Each of the factors had four levels: temperature (15, 20, 25, and 30°C), salinity (10, 20, 30, and 40), light (20, 100, 200 and 400 μmol/(m2•s)), and pH (5.5, 7, 8.5, and 10. Two-factor experiments were designed for each two environmental factors, with six combination treatments (temperature-salinity, temperature-light, temperature-pH, salinity-light, salinity-pH, and light-pH). Results showed that the allelopathic effect was significantly influenced by temperature, salinity, light, and pH. As single factors, the low temperature (15°C), low salinity (10), high-intensity light (400 μmol/(m2•s)), and high pH (10) treatments substantially enhanced the allelopathic effect. The strongest allelopathic effect of C. pilulifera on H. akashiwo was observed under the following treatments: 15°C and salinity of 40, 25°C and pH 10, 25°C with medium- to high-intensity light at 200-400 μmol/(m 2 •s), 400 μmol/(m2•s) and salinity of 10, 400 μmol/(m2•s) and pH 10, and pH 10 with a salinity of 40.

  16. Development of Radiation Breeding Technology of Macroalgae

    International Nuclear Information System (INIS)

    Macroalgae has been utilized as food material from long time ago, and recently newly recognized as functional materials and the source of bio-fuel. But, the study on the macroalgae is just beginning and the study on radiation effect and radiation breeding technology was not reported. In this study, the effect of radiation on the macroalgae Porphyra was investigated for the development of new mutant strains. Prphyra was successively cultivated in the laboratory chamber with optimized growth condition. Also, the radiation sensitivity of Porphyra was determined. To develop the mutant strain, irradiated Porphyra strains were screened for better growth and higher resistance against oxidative stress. The selected Porphyra was further cultivated in ocean site. Also, several genes from mutant Porphyra was heterologous expressed and studied for its dunctionality. This results can provide mutation technology of macroalgae and further contribute in the activation of fishery industry and national health enhancement

  17. Effects of antifouling biocides to the germination and growth of the marine macroalga, Hormosira banksii (Turner) Desicaine

    International Nuclear Information System (INIS)

    The International Maritime Organisation's (IMO) ban on the use of tributyltin in antifouling paints has inevitability increased the use of old fashioned antifoulants and/or the development of new paints containing 'booster biocides'. These newer paints are intended to be environmentally less harmful, however the broader environmental effects of these 'booster biocides' are poorly known. Germination and growth inhibition tests using the marine macroalga, Hormosira banksii (Turner) Desicaine were conducted to evaluate the toxicity of four new antifouling biocides in relation to tributyltin-oxide (TBTO). Each of the biocides significantly inhibited germination and growth of Hormosira banksii spores. Toxicity was in increasing order: diuron < zineb < seanine 211 < zinc pyrithione < TBTO. However, the lack of knowledge on partitioning in the environment makes it difficult to make a full assessment on whether the four biocides tested offer an advantage over organotin paints in terms of environmental impact

  18. Studies of marine macroalgae: saline desert water cultivation and effects of environmental stress on proximate composition. Final subcontract report. [Gracilaria tikvahiae; Ulva lactuca

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J.H.; DeBusk, T.A.; Peterson, J.E.

    1985-11-01

    The results presented in this report address the growth potential of marine macroalgae cultivated in desert saline waters, and the effects of certain environmental stresses (e.g., nitrogen, salinity, and temperature) on the proximate composition of several marine macroalgae. Two major desert saline water types were assayed for their ability to support the growth of Gracilaria, Ulva, and Caulerpa. Both water types supported short term growth, but long term growth was not supported. Carbohydrate levels in Gracilaria were increased by cultivation under conditions of high salinity, low temperature, and low nitrogen and phosphorous availability. Data suggests that it may be possible to maximize production of useful proximate constituents by cultivating the algae under optimum conditions for growth, and then holding the resulting biomass under the environmental conditions which favor tissue accumulation of the desired storage products. 16 refs., 21 figs., 19 tabs.

  19. Effects of sodium bicarbonate concentration on growth, photosynthesis, and carbonic anhydrase activity of macroalgae Gracilariopsis lemaneiformis, Gracilaria vermiculophylla, and Gracilaria chouae (Gracilariales, Rhodophyta).

    Science.gov (United States)

    Zhou, Wei; Sui, Zhenghong; Wang, Jinguo; Hu, Yiyi; Kang, Kyoung Ho; Hong, Hye Ran; Niaz, Zeeshan; Wei, Huihui; Du, Qingwei; Peng, Chong; Mi, Ping; Que, Zhou

    2016-06-01

    There is potential for bicarbonate to improve crop yields and economic efficiency of marine algae. However, few studies have focused on the effect of bicarbonate on the growth, photosynthesis, and enzyme activity associated with carbon utilization, especially in commercial macroalgae. Here, the addition of bicarbonate (up to 420 mg L(-1)) to macroalgal cultures has been evaluated for Gracilariopsis lemaneiformis, Gracilaria vermiculophylla, and Gracilaria chouae with respect to growth rate, photosynthetic activity, carbonic anhydrase activity, and biochemical composition. The results showed that the effects of NaHCO3 on growth, chlorophyll a, phycoerythrin, photosynthetic oxygen evolution, photochemical parameters of PSI and PSII, carbonic anhydrase activity, and nitrogen content were significant (P 336 mg L(-1) for Gp. lemaneiformis and >420 mg L(-1) for the other two species). Moreover, species-specific differences induced by supplementation with bicarbonate were discovered during culture. Optimal concentrations of NaHCO3 used in this study were 252 mg L(-1) for Gp. lemaneiformis and 336 mg L(-1) for G. vermiculophylla and G. chouae. These results suggest that an adequate supplementation of sodium bicarbonate is a viable strategy for promoting growth and photosynthetic activity in some macroalgae as well as for improving biochemical composition. The study will help to accelerate the growth rate of algae and improve the quality of thalli, and will also be useful for enhancing the understanding of carbon utilization in macroalgae. PMID:26960545

  20. Meiofaunal assemblages associated with native and non-indigenous macroalgae

    Science.gov (United States)

    Veiga, Puri; Sousa-Pinto, Isabel; Rubal, Marcos

    2016-07-01

    Meiofauna is a useful tool to detect effects of different disturbances; however, its relevance in the frame of biological invasions has been almost fully neglected. Meiofaunal assemblages associated with the invasive macroalga Sargassum muticum were studied and compared with those associated with two native macroalgae (Bifurcaria bifurcata and Chondrus crispus). We used a linear mixed model to determine the influence of habitat size (i.e. macroalgal biomass) in shaping meiofaunal assemblages. Results showed that habitat size (i.e. macroalgal biomass) shaped meiofaunal assemblages influencing its abundance, richness and structure. However, the identity of macroalga (i.e. species) appears also to play a significant role, particularly the differences of complexity among the studied species may shape their meiofaunal assemblages. Finally, the invasive macroalga appears to influence positively species richness. Our results highlight the need of including different faunal components to achieve a comprehensive knowledge on effects of invasive macroalgae and that meiofaunal assemblages may be a valuable tool to examine them.

  1. Impact of oxy-fuel combustion gases on mercury retention in activated carbons from a macroalgae waste: effect of water.

    Science.gov (United States)

    Lopez-Anton, M A; Ferrera-Lorenzo, N; Fuente, E; Díaz-Somoano, M; Suarez-Ruíz, I; Martínez-Tarazona, M R; Ruiz, B

    2015-04-01

    The aim of this study is to understand the different sorption behaviors of mercury species on activated carbons in the oxy-fuel combustion of coal and the effect of high quantities of water vapor on the retention process. The work evaluates the interactions between the mercury species and a series of activated carbons prepared from a macroalgae waste (algae meal) from the agar-agar industry in oxy-combustion atmospheres, focussing on the role that the high concentration of water in the flue gases plays in mercury retention. Two novel aspects are considered in this work (i) the impact of oxy-combustion gases on the retention of mercury by activated carbons and (ii) the performance of activated carbons prepared from biomass algae wastes for this application. The results obtained at laboratory scale indicate that the effect of the chemical and textural characteristics of the activated carbons on mercury capture is not as important as that of reactive gases, such as the SOx and water vapor present in the flue gas. Mercury retention was found to be much lower in the oxy-combustion atmosphere than in the O2+N2 (12.6% O2) atmosphere. However, the oxidation of elemental mercury (Hg0) to form oxidized mercury (Hg2+) amounted to 60%, resulting in an enhancement of mercury retention in the flue gas desulfurization units and a reduction in the amalgamation of Hg0 in the CO2 compression unit. This result is of considerable importance for the development of technologies based on activated carbon sorbents for mercury control in oxy-combustion processes. PMID:25585865

  2. Effect of solar ultraviolet radiation on growth in the marine macroalga Dictyota dichotoma (Phaeophyceae) at Helgoland and its ecological consequences

    Science.gov (United States)

    Kuhlenkamp, R.; Franklin, L. A.; Lüning, K.

    2001-03-01

    At Helgoland, in the North Sea, growth of the high sublittoral brown macroalga Dictyota dichotoma (Hudson) Lamoroux was examined in October (the time of tetraspore release) in an outdoor tank by exposing 2-day-old germlings to four solar radiation treatments achieved with different filter materials or an additional artificial light source: photosynthetically active radiation (PAR; 395-700 nm), PAR plus ultraviolet (UV)-A (320-700 nm), full solar spectrum, or solar spectrum plus artificial UV radiation (UVR). Based on length measurements over a period of 3 weeks, the growth rate in germlings strongly decreased in conditions with UVR compared to PAR: by 14% under PAR+UV-A, by 31% under the full solar spectrum and by 65% with additional UVR. Although growth rates of germlings under UVR were reduced mainly in the first week, the plants did not regain the size of the untreated plants even after 9 weeks. Regardless of the exposure, no defects in morphology or anatomy including the exposed apical meristem were detected, except for a reduction in cell division rates perhaps due to additional cost for photoprotective or repair mechanisms. Depending on the actual position of D. dichotoma plants in the natural habitat, individuals in high positions receive substantial amounts of the more harmful UV-B while those lower down might only receive UV-A during part of the day, thus the effect of UV-B on the growth of D. dichotoma will depend on its position in the field. The effects of tidal variation of the light climate and the implications of our results for the zonation of D. dichotoma are discussed.

  3. Diffusion boundary layers ameliorate the negative effects of ocean acidification on the temperate coralline macroalga Arthrocardia corymbosa.

    Directory of Open Access Journals (Sweden)

    Christopher E Cornwall

    Full Text Available Anthropogenically-modulated reductions in pH, termed ocean acidification, could pose a major threat to the physiological performance, stocks, and biodiversity of calcifiers and may devalue their ecosystem services. Recent debate has focussed on the need to develop approaches to arrest the potential negative impacts of ocean acidification on ecosystems dominated by calcareous organisms. In this study, we demonstrate the role of a discrete (i.e. diffusion boundary layer (DBL, formed at the surface of some calcifying species under slow flows, in buffering them from the corrosive effects of low pH seawater. The coralline macroalga Arthrocardia corymbosa was grown in a multifactorial experiment with two mean pH levels (8.05 'ambient' and 7.65 a worst case 'ocean acidification' scenario projected for 2100, each with two levels of seawater flow (fast and slow, i.e. DBL thin or thick. Coralline algae grown under slow flows with thick DBLs (i.e., unstirred with regular replenishment of seawater to their surface maintained net growth and calcification at pH 7.65 whereas those in higher flows with thin DBLs had net dissolution. Growth under ambient seawater pH (8.05 was not significantly different in thin and thick DBL treatments. No other measured diagnostic (recruit sizes and numbers, photosynthetic metrics, %C, %N, %MgCO3 responded to the effects of reduced seawater pH. Thus, flow conditions that promote the formation of thick DBLs, may enhance the subsistence of calcifiers by creating localised hydrodynamic conditions where metabolic activity ameliorates the negative impacts of ocean acidification.

  4. Instrumentation and handling effects on Antarctic fur seals (Arctocephalus gazella

    Directory of Open Access Journals (Sweden)

    Marie-Anne Blanchet

    2014-02-01

    Full Text Available The use of biologging instruments has greatly improved our understanding of the behaviour, physiology and ecology of free-ranging marine mammals. However, handling wild animals and attaching instruments to streamlined bodies can cause stress and potentially influence behaviour and swimming/diving energetics. The goals of this study, undertaken on Bouvetøya, were (1 to determine if the first trip to sea after instrumentation is representative of subsequent trips in lactating Antarctic fur seals, to explore potential handling effects and assess possible biases in having multiple short-duration deployments (inflating N, using a limited number of tags and (2 to evaluate potential effects of two different instrument combinations (SMRU satellite data relay loggers and very high frequency radio transmitters versus Wildlife Computers time–depth recorders and very high frequency radio transmitters on trip durations, dive parameters, female body condition and pup growth. Handling did not appear to have any effects on the parameters studied; data from the first and second trips did not differ significantly. This implies that multiple short-term deployments are unlikely to result in biased data in this species. Instrument type did have measurable effects; time-at-sea was greater and pup growth was lower for pairs in which mothers carried bulkier instruments. This suggests that instrument streamlining is important to avoid negative impacts and that bulkier equipment should be deployed on lactating females with caution and only for short periods. The study highlights that instrument effects should be taken into account when comparing data from experiments collected using different equipment packages.

  5. Effects of sedimentation on macroalgae : Species-specific responses are related to reproductive traits

    NARCIS (Netherlands)

    Eriksson, Klemens; Johansson, Gustav

    2005-01-01

    Although increases in sedimentation have been proposed to interfere with benthic communities in many coastal areas worldwide, few experimental studies have investigated the effect of sedimentation on community composition and assessed species-specific responses. In a field experiment on a rocky shor

  6. Allelopathic potential of extracts the from marine macroalga Plocamium brasiliense and their effects on pasture weed

    Directory of Open Access Journals (Sweden)

    Rainiomar Raimundo da Fonseca

    2012-08-01

    Full Text Available Four extracts from the marine red alga Plocamium brasiliense (Greville M.A.Howe & W.R.Taylor were prepared to identify and characterize their potential allelopathic effects on seed germination, radicle elongation and hypocotyl development of the weeds Mimosa pudica L. and Senna obtusifolia (L. Irwin & Barneby. The four extracts were prepared in a sequence of solvents of increasing polarity: n-hexane, dichloromethane, ethyl acetate and ethanol/water (7:3. The germination bioassay was carried out at 25 °C with a 12 h photoperiod and the radicle elongation and hypocotyl development at 25 °C with a 24 h photoperiod. The dichloromethane extract showed inhibitory effects on seed germination of both plants (35 and 14%, respectively, in M. pudica and S. obtusifolia, radical germination (52 and 41.7%, respectively and hypocotyl development (17.1 and 25.5%, respectively. Given the high sensitivity of this parameter to the potential allelopathic effects and the insufficient number of references found in the literature, these results are expected to stimulate new tests with other species of marine algae. Given the high sensitivity of the method for the detection of allelopathic potential, the species P. brasiliense emerges as a possible source of allelopathic substances against weed species. The results are attributed to the chemical composition, especially in relation to the presence of halogenated monoterpenes.

  7. Effect of depth on growth and pigment contents of the macroalgae Gracilaria bursa-pastoris

    OpenAIRE

    Eliane Marinho-Soriano

    2012-01-01

    The effects of environmental parameters on biomass, growth and pigment content of the red seaweed Gracilaria bursa-pastoris (S.G. Gmel.) P.C. Silva was investigated under field conditions in Thau Lagoon (France). The seaweed was cultivated in cages placed at three depths (1.0, 2.0 and 4.0 m) over a one-year period. The results showed elevated biomass and growth values in the spring and autumn, when temperature, light and photoperiod values were similar. The highest specific growth rates (SGR)...

  8. Effect of depth on growth and pigment contents of the macroalgae Gracilaria bursa-pastoris

    Directory of Open Access Journals (Sweden)

    Eliane Marinho-Soriano

    2012-08-01

    Full Text Available The effects of environmental parameters on biomass, growth and pigment content of the red seaweed Gracilaria bursa-pastoris (S.G. Gmel. P.C. Silva was investigated under field conditions in Thau Lagoon (France. The seaweed was cultivated in cages placed at three depths (1.0, 2.0 and 4.0 m over a one-year period. The results showed elevated biomass and growth values in the spring and autumn, when temperature, light and photoperiod values were similar. The highest specific growth rates (SGR were obtained at 1.0 m (4.95±0.29% day-1 and 2.0 m (4.45±0.33% day-1. At a depth of 4.0 m, the seaweed never exceeded 2% day-1 and obtained null values in the summer. The concentrations of phycoerythrin (RPE and chlorophyll (CHL a showed maximum values in the winter and minimum values in the summer. This evolution was related to water temperature, light intensity and nitrogen content in the algal tissue. The results obtained in this study show that the water depth influenced the growth and pigment composition of G. bursa-pastoris.

  9. Effects of Temperature Stress and Aquarium Conditions on the Red Macroalga Delisea pulchra and its Associated Microbial Community

    Science.gov (United States)

    Zozaya-Valdés, Enrique; Roth-Schulze, Alexandra J.; Thomas, Torsten

    2016-01-01

    In recent years, there has been an increase in the rate and severity of diseases affecting habitat-forming marine organisms, such as corals, sponges, and macroalgae. Delisea pulchra is a temperate red macroalga that suffers from a bleaching disease that is more frequent during summer, when seawater temperatures are elevated and the alga’s chemical defense is weakened. A bacterial cause for the disease is implied by previous studies showing that some isolated strains can cause bleaching in vitro and that host-associated microbial communities are distinct between diseased and healthy individuals. However, nothing is known about the successional events in the microbial community that occur during the development of the disease. To study this aspect in the future, we aimed here to develop an experimental setup to study the bleaching disease in a controllable aquarium environment. Application of a temperature stress (up to 27°C) did not cause a clear and consistent pattern of bleaching, suggesting that temperature alone might not be the only or main factor to cause the disease. The results also showed that the aquarium conditions alone are sufficient to produce bleaching symptoms. Microbial community analysis based on 16S rRNA gene fingerprinting and sequencing showed significant changes after 15 days in the aquarium, indicating that the native microbial associates of D. pulchra are not stably maintained. Microbial taxa that were enriched in the aquarium-held D. pulchra thalli, however, did not match on a taxonomic level those that have been found to be enriched in natural bleaching events. Together our observations indicate that environmental factors, other than the ones investigated here, might drive the bleaching disease in D. pulchra and that the aquarium conditions have substantial impact on the alga-associated microbiome. PMID:26925036

  10. Effects of temperature stress and aquarium conditions on the red macroalga Delisea pulchra and its associated microbial community

    Directory of Open Access Journals (Sweden)

    Enrique eZozaya-Valdés

    2016-02-01

    Full Text Available In recent years there has been an increase in the rate and severity of diseases affecting habitat-forming marine organisms, such as corals, sponges and macroalgae. Delisea pulchra is a temperate red macroalga that suffers from a bleaching disease that is more frequent during summer, when seawater temperatures are elevated and the alga’s chemical defense is weakened. A bacterial cause for the disease is implied by previous studies showing that some isolated strains can cause bleaching in vitro and that host-associated microbial communities are distinct between diseased and healthy individuals. However, nothing is known about the successional events in the microbial community that occur during the development of the disease. To study this aspect in the future, we aimed here to develop an experimental setup to study the bleaching disease in a controllable aquarium environment. Application of a temperature stress (up to 27° C did not cause a clear and consistent pattern of bleaching, suggesting that temperature alone might not be the only or main factor to cause the disease. The results also showed that the aquarium conditions alone seem to be sufficient to produce bleaching symptoms. Microbial community analysis based on 16S rRNA gene fingerprinting and sequencing showed significant changes after 15 days in the aquarium, indicating that the native microbial associates of D. pulchra are not stably maintained. Microbial taxa that were enriched in the aquarium-held D. pulchra thalli, however did not match on a taxonomic level those that have been found to be enriched in natural bleaching events. Together our observations indicate that environmental factors, other than the ones investigated here, might drive the bleaching disease in D. pulchra and that the aquarium conditions have substantial impact on the algal-associated microbiome.

  11. Resuspension created by bedload transport of macroalgae

    DEFF Research Database (Denmark)

    Canal Vergés, Paula; Kristensen, Erik; Flindt, Mogens

    2009-01-01

    Earlier studies have quantified that plant bound transport in shallow lagoons and estuaries may periodically be the dominating nutrient transport form. In some of these field studies turbidity increased when plant transport increased. The hypothesis in this study is therefore that macroalgae erode...... lactuca, Chaetomorpha linum and Ceramium sp., while the more rigid macroalgae like Fucus vesiculosus caused much higher turbidities (50-150 mg SPM l-1).This phenomena may explain the appearance of turbid waters in estuaries and lagoons in the absence of wind and wave action....... surface sediment while drifting as bed load. To improve the understanding of this ballistic effect of moving plants on the sediment surface, controlled annular flume experiments were performed. Plant transport was measured together with turbidity and suspended particulate matter during increasing water...

  12. Interactive effects of warming and species loss on model Antarctic microbial food webs

    OpenAIRE

    Newsham, K.K.; Garstecki, T.

    2007-01-01

    1. Predicting the effects of warming and species loss on ecosystems are two significant challenges currently facing ecologists. However, little is known of the interactive effects of these two factors. We hence tested whether or not warming and species loss interact to influence productivity and dissolved nitrogen concentrations in model Antarctic microbial food webs. Food webs, consisting of a uniform bacterial community and mixtures of six, four, two and zero bacterivorous flagellate specie...

  13. Diversity of pigmented Gram-positive bacteria associated with marine macroalgae from Antarctica.

    Science.gov (United States)

    Leiva, Sergio; Alvarado, Pamela; Huang, Ying; Wang, Jian; Garrido, Ignacio

    2015-12-01

    Little is known about the diversity and roles of Gram-positive and pigmented bacteria in Antarctic environments, especially those associated with marine macroorganisms. This work is the first study about the diversity and antimicrobial activity of culturable pigmented Gram-positive bacteria associated with marine Antarctic macroalgae. A total of 31 pigmented Gram-positive strains were isolated from the surface of six species of macroalgae collected in the King George Island, South Shetland Islands. On the basis of 16S rRNA gene sequence similarities ≥99%, 18 phylotypes were defined, which were clustered into 11 genera of Actinobacteria (Agrococcus, Arthrobacter, Brachybacterium, Citricoccus, Kocuria, Labedella, Microbacterium, Micrococcus, Rhodococcus, Salinibacterium and Sanguibacter) and one genus of the Firmicutes (Staphylococcus). It was found that five isolates displayed antimicrobial activity against a set of macroalgae-associated bacteria. The active isolates were phylogenetically related to Agrococcus baldri, Brachybacterium rhamnosum, Citricoccus zhacaiensis and Kocuria palustris. The results indicate that a diverse community of pigmented Gram-positive bacteria is associated with Antartic macroalgae and suggest its potential as a promising source of antimicrobial and pigmented natural compounds. PMID:26507390

  14. Combined nutrient and macroalgae loads lead to response in seagrass indicator properties.

    Science.gov (United States)

    Han, Qiuying; Soissons, Laura M; Bouma, Tjeerd J; van Katwijk, Marieke M; Liu, Dongyan

    2016-05-15

    Excess nutrients are potential factors that drive phase shifts from seagrasses to macroalgae. We carried out a manipulative field experiment to study the effects of macroalgae Ulva pertusa loading and nutrient addition to the water column on the nitrogen (N) and carbon (C) contents (i.e., fast indicators) as well as on the morphology and structure (i.e., slow indicators) of Zostera marina. Our results showed rapid impact of increased macroalgae and nutrient load on Z. marina C/N ratios. Also, macroalgae addition resulted in a trend of decreasing belowground biomass of seagrasses, and nutrient load significantly decreased above to belowground biomass ratio. Although some morphological/structural variables showed relatively fast responses, the effects of short-term disturbance by macroalgae and nutrients were less often significant than on physiological variables. Monitoring of seagrass physiological indicators may allow for early detection of eutrophication, which may initiate timely management interventions to avert seagrass loss. PMID:26975613

  15. The effect of environmental change on vascular plant and cryptogam communities from the Falkland Islands and the Maritime Antarctic

    OpenAIRE

    Convey Peter; Huiskes Ad; Bokhorst Stef; Aerts Rien

    2007-01-01

    Abstract Background Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant communities in the Maritime Antarctic region (cryptogams only) and the Falkland Islands (vascular plants only). We compared communities from the Falkland Islands (51°S, mean ann...

  16. Reflectance of Antarctic surfaces from multispectral radiometers: The correction of atmospheric effects

    International Nuclear Information System (INIS)

    Monitoring reflectance of polar icecaps has relevance in climate studies. In fact, climate changes produce variations in the morphology of ice and snow covers, which are detectable as surface reflectance change. Surface reflectance can be retrieved from remotely sensed data. However, absolute values independent of atmospheric turbidity and surface altitude can only be obtained after removing masking effects of the atmosphere. An atmospheric correction model, accounting for surface and sensor altitudes above sea level, is described and validated through data detected over Antarctic surfaces with a Barnes Modular Multispectral Radiometer having bands overlapping those of the Landsat Thematic Mapper. The model is also applied in a sensitivity analysis to investigate error induced in reflectance obtained from satellite data by indeterminacy in optical parameters of atmospheric constituents. Results show that indeterminacy in the atmospheric water vapor optical thickness is the main source of nonaccuracy in the retrieval of surface reflectance from data remotely sensed over Antarctic regions

  17. Effects of heavy metals and light levels on the biosynthesis of carotenoids and fatty acids in the macroalgae Gracilaria tenuistipitata (var. liui Zhang & Xia

    Directory of Open Access Journals (Sweden)

    Ernani Pinto

    2011-04-01

    Full Text Available We present here the effect of heavy metals and of different light intensities on the biosynthesis of fatty acids and pigments in the macroalga Gracilaria tenuistipitata (var. liui Zhang & Xia. In order to verify the fatty acid content, gas chromatography with flame ionization detection (GC-FID was employed. Pigments (major carotenoids and chlorophyl-a were monitored by liquid chromatography with diode array detection (HPLC-DAD. Cultures of G. tenuistipitata were exposed to cadmium (Cd2+, 200 ppb and copper (Cu2+, 200 ppb, as well as to different light conditions (low light: 100 µmol.photons.m-2.s-1, or high light: 1000 µmol.photons.m-2.s-1. Cd2+ and Cu2+ increased the saturated and monounsaturated fatty acid content [14:0, 16:0, 18:0, 18:1 (n-7 and 18:1 (n-9] and all major pigments (violaxanthin, antheraxanthin, lutein, zeaxanthin, chlorophyll-a and β-carotene. Both heavy metals decreased the levels of polyunsaturated fatty acids (PUFA [18:2 (n-6, 18:3 (n-6, 18:5 (n-4, 20:4 (n-6, 20:5 (n-3, 22:6 (n-3]. G. tenuistipitata cultures were exposed to high light intensity for five days and no statistically significant differences were observed in the content of fatty acids. On the other hand, the levels of pigments rose markedly for chlorophyll-a and all of the carotenoids studied.

  18. Effect of Seasonality on Distribution of Macroalgae in a Stream System (Xin'an Spring)in Shanxi Province, North China

    Institute of Scientific and Technical Information of China (English)

    Bian-Fang Hu; Shu-Lian Xie

    2006-01-01

    A survey of the seasonal distribution of macroalgae in a stream system in Shanxi Province, north China,was undertaken from July 2004 to April 2005. The relative abundance and percentage cover of macroalgae,and several environmental factors were monitored along a 20-m stretch at each of four sites, at intervals of approximately three months (one sampling per season). Several stream conditions were relatively constant over the sampling period (pH, maximum width and maximum depth), whereas others exhibited a distinct seasonal pattern (water temperature and specific conductance), and some fluctuated with no discernable seasonal pattern (current velocity and dissolved oxygen). Forty-two species of macroalgae were found, with a predominance of Chlorophyta (26 species, 61.9%). Rhodophyta and Charophyta represented the smallest proportion (1 species each, 2.38%). Six macroalgae species were the most widespread,occurring in all four sampling sites. Twelve species were found at only one site each. In terms of seasonality,eight species occurred throughout the year, whereas 16 species were found in only one season each. The macroalgal community at Xin'an Spring was species rich relative to other streams. Species richness per sampling site was negatively correlated with pH. Principal component analysis revealed that no single variable had much influence on the macroalgal seasonal dynamics. We calculated Sorensen similarity indices to compare our study with other continent-wide surveys of stream macroalgae, but the similarity indices were all very low. This study also shows that macroalgae in different locations have significant reproductive isolation.

  19. Model studies of the effects of global warming and Antarctic sea ice changes on Antarctic and global climates

    International Nuclear Information System (INIS)

    The authors discuss the results obtained in three experiments by changing the global ocean temperatures and the concentration and distribution of Antarctic sea ice in a General Circulation Model of July climate, with a view to determining the local and global impacts of Antarctic sea ice variations alone, as distinct with those coupled with global scale temperature changes which may be associated with global warming. In all cases there were significant changes in the upward flux of sensible heat over the sea ice zone associated with the reductions of sea ice. The response of weaker westerlies between 40 and 65 degree S was common to all three experiments. Their analyses suggest that a significant proportion of this is a response to the change in sea ice concentration alone. (Not surprisingly, further north of this region most of the changes induced in the wind structure in the global forcing experiment can be seen as due unambiguously to the differential changes in ocean temperatures.). This weakening of the westerlies means there is less mechanical forcing of the ocean in this region. From this they suggest that when consideration is given to the possible impact of feedbacks not considered in these experiments, sea ice changes alone, and particularly those in the Southern Hemisphere, have the potential to induce changes on a hemispheric scale

  20. Antimicrobial Activity of Iberian macroalgae

    OpenAIRE

    Salvador Soler, Noemi; Gómez Garreta, Ma. Amelia; Lavelli, Luca; Ribera Siguán, María Antonia

    2007-01-01

    The antibacterial and antifungal activity of 82 marine macroalgae (18 Chlorophyceae, 25 Phaeophyceae and 39 Rhodophyceae) was studied to evaluate their potential for being used as natural preservatives in the cosmetic industry. The bioactivity was analysed from crude extracts of fresh and lyophilised samples against three Gram-positive bacteria, two Gram-negative bacteria and one yeast using the agar diffusion technique. The samples were collected seasonally from Mediterranean and Atlantic co...

  1. Nutritional value of selected macroalgae

    OpenAIRE

    Patarra, Rita F.; Paiva, Lisete S.; Neto, Ana I.; Lima, Elisabete M. C.; Baptista, José A. B.

    2011-01-01

    Macroalgae are traditionally used in human and animal nutrition. Their protein and fiber content have been widely studied and differ according to the species, their geographic origin and their seasonal conditions. In addition to their value for human nutrition, seaweeds have multiple therapeutically applications (e.g., weight control, hypocholesterolemic, antioxidant and antitumor activities, others) and, in general, contribute and promote human health. In the archipelago of the Azores, the c...

  2. Effects of injected ice particles in the lower stratosphere on the Antarctic ozone hole

    Science.gov (United States)

    Nagase, H.; Kinnison, D. E.; Petersen, A. K.; Vitt, F.; Brasseur, G. P.

    2015-05-01

    The Antarctic ozone hole will continue to be observed in the next 35-50 years, although the emissions of chlorofluorocarbons (CFCs) have gradually been phased out during the last two decades. In this paper, we suggest a geo-engineering approach that will remove substantial amounts of hydrogen chloride (HCl) from the lower stratosphere in fall, and hence limit the formation of the Antarctic ozone hole in late winter and early spring. HCl will be removed by ice from the atmosphere at temperatures higher than the threshold under which polar stratospheric clouds (PSCs) are formed if sufficiently large amounts of ice are supplied to produce water saturation. A detailed chemical-climate numerical model is used to assess the expected efficiency of the proposed geo-engineering method, and specifically to calculate the removal of HCl by ice particles. The size of ice particles appears to be a key parameter: larger particles (with a radius between 10 and 100 µm) appear to be most efficient for removing HCl. Sensitivity studies lead to the conclusions that the ozone recovery is effective when ice particles are supplied during May and June in the latitude band ranging from 70°S to 90°S and in the altitude layer ranging from 10 to 26 km. It appears, therefore, that supplying ice particles to the Antarctic lower stratosphere could be effective in reducing the depth of the ozone hole. In addition, photodegradation of CFCs might be accelerated when ice is supplied due to enhanced vertical transport of this efficient greenhouse gas.

  3. Synergistic effects of iron and temperature on Antarctic plankton assemblages

    Directory of Open Access Journals (Sweden)

    J. M. Rose

    2009-06-01

    Full Text Available Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM and increased temperature (+4°C on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total phytoplankton abundance, phytoplankton and microzooplankton community composition, as well as photosynthetic parameters and nutrient drawdown. Unexpectedly, increased iron had a consistently negative impact on microzooplankton abundance, most likely a secondary response to changes in phytoplankton community composition. When iron and temperature were increased in concert, the resulting interactive effects were greatly magnified. This synergy between iron and temperature increases would not have been predictable by examining the effects of each variable individually. Our results suggest the possibility that if iron availability increases under future climate regimes, the impacts of predicted temperature increases on plankton assemblages in polar regions could be significantly enhanced. Such synergistic and antagonistic interactions between individual climate change variables highlight the importance of multivariate studies for marine global change experiments.

  4. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

    Energy Technology Data Exchange (ETDEWEB)

    Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joël [Laboratoire de Glaciologie et Géophysique de l’Environnement, CNRS, F-38041 Grenoble (France); Univ. Grenoble Alpes, LGGE, F-38041 Grenoble (France); Meusinger, Carl; Johnson, Matthew S. [Copenhagen Center for Atmospheric Research (CCAR), Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Jost, Rémy [Laboratoire de Interdisciplinaire de Physique (LIPHY) Univ. de Grenoble, Grenoble (France); Bhattacharya, S. K. [Research Center for Environmental Changes, Academia Sinica, Nangang, Taipei 115, Taiwan (China)

    2014-06-28

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [“Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry,” J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate ({sup 15}N, {sup 17}O, and {sup 18}O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ{sup 15}N, δ{sup 18}O, and Δ{sup 17}O). From these measurements an average photolytic isotopic fractionation of {sup 15}ε = (−15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of {sup 15}ε = (−47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from −40 to −74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of {sup 14}NO{sub 3}{sup −} and {sup 15}NO{sub 3}{sup −} in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying

  5. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

    International Nuclear Information System (INIS)

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [“Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry,” J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ15N, δ18O, and Δ17O). From these measurements an average photolytic isotopic fractionation of 15ε = (−15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of 15ε = (−47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from −40 to −74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of 14NO3− and 15NO3− in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying this model under the experimental temperature as well as considering the shift in width

  6. Effects of filamentous macroalgae mats on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Olesen, Birgit; Krause-Jensen, Dorte

    2012-01-01

    A laboratory experiment was conducted to assess the effect of filamentous algae mats on the performance of seedlings of the eelgrass, Zostera marina. The seedlings were covered by three levels (3, 6 and 9 cm) of natural (Chaetomorpha linum) and imitation algae mats and it was hypothesized that the...... effects of the natural algae on seedling growth may be more severe because of the metabolic demands of the algae. Results show that coverage by both C. linum and imitation algae significantly reduced seedling growth and increased allocation of resources to above ground tissues. No clear effects of algae...... type on seedling performance were found and since there were no differences in oxygen or sulphide concentrations between the treatments, we attribute the reductions in seedling growth to algal shading. In a comparison with other studies it is shown that lower turbulence, higher temperature, organically...

  7. High mortality of Zostera marina under high temperature regimes but minor effects of the invasive macroalgae Gracilaria vermiculophylla

    DEFF Research Database (Denmark)

    Höffle, Hannes; Thomsen, M.S.; Holmer, M.

    2011-01-01

    leaf elongation rates being negatively affected, while the leaf plastochrone interval increased. Relative growth rate was significantly higher at 21 C than at 18 C or 27 C, whereas rhizome elongation was significantly lowest at 27 C. Elemental sulphur content in the plant tissues increased...... but almost no mortality at the two lower temperatures. The higher mortality was probably caused by high sulphide levels in the sediment pore water (0.6 mmol l1 at 18 C compared to 3.7 mmol l1 at 27 C). Above-ground growth of the surviving shoots was also significantly affected by temperature, with...... significantly with temperature and was up to 34 times higher (S0 in rhizomes) at 27 C compared to the lower temperatures. In contrast to the temperature effects, cover by G. vermiculophylla did not cause significant effects on any seagrass responses. However, there was a (non-significant) negative effect of...

  8. Gene expression patterns of the coral Acropora millepora in response to contact with macroalgae

    OpenAIRE

    Shearer, TL; Rasher, DB; Snell, TW; Hay, ME

    2012-01-01

    Contact with macroalgae often causes coral mortality, but the roles of abrasion versus shading versus allelopathy in these interactions are rarely clear and effects on gene expression are unknown. Identification of gene expression changes within corals in response to contact with macroalgae can provide insight into the mode of action of allelochemicals, as well as reveal transcriptional strategies of the coral that mitigate damage from this competitive interaction, enabling the coral to survi...

  9. The effect of environmental change on vascular plant and cryptogam communities from the Falkland Islands and the Maritime Antarctic

    NARCIS (Netherlands)

    Bokhorst, S.F.; Huiskes, A.H.L.; Convey, P.; Aerts, R.A.M.

    2007-01-01

    Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant

  10. Effects of filamentous macroalgae on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Krause-Jensen, Dorte; Olesen, Birgit

    Seedling survival and patch establishment is a major bottle-neck for eelgrass (Zostera marina) re-colonization as mortality rates among the young seedlings are high, even in areas where conditions should support survival. We here focus on the potential negative effects of drifting macroalgal mats...... on eelgrass seedling performance. The covering of eelgrass shoots by algae decreases the light availability and may hamper the diffusive movement of oxygen, inorganic carbon and nutrients to and from the shoots. Moreover, the high productivity of the algae can result in large diurnal oxygen...... variations within the mat and periods of anoxia in the lower parts can possibly be followed by release of sulphide from the sediments. We assessed the impact of algae mats on seedling performance and evaluated the relative importance of light attenuation and low oxygen concentrations for seedling growth and...

  11. Diversity of intertidal macroalgae increases with nitrogen loading by invertebrates

    OpenAIRE

    Bracken, Matthew E. S.; Nielsen, K. J.

    2004-01-01

    Many ecological phenomena are characterized by context dependency, and the relationship between diversity and productivity is no exception. We examined the relationship between macroalgal diversity,and nutrient availability by evaluating the effects of reduced nutrients and their subsequent replacement via local-scale nutrient loading in tide pools. Macroalgae in Oregon coast high-intertidal pools have evolved in a nitrate-rich upwelling ecosystem, but instead of settling on low-intertidal re...

  12. Macroalgae - Production and Biorefining in Denmark

    DEFF Research Database (Denmark)

    Seghetta, Michele; Hou, Xiaoru; Bastianoni, Simone;

    Macroalgae is a key biomass for the development of circular economy. This study analyzes the environmental sustainability of a macroalgae production and conversion system in Denmark. A brown algae model based on Laminaria digitata and Saccharina latissima is utilized as feedstock for a biorefinery...... system which produces bioethanol, fish feed and liquid fertilizers. A Life Cycle Assessment was conducted from cradle to grave; i.e. from cultivation and harvest of biomass, to the use phase of the products....

  13. Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Inés G., E-mail: ines.gonzalez@co.ieo.es; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ{sup 15}N). In this study δ{sup 15}N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ{sup 15}N was not related to either inorganic nitrogen concentrations or δ{sup 15}N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ{sup 15}N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ{sup 15}N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10{sup 3} inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ{sup 15}N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ{sup 15}N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ{sup 15}N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ{sup 15}N in macroalgae.

  14. Environmental effects of the US Antarctic Program`s use of balloons in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    McCold, L.N.; Eddlemon, G.K.; Blasing, T.J.

    1995-06-01

    The USAP uses balloons in Antarctica to conduct scientific research, to facilitate safe air transport, and to provide data for global weather predictions. However, there is the possibility that balloons or their payloads may adversely affect Antarctic fauna or flora. The purpose of this study is to provide background information upon which the USAP may draw when complying with its responsibilities under the National Environmental Policy Act of 1969, the Antarctic Treaty, and the Madrid Protocol.

  15. Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

    Science.gov (United States)

    Viana, Inés G; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. PMID:23247291

  16. The effects of oil pollution on Antarctic benthic diatom communities over 5 years

    International Nuclear Information System (INIS)

    Highlights: • We examine the impact of hydrocarbon pollution on Antarctic benthic diatoms. • The effect of standard synthetic lubricant oil and a biodegradable oil were examined. • There were significant effects from both treatments for over 5 years. • There was little difference between the different types of oil. - Abstract: Although considered pristine, Antarctica has not been impervious to hydrocarbon pollution. Antarctica’s history is peppered with oil spills and numerous abandoned waste disposal sites. Both spill events and constant leakages contribute to previous and current sources of pollution into marine sediments. Here we compare the response of the benthic diatom communities over 5 years to exposure to a commonly used standard synthetic lubricant oil, an alternative lubricant marketed as more biodegradable, in comparison to a control treatment. Community composition varied significantly over time and between treatments with some high variability within contaminated treatments suggesting community stress. Both lubricants showed evidence of significant effects on community composition after 5 years even though total petroleum hydrocarbon reduction reached approximately 80% over this time period. It appears that even after 5 years toxicity remains high for both the standard and biodegradable lubricants revealing the temporal scale at which pollutants persist in Antarctica

  17. The Effect of Aqueous Alteration in Antarctic Carbonaceous Chondrites from Comparative ICP-MS Bulk Chemistry

    Science.gov (United States)

    Alonso-Azcarate, J.; Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Zolensky, M.

    2014-01-01

    Terrestrial ages of Antarctic carbonaceous chondrites (CC) indicate that these meteorites have been preserved in or on ice for, at least, tens of thousands of years. Due to the porous structure of these chondrites formed by the aggregation of silicate-rich chondrules, refractory inclusions, metal grains, and fine-grained matrix materials, the effect of pervasive terrestrial water is relevant. Our community defends that pristine CC matrices are representing samples of scarcely processed protoplanetary disk materials as they contain stellar grains, but they might also trace parent body processes. It is important to study the effects of terrestrial aqueous alteration in promoting bulk chemistry changes, and creating distinctive alteration minerals. Particularly because it is thought that aqueous alteration has particularly played a key role in some CC groups in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive. With the goal to learn more about terrestrial alteration in Antarctica we are obtaining reflectance spectra of CCs, but also performing ICP-MS bulk chemistry of the different CC groups. A direct comparison with the mean bulk elemental composition of recovered falls might inform us on the effects of terrestrial alteration in finds. With such a goal, in the current work we have analyzed some members representative of CO and CM chondrite groups.

  18. Effect of nutrient enrichments on the bacterial assemblage of Antarctic soils contaminated by diesel or crude oil

    OpenAIRE

    Delille, Daniel; Pelletier, Emilien; Delille, Bruno; Coulon, Fréderic

    2003-01-01

    There is an urgent need to develop new technologies to address the problem of soil remediation in high-latitude regions. A field study was initiated in January 1997 in two contaminated soils in Terre Adélie (Antarctica) with the objective of determining the long-term effectiveness of two bioremediation agents on total and hydrocarbon-degrading microbial assemblages under severe Antarctic conditions. This study was conducted in two steps, from January to July 1997 and from February to November...

  19. Designing an effective mark-recapture study of Antarctic blue whales.

    Science.gov (United States)

    Peel, David; Bravington, Mark; Kelly, Natalie; Double, Michael C

    2015-06-01

    To properly conserve and manage wild populations, it is important to have information on abundance and population dynamics. In the case of rare and cryptic species, especially in remote locations, surveys can be difficult and expensive, and run the risk of not producing sample sizes large enough to produce precise estimates. Therefore, it is crucial to conduct preliminary analysis to determine if the study will produce useable estimates. The focus of this paper is a proposed mark-recapture study of Antarctic blue whales (Balaenoptera musculus intermedia). Antarctic blue whales were hunted to near extinction up until the mid- 1960s, when commercial exploitation of this species ended. Current abundance estimates are a decade old. Furthermore, at present, there are no formal circumpolar-level cetacean surveys operating in Antarctic waters and, specifically, there is no strategy to monitor the potential recovery of Antarctic blue whales. Hence the work in this paper was motivated by the need to inform decisions on strategies for future monitoring of Antarctic blue whale population. The paper describes a model to predict the precision and bias of estimates from a proposed survey program. The analysis showed that mark-recapture is indeed a suitable method to provide a circumpolar abundance estimate of Antarctic blue whales, with precision of the abundance, at the midpoint of the program, predicted to be between 0.2 and 0.3. However, this was only if passive acoustic tracking was utilized to increase the encounter rate. The analysis also provided guidance on general design for an Antarctic blue whale program, showing that it requires a 12-year duration; although surveys do not necessarily need to be run every year if multiple vessels are available to clump effort. Mark-recapture is based on a number of assumptions; it was evident from the analysis that ongoing analysis and monitoring of the data would be required to check such assumptions hold (e.g., test for

  20. Effects of injected ice particles in the lower stratosphere on the Antarctic ozone hole

    OpenAIRE

    Nagase, H.; Kinnison, D.; Petersen, A.; F. Vitt; Brasseur, G.

    2015-01-01

    The Antarctic ozone hole will continue to be observed in the next 35-50 years, although the emissions of chlorofluorocarbons (CFCs) have gradually been phased out during the last two decades. In this paper, we suggest a geo-engineering approach that will remove substantial amounts of hydrogen chloride (HCl) from the lower stratosphere in fall, and hence limit the formation of the Antarctic ozone hole in late winter and early spring. HCl will be removed by ice from the atmosphere at temperatur...

  1. Field research on the effects of UV-B filters on terrestrial Antarctic vegetation

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Lud, D.; Moerdijk-Poortvliet, T.C.W.

    2001-01-01

    Patches of vegetation of six common species growing on Leonie Island (67 degrees 35' S, 68 degrees 20' W), Antarctic Peninsula region were covered with either UV-B transparent perspex screens or UV-B absorbing screens. Uncovered plots served as a control. Temperature and relative humidity were monit

  2. The effect of environmental change on vascular plant and cryptogam communities from the Falkland Islands and the Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    Convey Peter

    2007-12-01

    Full Text Available Abstract Background Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant communities in the Maritime Antarctic region (cryptogams only and the Falkland Islands (vascular plants only. We compared communities from the Falkland Islands (51°S, mean annual temperature 7.9°C, with those of Signy Island (60°S, -2.1°C and Anchorage Island (67°S, -2.6°C, and experimental temperature manipulations at each of the three islands using Open Top Chambers (OTCs. Results Despite the strong difference in plant growth form dominance between the Falkland Islands and the Maritime Antarctic, communities across the gradient did not differ in total diversity and species number. During the summer months, the experimental temperature increase at 5 cm height in the vegetation was similar between the locations (0.7°C across the study. In general, the response to this experimental warming was low. Total lichen cover showed a non-significant decreasing trend at Signy Island (p Conclusion These results suggest that small temperature increases may rapidly lead to decreased soil moisture, resulting in more stressful conditions for plants. The more open plant communities (grass and lichen appeared more negatively affected by such changes than dense communities (dwarf shrub and moss.

  3. Observational Evidence of a Hemispheric-wide Ice-ocean Albedo Feedback Effect on Antarctic Sea-ice Decay

    Science.gov (United States)

    Nihashi, Sohey; Cavalieri, Donald J.

    2007-01-01

    The effect of ice-ocean albedo feedback (a kind of ice-albedo feedback) on sea-ice decay is demonstrated over the Antarctic sea-ice zone from an analysis of satellite-derived hemispheric sea ice concentration and European Centre for Medium-Range Weather Forecasts (ERA-40) atmospheric data for the period 1979-2001. Sea ice concentration in December (time of most active melt) correlates better with the meridional component of the wind-forced ice drift (MID) in November (beginning of the melt season) than the MID in December. This 1 month lagged correlation is observed in most of the Antarctic sea-ice covered ocean. Daily time series of ice , concentration show that the ice concentration anomaly increases toward the time of maximum sea-ice melt. These findings can be explained by the following positive feedback effect: once ice concentration decreases (increases) at the beginning of the melt season, solar heating of the upper ocean through the increased (decreased) open water fraction is enhanced (reduced), leading to (suppressing) a further decrease in ice concentration by the oceanic heat. Results obtained fi-om a simple ice-ocean coupled model also support our interpretation of the observational results. This positive feedback mechanism explains in part the large interannual variability of the sea-ice cover in summer.

  4. Bioremediation capacity, nutritional value and biorefining of macroalga Saccharina latissima

    DEFF Research Database (Denmark)

    Silva Marinho, Goncalo

    Macroalgae have the ability to assimilate and convert waste nutrients (N and P) into valuable biomass. In this context, they have been extensively studied for their bioremediation potential for integrated multi-trophic aquaculture (IMTA). With a global aquaculture production of 23.8 million tonnes...... increasing attention as sustainable feedstock for biorefinery. Nevertheless, macroalgae resources are still very little explored in western countries. The aim of this study was fulfilled by the investigation of the bioremediation potential of the macroalga Saccharina latissima cultivated at a reference site...... in 2012, macroalgae are a valuable source of vitamins, minerals, lipids, protein, and dietary fibres. Macroalgae have been used as food since ancient times in Asian countries, while in Europe they have lately been introduced as healthy food. Moreover, recently macroalgae have been receiving...

  5. Checklist of the marine macroalgae of Vietnam

    OpenAIRE

    Nguyen, T.V.; Le, H.N.; Lin, S. M.; Steen, F. van der; De Clerck, O.

    2013-01-01

    Despite a rich seaweed flora, information about Vietnamese seaweeds is scattered throughout a large number of often regional publications and, hence, difficult to access. This paper presents an up-to-date checklist of the marine macroalgae of Vietnam, compiled by means of an exhaustive bibliographical search and revision of taxon names. A total of 827 species are reported, of which the Rhodophyta show the highest species number (412 species), followed by the Chlorophyta (180 species), Phaeoph...

  6. Antarctic seawater temperature evaluation based on stable isotope measurements on Adamussium colbecki shells: kinetic effects vs. isotopic equilibrium

    Science.gov (United States)

    Trevisiol, A.; Bergamasco, A.; Montagna, P.; Sprovieri, M.; Taviani, M.

    2013-10-01

    A year-long controlled growth experiment of 60 specimens of the Antarctic bivalve Adamussium colbecki was conducted in Terra Nova Bay (Ross Sea) to evaluate its reliability as a suitable archive of water mass properties. Nine shells were sub-sampled for stable oxygen and carbon isotope analysis to study the inter and intra specimen variations. Slow-growing A. colbecki precipitate their calcitic shells close to the expected oxygen and carbon isotopic equilibrium, whereas the fast-growing individuals are strongly influenced by biogenetic and kinetic effects. The equation of Kim and O'Neil (1997) is considered a fair approximation for the δ18O-temperature relationship in slow-growing individuals. The reconstructed temperature is closer to the mean experimental summer temperature than the annual one. This fact is interpreted as reflecting a possible winter decrease of shell growth, the salinity variation and the corrections for negative temperature on calibrating the δ18O-temperature relationship. Our results support the hypothesis that A. colbecki might represent a good archive for encoding Antarctic Shelf water summer temperature information. Further improvements in adopting A. colbecki as a paleotemperature archive will require the evaluation of the seasonal variability in shell growth rate through culturing slow-growing A. colbecki individuals at near-freezing temperatures to calibrate a species-specific δ18O-temperature equation.

  7. Comparative study on metal biosorption by two macroalgae in saline waters: single and ternary systems.

    Science.gov (United States)

    Figueira, Paula; Henriques, Bruno; Teixeira, Ana; Lopes, Cláudia B; Reis, Ana T; Monteiro, Rui J R; Duarte, A C; Pardal, M A; Pereira, E

    2016-06-01

    The biosorption capability of two marine macroalgae (green Ulva lactuca and brown Fucus vesiculosus) was evaluated in the removal of toxic metals (Hg, Cd and Pb) from saline waters, under realistic conditions. Results showed that, independently of the contamination scenario tested, both macroalgae have a remarkable capacity to biosorb Hg and Pb. In single-contaminant systems, by using only c.a. 500 mg of non-pre-treated algae biomass (size  Pb> > Cd, although Pb removal by U. lactuca was more inhibited than that achieved by F. vesiculosus. Under the experimental conditions used, none of the macroalgae was effective to remove Cd (maximum removal of 20 %). In all cases, the kinetics of biosorption was mathematically described with success. Globally, it became clear that the studied macroalgae may be part of simple, efficient, and cost-effective water treatment technologies. Nevertheless, Fucus vesiculosus has greater potential, since it always presented higher initial sorption rates and higher removal efficiencies. PMID:26961530

  8. Environmental contamination in Antarctic ecosystems.

    Science.gov (United States)

    Bargagli, R

    2008-08-01

    Although the remote continent of Antarctica is perceived as the symbol of the last great wilderness, the human presence in the Southern Ocean and the continent began in the early 1900s for hunting, fishing and exploration, and many invasive plant and animal species have been deliberately introduced in several sub-Antarctic islands. Over the last 50 years, the development of research and tourism have locally affected terrestrial and marine coastal ecosystems through fuel combustion (for transportation and energy production), accidental oil spills, waste incineration and sewage. Although natural "barriers" such as oceanic and atmospheric circulation protect Antarctica from lower latitude water and air masses, available data on concentrations of metals, pesticides and other persistent pollutants in air, snow, mosses, lichens and marine organisms show that most persistent contaminants in the Antarctic environment are transported from other continents in the Southern Hemisphere. At present, levels of most contaminants in Antarctic organisms are lower than those in related species from other remote regions, except for the natural accumulation of Cd and Hg in several marine organisms and especially in albatrosses and petrels. The concentrations of organic pollutants in the eggs of an opportunistic top predator such as the south polar skua are close to those that may cause adverse health effects. Population growth and industrial development in several countries of the Southern Hemisphere are changing the global pattern of persistent anthropogenic contaminants and new classes of chemicals have already been detected in the Antarctic environment. Although the Protocol on Environmental Protection to the Antarctic Treaty provides strict guidelines for the protection of the Antarctic environment and establishes obligations for all human activity in the continent and the Southern Ocean, global warming, population growth and industrial development in countries of the Southern

  9. Trace element seasonality in marine macroalgae of different functional-form groups.

    Science.gov (United States)

    Malea, Paraskevi; Chatziapostolou, Anastasia; Kevrekidis, Theodoros

    2015-02-01

    Novel information on the seasonality of element accumulation in seaweeds is provided. Seasonal patterns of As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr, U, V and Zn concentrations in macroalgae belonging to different functional-form groups (Ulva intestinalis, Ulva rigida, Codium fragile, Gracilaria gracilis) from the Thessaloniki Gulf, Aegean Sea were determined and compared. Uni- and multivariate data analyses were applied. Element concentrations generally decreased during spring and/or summer, probably due to the growth effect, but a reverse trend, particularly in Ulva species, was also observed. Most elements (Cd, Co, Cr, Cu, Mo, Ni, Pb, Sr) in Ulva species displayed a comparatively low monthly variability, indicating that the extent of seasonal variation is closely related to thallus morphology and growth strategy. In particular, these data suggest that Cd, Co, Cr, Cu, Mo, Ni, Pb and Sr contents in fast-growing, sheet-like macroalgae are less influenced by the season, compared to their contents in coarsely-branched and thick-leathery macroalgae; therefore, sheet-like macroalgae may be more appropriate to be used in biomonitoring of coastal waters. The data presented could be utilized in the development of biomonitoring programmes for the protection of coastal environments. PMID:25460058

  10. SHORT- AND LONG-TERM EFFECTS OF ELEVATED CO2 ON PHOTOSYNTHESIS AND RESPIRATION IN THE MARINE MACROALGA HIZIKIA FUSIFORMIS (SARGASSACEAE, PHAEOPHYTA) GROWN AT LOW AND HIGH N SUPPLIES(1).

    Science.gov (United States)

    Zou, Dinghui; Gao, Kunshan; Luo, Hanjin

    2011-02-01

    The short-term and long-term effects of elevated CO2 on photosynthesis and respiration were examined in cultures of the marine brown macroalga Hizikia fusiformis (Harv.) Okamura grown under ambient (375 μL · L(-1) ) and elevated (700 μL · L(-1) ) CO2 concentrations and at low and high N availability. Short-term exposure to CO2 enrichment stimulated photosynthesis, and this stimulation was maintained with prolonged growth at elevated CO2 , regardless of the N levels in culture, indicating no down-regulation of photosynthesis with prolonged growth at elevated CO2 . However, the photosynthetic rate of low-N-grown H. fusiformis was more responsive to CO2 enrichment than that of high-N-grown algae. Elevation of CO2 concentration increased the value of K1/2 (Ci) (the half-saturation constant) for photosynthesis, whereas high N supply lowered it. Neither short-term nor long-term CO2 enrichment had inhibitory effects on respiration rate, irrespective of the N supply, under which the algae were grown. Under high-N growth, the Q10 value of respiration was higher in the elevated-CO2 -grown algae than the ambient-CO2 -grown algae. Either short- or long-term exposure to CO2 enrichment decreased respiration as a proportion of gross photosynthesis (Pg) in low-N-grown H. fusiformis. It was proposed that in a future world of higher atmospheric CO2 concentration and simultaneous coastal eutrophication, the respiratory carbon flux would be more sensitive to changing temperature. PMID:27021713

  11. Genetic affinities between trans-oceanic populations of non-buoyant macroalgae in the high latitudes of the Southern Hemisphere.

    Science.gov (United States)

    Fraser, Ceridwen I; Zuccarello, Giuseppe C; Spencer, Hamish G; Salvatore, Laura C; Garcia, Gabriella R; Waters, Jonathan M

    2013-01-01

    Marine biologists and biogeographers have long been puzzled by apparently non-dispersive coastal taxa that nonetheless have extensive transoceanic distributions. We here carried out a broad-scale phylogeographic study to test whether two widespread Southern Hemisphere species of non-buoyant littoral macroalgae are capable of long-distance dispersal. Samples were collected from along the coasts of southern Chile, New Zealand and several subAntarctic islands, with the focus on high latitude populations in the path of the Antarctic Circumpolar Current or West Wind Drift. We targeted two widespread littoral macroalgal species: the brown alga Adenocystisutricularis (Ectocarpales, Heterokontophyta) and the red alga Bostrychiaintricata (Ceramiales, Rhodophyta). Phylogenetic analyses were performed using partial mitochondrial (COI), chloroplast (rbcL) and ribosomal nuclear (LSU / 28S) DNA sequence data. Numerous deeply-divergent clades were resolved across all markers in each of the target species, but close phylogenetic relationships - even shared haplotypes - were observed among some populations separated by large oceanic distances. Despite not being particularly buoyant, both Adenocystisutricularis and Bostrychiaintricata thus show genetic signatures of recent dispersal across vast oceanic distances, presumably by attachment to floating substrata such as wood or buoyant macroalgae. PMID:23894421

  12. Recent developments on biofuels production from microalgae and macroalgae

    DEFF Research Database (Denmark)

    Kumar, Kanhaiya; Ghosh, Supratim; Angelidaki, Irini;

    2016-01-01

    energetically and commercially viable. Macroalgae are low in lipid content. Therefore, the use of macroalgae is restricted for gaseous fuels or fermentative methods of liquid biofuels production. Anaerobic digestion of algal biomass is easy and seems promising as the process is simple in terms of engineering...

  13. Control biológico del fouling en tanques de cultivo de macroalgas mediante el gasterópodo Osilinus atratus (Wood, 1828)

    OpenAIRE

    Portillo, E.

    2002-01-01

    We tested the use of the gastropod Osilinus atratus (Wood, 1828) to control and eliminate fouling on the walls of macroalgae culture tanks. These gastropods use such fouling as a food source, and their continuous grazing excursions prevent the attachment and development of propagules. This system of biological fouling control via the co-culture of gastropods and macroalgae, besides being an environmentally friendly, is effective in reducing production costs and in limiting the negative effect...

  14. The effect of UV radiation on photosynthesis in an Antarctic diatom (Thalassiosira sp.): does vertical mixing matter?

    International Nuclear Information System (INIS)

    Full text: The reduction of the Antarctic stratospheric ozone resulted in significant increases in ultraviolet B radiation (UVBR, 280-320 nm) reaching the surface of the ocean. A series of laboratory and field experiments were conducted at Potter Cove (25 de Mayo Is., South Shetland Is., Antarctica) to study the effects of UVBR on photosynthesis of a typical Antarctic bloom forming diatom (Thalassiosira sp.) in fixed and moving incubations. There were three irradiance treatments: PART (with only photosynthetic active radiation, PAR, 400- 700 nm), UVAT (with PAR and ultraviolet A radiation, UVAR, 320-400 nm) and UVBT (with PAR, UVAR and UVBR). The three treatments were incubated in the field and laboratory with a solar simulator (SOLSI) in fixed frames at 0.5 and 5 m depth (Sfix and Bfix, respectively), while for the moving incubations were done within 6 h cycles (Mix). Considering the field and laboratory pooled data, results suggest an overall 45-50 % photosynthesis inhibition of Sfix incubations in relation with Mix ones. During SOLSI experiments no significant differences were found between irradiance treatments under normal and medium ozone concentrations. Under low ozone conditions, a 40 % reduction in photosynthesis was observed in the UVBT for Sfix . In contrast, no significant differences were observed between the irradiance treatments for Mix. Field experiment showed results similar to the laboratory ones, but in this case not only Sfix but Mix incubations presented a significant reduction in photosynthesis under low ozone. The differences between laboratory and field experiments are discussed in terms of the relative significance of UVBR dose and dose rate on both types of experiments. (author)

  15. Coral reef baselines: how much macroalgae is natural?

    Science.gov (United States)

    Bruno, John F; Precht, William F; Vroom, Peter S; Aronson, Richard B

    2014-03-15

    Identifying the baseline or natural state of an ecosystem is a critical step in effective conservation and restoration. Like most marine ecosystems, coral reefs are being degraded by human activities: corals and fish have declined in abundance and seaweeds, or macroalgae, have become more prevalent. The challenge for resource managers is to reverse these trends, but by how much? Based on surveys of Caribbean reefs in the 1970s, some reef scientists believe that the average cover of seaweed was very low in the natural state: perhaps less than 3%. On the other hand, evidence from remote Pacific reefs, ecological theory, and impacts of over-harvesting in other systems all suggest that, historically, macroalgal biomass may have been higher than assumed. Uncertainties about the natural state of coral reefs illustrate the difficulty of determining the baseline condition of even well studied systems. PMID:24486044

  16. Factors Controlling the Distribution of Trace Metals in Macroalgae

    Institute of Scientific and Technical Information of China (English)

    王宝利; 刘丛强

    2004-01-01

    This paper presents the concentrations of trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) in macroalgae from five areas. Significant differences were noticed in trace metal concentration in macroalgae, and a large range of variations between the minimum and maximum concentrations of trace metals was found. Trace metals detected in macroalgae generally occur in adsorbed and absorbed forms. Environmental and biological factors jointly control the trace metal compositions and concentrations in macroalgae. The complexity and variation of these factors cause significant differences in trace metal concentrations in macroalgae. Environmental factors play a more important role in controlling trace metal compositions and concentrations when external available trace metals are beyond requirement for algal metabolism and growth, especially for non-essential trace metals; however, when the external available trace metals just satisfy the needs of algal metabolism and growth, biological factors would play a more important role, especially for essential trace metals. Interactions among the trace metals can also influence their compositions and concentrations in macroalgae. It is also discussed how to make macroalgae as an excellent biomonitor for trace metals.

  17. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...

  18. THE EFFECTS OF ULTRAVIOLET-B RADIATION ON ANTARCTIC SEA-ICE ALGAE(1).

    Science.gov (United States)

    Ryan, Ken G; McMinn, Andrew; Hegseth, Else N; Davy, Simon K

    2012-02-01

    The impacts of ultraviolet-B radiation (UVB) on polar sea-ice algal communities have not yet been demonstrated. We assess the impacts of UV on these communities using both laboratory experiments on algal isolates and by modification of the in situ spectral distribution of the under-ice irradiance. In the latter experiment, filters were attached to the upper surface of the ice so that the algae were exposed in situ to treatments of ambient levels of PAR and UV radiation, ambient radiation minus UVB, and ambient radiation minus all UV. After 16 d, significant increases in chl a and cell numbers were recorded for all treatments, but there were no significant differences among the different treatments. Bottom-ice algae exposed in vitro were considerably less tolerant to UVB than those in situ, but this tolerance improved when algae were retained within a solid block of ice. In addition, algae extracted from brine channels in the upper meter of sea ice and exposed to PAR and UVB in the laboratory were much more tolerant of high UVB doses than were any bottom-ice isolates. This finding indicates that brine algae may be better adapted to high PAR and UVB than are bottom-ice algae. The data indicate that the impact of increased levels of UVB resulting from springtime ozone depletion on Antarctic bottom-ice communities is likely to be minimal. These algae are likely protected by strong UVB attenuation by the overlying ice and snow, by other inorganic and organic substances in the ice matrix, and by algal cells closer to the surface. PMID:27009652

  19. Short Communication: Effects of temperature on growth, pigment composition and protein content of an Antarctic Cyanobacterium Nostoc commune

    Directory of Open Access Journals (Sweden)

    RANJANA TRIPATHI

    2012-11-01

    Full Text Available Tripathi R, Dhuldhaj UP, Singh S. 2012. Short Communication: Effects of temperature on growth, pigment composition and protein content of an Antarctic Cyanobacterium Nostoc commune. Nusantara Bioscience 4: 134-137. Effect of temperature variation on biomass accumulation, pigment composition and protein content were studied for the cyanobacterium Nostoc commune, isolated from Antarctica. Results confirmed the psychrotrophic behavior (optimum growth temperature 25◦C of the cyanobacterium. Low temperature increased the duration of lag phase and exponential growth phase. Maximum increase in biomass was recorded on 24th day at 25◦C and on 12th day at 50C. The downshift from 25 to 5◦C had almost negligible effect on chl a content. Maximal protein content was recorded for cultures growing at 50C on 12th day. The carotenoids/chl a ratio was maximum (2.48 at 50C on 9th day. It remained almost constant for cultures growing at 5 and 350C. There was an induction in protein synthesis following downshift in temperature from 25 to 5◦C.

  20. Antarctic research today

    International Nuclear Information System (INIS)

    With the appetite for living and dead natural resources, the political and economical interest concerning the Antarctic increases throughout the world. There are three interrelated main subjects accounting for the international interest: The shelf tectonic puzzle of the original continent of Gondwana, where the Antarctic is situated in the centre, between Australia, South Africa and South America, and the hopes concerning the existence of mineral resources under the ice of the Antarctic are based thereon. The Antarctic forms the biggest unified living space of the world. (orig.)

  1. Macroalgae as feedstock for cultivation of marine bacteria

    OpenAIRE

    França, Lucas Vagueiro de

    2015-01-01

    Alginate, laminarin and mannitol amount up to 60% of dry weight in brown macroalgae. The presence of alginate and laminarin-degrading enzymes and mannitol metabolic machinery have been confirmed by Matís, a partner in European BlueGenics project. Thus, in a biorefinery perspective, R. marinus can potentially perform the saccharification and fermentation of brown macroalgae carbohydrates to yield commercial valuable biocompounds, as thermostable enzymes and glycosidic carotenoids. Rhodothermus...

  2. Integrated system for macroalgae production and conversion into biogas

    OpenAIRE

    Nobre, A.; Gonçalves, P. R.; Costa, J.C.; Alves, M.M.

    2010-01-01

    Recently research on energy from macroalgae is being reconsidered driven by the following factors: fuel price increase, CO2 mitigation policies and interest on renewable energy sources after the Kyoto protocol, and need for energy crops not competing with land for food production. However, the commercial expansion of this energy source is limited by its economic feasibility. In this presentation we analyse the development of integrated systems that promote synergies between macroalgae/biogas ...

  3. Influences of macroalga-derived dissolved organic carbon on the aquatic toxicity of copper and cadmium.

    Science.gov (United States)

    Tsui, Martin T K; Wang, Wen-Xiong; Wong, Ming H

    2006-12-01

    In this study, the effect of dissolved organic carbon (DOC) derived from macroalga (Sargassum) on the acute toxicity of copper (Cu) and cadmium (Cd) to a freshwater cladoceran (Daphnia magna) was investigated. Potassium-loaded macroalga was incubated with ultrapure water to extract macroalgal DOC, which was then spiked with the constituents of the Elendt M7 hard water media. The 48 h median lethal concentration of Cu increased linearly with DOC levels but that of Cd was relatively independent of DOC levels (0-44 mg l(-1)). The independence of Cd toxicity on DOC level might be due to the competitive effect of high calcium concentrations in the media with Cd for the binding sites of DOC. The decreased Cu toxicity was a result of reduced Cu uptake as evidenced in a separate accumulation test. Also, the capability of the macroalgal DOC on reducing Cu toxicity was found to be comparable to DOC tested in other studies. Therefore, the present study suggested that the biosorption treatment process using macroalgae should consider the effect of DOC release from the biomass as a step of modifying the metal toxicity as well as influencing metal biosorption capacity. PMID:16709424

  4. The comparative effects of oil dispersants and oil/dispersant conjugates on germination of the marine macroalga Phyllospora comosa (Fucales: Phaeophyta)

    International Nuclear Information System (INIS)

    Germination inhibition of the marine macrophyte Phyllospora comosa was utilized as a sub-lethal end-point to assess and compare the effects of four oil dispersants and dispersed diesel fuel and crude oil combinations. Inhibition of germination by the water-soluble fraction of diesel fuel increased following the addition of each of the dispersants; the nominal 48-h EC50 concentration of diesel fuel declined from 6800 to approximately 400 μl 1-1 nominal for each dispersed combination. This contrasted with crude oil, where the addition of two dispersants resulted in an enhanced germination rate and an increase in nominal EC50 concentrations from 130 μl 1-1 for the undispersed crude to 4000 and 2500 μl 1-1. The results indicate that, while germination inhibition of P. comosa may be enhanced by the chemical dispersal of oil response varies with type of both oil and oil dispersant. (author)

  5. Effects of sewage contamination on macro-algae and shellfish at Moa Point, New Zealand, using stable carbon and nitrogen isotopes

    International Nuclear Information System (INIS)

    Stable carbon and nitrogen isotopes have been used to characterise sewage discharge and effects on seaweed (Ulva lactuca L.), blue mussels (Mytilus galloprovincialis), and limpets (Cellana denticulata) from Moa Point Bay, New Zealand. The nitrogen (15N / 14N) ratio is shown to be a good tracer of sewage pollution in Ulva lactuca and associated grazers (Cellana denticulata) as a result of the increased contribution of urea and ammonia to the surrounding marine environment from the sewage outfall. The carbon (13C / 12C) ratio is suggested as a more appropriate sewer tracer for mussels (Mytilus galloprovincialis), which filter feed the particulate organic matter from the effluent. Lower carbon : nitrogen ratios were found in U. lactuca sampled from the outfall region, compared to uncontaminated control sites, however carbon : nitrogen ratios do not vary significantly amongst shellfish species. (author). 18 refs., 4 figs., 2 tabs

  6. Influence of n-Hexane on in Situ Transesterification of Marine Macroalgae

    Directory of Open Access Journals (Sweden)

    Angel Sánchez

    2012-02-01

    Full Text Available The purpose of this work is to investigate the influence of n-hexane addition on in situ transesterification of a solid raw material for biodiesel production. Extraction and reaction of macroalgae oil has been performed simultaneously in a batch reactor adding n-hexane with the reactants. In order to analyze the influence of n-hexane on the transesterification, the reaction was also carried out with sunflower oil. The results show that the presence of n-hexane does not have an important effect on the transesterification. It was also observed that this method requires large quantities of methanol to carry out the reaction. The best reaction conditions for in situ transesterification of marine macroalgae were 300:1 methanol-to-oil molar ratio, 1% catalyst concentration, 60 °C reaction temperature and 11 h reaction time, resulting in a methyl esters yield of 17.1%. Thus, biodiesel production from macroalgae by transesterification in situ could be feasible, using hexane for the extraction and eliminating the previous extraction. This integrated method is thus effective and technically attractive.

  7. Macroalgae for CO2 Capture and Renewable Energy - A Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, Kristine [Gas Technology Inst., Des Plaines, IL (United States)

    2011-01-31

    The objective of this project was to demonstrate, at a pilot scale, the beneficial use of carbon dioxide (CO2) through a technology designed to capture CO2 from fossil-fuel fired power plant stack gas, generating macroalgae and converting the macroalgae at high efficiency to renewable methane that can be utilized in the power plant or introduced into a natural gas pipeline. The proposed pilot plant would demonstrate the cost-effectiveness and CO2/ NOx flue-gas removal efficiency of an innovative algal scrubber technology where seaweeds are grown out of water on specially-designed supporting structures contained within greenhouses where the plants are constantly bathed by recycled nutrient sprays enriched by flue gas constituents. The work described in this document addresses Phase 1 of the project only. The scope of work for Phase 1 includes the completion of a preliminary design package; the collection of additional experimental data to support the preliminary and detailed design for a pilot scale utilization of CO2 to cultivate macroalage and to process that algae to produce methane; and a technological and economic analysis to evaluate the potential of the system. Selection criteria for macroalgae that could survive the elevated temperatures and potential periodic desiccation of near desert project sites were identified. Samples of the selected macroalgae species were obtained and then subjected to anaerobic digestion to determine conversions and potential methane yields. A Process Design Package (PDP) was assembled that included process design, process flow diagram, material balance, instrumentation, and equipment list, sizes, and cost for the Phase 2 pilot plant. Preliminary economic assessments were performed under the various assumptions made, which are purposely conservative. Based on the results, additional development work should be conducted to delineate the areas for improving efficiency, reducing

  8. DNA Barcoding Assessment of Green Macroalgae in Coastal Zone Around Qingdao,China

    Institute of Scientific and Technical Information of China (English)

    DU Guoying; WU Feifei; MAO Yunxiang; GUO Shenghua; XUE Hongfan; BI Guiqi

    2014-01-01

    An assessment with assistance of DNA barcoding was conducted on green macroalgae in coastal zone around Qingdao, China, during the period of April-December, 2011. Three markers were applied in molecular discrimination, including the plastid elongation factor tufA gene, the internal transcribed spacer (ITS) region of the ribosomal cistron and rubisco large subunit gene 3’ regions (rbcL-3P). DNA barcoding discriminated 8 species, excluding species of genus Cladophora and Bryopsis due to failures in amplification. We ascertained and corrected 4 species identified by morphological methods for effectively assisting the classification. The gene tufA presented more advantages as an appropriate DNA marker with the strongest amplification success rate and species discrimination power than the other two genes. The poorest sequencing success largely handicapped the application of ITS. Samples identified by tufA and rbcL as Ulva flexuosa were clustered into the clade of U. prolifera by ITS in the neighbor-joining tree. Confu-sion with discrimination of the complex of U. linza, U. procera and U. prolifera (as the LPP complex) still existed for the three DNA markers. Based on our results, rbcL is recommended as a preferred marker for assisting tufA to discriminate green macroalgae. In distinguishing green-tide-forming Ulva species, the free-floating sample collected from the green tide in 2011 was proved to be iden-tical with U. prolifera in Yellow Sea for ITS and rbcL genes. This study presents a preliminary survey of green macroalgae distrib-uted in the coastal area around Qingdao, and proves that DNA barcoding is a powerful tool for taxonomy of green macroalgae.

  9. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    Science.gov (United States)

    Gameiro, Carla; Utkin, Andrei B.; Cartaxana, Paulo

    2015-12-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area. Three bands characterised the LIF spectra of red macroalgae with emission maxima in the ranges 577-583 nm, 621-642 nm and 705-731 nm. Green and brown macroalgae showed one emission maximum in the red region (687-690 nm) and/or one in the far-red region (726-732 nm). Characteristics of LIF emission spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin-blade green macroalgae Ulva rigida caused a shift to longer wavelengths of the red emission maximum and the development of a fluorescence peak at the far-red region. Water loss from Ulva's algal tissue also led to a decrease in the red/far-red Chl fluorescence ratio (F685/F735), indicating an increase in the density of chloroplasts in the shrinking macroalgal tissue during low tide exposure.

  10. Controls and variability of solute and sedimentary fluxes in Antarctic and sub-Antarctic Environments

    Science.gov (United States)

    Zwolinski, Zbigniew

    2015-04-01

    The currently prepared SEDIBUD Book on "Source-to-Sink Fluxes in Undisturbed Cold Environments" (edited by Achim A. Beylich, John C. Dixon and Zbigniew Zwolinski and published by Cambridge University Press) is summarizing and synthesizing the achievements of the International Association of Geomorphologists` (I.A.G./A.I.G.) Working Group SEDIBUD (Sediment Budgets in Cold Environments), which has been active since 2005 (http://www.geomorph.org/wg/wgsb.html). The book comprises five parts. One of them is part about sub-Antarctic and Antarctic Environments. This part "Sub-Antarctic and Antarctic Environments" describes two different environments, namely oceanic and continental ones. Each part contains results of research on environmental drivers and rates of contemporary solute and sedimentary fluxes in selected sites. Apart from describing the environmental conditions of the whole continent of Antarctica and sub-Antarctic islands (Zb.Zwolinski, M.Kejna, A.N.Lastochkin, A.Zhirov, S.Boltramovich) this part of the book characterizes terrestrial polar oases free from multi-year ice and snow covers (Zb.Zwolinski). The detailed results of geoecological and sedimentological research come from different parts of Antarctica. Antarctic continental shelf (E.Isla) is an example of sub-Antarctic oceanic environment. South Shetlands, especially King George Island (Zb.Zwolinski, M.Kejna, G.Rachlewicz, I.Sobota, J.Szpikowski), is an example of sub-Antarctic terrestrial environment. Antarctic Peninsula (G.Vieira, M.Francelino, J.C.Fernandes) and surroundings of McMurdo Dry Valleys (W.B.Lyons, K.A.Welch, J.Levy, A.Fountain, D.McKnight) are examples of Antarctic continental environments. The key goals of the Antarctic and sub-Antarctic book chapters are following: (i) identify the main environmental drivers and rates of contemporary solute and sedimentary fluxes, and (ii) model possible effects of projected climate change on solute and sedimentary fluxes in cold climate environments

  11. Acetone-butanol Fermentation of Marine Macroalgae

    Energy Technology Data Exchange (ETDEWEB)

    Huesemann, Michael H.; Kuo, Li-Jung; Urquhart, Lindsay A.; Gill, Gary A.; Roesijadi, Guritno

    2012-03-01

    Mannitol and laminarin, which are present at high concentrations in the brown macroalga Saccharina spp., a type of kelp, are potential biochemical feedstocks for butanol production. To test their bioconversion potential, aqueous extracts of the kelp Saccharina spp., mannitol, and glucose (a product of laminarin hydrolysis) were subjected to acetone-butanol fermentation by Clostridium acetobutylicum (ATCC 824). Both mannitol and glucose were readily fermented. Mixed substrate fermentations with glucose and mannitol resulted in diauxic growth of C. acetobutylicum with glucose depletion preceding mannitol utilization. Fermentation of kelp extract exhibited triauxic growth, with an order of utilization of free glucose, mannitol, and bound glucose, presumably laminarin. The lag in laminarin utilization reflected the need for enzymatic hydrolysis of this polysaccharide into fermentable sugars. The butanol and total solvent yields were 0.12 g/g and 0.16 g/g, respectively, indicating that significant improvements are still needed to make industrial-scale acetone-butanol fermentations of seaweed economically feasible.

  12. Cesium and strontium in Black Sea macroalgae

    International Nuclear Information System (INIS)

    The trace level of metals and particularly radioactive ones should be monitored to evaluate the transfer along the trophic chain, assess the risk for biota and can be used for global changes assessment. Plants respond rapidly to all changes in the ecosystem conditions and are widely used as indicators and predictors for changes in hydrology and geology. In this work we represent our successful development and applications of a methodology for monitoring of stable and radioactive strontium and cesium in marine biota (Black Sea algae's). In case of radioactive release they are of high interest. We use ED-XRF, gamma spectrometers and LSC instrumentation and only 0.25 g sample. Obtained results are compared with those of other authors in same regions. The novelty is the connection between the radioactive isotopes and their stable elements in algae in time and space scale. All our samples were collected from Bulgarian Black Sea coast. - Highlights: • An extraction chromatography method for radiochemical separation of Sr and Cs. • Assessment of Sr and Cs accumulation capacity of six Black Sea macroalgae species. • Connection between the isotopes and their stable elements content in algae. • Assessment of Sr and Cs content in ecosystems along the Bulgarian coast

  13. Satellite remote sensing of the island mass effect on the Sub-Antarctic Kerguelen Plateau, Southern Ocean

    Science.gov (United States)

    Jena, Babula

    2016-09-01

    The presence of the Kerguelen Plateau and surrounding bathymetric features has a strong influence on the persistently eastward flowing Antarctic Circumpolar Current (ACC), resulting in enhancement of surface chlorophyll-a (Chl- a) in the downstream section of the plateau along the polar front (PF). The phenomenon is reported in this paper as the island mass effect (IME). Analysis of climatological Chl- a datasets from Aqua- Moderate Resolution Imaging Spectroradiometer (Aqua- MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) shows distinct bloomy plumes (Chl- a>0.5 mg/m3) during austral spring-summer spreading as far as ~1800 km offshore up to 98°E along the downstream of the north Kerguelen Plateau (NKP). Similar IME phenomena is apparent over the south Kerguelen Plateau (SKP) with the phytoplankton bloom extending up to 96.7°E, along the southern boundary of ACC. The IME phenomena are pronounced only during austral spring-summer period with the availability of light and sedimentary source of iron from shallow plateau to sea surface that fertilizes the mixed layer. The NKP bloom peaks with a maximum areal extent of 1.315 million km2 during December, and the SKP bloom peaks during January with a time lag of one month. The blooms exist for at least 4 months of a year and are significant both as the base of regional food web and for regulating the biogeochemical cycle in the Southern Ocean. Even though the surface water above the Kerguelen Plateau is rich in Chl- a, an exception of an oligotrophic condition dominated between NKP and SKP due to apparent intrusion of iron limited low phytoplankton regime waters from the Enderby basin through the northeastward Fawn Trough Current.

  14. Satellite remote sensing of the island mass effect on the Sub-Antarctic Kerguelen Plateau, Southern Ocean

    Science.gov (United States)

    Jena, Babula

    2016-04-01

    The presence of the Kerguelen Plateau and surrounding bathymetric features has a strong influence on the persistently eastward flowing Antarctic Circumpolar Current (ACC), resulting in enhancement of surface chlorophyll-a (Chl-a) in the downstream section of the plateau along the polar front (PF). The phenomenon is reported in this paper as the island mass effect (IME). Analysis of climatological Chl-a datasets from Aqua- Moderate Resolution Imaging Spectroradiometer (Aqua- MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) shows distinct bloomy plumes (Chl-a>0.5 mg/m3) during austral spring-summer spreading as far as ~1800 km offshore up to 98°E along the downstream of the north Kerguelen Plateau (NKP). Similar IME phenomena is apparent over the south Kerguelen Plateau (SKP) with the phytoplankton bloom extending up to 96.7°E, along the southern boundary of ACC. The IME phenomena are pronounced only during austral spring-summer period with the availability of light and sedimentary source of iron from shallow plateau to sea surface that fertilizes the mixed layer. The NKP bloom peaks with a maximum areal extent of 1.315 million km2 during December, and the SKP bloom peaks during January with a time lag of one month. The blooms exist for at least 4 months of a year and are significant both as the base of regional food web and for regulating the biogeochemical cycle in the Southern Ocean. Even though the surface water above the Kerguelen Plateau is rich in Chl-a, an exception of an oligotrophic condition dominated between NKP and SKP due to apparent intrusion of iron limited low phytoplankton regime waters from the Enderby basin through the northeastward Fawn Trough Current.

  15. Biofuel Production Based on Carbohydrates from Both Brown and Red Macroalgae: Recent Developments in Key Biotechnologies

    OpenAIRE

    Shigeyuki Kawai; Kousaku Murata

    2016-01-01

    Marine macroalgae (green, red and brown macroalgae) have attracted attention as an alternative source of renewable biomass for producing both fuels and chemicals due to their high content of suitable carbohydrates and to their advantages over terrestrial biomass. However, except for green macroalgae, which contain relatively easily-fermentable glucans as their major carbohydrates, practical utilization of red and brown macroalgae has been regarded as difficult due to the major carbohydrates (...

  16. Co-liquefaction of micro- and macroalgae in subcritical water.

    Science.gov (United States)

    Jin, Binbin; Duan, Peigao; Xu, Yuping; Wang, Feng; Fan, Yunchang

    2013-12-01

    Co-liquefaction of microalgae (Spirulina platensis, SP) and macroalgae (Entermorpha prolifera, EP) was studied in subcritical water by using a stainless-steel batch reactor at different temperature (250 to 370°C), time (5 to 120 min), SP/EP mass ratio (0 to 100%), and water/algae mass ratio (1:1 to 6:1). The results suggested that a positive synergetic effect existed during the co-liquefaction of SP and EP, and this synergetic effect was dependent on reaction conditions. Co-liquefaction alleviated the severe reaction conditions compared to the separate liquefaction of SP and EP and also promoted the in situ deoxygenation of the bio-oil. The higher-heating-value of bio-oil produced from the co-liquefaction of SP and EP (wSP:wEP=1) is 35.3 MJ/kg. The energy recovery from the co-liquefaction is larger than the average value from the separate liquefaction of SP and EP. Co-liquefaction did not affect the molecular composition but affect the relative amount of each component in the bio-oil. PMID:24096026

  17. Inhibition of coral recruitment by macroalgae and cyanobacteria

    Science.gov (United States)

    Kuffner, I.B.; Walters, L.J.; Becerro, M.A.; Paul, V.J.; Ritson-Williams, R.; Beach, K.S.

    2006-01-01

    Coral recruitment is a key process in the maintenance and recovery of coral reef ecosystems. While intense competition between coral and algae is often assumed on reefs that have undergone phase shifts from coral to algal dominance, data examining the competitive interactions involved, particularly during the larval and immediate post-settlement stage, are scarce. Using a series of field and outdoor seawater table experiments, we tested the hypothesis that common species of macroalgae and cyanobacteria inhibit coral recruitment. We examined the effects of Lyngbya spp., Dictyota spp., Lobophora variegata (J. V. Lamouroux) Womersley, and Chondrophycus poiteaui (J. V. Lamouroux) Nam (formerly Laurencia poiteaui) on the recruitment success of Porites astreoides larvae. All species but C. poiteaui caused either recruitment inhibition or avoidance behavior in P. astreoides larvae, while L. confervoides and D. menstrualis significantly increased mortality rates of P. astreoides recruits. We also tested the effect of some of these macrophytes on larvae of the gorgonian octocoral Briareum asbestinum. Exposure to Lyngbya majuscula reduced survival and recruitment in the octocoral larvae. Our results provide evidence that algae and cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. On reefs experiencing phase shifts or temporary algal blooms, the restocking of adult coral populations may be slowed due to recruitment inhibition, thereby perpetuating reduced coral cover and limiting coral community recovery. ?? Inter-Research 2006.

  18. Technical and Economic Evaluation of Macroalgae Cultivation for Fuel Production (Draft)

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D. A.; Hock, S. M.

    1985-04-01

    The potential of macroalgae as sources of renewable liquid and gaseous fuels is evaluated. A series of options for production of macroalgae feedstock is considered. Because of their high carbohydrate content, the fuel products for which macroalgae are most suitable are methane and ethanol. Fuel product costs were compared with projected fuel costs in the year 1995.

  19. Downslope föhn winds over the Antarctic Peninsula and their effect on the Larsen Ice Shelves

    Science.gov (United States)

    Grosvenor, D. P.; King, J. C.; Choularton, T. W.; Lachlan-Cope, T.

    2014-03-01

    Mesoscale model simulations are presented of a westerly föhn event over the Antarctic Peninsula mountain ridge and onto the Larsen C Ice Shelf, just south of the recently collapsed Larsen B Ice Shelf. Aircraft observations showed the presence of föhn jets descending near to the ice shelf surface with maximum wind speeds at 250-350 m in height. Surface flux measurements suggested that melting was occurring. Simulated profiles of wind speed, temperature and wind direction were very similar to the observations. However, the good match only occurred at a model time corresponding to ˜9 h before the aircraft observations were made since the model föhn jets died down after this. Through comparison to an Automatic Weather Station (AWS) on the ice shelf surface (east side of the ridge) this was attributed to problems with the time evolution of the large scale meteorology of the analysis used to nudge the upper levels of the model. Timing issues aside, the otherwise good comparison between the model and observations gave confidence that the model flow structure was similar to that in reality. Details of the model jet structure are explored and discussed and are found to have ramifications for the placement of AWS stations on the ice shelf in order to detect föhn flow. Cross sections of the flow are also examined and were found to compare well to the aircraft measurements. Gravity wave breaking above the mountain crest likely created a situation similar to hydraulic flow and allowed föhn flow and ice shelf surface warming to occur despite strong upwind blocking, which in previous studies of this region has generally not been considered. The surface energy budget of the model during the melting periods showed that the net downwelling shortwave surface flux was the largest contributor to the melting energy, indicating that the cloud clearing effect of föhn events is likely to be the most important factor for increased melting relative to non-föhn days. The results also

  20. A Comparison of Lignin, Macroalgae, Wood and Straw Fast Pyrolysis

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Dam-Johansen, Kim;

    2013-01-01

    A fast pyrolysis study on lignin and macroalgae (non-conventional biomass) and wood and straw (conventional biomass) were carried out in a pyrolysis centrifugal reactor at pyrolysis temperature of 550 ºC. The product distributions and energy recoveries were measured and compared among...... these biomasses. The fast pyrolysis of macroalgae showed a promising result with a bio-oil yield of 65 wt% dry ash free basis (daf) and 76 % energy recovery in the bio-oil while the lignin fast pyrolysis provides a bio-oil yield of 47 wt% daf and energy recovery in bio-oil of 45 %. The physiochemical properties...

  1. Synergistic effects of iron and temperature on Antarctic phytoplankton and microzooplankton assemblages

    Directory of Open Access Journals (Sweden)

    J. M. Rose

    2009-12-01

    Full Text Available Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM and increased temperature (+4°C on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total phytoplankton abundance, phytoplankton and microzooplankton community composition, as well as photosynthetic parameters and nutrient drawdown. Unexpectedly, increased iron had a consistently negative impact on microzooplankton abundance, most likely a secondary response to changes in phytoplankton community composition. When iron and temperature were increased in concert, the resulting interactive effects were greatly magnified. This synergy between iron and temperature increases would not have been predictable by examining the effects of each variable individually. Our results suggest the possibility that if iron availability increases under future climate regimes, the impacts of predicted temperature increases on plankton assemblages in polar regions could be significantly enhanced. Such synergistic and antagonistic interactions between individual climate change variables highlight the importance of multivariate studies for marine global change experiments.

  2. The effects of climate uncertainty on the stability of the Antarctic ice sheet during the mid-Pliocene warm period

    OpenAIRE

    Jorge Bernales; Tonio Häfliger; I. Rogozhina; M. Thomas

    2015-01-01

    The mid-Pliocene (3.15 to 2.85 million years before present) is the most recent period in Earth’s history when temperatures and CO2 concentrations were sustainedly higher than pre-industrial values [1], representing an ideal interval for studying the climate system under conditions similar to those projected for the end of this century. In these projections, the response of the Antarctic ice sheet (AIS) remains uncertain, including areas generally considered stable under a warming...

  3. Combined effects of agitation and aeration on the chitinolytic enzymes production by the Antarctic fungus Lecanicillium muscarium CCFEE 5003

    Directory of Open Access Journals (Sweden)

    Fenice Massimiliano

    2012-01-01

    Full Text Available Abstract Background The Antarctic fungus Lecanicillium muscarium CCFEE 5003 is one of the most powerful chitinolytic organisms. It can produce high level of chitinolytic enzymes in a wide range of temperatures (5-30°C. Chitinolytic enzymes have lot of applications but their industrial production is still rather limited and no cold-active enzymes are produced. In view of massive production of L. muscarium chitinolytic enzymes, its cultivation in bioreactors is mandatory. Microbial cultivation and/or their metabolite production in bioreactors are sometime not possible and must be verified and optimized for possible exploitation. Agitation and aeration are the most important parameters in order to allow process up-scaling to the industrial level. Results In this study, submerged cultures of L. muscarium CCFEE 5003 were carried out in a 2-L bench-top CSTR bioreactor in order to optimise the production of chitinolytic enzymes. The effect of stirrer speed (range 200-500 rpm and aeration rate (range 0.5-1.5 vvm combination was studied, by Response Surface Methodology (RSM, in a medium containing 1.0% yeast nitrogen base and 1% colloidal chitin. Optimization was carried out, within a "quadratic D-optimal" model, using quantitative and quantitative-multilevel factors for aeration and agitation, respectively. The model showed very good correlation parameters (R2, 0.931; Q2, 0.869 and the maximum of activity (373.0 U/L was predicted at ca. 327 rpm and 1.1 vvm. However, the experimental data showed that highest activity (383.7 ± 7.8 U/L was recorded at 1 vvm and 300 rpm. Evident shear effect caused by stirrer speed and, partially, by high aeration rates were observed. Under optimized conditions in bioreactor the fungus was able to produce a higher number of chitinolytic enzymes than those released in shaken flasks. In addition, production was 23% higher. Conclusions This work demonstrated the attitude of L. muscarium CCFEE 5003 to grow in bench

  4. Antarctic specific features of the greenhouse effect. A radiative analysis using measurements and models

    International Nuclear Information System (INIS)

    CO2 is the strongest anthropogenic forcing agent for climate change since pre-industrial times. Like other greenhouse gases, CO2 absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. For this region, it is shown that the greenhouse effect of CO2 is around zero or even negative. Moreover, for central Antarctica an increase in CO2 concentration leads to an increased long-wave energy loss to space, which cools the earth-atmosphere system. These unique findings for central Antarctica are in contrast to the well known general warming effect of increasing CO2. The work contributes to explain the non-warming of central Antarctica since 1957.

  5. Antarctic specific features of the greenhouse effect. A radiative analysis using measurements and models

    Energy Technology Data Exchange (ETDEWEB)

    Schmithuesen, Holger

    2014-12-10

    CO{sub 2} is the strongest anthropogenic forcing agent for climate change since pre-industrial times. Like other greenhouse gases, CO{sub 2} absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. For this region, it is shown that the greenhouse effect of CO{sub 2} is around zero or even negative. Moreover, for central Antarctica an increase in CO{sub 2} concentration leads to an increased long-wave energy loss to space, which cools the earth-atmosphere system. These unique findings for central Antarctica are in contrast to the well known general warming effect of increasing CO{sub 2}. The work contributes to explain the non-warming of central Antarctica since 1957.

  6. Effect of Cd on GSH and GSH-related enzymes of Chlamydomonas sp. ICE-L existing in Antarctic ice

    Institute of Scientific and Technical Information of China (English)

    DING Yu; MIAO Jin-lai; LI Guang-you; WANG Quan-fu; KAN Guang-feng; WANG Guo-dong

    2005-01-01

    Glutathione(GSH) and GSH-related enzymes play a great role in protecting organisms from oxidative damage. The GSH level and GSH-related enzymes activities were investigated as well as the growth yield and malonyldialdehyde(MDA) content in the Antarctic ice microalga Chlamydomonas sp. ICE-L exposure to the different cadmium concentration in this paper. The results showed that the higher concentration Cd inhibited the growth of ICE-L significantly and Cd would induce formation of MDA. At the same time, it is clear that GSH level, glutathione peroxidases(GPx) activity and glutathione S-transferases(GST), activity were higher in ICE-L exposed to Cd than the control. But GR activity dropped notably when ICE-L were cultured in the medium containing Cd. Increase of GSH level, GPx and GST activities acclimate to oxidative stress induced by Cd and protect Antarctic ice microalga Chlamydomonas sp. ICE-L from toxicity caused by Cd exposure. These parameters may be used to assess the biological impact of Cd in the Antarctic pole region environment.

  7. Antarctic Specific Features of the Greenhouse Effect : A Radiative Analysis Using Measurements and Models

    OpenAIRE

    Schmithüsen, Holger

    2015-01-01

    CO2 is the strongest anthropogenic forcing agent for climate change since pre-industrial times. Like other greenhouse gases, CO2 absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. For this region, it is shown that the greenhouse effect of...

  8. The state of permafrost surrounding "Gabriel de Castilla" Spanish Antarctic Station (Deception Island, Antarctica): Studying the possible degradation due to the infrastructures heating effect.

    Science.gov (United States)

    Recio, Cayetana; Ángel de Pablo, MIguel; Ramos, MIguel; Molina, Antonio

    2015-04-01

    Permafrost degradation is one of the effects of the global warming. Many studies reveal the increase of active layer and reduction on permafrost table thickness, also in Antarctica. However, these trends on permafrost can be accelerated by the human activities, as the heating produced by the Antarctic stations infrastructures when they are not properly isolated from the ground. In Deception island, South Shetland Archipelago, we started 3 years ago a monitoring program at the 26 years old "Gabriel de Castilla" Spanish Antarctic Station (SAS), It is focused on charactering the state of permafrost, since in the coastal scarps at tens of meters from the station an increase on erosion had been detected. Although the main cause of the erosion of this coastal volcanoclastic materials is the 2 meters thick icefield which forms during the winter in the inner sea of this volcanic island, we want to detect any possible contribution to the coastal erosion caused by the permafrost degradation related to the SAS presence. We present our preliminary analysis based on three years of continuous ground temperature data, monitored at a shallow borehole (70 cm deep) in the SAS edge, together with the active layer thickness measured around the station and their vicinities in two thawing seasons. We complete this study with the analysis of the continuous temperature data taken inside the SAS and the air and ground temperatures below the station, acquired during the last Antarctic Campaign (December 2014-February 2015). These preliminary results are fundamental 1) to discard any contribution from the SAS presence, and to help to improve its thermal isolation, 2) to help improve our knowledge about the thermal state of permafrost in the area, and 3) to help to understand the causes of the coastal erosion in the volcanic Deception Island.

  9. The effects of climate uncertainty on the stability of the Antarctic ice sheet during the mid-Pliocene warm period

    Science.gov (United States)

    Bernales, Jorge; Häfliger, Tonio; Rogozhina, Irina; Thomas, Maik

    2015-04-01

    The mid-Pliocene (3.15 to 2.85 million years before present) is the most recent period in Earth's history when temperatures and CO2 concentrations were sustainedly higher than pre-industrial values [1], representing an ideal interval for studying the climate system under conditions similar to those projected for the end of this century. In these projections, the response of the Antarctic ice sheet (AIS) remains uncertain, including areas generally considered stable under a warming climate. Therefore, a better understanding of AIS's behaviour during periods like the mid-Pliocene will provide valuable information on the potential vulnerability of the composite parts of the AIS in the future. For this purpose, we have designed numerical experiments of the AIS dynamics during the mid-Pliocene warm period using the continental-scale ice sheet-shelf model SICOPOLIS [2]. To account for the uncertainties in the configuration of the AIS and climate conditions prior to this period, we employ a wide range of initial ice sheet configurations and climatologies, including modern observations, the results from the Pliocene Model Intercomparison Project (PlioMIP) climate experiments [3], and perturbations to single climatic fields, allowing us to assess the vulnerability of different AIS sectors to specific forcing mechanisms. Our simulations show that the West Antarctic ice sheet remains largely ice-free under the chosen range of climate conditions, except for small portions grounded above sea level. On the contrary, the East Antarctic ice sheet (EAIS) shows no signs of potential collapse, with an ice loss over a few peripheral sectors largely compensated by an increase in ice volume over the interior due to increased precipitation rates and surface temperatures remaining well below the freezing point. Furthermore, our results contrast with existing hypotheses that cast doubt on the stability of the EAIS during the mid-Pliocene warm period. References [1] Cook, C. P., et al

  10. Eelgrass re-establishment in shallow estuaries is affected by drifting macroalgae

    DEFF Research Database (Denmark)

    Canal-Verges, Paula; Potthoff, M.; Hansen, F. T.;

    2014-01-01

    surface sediment. Furthermore, drifting macroalgae ballistically damage eelgrass beds and increase seedling mortality. The frequency and impact of drifting macroalgae in Odense Fjord was evaluated with an agent-based model. The aims of this model were to understand and predict the mobility...... of opportunistic (Chaetomorpha linum) and non-ephemeral (Fucus vesiculosus) macroalgae and to describe and quantify the intensity and spatial distribution of bottom substrate physically affected by drifting macroalgae. The longest simulated movement by macroalgae was found to be 270 and 170 km for brown and green...... algae respectively; while the macroalgae losses (export) out of the fjord were up to 11% of the total biomass; the simulated area impacted by macroalgae drift varied between 16% and 96.5% of the total ford area; finally the degree on physically impacted area varied from 0.01 to 28.5 m of algae track m...

  11. Effects of solar ultraviolet radiation on antarctic phytoplankton during springtime ozone depletion

    International Nuclear Information System (INIS)

    In recent years, much attention has been given to the formation of the seasonal ozone open-quotes holeclose quotes over Antarctica, with the concomitant increase in ultraviolet-B [UV-B, 280-320-nanometer (nm)] radiation levels. The enhanced UV-B radiation can be very damaging to biological systems and has been shown to cause a significant decrease in rates of primary production. This paper describes the impact of open-quotes normalclose quotes ultraviolet radiation (UVR), as well as enhanced UV-B radiation, on natural assemblages of phytoplankton as well as on just the nanoplankton fraction cells less than 20 micrometers (μm). The studies also included estimation of the impact of UVR as influenced by the taxonomic composition of the phytoplankton and the mitigating effect of cellular UV-absorbing compounds. All studies were carried out at Palmer Station (64.7 degrees S 64.1 degrees W) on Anvers Island from early October to the end of December 1993. This period provided excellent opportunities to document the impact of enhanced UV-B radiation on phytoplankton because the ozone hole was very well developed over Palmer Station in the month of October; column ozone concentrations ranged from 140 to 220 Dobson units (DU). 10 refs, 3 figs

  12. Nitrate and chloride in Antarctic ice cores - postdepositional effects and the preservation of atmospheric signals (Invited)

    Science.gov (United States)

    Pasteris, D.; McConnell, J. R.; Edwards, R.; Isaksson, E. D.; Albert, M. R.

    2013-12-01

    Continuous nitrate and chloride measurements have been made from an array of ice cores located in interior Dronning Maud Land that cover the last 2000 years. The average snow accumulation rates at the ice core sites range from 2.7 to 10 cm weq yr-1, which has enabled the study of how accumulation rate affects the preservation and diffusion of nitrate and chloride in the snow. High-resolution dating of the ice cores by tie-point matching with the WAIS Divide ice core has allowed the effects of temporal changes in accumulation rate to also be observed. Results show a strong linear dependence of nitrate concentration on site-average accumulation rate, suggesting that fresh snow concentrations and reemission rates of nitrate from the snowpack are homogenous across the study area. Bulk chloride to sodium ratios over scales greater than 1 m are close to bulk sea salt composition at all of the sites, suggesting that little net gain or loss of volatile chloride has occurred. However, the chloride signal is heavily diffused relative to sodium and the extent of diffusion does not increase with depth in the ice cores, suggesting that it is a near-surface phenomenon. Possible mechanisms behind the observed chloride diffusion pattern will be discussed. Lastly, a sustained decline in nitrate concentration occurred during the Little Ice Age (LIA, 1500-1900 C.E.), but the high-resolution snow accumulation records show that it is not caused by a decrease in accumulation rate during that time. The nitrate record is highly correlated with published methane isotope data from Antarctica (δ13CH4), suggesting that the decline during the LIA was caused by a decrease in a biomass burning nitrate source. Average nitrate concentration versus site-average inverse accumulation rate Composite time series of nitrate (thick black line), δ13CH4 (thin red line with diamonds), and black carbon (dashed black line).

  13. Biogas from Macroalgae: is it time to revisit the idea?

    Directory of Open Access Journals (Sweden)

    Hughes Adam D

    2012-11-01

    Full Text Available Abstract The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example.

  14. The potential of freshwater macroalgae as a biofuels feedstock and the influence of nutrient availability on freshwater macroalgal biomass production

    Science.gov (United States)

    Yun, Jin-Ho

    Extensive efforts have been made to evaluate the potential of microalgae as a biofuel feedstock during the past 4-5 decades. However, filamentous freshwater macroalgae have numerous characteristics that favor their potential use as an alternative algal feedstock for biofuels production. Freshwater macroalgae exhibit high rates of areal productivity, and their tendency to form dense floating mats on the water surface imply significant reductions in harvesting and dewater costs compared to microalgae. In Chapter 1, I reviewed the published literature on the elemental composition and energy content of five genera of freshwater macroalgae. This review suggested that freshwater macroalgae compare favorably with traditional bio-based energy sources, including terrestrial residues, wood, and coal. In addition, I performed a semi-continuous culture experiment using the common Chlorophyte genus Oedogonium to investigate whether nutrient availability can influence its higher heating value (HHV), productivity, and proximate analysis. The experimental study suggested that the most nutrient-limited growth conditions resulted in a significant increase in the HHV of the Oedogonium biomass (14.4 MJ/kg to 16.1 MJ/kg). Although there was no significant difference in productivity between the treatments, the average dry weight productivity of Oedogonium (3.37 g/m2/day) was found to be much higher than is achievable with common terrestrial plant crops. Although filamentous freshwater macroalgae, therefore, have significant potential as a renewable source of bioenergy, the ultimate success of freshwater macroalgae as a biofuel feedstock will depend upon the ability to produce biomass at the commercial-scale in a cost-effective and sustainable manner. Aquatic ecology can play an important role to achieve the scale-up of algal crop production by informing the supply rates of nutrients to the cultivation systems, and by helping to create adaptive production systems that are resilient to

  15. Sugars in Antarctic aerosol

    Science.gov (United States)

    Barbaro, Elena; Kirchgeorg, Torben; Zangrando, Roberta; Vecchiato, Marco; Piazza, Rossano; Barbante, Carlo; Gambaro, Andrea

    2015-10-01

    The processes and transformations occurring in the Antarctic aerosol during atmospheric transport were described using selected sugars as source tracers. Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were measured in the Antarctic aerosol collected during four different sampling campaigns. For quantification, a sensitive high-pressure anion exchange chromatography was coupled with a single quadrupole mass spectrometer. The method was validated, showing good accuracy and low method quantification limits. This study describes the first determination of sugars in the Antarctic aerosol. The total mean concentration of sugars in the aerosol collected at the "Mario Zucchelli" coastal station was 140 pg m-3; as for the aerosol collected over the Antarctic plateau during two consecutive sampling campaigns, the concentration amounted to 440 and 438 pg m-3. The study of particle-size distribution allowed us to identify the natural emission from spores or from sea-spray as the main sources of sugars in the coastal area. The enrichment of sugars in the fine fraction of the aerosol collected on the Antarctic plateau is due to the degradation of particles during long-range atmospheric transport. The composition of sugars in the coarse fraction was also investigated in the aerosol collected during the oceanographic cruise.

  16. Towers for Antarctic Telescopes

    Science.gov (United States)

    Hammerschlag, R. H.; Bettonvil, F. C. M.; Jägers, A. P. L.; Nielsen, G.

    To take advantage of the exceptional seeing above the boundary layer on Antarctic sites, a high-resolution telescope must be mounted on a support tower. An open transparent tower of framework minimizes the upward temperature-disturbed airflow. A typical minimum height is 30m. The tower platform has to be extremely stable against wind-induced rotational motions, which have to be less than fractions of an arc second, unusually small from a mechanical engineering viewpoint. In a traditional structure, structural deflections result in angular deflections of the telescope platform, which introduce tip and tilt motions in the telescope. However, a structure that is designed to deflect with parallel motion relative to the horizontal plane will undergo solely translation deflections in the telescope platform and thus will not degrade the image. The use of a parallel motion structure has been effectively demonstrated in the design of the 15-m tower for the Dutch Open Telescope (DOT) on La Palma. Special framework geometries are developed, which make it possible to construct high towers in stories having platforms with extreme stability against wind-induced tilt. These geometric solutions lead to constructions, being no more massive than a normal steel framework carrying the same load. Consequently, these lightweight towers are well suited to difficult sites as on Antarctica. A geometry with 4 stories has been worked out.

  17. Deterrent activities in the crude lipophilic fractions of Antarctic benthic organisms: chemical defences against keystone predators

    Directory of Open Access Journals (Sweden)

    Laura Núñez-Pons

    2014-04-01

    Full Text Available Generalist predation constitutes a driving force for the evolution of chemical defences. In the Antarctic benthos, asteroids and omnivore amphipods are keystone opportunistic predators. Sessile organisms are therefore expected to develop defensive mechanisms mainly against such consumers. However, the different habits characterizing each predator may promote variable responses in prey. Feeding-deterrence experiments were performed with the circumpolar asteroid macropredator Odontaster validus to evaluate the presence of defences within the apolar lipophilic fraction of Antarctic invertebrates and macroalgae. A total of 51% of the extracts were repellent, yielding a proportion of 17 defended species out of the 31 assessed. These results are compared with a previous study in which the same fractions were offered to the abundant circum-Antarctic amphipod Cheirimedon femoratus. Overall, less deterrence was reported towards asteroids (51% than against amphipods (80.8%, principally in sponge and algal extracts. Generalist amphipods, which establish casual host–prey sedentary associations with biosubstrata (preferentially sponges and macroalgae, may exert more localized predation pressure than sea stars on certain sessile prey, which would partly explain these results. The nutritional quality of prey may interact with feeding deterrents, whose production is presumed to be metabolically expensive. Although optimal defence theory posits that chemical defences are managed and distributed as to guarantee protection at the lowest cost, we found that only a few organisms localized feeding deterrents towards most exposed and/or valuable body regions. Lipophilic defensive metabolites are broadly produced in Antarctic communities to deter opportunistic predators, although several species combine different defensive traits.

  18. Antarctic ozone depletion

    International Nuclear Information System (INIS)

    Antarctic ozone depletion is most severe during the southern hemisphere spring, when the local reduction in the column amount may be as much as 50 percent. The extent to which this ozone poor air contributes to the observed global ozone loss is a matter of debate, but there is some evidence that fragments of the 'ozone hole' can reach lower latitudes following its breakup in summer. Satellite data show the seasonal evolution of the ozone hole. A new dimension has been added to Antarctic ozone depletion with the advent of large volcanic eruptions such as that from Mount Pinatubo in 1991. (author). 5 refs., 1 fig

  19. Mechanisms of metal tolerance in marine macroalgae, with emphasis on copper tolerance in Chlorophyta and Rhodophyta.

    Science.gov (United States)

    Moenne, Alejandra; González, Alberto; Sáez, Claudio A

    2016-07-01

    Green and red macroalgae are closely related organisms, and with terrestrial plants, and constitute the base of marine food webs in coastal ecosystems. Green and red seaweeds, as all living organisms, require essential metals, such as copper, iron, zinc, which can act as co-factors for several proteins and enzymes; however, these metals in excess can induce stress and impair cell viability. Most important negative effects of metal excess are related to the induction of an oxidative stress condition, characterized by the over-accumulation of Reactive Oxygen Species (ROS). In this respect, copper, abundant in wastewaters disposed to coastal environments from domestic and industrial activities, has been one of the most studied metals. Different investigations have provided evidence that green and red macroalgae display several defenses against copper excess to prevent, or at least reduce, stress and damage, among which are cellular exclusion mechanisms, synthesis of metal-chelating compounds, and the activation of the antioxidant system. Most important defense mechanisms identified in green and red seaweed involve: metal-binding to cell wall and epibionts; syntheses of metallothioneins and phytochelatins that accumulate in the cytoplasm; and the increase in the activity of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione peroxidase and catalase, and greater production of antioxidant metabolites as glutathione and ascorbate in organelles and the cytoplasm. In this review, we go through historical records, latest advances, and pending tasks aiming to expand our current knowledge on defense mechanisms to copper excess in green and red macroalgae, with emphasis on biochemical and molecular aspects. PMID:27107242

  20. Gene expression patterns of the coral Acropora millepora in response to contact with macroalgae

    Science.gov (United States)

    Shearer, T. L.; Rasher, D. B.; Snell, T. W.; Hay, M. E.

    2012-12-01

    Contact with macroalgae often causes coral mortality, but the roles of abrasion versus shading versus allelopathy in these interactions are rarely clear, and effects on gene expression are unknown. Identification of gene expression changes within corals in response to contact with macroalgae can provide insight into the mode of action of allelochemicals, as well as reveal transcriptional strategies of the coral that mitigate damage from this competitive interaction, enabling the coral to survive. Gene expression responses of the coral Acropora millepora after long-term (20 days) direct contact with macroalgae ( Chlorodesmis fastigiata, Dictyota bartayresiana, Galaxaura filamentosa, and Turbinaria conoides) and short-term (1 and 24 h) exposure to C. fastigiata thalli and their hydrophobic extract were assessed. After 20 days of exposure, T. conoides thalli elicited no significant change in visual bleaching or zooxanthellae PSII quantum yield within A. millepora nubbins, but stimulated the greatest alteration in gene expression of all treatments. Chlorodesmis fastigiata, D. bartayresiana, and G. filamentosa caused significant visual bleaching of coral nubbins and reduced the PSII quantum yield of associated zooxanthellae after 20 days, but elicited fewer changes in gene expression relative to T. conoides at day 20. To evaluate initial molecular processes leading to reduction of zooxanthella PSII quantum yield, visual bleaching, and coral death, short-term exposures to C. fastigiata thalli and hydrophobic extracts were conducted; these interactions revealed protein degradation and significant changes in catalytic and metabolic activity within 24 h of contact. These molecular responses are consistent with the hypothesis that allelopathic interactions lead to alteration of signal transduction and an imbalance between reactive oxidant species production and antioxidant capabilities within the coral holobiont. This oxidative imbalance results in rapid protein degradation

  1. Herbivory on macro-algae affects colonization of beach-cast algal wrack by detritivores but not its decomposition

    Directory of Open Access Journals (Sweden)

    Philip Eereveld

    2013-05-01

    Full Text Available Spatial subsidies have increasingly been considered significant sources of matter and energy to unproductive ecosystems. However, subsidy quality may both differ between subsidizing sources and vary over time. In our studies, sub-littoral herbivory by snails or isopods on red or brown macro-algae induced changes in algal tissues that affected colonization of beach-cast algal wrack by supra-littoral detritivores (amphipods. However, microbial decay and decomposition through the joint action of detritivores and microbes of algal wrack in the supra-littoral remained unaffected by whether or not red or brown algae had been fed upon by snails or isopods. Thus, herbivory on marine macro-algae affects the cross-system connection of sub-littoral and supra-littoral food webs transiently, but these effects diminish upon ageing of macro-algal wrack in the supra-littoral zone.

  2. Biofuel Production Based on Carbohydrates from Both Brown and Red Macroalgae: Recent Developments in Key Biotechnologies

    Directory of Open Access Journals (Sweden)

    Shigeyuki Kawai

    2016-02-01

    Full Text Available Marine macroalgae (green, red and brown macroalgae have attracted attention as an alternative source of renewable biomass for producing both fuels and chemicals due to their high content of suitable carbohydrates and to their advantages over terrestrial biomass. However, except for green macroalgae, which contain relatively easily-fermentable glucans as their major carbohydrates, practical utilization of red and brown macroalgae has been regarded as difficult due to the major carbohydrates (alginate and mannitol of brown macroalgae and 3,6-anhydro-L-galactose of red macroalgae not being easily fermentable. Recently, several key biotechnologies using microbes have been developed enabling utilization of these brown and red macroalgal carbohydrates as carbon sources for the production of fuels (ethanol. In this review, we focus on these recent developments with emphasis on microbiological biotechnologies.

  3. Bioremediation of a complex industrial effluent by biosorbents derived from freshwater macroalgae.

    Directory of Open Access Journals (Sweden)

    Joel T Kidgell

    Full Text Available Biosorption with macroalgae is a promising technology for the bioremediation of industrial effluents. However, the vast majority of research has been conducted on simple mock effluents with little data available on the performance of biosorbents in complex effluents. Here we evaluate the efficacy of dried biomass, biochar, and Fe-treated biomass and biochar to remediate 21 elements from a real-world industrial effluent from a coal-fired power station. The biosorbents were produced from the freshwater macroalga Oedogonium sp. (Chlorophyta that is native to the industrial site from which the effluent was sourced, and which has been intensively cultivated to provide a feed stock for biosorbents. The effect of pH and exposure time on sorption was also assessed. These biosorbents showed specificity for different suites of elements, primarily differentiated by ionic charge. Overall, biochar and Fe-biochar were more successful biosorbents than their biomass counterparts. Fe-biochar adsorbed metalloids (As, Mo, and Se at rates independent of effluent pH, while untreated biochar removed metals (Al, Cd, Ni and Zn at rates dependent on pH. This study demonstrates that the biomass of Oedogonium is an effective substrate for the production of biosorbents to remediate both metals and metalloids from a complex industrial effluent.

  4. ASSESSMENT OF MACROALGAE HARVESTING FROM THE BALTIC SEA FROM AN ENERGY BALANCE PERSPECTIVE

    OpenAIRE

    Tatarchenko, Olena

    2011-01-01

    Energy balance of large-scale and small-scale scenarios of macroalgae harvesting for biogas production was assessed from the energy balance perspective. Evaluation was based on primary energy Input Output (IO) ratio where all primary energy inputs into the stages of the process life-cycle were summarized and divided by the final energy output from the system. Estimations were made for three cases of possible methane yield from macroalgae as well as for different scenarios of macroalgae co-dig...

  5. Marine macrophytes : Macroalgae species and life forms from Golden Beach, Similajau National Park, Bintulu, Sarawak, Malaysia

    OpenAIRE

    Muta Harah, Zakaria; Japar Sidik, Bujang; Raesah, Amit; Suzalina Akma, Awing; Ogawa, Hisao

    2006-01-01

    A study on macroalgae was carried out around Golden Beach, Similajau National Park during the month of April 2005. Collections and recordings of macroalgae species and life forms were conducted during low tide period. A total of 35 macroalgae were identified belonging to 27 genera comprising of 10 species (28.6%) Chlorophyta, 6 species (17.1%) Phaeophyta and 19 species (54.3%) Rhodophyta. Sargassum paniculatum, the common species inhabited the sand and rock substrates. Entero-morpha intestina...

  6. Cultivo de macroalgas nos Açores… Oportunidades e desafios

    OpenAIRE

    Patarra, Rita F.; Buschmann, Alejandro H.; Abreu, Maria H.; Neto, Ana I.

    2014-01-01

    As macroalgas marinhas têm uma grande diversidade de aplicações. Nos Açores, várias espécies têm sido usadas tradicionalmente para alimentação humana e para extração de agar, um ficocolóide aplicado na indústria alimentar e farmacêutica. As exigências no controlo da qualidade das matérias-primas e as práticas atuais de colheita de macroalgas marinhas selvagens na Europa exigem uma gestão eficaz deste recurso natural e, simultaneamente, tornam premente a necessidade de se implementarem métodos...

  7. Alien macroalgae in Denmark - a broad-scale national perspective

    DEFF Research Database (Denmark)

    Thomsen, Mads S.; Wernberg, Thomas; Stæhr, Peter Anton;

    2007-01-01

    Most studies documenting the importance of alien macroalgae relative to native species are based on smaller-scale sampling programmes. Between 1989 and 2003, a Danish monitoring programme collected data on the percentage cover of macroalgae at more than 600 locations throughout the country. We...... examined this data set to estimate the relative abundance of alien species in the algal flora on large spatiotemporal scales, i.e. across depth ranges, regions and years. Of the 10 alien macroalgal species known to inhabit Danish coastal waters, nine were found in the survey. Most of the alien species were...... only present in low quantities (<1% of the entire flora). In contrast, the two most common alien species, Sargassum muticum and Bonnemaisonia hamifera, constituted 2-7% of the assemblages, depending on depth, region and year. Sargassum muticum was abundant from 0 to 5 m in the northwestern region...

  8. Investigation of mangrove macroalgae as biomonitors of estuarine metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Melville, Felicity [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)], E-mail: f.melville@cqu.edu.au; Pulkownik, Alex [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)

    2007-11-15

    This study examined the potential use of macroalgae epiphytic on mangrove aerial roots as biomonitors of estuarine contamination. The metal concentrations of macroalgae were investigated in four estuaries in the vicinity of Sydney, Australia, and compared to water and sediment metal concentrations over three seasonal surveys. Macroalgal metal concentrations (copper, zinc, cadmium, chromium, lead, nickel, manganese and iron) appeared to be more associated with sediment metal concentrations than water concentrations, suggesting they may be useful biomonitors of estuarine sediment contamination. Algae in the more contaminated estuaries generally contained higher metal concentrations. However, concentrations of iron, nickel and manganese appeared to be similar in the algae despite the varying sediment concentrations, while accumulation of copper, zinc, lead and chromium appeared to be associated with ambient environmental concentrations. The uptake of metals also varied among the different species, suggesting that algal parameters, such as morphology, may also influence metal uptake and accumulation.

  9. Selecting reliable and robust freshwater macroalgae for biomass applications.

    Directory of Open Access Journals (Sweden)

    Rebecca J Lawton

    Full Text Available Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m⁻² day⁻¹, lowest ash content (3-8%, lowest water content (fresh weigh: dry weight ratio of 3.4, highest carbon content (45% and highest bioenergy potential (higher heating value 20 MJ/kg compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO₂ across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E. in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E. in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E. in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with

  10. Prebiotics from Marine Macroalgae for Human and Animal Health Applications

    OpenAIRE

    Laurie O’Sullivan; Brian Murphy; Peter McLoughlin; Patrick Duggan; Peadar G. Lawlor; Helen Hughes; Gardiner, Gillian E.

    2010-01-01

    The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds) are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential...

  11. Chemically mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, V.J.; Kuffner, I.B.; Walters, L.J.; Ritson-Williams, R.; Beach, K.S.; Becerro, M.A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment. ?? 2011 Inter-Research.

  12. Chemically-mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, Valerie J.; Kuffner, Ilsa B.; Walters, Linda J.; Ritson-Williams, Raphael; Beach, Kevin S.; Becerro, Mikel A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment.

  13. Modelling the Antarctic Ice Sheet

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke; Holm, A.

    2015-01-01

    Science) Antarctic Ice Sheet (DAIS) model (Shaffer 2014) is forced by reconstructed time series of Antarctic temperature, global sea level and ocean subsurface temperature over the last two glacial cycles. In this talk a modelling work of the Antarctic ice sheet over most of the Cenozoic era using the......The Antarctic ice sheet is a major player in the Earth’s climate system and is by far the largest depository of fresh water on the planet. Ice stored in the Antarctic ice sheet (AIS) contains enough water to raise sea level by about 58 m, and ice loss from Antarctica contributed significantly to...... DAIS model will be presented. G. Shaffer (2014) Formulation, calibration and validation of the DAIS model (version 1), a simple Antarctic ice sheet model sensitive to variations of sea level and ocean subsurface temperature, Geosci. Model Dev., 7, 1803‐1818...

  14. Antarctic Tourism and Maritime Heritage

    OpenAIRE

    Basberg, Bjørn L.

    2010-01-01

    Maritime activities in the Antarctic region date back to the eighteenth century. They evolved from exploration and discoveries to commercial enterprises, especially sealing, whaling and fishing. Antarctic tourism is a much more recent phenomenon, developing mainly from the 1950s and 1960s. Today over 40,000 tourists visit the Antarctic annually, most of them on cruise ships. This essay reviews the historical development of this tourism. The focus is on how maritime heritage has been treated a...

  15. Antarctic science preserve polluted

    Science.gov (United States)

    Simarski, Lynn Teo

    Geophysicists are alarmed at the electromagnetic pollution of a research site in the Antarctic specifically set aside to study the ionosphere and magnetosphere. A private New Zealand communications company called Telecom recently constructed a satellite ground station within the boundaries of this Site of Special Scientific Interest (SSSI), protected since the mid-1970s. The placement of a commercial facility within this site sets an ominous precedent not only for the sanctity of other SSSIs, but also for Specially Protected Areas—preserves not even open to scientific research, such as certain penguin rookeries.The roughly rectangular, one-by-one-half mile site, located at Arrival Heights not far from McMurdo Station, is one of a number of areas protected under the Antarctic treaty for designated scientific activities. Many sites are set aside for geological or biological research, but this is the only one specifically for physical science.

  16. Comparative study of middle atmosphere temperature at Rothera with Lidar and SABER, and the effect of the Antarctic Vortex

    Science.gov (United States)

    Tan, B.; Harvey, L.; Chu, X.; Espy, P. J.; Gardner, C. S.

    2009-12-01

    The data collected by Fe Boltzmann lidar from 2003 to 2005 at Rothera, Antarctica (67.5 S, 68.0 W) are used to generate temperature morphology in stratosphere and mesosphere covering an entire year. Satellite temperatures by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) are compared to the lidar data and show good agreements in general. SABER provides near global coverage on a daily basis but yaws toward the Northern Hemisphere resulting in months when comparisons are not available. The lidar measures the temperature profile over Rothera at high vertical resolution while the vertical resolution of SABER is 2-3 km. Large variability in temperature is observed in austral fall and spring around 60 km. In this work, we explore the extent to which the observed variability is due to sampling inside, at the edge, or outside the Antarctic polar vortex. The edge of the vortex is co-located with very large temperature gradient and daily movement of the vortex likely contributes to a geophysical explanation for large temperature variations. The position of the vortex edge, based on GEOS-5 temperatures and winds, is used to aid in the interpretation of the temperature structure as a function of altitude and time. Results will be shown that indicate notable differences between profiles sampled in the different air mass regions.

  17. Fate of macroalgae in benthic systems: Carbon and nitrogen cycling within the microbial community

    NARCIS (Netherlands)

    Hardison, A.; Canuel, E.A.; Anderson, I.C.; Veuger, B.

    2010-01-01

    High nutrient loading to coastal bays is often accompanied by the presence of bloom-forming macroalgae, which take up and sequester large amounts of C and N while growing. This pool is temporary, however, as nuisance macroalgae exhibit a bloom and die-off cycle, influencing the biogeochemical functi

  18. Comparative Studies on the Carbohydrate Composition of Marine Macroalgae: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Mack, R. W.

    1985-01-01

    The purpose of this subcontract is to evaluate carbohydrates from macroalgae common to the Gulf of Mexico. Information from these analyses will be used to provide an indication of the feasibility of fermenting macroalgae to ethanol. Knowledge of the carbohydrates will allow for assessment of required pretreatments and utilization efficiencies in converting algal feedstocks to ethanol.

  19. Satellite magnetic anomalies of the Antarctic crust

    Directory of Open Access Journals (Sweden)

    D. E. Alsdorf

    2000-06-01

    Full Text Available Spatially and temporally static crustal magnetic anomalies are contaminated by static core field effects above spherical harmonic degree 12 and dynamic, large-amplitude external fields. To extract crustal magnetic anomalies from the measurements of NASA's Magsat mission, we separate crustal signals from both core and external field effects. In particular, we define Magsat anomalies relative to the degree 11 field and use spectral correlation theory to reduce them for external field effects. We obtain a model of Antarctic crustal thickness by comparing the region's terrain gravity effects to free-air gravity anomalies derived from the Earth Gravity Model 1996 (EGM96. To separate core and crustal magnetic effects, we obtain the pseudo-magnetic effect of the crustal thickness variations from their gravity effect via Poisson's theorem for correlative potentials. We compare the pseudo-magnetic effect of the crustal thickness variations to field differences between degrees 11 and 13 by spectral correlation analysis. We thus identify and remove possible residual core field effects in the Magsat anomalies relative to the degree 11 core field. The resultant anomalies reflect possible Antarctic contrasts due both to crustal thickness and intracrustal variations of magnetization. In addition, they provide important constraints on the geologic interpretation of aeromagnetic survey data, such as are available for the Weddell Province. These crustal anomalies also may be used to correct for long wavelength errors in regional compilations of near-surface magnetic survey data. However, the validity of these applications is limited by the poor quality of the Antarctic Magsat data that were obtained during austral Summer and Fall when south polar external field activity was maximum. Hence an important test and supplement for the Antarctic crustal Magsat anomaly map will be provided by the data from the recently launched Ørsted mission, which will yield coverage

  20. Wind profile radar for study of Antarctic air circulation

    International Nuclear Information System (INIS)

    After a brief discussion of meteorological methods used in the Antarctic, the paper gives an outline of a coordinated international research project whose objective is to set up a wind profiler radar station that would give meteorologists information regarding Antarctic atmospheric dynamics useful in their investigation of the causes and effects of the hole in the ozone layer. The radar instrumentation is to provide continuous readings of wind velocity at varying altitudes above the polar continent

  1. Tropical Atlantic marine macroalgae with bioactivity against virulent and antibiotic resistant Vibrio

    Directory of Open Access Journals (Sweden)

    Giselle Cristina Silva

    2013-03-01

    Full Text Available The antibacterial activity of ethanol, methanol, hexane and acetone-based extracts of the macroalgae Padina gymnospora (PG, Hypnea musciformes (HM, Ulva fasciata (UF and Caulerpa prolifera (CP was investigated. The disk diffusion method was used to evaluate the algae antimicrobial effect against standard strains of Vibrio parahaemolyticus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica and five virulent antibiotic-resistant strains of V. brasiliensis, V. xuii and V. navarrensis (isolated from the hemolymph of Litopenaeus vannamei. Ethanol extracts of PG and HM inhibited all Vibrio strains. E. coli and P. aeruginosa were only susceptible to ethanol extracts of PG. Among the methanol extracts, only UF was bioactive, inhibiting V. navarrensis. The observed inhibitory effect of ethanol extracts of PG, HM and UF against virulent antibiotic-resistant bacteria suggests these macroalgal species constitute a potential source of bioactive compounds.

  2. Macroalgae as a Biomass Feedstock: A Preliminary Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roesijadi, Guritno; Jones, Susanne B.; Snowden-Swan, Lesley J.; Zhu, Yunhua

    2010-09-26

    A thorough of macroalgae analysis as a biofuels feedstock is warranted due to the size of this biomass resource and the need to consider all potential sources of feedstock to meet current biomass production goals. Understanding how to harness this untapped biomass resource will require additional research and development. A detailed assessment of environmental resources, cultivation and harvesting technology, conversion to fuels, connectivity with existing energy supply chains, and the associated economic and life cycle analyses will facilitate evaluation of this potentially important biomass resource.

  3. Prebiotics from marine macroalgae for human and animal health applications.

    LENUS (Irish Health Repository)

    O'Sullivan, Laurie

    2010-01-01

    The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds) are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and\\/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential applications of prebiotics, followed by an outline of the chemistry of seaweed polysaccharides. Their potential for use as prebiotics for both humans and animals will be highlighted by reviewing data from both in vitro and in vivo studies conducted to date.

  4. Biodiversity and biogeography of Antarctic and sub-Antarctic mollusca

    Science.gov (United States)

    Linse, Katrin; Griffiths, Huw J.; Barnes, David K. A.; Clarke, Andrew

    2006-04-01

    For many decades molluscan data have been critical to the establishment of the concept of a global-scale increase in species richness from the poles to the equator. Low polar diversity is key to this latitudinal cline in diversity. Here we investigate richness patterns in the two largest classes of molluscs at both local and regional scales throughout the Southern Ocean. We show that biodiversity is very patchy in the Southern Ocean (at the 1000-km scale) and test the validity of historical biogeographic sub-regions and provinces. We used multivariate analysis of biodiversity patterns at species, genus and family levels to define richness hotspots within the Southern Ocean and transition areas. This process identified the following distinct sub-regions in the Southern Ocean: Antarctic Peninsula, Weddell Sea, East Antarctic—Dronning Maud Land, East Antarctic—Enderby Land, East Antarctic—Wilkes Land, Ross Sea, and the independent Scotia arc and sub Antarctic islands. Patterns of endemism were very different between the bivalves and gastropods. On the basis of distributional ranges and radiation centres of evolutionarily successful families and genera we define three biogeographic provinces in the Southern Ocean: (1) the continental high Antarctic province excluding the Antarctic Peninsula, (2) the Scotia Sea province including the Antarctic Peninsula, and (3) the sub Antarctic province comprising the islands in the vicinity of the Antarctic Circumpolar Current.

  5. Mitochondrial plasticity in response to changing abiotic factors in Antarctic fish and cephalopods

    OpenAIRE

    Strobel, Anneli

    2013-01-01

    Antarctic species possess very low metabolic rates and poor capacities to change their physiological state, thus making them extremely vulnerable to changing environmental conditions. Mitochondria are a key element in shaping whole organism energy turnover and functional capacity. In my study, the effects of rising temperature and increased seawater PCO2 on the energy metabolism were compared between various nototheniids from sub-Antarctic and cold-temperate and Antarctic waters, and between ...

  6. Microphytobenthos and benthic macroalgae determine sediment organic matter composition in shallow photic sediments

    Science.gov (United States)

    Hardison, A. K.; Canuel, E. A.; Anderson, I. C.; Tobias, C. R.; Veuger, B.; Waters, M.

    2013-02-01

    Benthic macroalgae are a common symptom of eutrophication in shallow coastal bays as a result of increased nutrient loads. Microphytobenthos (MPB) and benthic macroalgae play an important role in system metabolism within shallow coastal bays. However, their independent and interactive influences on sediment organic matter (SOM) are not well understood. We investigated the influence of macroalgae and MPB on SOM quantity and quality in an experimental mesocosm system using bulk and molecular level (total hydrolyzable amino acids, THAA; phospholipid linked fatty acids, PLFA; pigment) analyses. Our experiment used an incomplete factorial design made up of two factors, each with two levels: (1) light (ambient vs. dark) and (2) macroalgae (presence vs. absence of live macroalgae). Over the course of the 42-day experiment, total organic carbon (TOC) and total nitrogen (TN) increased under ambient light by 173 ± 14 and 141 ± 7%, respectively, compared to in the dark (78 ± 29 and 39 ± 22%). THAA comprised a substantial fraction of SOM (∼16% of TOC, 35% of TN) and followed TOC and TN accumulation patterns. Mole percent composition of the THAA pool indicated that SOM was composed of more labile organic material (e.g. L-glutamic acid, phenylalanine) under ambient light conditions while SOM in dark treatments was more degraded, with higher proportions of glycine and D-alanine. PLFA content, which represents viable biomass, made up ∼1% of TOC and contained high levels of algal fatty acids in the light, particularly PLFA derived from diatoms. In the presence of MPB (i.e. light and macroalgae treatments), SOM lability increased, resulting in the observed increases in bacterial PLFA concentrations. Macroalgae, which were added to half of the light treatments, decreased SOM accumulation compared to light treatments without macroalgae, with TOC and TN increasing by only 130 ± 32 and 94 ± 24 %, respectively. This decrease likely resulted from shading by macroalgae, which

  7. Microphytobenthos and benthic macroalgae determine sediment organic matter composition in shallow photic sediments

    Directory of Open Access Journals (Sweden)

    A. K. Hardison

    2013-02-01

    Full Text Available Benthic macroalgae are a common symptom of eutrophication in shallow coastal bays as a result of increased nutrient loads. Microphytobenthos (MPB and benthic macroalgae play an important role in system metabolism within shallow coastal bays. However, their independent and interactive influences on sediment organic matter (SOM are not well understood. We investigated the influence of macroalgae and MPB on SOM quantity and quality in an experimental mesocosm system using bulk and molecular level (total hydrolyzable amino acids, THAA; phospholipid linked fatty acids, PLFA; pigment analyses. Our experiment used an incomplete factorial design made up of two factors, each with two levels: (1 light (ambient vs. dark and (2 macroalgae (presence vs. absence of live macroalgae. Over the course of the 42-day experiment, total organic carbon (TOC and total nitrogen (TN increased under ambient light by 173 ± 14 and 141 ± 7%, respectively, compared to in the dark (78 ± 29 and 39 ± 22%. THAA comprised a substantial fraction of SOM (∼16% of TOC, 35% of TN and followed TOC and TN accumulation patterns. Mole percent composition of the THAA pool indicated that SOM was composed of more labile organic material (e.g. L-glutamic acid, phenylalanine under ambient light conditions while SOM in dark treatments was more degraded, with higher proportions of glycine and D-alanine. PLFA content, which represents viable biomass, made up ∼1% of TOC and contained high levels of algal fatty acids in the light, particularly PLFA derived from diatoms. In the presence of MPB (i.e. light and macroalgae treatments, SOM lability increased, resulting in the observed increases in bacterial PLFA concentrations. Macroalgae, which were added to half of the light treatments, decreased SOM accumulation compared to light treatments without macroalgae, with TOC and TN increasing by only 130 ± 32 and 94 ± 24 %, respectively. This decrease likely resulted from shading by

  8. Ecuadorian antarctic act

    International Nuclear Information System (INIS)

    To develop research in this continent involves to take communion with earth where the cold pole of the planet is located, the stormiest sea of the world surround it and where the capricious continental and geographical distribution permits the pass of meteorological violent and continuous systems. The Ecuador, in execution of the acquired commitments like Full Member of the System of the Antarctic Treaty, carried out the VII Expedition to the White Continent with an extensive program of scientific investigation in the field of: Sciences of Life, Sciences of the Earth and Atmospheric Sciences, so much in the environment of the Pacific Southeast, the Drake Pass, Bransfield Strait and the nearby ecosystems antarctic to Point Fort William in the Greenwich Island, site where the Ecuadorian station Pedro Vicente Maldonado is located. The scientific articles, result of the fruitful work of national investigator is consigned in this fourth edition. This publication constitutes our contribution to the world in the knowledge, understanding and handling of the marvelous White Continent from the middle of our planet, Ecuador

  9. Bioremediation for coal-fired power stations using macroalgae.

    Science.gov (United States)

    Roberts, David A; Paul, Nicholas A; Bird, Michael I; de Nys, Rocky

    2015-04-15

    Macroalgae are a productive resource that can be cultured in metal-contaminated waste water for bioremediation but there have been no demonstrations of this biotechnology integrated with industry. Coal-fired power production is a water-limited industry that requires novel approaches to waste water treatment and recycling. In this study, a freshwater macroalga (genus Oedogonium) was cultivated in contaminated ash water amended with flue gas (containing 20% CO₂) at an Australian coal-fired power station. The continuous process of macroalgal growth and intracellular metal sequestration reduced the concentrations of all metals in the treated ash water. Predictive modelling shows that the power station could feasibly achieve zero discharge of most regulated metals (Al, As, Cd, Cr, Cu, Ni, and Zn) in waste water by using the ash water dam for bioremediation with algal cultivation ponds rather than storage of ash water. Slow pyrolysis of the cultivated algae immobilised the accumulated metals in a recalcitrant C-rich biochar. While the algal biochar had higher total metal concentrations than the algae feedstock, the biochar had very low concentrations of leachable metals and therefore has potential for use as an ameliorant for low-fertility soils. This study demonstrates a bioremediation technology at a large scale for a water-limited industry that could be implemented at new or existing power stations, or during the decommissioning of older power stations. PMID:25646673

  10. Trace metals and radionuclides in macroalgae from Moroccan coastal waters.

    Science.gov (United States)

    Benkdad, Azzouz; Laissaoui, Abdelmourhit; Tornero, Maria Victoria; Benmansour, Moncef; Chakir, ElMahjoub; Garrido, Ignacio Moreno; Moreno, Julian Blasco

    2011-11-01

    Macroalgae species Codium sp, Bangia atropurpurea, Membranoptera alata, Plocamium cartilagineum, Dictyota dichotoma, Fucus spiralis and Stypocaulon scoparia were collected from seven stations along the north coast of Morocco. Samples were analysed to determine activities of naturally occurring radionuclides ((210)Pb, U isotopes and (40)K) and concentrations of metals (Zn, Fe, Co, Cu, Ni, Mn, Pb, Cd, As and Cr) using radiometric and ICP-OES techniques, respectively. Metal concentrations were within ranges reported in the scientific literature, and concentrations of bio-essential elements were in the order Mn>Fe> Zn>Cu in all samples. Brown algae had the highest concentrations of almost all metals, and concentrations decreased in the order brown>red>green algae. With respect to radionuclides, the red alga P. cartilagineum had the highest activities of (210)Pb, in most cases an order of magnitude higher than for the green alga Codium sp. (234)U and (238)U activities in all algae samples were in the range 0.96- 7.61 and 1.16-6.14 Bq/kg dry weight, respectively. Our analyses of radionuclide activities and metal concentrations in marine macroalgae showed large differences among taxa. These results provide insights into which algal species should be used for biomonitoring programmes. PMID:21298402

  11. Isotopic shift for defining habitat exploitation by the Antarctic limpet Nacella concinna from rocky coastal habitats (Marian Cove, King George Island)

    Science.gov (United States)

    Choy, Eun Jung; Park, Hyun; Kim, Jeong-Hoon; Ahn, In-Young; Kang, Chang-Keun

    2011-05-01

    δ 13C and δ 15N of the Antarctic limpet Nacella concinna tissues and their potential food sources were used to determine their dietary origins and their movements between diverse habitats of intertidal and subtidal rocky shores and tide pools of Marian Cove, King George Island, Antarctica in the austral summer. δ 13C and δ 15N of the organic matter sources of epilithic microalgae, macroalgae and suspended particulate organic matter (SPOM) were readily distinguishable to discern their relative contribution to the limpet diets, with the most depleted values being found in SPOM and the most enriched in macroalgae. The limpets exhibited a spatial trend in distribution due to their seasonal migration, with smaller individuals in the subtidal zone compared with larger ones on the intertidal sites. The limpet isotopes had relatively broad ranges of δ 13C and δ 15N (-26.6 to -12.8‰ and 2.6-7.1‰, respectively), suggesting a dietary shift between habitats as well as size classes. The stable isotope ratios for each habitat seem likely to reflect the differing availabilities of the three potential food sources. Isotope mixing model results indicate a spatial shift in dietary mixture between habitats as well as limpet size classes. Epilithic microalgae and phytoplankton made great contributions to the diet of the subtidal limpets. Together with epilithic microalgae, macroalgae were significant contributors to the intertidal limpets where macroalgae were abundant. A higher contribution of macroalgae to the limpet diets was found in the tide pools. In contrast, while phytoplankton was an important food source for the limpet spat, a great dietary dependence on epilithic microalgae was found in the small-size limpets from the lower intertidal zone. Our results suggest that limpet grazing can determine microalgal and/or macroalgal abundance and coverage on the Antarctic rocky-shore ecosystem, and trophic structure of benthic food web can change along environmental

  12. Macroalgae Analysis A National GIS-based Analysis of Macroalgae Production Potential Summary Report and Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Roesijadi, Guritno; Coleman, Andre M.; Judd, Chaeli; Van Cleve, Frances B.; Thom, Ronald M.; Buenau, Kate E.; Tagestad, Jerry D.; Wigmosta, Mark S.; Ward, Jeffrey A.

    2011-12-01

    The overall project objective is to conduct a strategic analysis to assess the state of macroalgae as a feedstock for biofuels production. The objective in FY11 is to develop a multi-year systematic national assessment to evaluate the U.S. potential for macroalgae production using a GIS-based assessment tool and biophysical growth model developed as part of these activities. The initial model development for both resource assessment and constraints was completed and applied to the demonstration areas. The model for macroalgal growth was extended to the EEZ off the East and West Coasts of the United States, and a plan to merge the findings for an initial composite assessment was developed. In parallel, an assessment of land-based, port, and offshore infrastructure needs based on published and grey literature was conducted. Major information gaps and challenges encountered during this analysis were identified. Also conducted was an analysis of the type of local, state, and federal requirements that pertain to permitting land-based facilities and nearshore/offshore culture operations

  13. Microphytobenthos and benthic macroalgae determine sediment organic matter composition in shallow photic sediments

    Directory of Open Access Journals (Sweden)

    A. K. Hardison

    2013-08-01

    Full Text Available Microphytobenthos and benthic macroalgae play an important role in system metabolism within shallow coastal bays. However, their independent and interactive influences on sediment organic matter (SOM are not well understood. We investigated the influence of macroalgae and microphytobenthos on SOM quantity and quality in an experimental mesocosm system using bulk and molecular level (total hydrolyzable amino acids, THAA; phospholipid linked fatty acids, PLFA; pigment analyses. Our experiment used an incomplete factorial design made up of two factors, each with two levels: (1 light (ambient vs. dark and (2 macroalgae (presence vs. absence of live macroalgae. Over the course of the 42-day experiment, total organic carbon (TOC and total nitrogen (TN increased under ambient light by 173 ± 14 and 141 ± 7%, respectively, compared to in the dark (78 ± 29 and 39 ± 22%. THAA comprised a substantial fraction of SOM (~ 16% of TOC, 35% of TN and followed TOC and TN accumulation patterns. Mole percent composition of the THAA pool indicated that SOM was composed of more labile organic material (e.g., L-glutamic acid, phenylalanine under ambient light conditions while SOM in dark treatments was more degraded, with higher proportions of glycine and D-alanine. PLFA content, which represents viable biomass, made up ~ 1% of TOC and contained high levels of algal fatty acids in the light, particularly PLFA derived from diatoms. In the presence of microphytobenthos (i.e., light and macroalgae treatments, SOM lability increased, resulting in the observed increases in bacterial PLFA concentrations. Macroalgae, which were added to half of the light treatments, decreased SOM accumulation compared to light treatments without macroalgae, with TOC and TN increasing by only 130 ± 32 and 94 ± 24%, respectively. This decrease likely resulted from shading by macroalgae, which reduced production of microphytobenthos. The presence of macroalgae decreased SOM lability as

  14. Constitution of fish assemblages in three nearshore habitats and the effect of benthic macroalgae on fish assemblages in Gouqi Island%拘杞岛近岸3种生境鱼类群落组成及岩礁区底栖海藻对鱼类群落结构的影响

    Institute of Scientific and Technical Information of China (English)

    王蕾; 章守宇; 汪振华; 王凯; 林军

    2011-01-01

    Macroalgae covering on the rocky reef around coast of Gouqi Island were surveyed and sampled through diving during 2005 to 2006 and May to June 2010, in order to find out the distribution, constitution and life history of macroalgae. Two composing patterns of macroalgae were shown in the subtidal zone of rocky reef; one was dominated by standing macroalgae Sargassum horneri; another was dominated by smaller macroalgaes, such as Ulva pertusa, which is widely distributed both in intertidal and subtidal zone. The life history of S. Horneri showed the four stages of the larger kelp bed: young seedling development period (August to September) ,slow growth period of seeding (October to February in next year) ,fast growth and reproduction period (March to May) .decomposing and declining period (June to July). The smaller kelp bed exists the whole year, without much difference to outside of the kelp bed. To estimate the composition of fish assemblages in three habitats around Gouqi Island nearshore, I. E. Rocky reef, sandy beach and mussel cultivation rafts,we sampled the fish assemblages in three habitats by combined gill nets every month from February 2009 to January 2010. The indexes of Jaccard similarity, Margalef richness and Shannon-wiener diversity were used to compare the variety of fish community structures among habitats, combined with statistical analysis of variance, UPGMA and nMDS. It showed that the differences of fish community structures among above three habitats were significant. The dominant fish species in rocky reef habitat were Sebastiscus marmoratus, Agrammus agrammus and N. Albiflora. Fish community was mainly based on the demersal omnivorous rocky fishes, which prey mainly on benthic invertebrates living on macroalgaes. The dominant fish species in sandy beach habitat were Paraplagusia japonica and Nibea albiflora. Fish community was mainly based on the mid-lower migration fishes. For fish assemblages in mussel cultivation raft habitat, which were

  15. Constitution of fish assemblages in three nearshore habitats and the effect of benthic macroalgae on fish assemblages in Gouqi Island%拘杞岛近岸3种生境鱼类群落组成及岩礁区底栖海藻对鱼类群落结构的影响

    Institute of Scientific and Technical Information of China (English)

    王蕾; 章守宇; 汪振华; 王凯; 林军

    2011-01-01

    Macroalgae covering on the rocky reef around coast of Gouqi Island were surveyed and sampled through diving during 2005 to 2006 and May to June 2010, in order to find out the distribution, constitution and life history of macroalgae. Two composing patterns of macroalgae were shown in the subtidal zone of rocky reef; one was dominated by standing macroalgae Sargassum horneri; another was dominated by smaller macroalgaes, such as Ulva pertusa, which is widely distributed both in intertidal and subtidal zone. The life history of S. Horneri showed the four stages of the larger kelp bed: young seedling development period (August to September) ,slow growth period of seeding (October to February in next year) ,fast growth and reproduction period (March to May) .decomposing and declining period (June to July). The smaller kelp bed exists the whole year, without much difference to outside of the kelp bed. To estimate the composition of fish assemblages in three habitats around Gouqi Island nearshore, I. E. Rocky reef, sandy beach and mussel cultivation rafts,we sampled the fish assemblages in three habitats by combined gill nets every month from February 2009 to January 2010. The indexes of Jaccard similarity, Margalef richness and Shannon-wiener diversity were used to compare the variety of fish community structures among habitats, combined with statistical analysis of variance, UPGMA and nMDS. It showed that the differences of fish community structures among above three habitats were significant. The dominant fish species in rocky reef habitat were Sebastiscus marmoratus, Agrammus agrammus and N. Albiflora. Fish community was mainly based on the demersal omnivorous rocky fishes, which prey mainly on benthic invertebrates living on macroalgaes. The dominant fish species in sandy beach habitat were Paraplagusia japonica and Nibea albiflora. Fish community was mainly based on the mid-lower migration fishes. For fish assemblages in mussel cultivation raft habitat, which were

  16. An evaluation of the toxicity and bioaccumulation of cisplatin in the marine environment using the macroalga, Ulva lactuca

    International Nuclear Information System (INIS)

    The cytotoxic drug, cisplatin (cis-PtCl2(NH3)2), has been added to cultures of the marine macroalga, Ulva lactuca, under various experimental conditions. Both accumulation and internalisation over a 48 h period was greater when cisplatin was added to coastal sea water (salinity = 33) from a distilled water solution than when added to either sea water or estuarine water (salinity = 16.5) from a saline solution. This effect is attributed to the greater abundance of the more reactive monoaqua complex (cis-PtCl(OH2)(NH3)2+) in the distilled water solution and kinetic constraints on its conversion back to cis-PtCl2(NH3)2 in sea water. Despite its mode of action at the cellular level, cisplatin added up to concentrations of 150 nM did not incur a measurable reduction in the efficiency of photochemical energy conversion under any of experimental conditions tested. - Highlights: → This study is the first to examine the biogeochemistry and toxicity of a cytotoxic drug in the marine environment. → Cisplatin is accumulated and internalised by the marine macroalga, Ulva lactuca. → Accumulation is greater when the drug is administered from a distilled water solution than from a saline solution. → Results are consistent with the greater abundance of the more reactive aquated complexes in pure water. → Cisplatin is not phytotoxic to the alga over the concentration range (<150 nM) studied. - The cytotoxic drug, cisplatin, is accumulated and internalised by the marine macroalga, Ulva lactuca, but is not phytotoxic up to concentrations of 150 nM

  17. Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the sub-Antarctic ecoregion

    Directory of Open Access Journals (Sweden)

    Sebastián Rosenfeld

    2014-11-01

    Full Text Available Egg masses of the Patagonian squid Doryteuthis (Amerigo gahi attached to giant kelp (Macrocystis pyrifera in the Magellanic channels of the sub-Antarctic ecoregion in southern South America is documented for the first time. Of seven egg masses observed between 2008 and 2011, one was taken to the laboratory to be analysed and photographed. Comprising long transparent capsules containing eggs, the masses were strongly attached to the stipes of M. pyrifera. This macroalgae is a potentially important economic resource due to its multiple industrial uses; this study shows that it also serves an important ecological role as a spawning substrate for D. gahi.

  18. Laboratory experiments examining inducible defense show variable responses of temperate brown and red macroalgae Experimentos de laboratorio para examinar las defensas inducibles muestran respuestas variables en macroalgas pardas y rojas de ambientes templados

    Directory of Open Access Journals (Sweden)

    EVA ROTHÄUSLER

    2005-12-01

    Full Text Available Macroalgae can defend themselves against generalist and specialist herbivores via morphological and/or chemical traits. Herein we examined the defensive responses (via relative palatability of two brown (Lessonia nigrescens, Glossophora kunthii and two red algae (Grateloupia doryphora, Chondracanthus chamissoi from the northern-central coast of Chile against selected generalist meso-herbivores. Two laboratory experiments were conducted to investigate whether (i algae can respond generally to grazing pressure of meso-herbivores (amphipods, isopods and juvenile sea urchins and whether (ii these algal responses were inducible. In order to examine palatability and thus effectiveness of responses, feeding assays were run after each experiment using fresh algal pieces and artificial agar-based food. Lessonia nigrescens responded to amphipods but not to sea urchins, and G. kunthii showed inducible response against one species of amphipods. Grateloupia doryphora did not respond against any of the tested grazers, whereas C. chamissoi responded against one species of amphipods and the tested isopod. Our results indicate variable responses of macroalgae against selected generalist meso-herbivores and evidence of an inducible defense in the brown alga G. kunthii.Muchas macroalgas poseen la capacidad de defenderse contra herbívoros generalistas y especialistas utilizando defensas químicas y/o morfológicas. En este trabajo se examinó la respuesta de la palatabilidad ante meso-herbívoros generalistas de dos algas pardas (Lessonia nigrescens, Glossophora kunthii y dos algas rojas (Grateloupia doryphora, Chondracanthus chamissoi de la costa Norte de Chile. Se realizaron dos experimentos de laboratorio para investigar si: (i las algas pueden responder al pastoreo realizado por meso-herbivoros generalistas (anfípodos, isópodos y erizos juveniles y (ii si la respuesta de estas algas es inducible. Para examinar la palatabilidad y de esta forma la efectividad

  19. Design of experiments to assess pre-treatment and co-digestion strategies that optimize biogas production from macroalgae Gracilaria vermiculophylla

    OpenAIRE

    Oliveira, J. V. M.; Alves, M.M.; Costa, J.C.

    2014-01-01

    A design of experiments was applied to evaluate different strategies to enhance the methane yield of macroalgae Gracilaria vermiculophylla. Biochemical Methane Potential (BMP) of G. vermiculophylla after physical pre-treatment (washing and maceration) reached 481 ± 9 L CH4 kg−1 VS, corresponding to a methane yield of 79 ± 2%. No significant effects were achieved in the BMP after thermochemical pre-treatment, although the seaweeds solubilisation increased up to 44%. Co-digestion with glycerol ...

  20. Valuable biomolecules from nine North Atlantic red macroalgae

    DEFF Research Database (Denmark)

    Razi Parjikolaei, Behnaz; Bruhn, Annette; Eybye, Karin Loft;

    2016-01-01

    In modern society, novel marine resources are scrutinized pursuing compounds of use in the medical, pharmaceutical, biotech, food or feed industry. Few of the numerous marine macroalgae are currently exploited. In this study, the contents of nutritional compounds from nine common North Atlantic red......, glutamic acid, and arginine, respectively. The amino acid score of the nine algae varied from 44% to 92%, the most commonly first limiting amino acid being histidine. Lutein, β-carotene, and zeaxanthin were the identified carotenoids. Contents of all macro and trace minerals, with the exception of...... phosphorus, were higher than those described for conventional food. Low sodium/potassium ratios (0.08 - 2.54) suggested a potential for using the ash fraction for sodium salt replacement. The algae constituted rich sources of carbohydrates (40% to 71% of DM) which show their potential for a broader...

  1. Prebiotics from Marine Macroalgae for Human and Animal Health Applications

    Directory of Open Access Journals (Sweden)

    Laurie O’Sullivan

    2010-07-01

    Full Text Available The marine environment is an untapped source of bioactive compounds. Specifically, marine macroalgae (seaweeds are rich in polysaccharides that could potentially be exploited as prebiotic functional ingredients for both human and animal health applications. Prebiotics are non-digestible, selectively fermented compounds that stimulate the growth and/or activity of beneficial gut microbiota which, in turn, confer health benefits on the host. This review will introduce the concept and potential applications of prebiotics, followed by an outline of the chemistry of seaweed polysaccharides. Their potential for use as prebiotics for both humans and animals will be highlighted by reviewing data from both in vitro and in vivo studies conducted to date.

  2. A model study of the effect of climate and sea-level change on the evolution of the Antarctic Ice Sheet from the Last Glacial Maximum to 2100

    Science.gov (United States)

    Maris, M. N. A.; van Wessem, J. M.; van de Berg, W. J.; de Boer, B.; Oerlemans, J.

    2015-08-01

    Due to a scarcity of observations and its long memory of uncertain past climate, the Antarctic Ice Sheet remains a largely unknown factor in the prediction of global sea level change. As the history of the ice sheet plays a key role in its future evolution, in this study we model the Antarctic Ice Sheet from the Last Glacial Maximum (21 kyr ago) until the year 2100 with the ice-dynamical model ANICE. We force the model with different temperature, surface mass balance and sea-level records to investigate the importance of these different aspects for the evolution of the ice sheet. Additionally, we compare the model output from 21 kyr ago until the present with observations to assess model performance in simulating the total grounded ice volume and the evolution of different regions of the Antarctic Ice Sheet. Although there are some clear limitations of the model, we conclude that sea-level change has driven the deglaciation of the ice sheet, whereas future temperature change and the history of the ice sheet are the primary cause of changes in ice volume in the future. We estimate the change in grounded ice volume between its maximum (around 15 kyr ago) and the present-day to be between 8.4 and 12.5 m sea-level equivalent and the contribution of the Antarctic Ice Sheet to the global mean sea level in 2100, with respect to 2000, to be -22 to 63 mm.

  3. Macrofaunal community response to extreme concentrations of green macroalgae in a naturally eutrophic estuary

    Science.gov (United States)

    Increases in the size and frequency of green macroalgal (GMA) blooms in estuarine systems are strongly linked to anthropogenic nutrient enrichment, making it an important concern in managing estuarine water quality worldwide. However, the relationship between macroalgae and anth...

  4. Growth - Production of Macroalgae for Human Consumption in the Pacific Northwest

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This proposal will focus on the production of fresh macroalgae in a land-based system. This type of production system avoids the regulatory and permitting issues...

  5. Proximate - Production of Macroalgae for Human Consumption in the Pacific Northwest

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This proposal will focus on the production of fresh macroalgae in a land-based system. This type of production system avoids the regulatory and permitting issues...

  6. Diatom Control - Production of Macroalgae for Human Consumption in the Pacific Northwest

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This proposal will focus on the production of fresh macroalgae in a land-based system. This type of production system avoids the regulatory and permitting issues...

  7. Energy analysis of using macroalgae from eutrophic waters as a bioethanol feedstock

    DEFF Research Database (Denmark)

    Seghetta, Michele; Østergård, Hanne; Bastianoni, Simone

    2014-01-01

    Eutrophication is an environmental problem in a majority of shallow water basins all over the world. The undesired macroalgae has been proposed as a biomass resource for bioethanol production and we have analysed the environmental sustainability of two case studies: Orbetello Lagoon (OL), Italy......, and Koge Bay (KB), Denmark. Today, macroalgae are collected and stored in landfills to provide a solution for the excess production. An emergy assessment revealed that the main environmental support for macroalgae growth relates to water in both case studies. In OL, rain represents 51% of the emergy...... analysed with the full-requirement approach as well as with a marginal-requirement approach accounting only what the bioethanol production requires of additional processes, i.e. mainly transportation and conversion of the macroalgae in a biorefinery facility which is assumed to be situated close to an...

  8. Effects of temperature and fertilization on the structure of total versus active bacterial communities from sub-Antarctic seawater exposed to crude oil and diesel fuel

    Directory of Open Access Journals (Sweden)

    Arturo Rodríguez-Blanco

    2013-05-01

    Full Text Available Polar environments are exposed to the risk of oil pollution. However, there is limited knowledge regarding how the variation of physicochemical factors influencing biodegradation may affect bacterial community structure. The effects of temperature (4, 10 and 20°C and organic fertilization (Inipol EAP 22 on community structure and diversity of bacteria inhabiting Kerguelen sub-Antarctic waters were studied in crude- and diesel-amended microcosms. Dynamics of total (i.e., 16S rDNA-based and metabolically active (i.e., 16S rRNA-based bacterial community structure and diversity were monitored using capillary-electrophoresis single-strand conformation polymorphism. Results showed that total and active community structures were differently influenced by temperature and fertilization in the presence of hydrocarbons. Both fertilization and temperature induced changes in total community structure in the presence of crude oil and diesel. However, temperature showed a limited influence on active community structure, and fertilization induced changes in the presence of crude oil only. Simpson's index decreased for total bacterial communities at all temperatures in the presence of crude oil and diesel, whereas a lower reduction was observed for active bacterial populations. In the presence of fertilizer, the diversity of the whole community approached control values after seven incubation weeks; this was not observed for the active bacterial community. This study evidenced qualitative differences in total and active bacterial community structures of Kerguelen seawaters in the presence of hydrocarbons and different responses relative to variation in temperature and fertilization. These factors and hydrocarbons composition have to be taken into account to understand bacterial community dynamics after an oil spill.

  9. Antarctic Miocene Climate

    Science.gov (United States)

    Ashworth, A. C.; Lewis, A. R.

    2013-12-01

    Fossils from Antarctic Miocene terrestrial deposits, coupled with stratigraphic, geochemical and paleontological data from marine boreholes, provide new insights into the climatic history of the continent. During the Miocene, ice caps coalesced to form ice sheets and vegetated surfaces gave way to barren expanses. The cryospheric changes especially have global climatic implications. The fossil data consists of diatoms, pollen and spores, and macroscopic remains of plants, ostracods, insects, molluscs and a fish. Plant fossils include wood and leaves of Nothofagus (southern beech), seeds of several vascular plants, including Ranunculus (buttercup), Hippuris (mare's-tail) and Myriophyllum (watermilfoil), megaspores of Isoetes (quillwort), and moss species. The insect chitin consists of larval head capsules of Chironomidae (midges) and exoskeletal parts of Coleoptera (beetles). The molluscs include freshwater gastropods and bivalves. The majority of these taxa are likely descendants of taxa that had survived on the continent from the Paleogene or earlier. Even though early Miocene glaciations may have been large, the climate was never cold enough to cause the extinction of the biota, which probably survived in coastal refugia. Early Miocene (c. 20 Ma) macrofossils from the McMurdo Dry Valleys (77°S) support palynological interpretations from the Cape Roberts and ANDRILL marine records that the upland vegetation was a shrub tundra. Mean summer temperature (MST) in the uplands was c. 6°C and possibly higher at the coast. The climate was wet, supporting mires and lakes. By the mid-Miocene, even though the climate continued to be wet. MST was c. 4°C which was too cold to support Nothofagus and most vascular plant species. Stratigraphic evidence indicates that the time between the Early and Mid-Miocene was a time of repeated ice advances and retreats of small glaciers originating from ice caps. At c. 14 Ma there appears to have been a modal shift in climate to

  10. Demineralization of Sargassum spp. Macroalgae Biomass: Selective Hydrothermal Liquefaction Process for Bio-Oil Production

    OpenAIRE

    Díaz-Vázquez, Liz M.; Rojas-Pérez, Arnulfo; Fuentes-Caraballo, Mariela; Robles, Isis V.; Jena, Umakanta; Das, K. C.

    2015-01-01

    Algae biomasses are considered a viable option for the production of biofuel because of their high yields of oil produced per dry weight. Brown macroalgae Sargassum spp. are one of the most abundant species of algae in the shores of Puerto Rico. Its availability in large quantity presents a great opportunity for use as a source of renewable energy. However, high ash content of macroalgae affects the conversion processes and the quality of resulting fuel products. This research studied the eff...

  11. Macroalgae response to a mercury contamination gradient in a temperate coastal lagoon (Ria de Aveiro, Portugal)

    OpenAIRE

    Coelho, J.P.; Pereira, M. E.; Duarte, A.; Pardal, M.A.

    2005-01-01

    Primary producers represent an important pathway for mercury incorporation in aquatic food webs. With eutrophication processes occurring worldwide, macroalgae may represent a substantial pool of mercury, as a result of its high growth rate and capacity to bind trace metals. The main aim of this work was to evaluate the response of the macroalgae to a human-induced environmental mercury gradient in a temperate coastal lagoon, by assessing the total and organic mercury contamination levels of t...

  12. Distribution patterns of intertidal and shallow water caprellids associated with macroalgae along the Iberian Peninsula

    OpenAIRE

    Guerra García, José Manuel; Ros Clemente, Macarena; Gordillo, Ismael; Cabezas Rodríguez, María del Pilar; Baeza-Rojano Pageo, Elena; Izquierdo, David; Corzo, J.; Domínguez, J.; Varona, S.

    2011-01-01

    This study investigated the patterns of caprellids associated with macroalgae from the intertidal and shallow waters (0-5 m) of the Iberian Peninsula. Nineteen stations and 250 samples of algae demonstrated the presence of 46 algal species (22 intertidal and 24 subtidal). Eleven caprellid species dwelled in th ese macroalgae with Caprella penantis and C. acanthifera being the most abundant species. Caprella acanthifera , Phtisica marina and Pseudoprotella phasma inhabited the whole ...

  13. Evolution and ecology of antarctic sponges

    OpenAIRE

    Vargas Ramirez, Sergio

    2012-01-01

    Sponges are abundant and species-rich in Antarctic waters, and play important roles in the benthic ecosystems of the continent. The taxonomy of Antarctic sponges is, to some extent, well established, yet the phylogenetic relationships of this fauna remain unknown. Here, the first contributions to the knowledge of the evolution of Antarctic sponges are presented. A molecular phylogeny for the common Antarctic shelf glass sponge genus Rossella is provided. Based on nuclear and mitochondrial mar...

  14. Lipid content and fatty acid composition of Mediterranean macro-algae as dynamic factors for biodiesel production

    Directory of Open Access Journals (Sweden)

    Dahlia M. El Maghraby

    2015-01-01

    Full Text Available Using the total lipid contents and fatty acid profiles, the marine macro-algae Jania rubens (Rhodophyceae, Ulva linza (Chlorophyceae and Padina pavonica (Phaeophyceae were evaluated for biodiesel production during the spring, summer and autumn. Seawater parameters such as pH, salinity and temperature were measured. The total lipid content varied from 1.56% (J. rubens to 4.14% (U. linza of dry weight, with the highest values occurring in spring. The fatty acid methyl ester profiles were analysed using gas chromatography. The highest percentage of total fatty acids was recorded in P. pavonica, with 6.2% in autumn, whereas the lowest was in J. rubens, with 68.6% in summer. The relative amount of saturated to unsaturated fatty acids was significantly higher in P. pavonica than in the other macro-algae. Seasonal variations in pH, salinity and temperature had no significant effect on the total lipid and fatty acid contents. Principal component analysis grouped brown and green algae together, whereas red alga grouped out. Furthermore, methyl ester profiles indicate that brown and green seaweeds are preferred, followed by red seaweeds, which appears to have little potential for oil-based products. Therefore, these seaweeds are not targets for biodiesel production.

  15. Photoacclimation modulates excessive photosynthetically active and ultraviolet radiation effects in a temperate and an Antarctic marine diatom

    NARCIS (Netherlands)

    van de Poll, W.H.; Alderkamp, A.C.; Janknegt, P.J.; Roggeveld, J; Buma, A.G.J.

    2006-01-01

    The influence of photoacclimation on the effects of excessive photosynthetically active (PAR; 400-700 nm) and ultraviolet (UVR; 280-400 nm) radiation was assessed for the marine diatoms Thalassiosira weissflogii (Grunow) Fryxell and Hasle and Thalassiosira antarctica (Comber). Low and high PAR accli

  16. Investigating the Effect of Recruitment Variability on Length-Based Recruitment Indices for Antarctic Krill Using an Individual-Based Population Dynamics Model

    OpenAIRE

    Stéphane Thanassekos; Cox, Martin J.; Keith Reid

    2014-01-01

    Antarctic krill (Euphausia superba; herein krill) is monitored as part of an on-going fisheries observer program that collects length-frequency data. A krill feedback management programme is currently being developed, and as part of this development, the utility of data-derived indices describing population level processes is being assessed. To date, however, little work has been carried out on the selection of optimum recruitment indices and it has not been possible to assess the performance...

  17. Antarctic Ozone Hole, 2000

    Science.gov (United States)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  18. Depletion in Antarctic ozone and associated climatic change

    International Nuclear Information System (INIS)

    Perhaps the most significant discovery in the atmospheric sciences in the last decade has been the observation of large decreases in ozone. These losses in ozone occur during austral spring, and from 1979 the severity of the depletion increased non-monotonically until September of 1987 when the lowest column ozone amounts ever recorded were observed in Antarctica. While the surprising ozone hole in the remote icy continent of Antarctica emphasizes the potential importance and complexity of processes in the high latitude stratosphere, it also motivated this study on the nature of greenhouse effect on polar climate due to perturbations in column ozone amount in association with observed increases in other trace gases in the Antarctic atmosphere. The authors have examined the potential climatic effects of changes in the concentration of greenhouse gases on thermal structure of the Antarctic atmosphere using both steady-state and time-dependent climate models. When the authors incorporate the greenhouse effect of increases in methane, nitrous oxide, carbon dioxide and chlorofluorocarbons in association with decrease in ozone at the levels of maximum concentration in their radiative flux computations for the Antarctic region, the net result is a surface warming which is in fair agreement with that inferred from mean Antarctic temperature series. Further, the stratospheric cooling due to the ozone hole phenomenon is not only restricted to low and middle stratosphere but also extends deep into the upper Antarctic stratosphere, particularly in the beginning of November. In view of this, it is possible that the polar stratospheric warming phenomenon associated with planetary wave events could be significantly disturbed by ozone depletion in the Antarctic atmosphere, leading to appreciable perturbations in the general circulation

  19. Fenóis halogenados e/ou sulfatados de macroalgas marinhas Halogenated and/or sulfated phenols from marine macroalgae

    Directory of Open Access Journals (Sweden)

    Luciana Retz de Carvalho

    2000-12-01

    Full Text Available During the biological evolution, marine macroalgae have developed biochemicals tools in order to utilize components of seawater such as sulfates and halogens, to produce a variety of chemicals (secondary metabolites.This review shows and discuss the occurrence of sulfated and/or halogenated phenolic compounds in seaweeds.

  20. CHAMP Magnetic Anomalies of the Antarctic Crust

    Science.gov (United States)

    Kim, Hyung Rae; Gaya-Pique, Luis R.; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo

    2003-01-01

    Regional magnetic signals of the crust are strongly masked by the core field and its secular variations components and hence difficult to isolate in the satellite measurements. In particular, the un-modeled effects of the strong auroral external fields and the complicated- behavior of the core field near the geomagnetic poles conspire to greatly reduce the crustal magnetic signal-to-noise ratio in the polar regions relative to the rest of the Earth. We can, however, use spectral correlation theory to filter the static lithospheric and core field components from the dynamic external field effects. To help isolate regional lithospheric from core field components, the correlations between CHAMP magnetic anomalies and the pseudo magnetic effects inferred from gravity-derived crustal thickness variations can also be exploited.. Employing these procedures, we processed the CHAMP magnetic observations for an improved magnetic anomaly map of the Antarctic crust. Relative to the much higher altitude Orsted and noisier Magsat observations, the CHAMP magnetic anomalies at 400 km altitude reveal new details on the effects of intracrustal magnetic features and crustal thickness variations of the Antarctic.

  1. The effects of a spillage of diesel fuel on a rocky shore in the sub-Antarctic region (Macquarie Island)

    International Nuclear Information System (INIS)

    On 3 December 1987, the supply ship Nella Dan ran aground at Macquarie island (54o29'S. 158o58'E) releasing about 270 000 1 of oil, mostly light marine diesel, into the sea. At the time of the incident, many marine invertebrates were washed up dead along 2 km of shoreline. Twelve months later, the shore community was investigated using (1) algal and invertebrate populations of the littoral and sublittoral rocky shore, and (2) the invertebrate communities living in the holdfasts of the giant kelp Durvillaea antarctica, which were collected for later examination. Investigations were undertaken at both affected and control locations. Analyses of differences in community structure involved nested ANOVA and multi-dimensional scaling techniques. On the rocky substrate, the effect of the spill was restricted to some biota of the lower littoral and sublittoral zones -particularly echinoderms and the patellid limpet Nacella macquariensis. There were differences in cover for some algal species between locations. Within the kelp holdfasts, communities were dominated by peracarid crustaceans at control locations and by polychaetes (particularly the opportunistic groups - capitellids, cirratulids and spionids) at oil-affected locations. The communities have recently been re-surveyed (in the summer of 1994-95) to assist in the interpretation of the results and to gauge the extent of recovery of the affected biota. (author)

  2. Antibacterial Potential of Macroalgae Collected from the Madappam Coast, India

    Directory of Open Access Journals (Sweden)

    N. Srivastava

    2010-11-01

    Full Text Available In vitro antimicrobial activity of two selected marine macroalgae has been evaluated in the present research, which lies in identifying certain seaweeds whose extract can act as an alternative to commonly used antibiotics hence possessing activity against human pathogens. Extract from two species of seaweed samples namely Caulerpa racemosa and Grateloupia lithophila were collected from different locations at Gulf of Mannar, Southeast Coastal Region, M andapam, Tamil Nadu, India and w ere screened for antimicrobial activity. Extracts of Methanol, Ethanol, Butanol, Acetone, Chloroform and Dichloromethane were tested against selected human pathogens. Both the seaweeds collected had shown moderate antibacterial activity with <15 mm of zone of inhibition. Out of which only butanolic extract of has shown significant activity. Phytochemical screening revealed the presence of alkaloid and phenolic compounds in both the seaweeds whereas flavonoids and steroids were found to be present in only Caulerpa racemosa. The screening result confirms that these seaweeds can be further studied and used as possible source of antimicrobial compounds.

  3. Feeding repellence in Antarctic bryozoans

    Science.gov (United States)

    Figuerola, Blanca; Núñez-Pons, Laura; Moles, Juan; Avila, Conxita

    2013-11-01

    The Antarctic sea star Odontaster validus and the amphipod Cheirimedon femoratus are important predators in benthic communities. Some bryozoans are part of the diet of the asteroid and represent both potential host biosubstrata and prey for this omnivorous lysianassid amphipod. In response to such ecological pressure, bryozoans are expected to develop strategies to deter potential predators, ranging from physical to chemical mechanisms. However, the chemical ecology of Antarctic bryozoans has been scarcely studied. In this study we evaluated the presence of defenses against predation in selected species of Antarctic bryozoans. The sympatric omnivorous consumers O. validus and C. femoratus were selected to perform feeding assays with 16 ether extracts (EE) and 16 butanol extracts (BE) obtained from 16 samples that belonged to 13 different bryozoan species. Most species (9) were active (12 EE and 1 BE) in sea star bioassays. Only 1 BE displayed repellence, indicating that repellents against the sea star are mainly lipophilic. Repellence toward C. femoratus was found in all species in different extracts (10 EE and 12 BE), suggesting that defenses against the amphipod might be both lipophilic and hydrophilic. Interspecific and intraspecific variability of bioactivity was occasionally detected, suggesting possible environmental inductive responses, symbiotic associations, and/or genetic variability. Multivariate analysis revealed similarities among species in relation to bioactivities of EE and/or BE. These findings support the hypothesis that, while in some cases alternative chemical or physical mechanisms may also provide protection, repellent compounds play an important role in Antarctic bryozoans as defenses against predators.

  4. Antarctic snow and global climate

    International Nuclear Information System (INIS)

    Global circulation models (GCM) indicate that global warming will be most pronounced at polar regions and high latitudes, causing concern about the stability of the Antarctic ice cap. A project entitled the Seasonal Snow in Antarctica examined the properties of the near surface snow to determine the current conditions that influence snow cover development. The goal was to assess the response of the snow cover in Queen Maud Land (QML) to an increased atmospheric carbon dioxide content. The Antarctic snow cover in QML was examined as part of the FINNARP expeditions in 1999 and 2000 which examined the processes that influence the snow cover. Its energy and mass balance were also assessed by examining the near surface snow strata in shallow (1-2 m) pits and by taking measurements of environmental variables. This made it possible to determine if the glacier is in danger of melting at this northerly location in the Antarctic. The study also made it possible to determine which variables need to change and by how much, for significant melting to occur. It was shown that the Antarctic anticyclone creates particular conditions that protect the snow cover from melting. The anticyclone brings dry air from the stratosphere during most of the year and is exempt from the water vapour feedback. It was concluded that even a doubling of atmospheric carbon dioxide will not produce major snow melt runoff. 8 refs

  5. Effects of petroleum hydrocarbon on growth and photosynthesis in sea weed macroalga Ulva pertusa%石油烃对孔石莼生长及光合作用的影响

    Institute of Scientific and Technical Information of China (English)

    王珊; 刘瑀; 张松

    2011-01-01

    Effects of three petroleum hydrocarbon solutions ( marine fuel L D. 0. , Saudi Arabian light crude oil and marine lubricating oil) at growth and photosynthesis in sea weed Ulva pertusa were studied to provide basic data for oil spill monitoring and risk assessment. The concentration of L. D. 0. And Saudi Arabian light crude oil petroleum hydrocarbon was 0, 5, 10, 15, 25, and 50 mg/L and of marine lubricating petroleum hydrocarbon was 0,5, 10, 20, 25, 50, and 100 mg/L. The result showed that the sea weed was found to survive in three oil solutions under low concentration, but high oil concentration (LD. 0. = 50 mg/L;Saudi Arabian light crude oil =50 mg/L; marine lubricating oil =100 mg/L) to be dead totally within 96 h. The Chlorophyll contents, photosynthetic rate and respiratory rate were decreased in the sea weed exposed to the elevated concentrations of three petroleum hydrocarbon solutions, and the Chlorophyll contents and photosynthetic rate of the sea weed was shown the tendency of undulate. However, the photosynthetic rate was decreased in the sea weed in marine lubricating oil petroleum hydrocarbon solutions with increasing oil concentration.%研究了3种石油烃(船舶燃油(LD.O.)、沙特阿拉伯轻质原油(沙轻原油)和船用润滑油(润滑油))溶液对孔石莼Ulva pertusa的生长和光合作用的影响.LD.O.和沙轻原油石油烃的浓度分别设置为0、5、10、15、25、50 mg/L,润滑油石油烃浓度分别设置为0、5、10、20、25、50、100 mg/L.结果表明:孔石莼在3种石油烃较低的浓度下均可存活,但当石油烃浓度升高到一定量时(L D.O.=50 mg/L;沙轻原油=50 mg/L;润滑油=100 mg/L),96 h内全部死亡;在3种石油烃不同浓度的溶液中,孔石莼的叶绿素含量、光合速率及呼吸速率总体趋势是随着石油烃浓度的升高而降低,叶绿素含量及光合速率的变化基本呈波浪式,但在润滑油石油烃各浓度溶液中,孔石莼的光合速率则随着油浓度的

  6. Physiological responses of macroalga Gracilaria lemaneiformis (Rhodophyta) to UV-B radiation exposure

    Science.gov (United States)

    Zhu, Lin; Xiao, Hui; Wang, Ying; Jian, Xiaoyang; Zhang, Zhipeng; Zhang, Huanxin; Tang, Xuexi

    2015-03-01

    This paper aims to evaluate the effects of ultraviolet-B radiation (UVBR) on Gracilaria lemaneiformis, a commercial red macroalga and an important source of agar. To study the in-vitro effect of UVBR on G. lemaneiformis, this plant was cultivated and exposed to photosynthetically active radiation (PAR) at 40 μmol photons/(m2 ·s) and enhanced UVBR (0, 0.36, 0.72, 1.08, 1.44, and 1.80 kJ/(m2 ·d)) for 13 days. The samples were processed for histochemical analysis, and the growth rate, photosynthetic pigment contents, photosynthetic performance, reactive oxygen species levels, membrane permeability, malonyl dialdehyde contents and antioxidant capacity of G. lemaneiformis were investigated. After 13 days of exposure to PAR+UVBR, G. lemaneiformis showed photodamage and photoinhibition of photosynthetic pigments (chlorophyll a and phycoerythrin), leading to a decreased photosynthetic efficiency. Further, there was a corresponding decrease in the relative growth rates and depigmentation and partial necrosis of the apical segments were noted after exposure to PAR+UVBR. Additionally, UVBR induced excess production of superoxide radicals and hydrogen peroxide, eliciting a marked cellular membrane damage and antioxidative response.

  7. Emplacement of Antarctic ice sheet mass affects circumpolar ocean flow

    NARCIS (Netherlands)

    Rugenstein, M.; Stocchi, P.; van der Heydt, A.; Brinkhuis, H.

    2014-01-01

    During the Cenozoic the Antarctic continent experienced large fluctuations in ice-sheet volume. We investigate the effects of Glacial Isostatic Adjustment (GIA) on Southern Ocean circulation for the first continental scale glaciation of Antarctica (~ 34 Myr) by combining solid Earth and ocean dynami

  8. The Macroalgae Biorefinery for Production of Bioethanol and Fish Feed from the Two Brown Algae: Laminaria Digitata and Saccharina Latissima

    DEFF Research Database (Denmark)

    Hou, Xiaoru; Bjerre, Anne-Belinda; Hansen, Jonas Høeg;

    A new Danish macroalgae project (Acronym MAB3) financed by the Danish Strategic Research Council presents an integrated macroalgae biorefinery concept. It was started from march 2012 and will continue for the next 4 years (2012-2016). Initial studies on the first harvested materials of wild Lamin...

  9. Diversity and Abundance of Marine Macroalgae along Borli Coast: a Zone under Western Ghats, Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Poonam Kurve

    2015-03-01

    Full Text Available Richness of Marine macroalgae species along the Konkan coastline has been well reported by few researchers. Yet, there are many coastal villages in Konkan where the research is still to be undertaken. Borli is one such village having rocky shore which provides perfect habitat for growth of macroalgae. In our study during (June 2012 to May 2013 we found, total 35 species of marine macroalgae. Rhodophyceae is a dominating class contributing 15 species followed by Phaeophyceae and Chlorophyceae with 12 and 8 species respectively. The algal diversity of Borli coast needs to be documented as this coast is a part of Western Ghats that has solicited the interest from scientist fraternity world over. Further, nearby coasts are frequented by tourists and this coast is quite likely to have an impact of anthropogenic invasion.

  10. Desiccation induces accumulations of antheraxanthin and zeaxanthin in intertidal macro-alga Ulva pertusa (Chlorophyta.

    Directory of Open Access Journals (Sweden)

    Xiujun Xie

    Full Text Available For plants and algae, exposure to high light levels is deleterious to their photosynthetic machineries. It also can accelerate water evaporation and thus potentially lead to drought stress. Most photosynthetic organisms protect themselves against high light caused photodamages by xanthophyll cycle-dependent thermal energy dissipation. It is generally accepted that high light activates xanthophyll cycle. However, the relationship between xanthophyll cycle and drought stress remains ambiguous. Herein, Ulva pertusa (Chlorophyta, a representative perennial intertidal macro-algae species with high drought-tolerant capabilities and simple structures, was used to investigate the operation of xanthophyll cycle during desiccation in air. The results indicate that desiccation under dim light induced accumulation of antheraxanthin (Ax and zeaxanthin (Zx at the expense of violaxanthin (Vx. This accumulation could be arrested by dithiothreitol completely and by uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone partially, implying the participation of Vx de-epoxidase in conversion of Vx to Ax and Zx. Treatment with inhibitors of electron transport along thylakoid membrane, e.g. DCMU, PG and DBMIB, did not significantly arrest desiccation-induced accumulation of Ax and Zx. We propose that for U. pertusa, besides excess light, desiccation itself could also induce accumulation of Ax and Zx. This accumulation could proceed without electron transport along thylakoid membrane, and is possibly resulting from the reduction of thylakoid lumen volume during desiccation. Considering the pleiotropic effects of Ax and Zx, accumulated Ax and Zx may function in protecting thylakoid membrane and enhancing thermal quenching during emersion in air.

  11. Environmental life cycle optimization of essential terpene oils produced by the macroalga Ochtodes secundiramea.

    Science.gov (United States)

    Pérez-López, Paula; Jeffryes, Clayton; Agathos, Spiros N; Feijoo, Gumersindo; Rorrer, Gregory; Moreira, María Teresa

    2016-01-15

    The macroalga Ochtodes secundiramea is a well-known producer of essential terpene oils with promising biological activities and similar applications to those of microalgal biocompounds in the pharmaceutical, food or cosmetics sectors. This study assesses the environmental impacts associated with the production of five essential terpene oils (myrcene, 10Z-bromomyrcene, 10E-bromo-3-chloromyrcene, apakaochtodene B and acyclic C10H14Br2) by O. secundiramea cultivated in a closed airlift photobioreactor with artificial illumination. The results of the life cycle assessment (LCA) allowed analyzing the effect of implementing a semi-continuous operation on several stages of the life cycle of the products, which may lead to impact reductions from 1% up to 25%. Regarding the most problematic aspects of the process, the cultivation in the photobioreactor (S4) was identified as the main stage responsible for the environmental burdens, with contributions ranging between 60% and 80% of the total impacts for a semi-continuous production maintained during one year of operation. The electricity supply is the key activity affecting eight of the ten assessed categories and involves between 50% and 60% of the impact of the process. S4 is the main cause of the high energy requirements, with 86% of the total electricity consumption. Additionally, several scenarios aiming at improving the environmental profile of the system were evaluated. The application of LCA finally led to the proposal of two optimized scenarios with improvements between 8% and 40% with respect to the baseline case study. PMID:26519589

  12. Antioxidant Activity of the Brown Macroalgae Fucus spiralis Linnaeus Harvested from the West Coast of Ireland

    Directory of Open Access Journals (Sweden)

    Anna Soler-vila

    2013-05-01

    Full Text Available The extraction and isolation of natural antioxidants with potential in reducing the incidences of oxidative stress in the body and their potential inclusion into functional foods is a major topic of research at present. In this study, the aim was to investigate food-friendly Accelerated Solvent Extraction® (ASE® samples and a Viscozyme® hydrolysate of the brown macroalga Fucus spiralis Linnaeus for total phenolic content and antioxidant activities. Furthermore, the effect of ultra-filtration steps on the total phenolic content and antioxidant activities of the Fucus spiralis hydrolysate were also evaluated.ethanolic-aqueous and methanolic-aqueous ASE® extracts displayed high phenolic contents of 37.03±3.01 and 39.04±5.72 µg phloroglucinol equivalents mg/sample, respectively. Both the Fucus spiralis Viscozyme® hydrolysate and ASE® extracts displayed in vitro antioxidant activities. Our findings suggest that food-friendly extracts of Fucus spiralis show potential as alternative sources of antioxidants.

  13. Large-scale bioprospecting of cyanobacteria, micro- and macroalgae from the Aegean Sea.

    Science.gov (United States)

    Montalvão, Sofia; Demirel, Zeliha; Devi, Prabha; Lombardi, Valter; Hongisto, Vesa; Perälä, Merja; Hattara, Johannes; Imamoglu, Esra; Tilvi, Supriya Shet; Turan, Gamze; Dalay, Meltem Conk; Tammela, Päivi

    2016-05-25

    Marine organisms constitute approximately one-half of the total global biodiversity, being rich reservoirs of structurally diverse biofunctional components. The potential of cyanobacteria, micro- and macroalgae as sources of antimicrobial, antitumoral, anti-inflammatory, and anticoagulant compounds has been reported extensively. Nonetheless, biological activities of marine fauna and flora of the Aegean Sea have remained poorly studied when in comparison to other areas of the Mediterranean Sea. In this study, we screened the antimicrobial, antifouling, anti-inflammatory and anticancer potential of in total 98 specimens collected from the Aegean Sea. Ethanol extract of diatom Amphora cf capitellata showed the most promising antimicrobial results against Candida albicans while the extract of diatom Nitzschia communis showed effective results against Gram-positive bacterium, S. aureus. Extracts from the red alga Laurencia papillosa and from three Cystoseira species exhibited selective antiproliferative activity against cancer cell lines and an extract from the brown alga Dilophus fasciola showed the highest anti-inflammatory activity as measured in primary microglial and astrocyte cell cultures as well as by the reduction of proinflammatory cytokines. In summary, our study demonstrates that the Aegean Sea is a rich source of species that possess interesting potential for developing industrial applications. PMID:26902670

  14. Macroalgae-Derived Biofuel: A Review of Methods of Energy Extraction from Seaweed Biomass

    Directory of Open Access Journals (Sweden)

    John J. Milledge

    2014-11-01

    Full Text Available The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, but as yet there is no successful economically viable commercial system producing biofuel. However, the majority of the research has focused on producing fuels from microalgae rather than from macroalgae. This article briefly reviews the methods by which useful energy may be extracted from macroalgae biomass including: direct combustion, pyrolysis, gasification, trans-esterification to biodiesel, hydrothermal liquefaction, fermentation to bioethanol, fermentation to biobutanol and anaerobic digestion, and explores technical and engineering difficulties that remain to be resolved.

  15. Pretreatment of the macroalgae Chaetomorpha linum for the production of bioethanol - Comparison of five pretreatment technologies

    DEFF Research Database (Denmark)

    Schultz-Jensen, Nadja; Thygesen, Anders; Thomsen, Sune Tjalfe;

    2013-01-01

    A qualified estimate for pretreatment of the macroalgae Chaetomorpha linum for ethanol production was given, based on the experience of pretreatment of land-based biomass. C. linum was subjected to hydrothermal pretreatment (HTT), wet oxidation (WO), steam explosion (STEX), plasma-assisted pretre......A qualified estimate for pretreatment of the macroalgae Chaetomorpha linum for ethanol production was given, based on the experience of pretreatment of land-based biomass. C. linum was subjected to hydrothermal pretreatment (HTT), wet oxidation (WO), steam explosion (STEX), plasma...

  16. Extremophiles in an Antarctic Marine Ecosystem

    Directory of Open Access Journals (Sweden)

    Iain Dickinson

    2016-01-01

    Full Text Available Recent attempts to explore marine microbial diversity and the global marine microbiome have indicated a large proportion of previously unknown diversity. However, sequencing alone does not tell the whole story, as it relies heavily upon information that is already contained within sequence databases. In addition, microorganisms have been shown to present small-to-large scale biogeographical patterns worldwide, potentially making regional combinations of selection pressures unique. Here, we focus on the extremophile community in the boundary region located between the Polar Front and the Southern Antarctic Circumpolar Current in the Southern Ocean, to explore the potential of metagenomic approaches as a tool for bioprospecting in the search for novel functional activity based on targeted sampling efforts. We assessed the microbial composition and diversity from a region north of the current limit for winter sea ice, north of the Southern Antarctic Circumpolar Front (SACCF but south of the Polar Front. Although, most of the more frequently encountered sequences  were derived from common marine microorganisms, within these dominant groups, we found a proportion of genes related to secondary metabolism of potential interest in bioprospecting. Extremophiles were rare by comparison but belonged to a range of genera. Hence, they represented interesting targets from which to identify rare or novel functions. Ultimately, future shifts in environmental conditions favoring more cosmopolitan groups could have an unpredictable effect on microbial diversity and function in the Southern Ocean, perhaps excluding the rarer extremophiles.

  17. Antarctic tourism and the maritime heritage

    OpenAIRE

    Basberg, Bjørn L.

    2008-01-01

    Maritime activity in the Antarctic region goes back to the 18th Century. It evolved from exploration and discoveries to commercial activities, especially sealing and whaling. Antarctic tourism is a more recent phenomenon, developing gradually from the 1960s. Today, more than 20.000 tourists visit the Antarctic annually – mostly on cruise ships. The paper reviews the historical development of these activities. The main focus is on how the maritime heritage has been dealt with an...

  18. Removing constraints on the biomass production of freshwater macroalgae by manipulating water exchange to manage nutrient flux.

    Directory of Open Access Journals (Sweden)

    Andrew J Cole

    Full Text Available Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1-1 vol.day-1 using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25% with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5-1 vol.day-1, where uptake rates peaked at 1.09 g.m-2.day-1 for nitrogen and 0.13 g.m-2.day-1 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2% for nitrogen and 22.1% for phosphorous. In this study a nitrogen flux of 1.45 g.m-2.day-1 and a phosphorous flux of 0.6 g.m-2.day-1 was the minimum required to maintain the growth of Oedogonium at 16-17 g DW.m-2.day-1 and a crude protein content of 25%. A simple model of minimum inputs shows that for every gram of dry weight biomass production (g DW.m-2.day-1, Oedogonium requires 0.09 g.m-2.day-1 of nitrogen and 0.04 g.m-2.day-1 of phosphorous to maintain growth without nutrient limitation whilst simultaneously maintaining a high-nutrient uptake rate and efficiency. As such the integrated culture of freshwater macroalgae with aquaculture for the purposes of nutrient recovery is a feasible solution for the bioremediation of wastewater and the

  19. Antarctic skuas recognize individual humans.

    Science.gov (United States)

    Lee, Won Young; Han, Yeong-Deok; Lee, Sang-Im; Jablonski, Piotr G; Jung, Jin-Woo; Kim, Jeong-Hoon

    2016-07-01

    Recent findings report that wild animals can recognize individual humans. To explain how the animals distinguish humans, two hypotheses are proposed. The high cognitive abilities hypothesis implies that pre-existing high intelligence enabled animals to acquire such abilities. The pre-exposure to stimuli hypothesis suggests that frequent encounters with humans promote the acquisition of discriminatory abilities in these species. Here, we examine individual human recognition abilities in a wild Antarctic species, the brown skua (Stercorarius antarcticus), which lives away from typical human settlements and was only recently exposed to humans due to activities at Antarctic stations. We found that, as nest visits were repeated, the skua parents responded at further distances and were more likely to attack the nest intruder. Also, we demonstrated that seven out of seven breeding pairs of skuas selectively responded to a human nest intruder with aggression and ignored a neutral human who had not previously approached the nest. The results indicate that Antarctic skuas, a species that typically inhabited in human-free areas, are able to recognize individual humans who disturbed their nests. Our findings generally support the high cognitive abilities hypothesis, but this ability can be acquired during a relatively short period in the life of an individual as a result of interactions between individual birds and humans. PMID:26939544

  20. Recent Rapid Regional Climate Warming on the Antarctic Peninsula

    Science.gov (United States)

    Vaughan, D. G.; Marshall, G. J.; Connolley, W. M.; Parkinson, C.; Mulvaney, R.; Hodgson, D. A.; King, J. C.; Pudsey, C. J.; Turner, J.

    2002-12-01

    The Intergovernmental Panel on Climate Change (IPCC) confirmed that global warming was 0.6 ñ 0.2 degrees C during the 20th Century and cited increases in greenhouse gases as a likely contributor. But this average conceals the complexity of observed climate change, which is seasonally biased, decadally variable and geographically patchy. In particular, over the last 50 years three high-latitude areas have undergone recent rapid regional (RRR) warming ? substantially more rapid than the global mean. We discuss the spatial and temporal significance of RRR warming in one area, the Antarctic Peninsula. New analyses of station records show no ubiquitous polar amplification of global warming but significant RRR warming on the Antarctic Peninsula. We investigate the likelihood that this could be amplification of a global warming, and use climate-proxy data to indicate that this RRR warming on the Antarctic Peninsula is unprecedented over the last two millennia and unlikely to be a natural mode of variability. We can show a strong connection between RRR warming and reduced sea-ice duration in an area on the west of the Antarctic Peninsula, but here we cannot yet distinguish cause and effect. Thus for the present we cannot determine which process causes the RRR warming, and until the mechanism initiating and sustaining it is understood, and is convincingly reproduced in climate models, we lack a sound basis for predicting climate change in this region over the coming century.

  1. Antimicrobial activity of methanolic extracts of selected marine macroalgae against some pathogenic microorganisms

    Directory of Open Access Journals (Sweden)

    Ehab Omer Abdalla

    2016-05-01

    Full Text Available Objective: To evaluate the antimicrobial activity of methanolic extracts of six marine macroalgae belonging to green algae (Chlorophyceae, brown algae (Phaeophyceae and the red algae (Rhodophyceae collected from the intertidal area of the Sudanese Red Sea coast near Port Sudan. Methods: Methanol was used for extracting the active principles of the algae and the disc diffusion method was performed to examine the activity and the minimum inhibitory concentration of the samples against four pathogenic bacteria and two fungi. Results: All tested algal extracts exhibited considerable bioactivity and inhibited the growth of all pathogenic microorganisms under investigation. The green alga Caulerpa racemosa produced the maximum inhibition zone (21 mm against Candida albicans while the red alga Laurencia papillosa showed low antimicrobial activity with the minimum inhibition zone of 10 mm against Pseudomonas aeruginosa. The tested algal extracts did not show any special antimicrobial influence on the selected microorganisms when they were considered as Grampositive and Gram-negative bacteria and fungi but the most efficient methanolic extracts in inhibiting microbial growth were those of green macroalgae followed by the brown and the red macroalgae respectively. Conclusions: The study demonstrated that the tested marine macroalgae from Sudanese Red Sea coast may represent a potential and alternative source for secondary metabolites with antimicrobial activity.

  2. Distribution of vascular plants and macroalgae along salinity and elevation gradients in Oregon tidal marshes

    Science.gov (United States)

    Sea level rise due to global climate change may affect the spatial distribution of plants and macroalgae within tidal estuaries. We present preliminary results from on-going research in Oregon to determine how these potential abiotic drives correlate with the presence or absence...

  3. Distribution of epiphytic macroalgae on the thalli of their hosts in Cuba

    Directory of Open Access Journals (Sweden)

    Yander Luis Diez García

    2013-12-01

    Full Text Available We investigated the distribution of epiphytic macroalgae on the thalli of their hosts at eight localities along the southeastern coast of Cuba between June 2010 and March 2011. We divided he epiphytes in two groups according to their distribution on the host: those at the base of the thallus and those on its surface. We determining the dissimilarity between the zones and the species involved. We identified 102 taxa of epiphytic macroalgae. There were significant differences between the two zones. In 31 hosts, the number of epiphytes was higher on the surface of the thallus, whereas the number of epiphytes was higher at the thallus base in 25 hosts, and the epiphytes were equally distributed between the two zones in five hosts (R=−0.001, p=0.398. The mean dissimilarity between the two zones, in terms of the species composition of the epiphytic macroalgae, was 96.64%. Hydrolithon farinosum and Polysiphonia atlantica accounted for 43.76% of the dissimilarity. Among macroalgae, the structure of the thallus seems to be a determinant of their viability as hosts for epiphytes.

  4. Macroalgas submareales de la bahía de Todos Santos, Baja California, México Submareal macroalgae of the Todos Santos Bay, Baja California, Mexico

    Directory of Open Access Journals (Sweden)

    Raúl Aguilar-Rosas

    2010-12-01

    Full Text Available Con el fin de identificar y caracterizar la composición de especies de la zona submareal de la bahía de Todos Santos, Baja California, México; se realizaron muestreos de macroalgas marinas bentónicas en 7 sitios durante 1995-2000. Como resultado de 25 buceos Scuba entre 3 y 33 m de profundidad se encontraron 150 especies de macroalgas para el área de estudio; 10 son Chlorophyta, 26 Phaeophyta y 114 Rhodophyta. Del total, 47 son registros nuevos para el área de estudio y 2 de éstos, Faucheocolax attenuata Setchell y Minium parvum R.L. Moe, son nuevos para la flora marina del Pacífico de México. Se incluye una revisión de las investigaciones en las que se han considerado las macroalgas presentes en la bahía de Todos Santos y una discusión sobre la composición de las especies encontradas, su distribución vertical y reproducción, así como sobre las especies epífitas y parásitas del área.In order to identify and characterize the species composition of the subtidal zone of the Todos Santos Bay, Baja California, Mexico, benthic marine macroalgae were sampled at 7 sites from 1995 to 2000. As a result of 25 scuba at derds for the study area, of which Faucheocolax attenuata Setchell and R.L Moe Minium parvum are new to the marine flora of Pacific Mexico. We include a research that consider the macroalpths between 3 and 33 m we found a total of 150 species of macroalgae for the study area, of which 10 are Chlorophyta, 26 Phaeophyta and 114 Rhodophyta; 47 species represent new recogae in the Todos Santos Bay and a discussion on the composition of species found, its vertical distribution and reproduction, particularly the species epiphytes and parasites present in the study area.

  5. Low genetic diversity in Antarctic populations of the lichen-forming ascomycete Cetraria aculeata and its photobiont

    Directory of Open Access Journals (Sweden)

    Stephanie Domaschke

    2012-03-01

    Full Text Available Lichens, symbiotic associations of fungi (mycobionts and green algae or cyanobacteria (photobionts, are poikilohydric organisms that are particularly well adapted to withstand adverse environmental conditions. Terrestrial ecosystems of the Antarctic are therefore largely dominated by lichens. The effects of global climate change are especially pronounced in the maritime Antarctic and it may be assumed that the lichen vegetation will profoundly change in the future. The genetic diversity of populations is closely correlated to their ability to adapt to changing environmental conditions and to their future evolutionary potential. In this study, we present evidence for low genetic diversity in Antarctic mycobiont and photobiont populations of the widespread lichen Cetraria aculeata. We compared between 110 and 219 DNA sequences from each of three gene loci for each symbiont. A total of 222 individuals from three Antarctic and nine antiboreal, temperate and Arctic populations were investigated. The mycobiont diversity is highest in Arctic populations, while the photobionts are most diverse in temperate regions. Photobiont diversity decreases significantly towards the Antarctic but less markedly towards the Arctic, indicating that ecological factors play a minor role in determining the diversity of Antarctic photobiont populations. Richness estimators calculated for the four geographical regions suggest that the low genetic diversity of Antarctic populations is not a sampling artefact. Cetraria aculeata appears to have diversified in the Arctic and subsequently expanded its range into the Southern Hemisphere. The reduced genetic diversity in the Antarctic is most likely due to founder effects during long-distance colonization.

  6. Investigation of carbon dioxide phase shift possibility under extreme Antarctic winter conditions

    CERN Document Server

    Vashchenko, V M

    2014-01-01

    The Antarctic winter atmosphere minimal temperature and pressure series reveal that $CO_2$ phase shift (deposition) is possible in some extreme cases, even leading to possible $CO_2$ snow phenomenon at Vostok Antarctic station and in other near South Pole regions. A hypothesis has been formulated that stable $CO_2$ snow cover might have formed in Earth past which may influence interpretation of glacial chronology records. This effect may also manifest in other minor gases. Its global climate role is discussed.

  7. Environmental radioactivity in the antarctic station

    International Nuclear Information System (INIS)

    Study about environmental radioactivity in the Peruvian antarctic station Machu Pichu they were carried out during the last three periods to the southern summer. The objective of the project it is to evaluate environmental component in order to elaborate a study it base on the levels background radioactivity and artificial in the antarctic region

  8. Roles of epiphytes associated with macroalgae in benthic food web of a eutrophic coastal lagoon

    Science.gov (United States)

    Zheng, Xinqing; Huang, Lingfeng; Lin, Rongcheng; Du, Jianguo

    2015-11-01

    Macroalgae perform a significant function in the trophic dynamics in many coastal lagoons, and conventionally, they are the key trophic base that fuels the overall aquatic food web. However, few studies have considered the trophic contribution of epiphytes that attach to macroalgae in the diet of benthic primary consumers or their contribution to the trophic base of the aquatic food web. In this study, macrobenthic invertebrate biomass was combined with multiple-isotope-mixing models to distinguish the trophic importance of macroalgae and their associated epiphytic assemblages in the benthic food web during Ulva lactuca bloom in the Yundang Lagoon, a eutrophic coastal lagoon in Xiamen, China. Amphipods primarily dominated the zoobenthos, with the biomass varied from 40.9 g/m2 in January to 283.9 g/m2 in March. They mainly fed on U. lactuca and its associated epiphytes, which jointly contributed more than 60% to amphipod diets, but species-specific feeding habits were exhibited among amphipods. Using the zoobenthos biomass as a weighting factor, the contribution of U. lactuca and its epiphytes to total benthic communities during U. lactuca bloom exceeded 65%.The epiphytes were clearly utilized more than U. lactuca, with a median contribution ranging from 48.5% in January to 66.6% in March. Our findings demonstrate the trophic importance of the epiphytes in macroalgae-based coastal habitats, as found in many seagrass beds. Therefore, we propose that further food web studies of macroalgae-based ecosystems should pay greater attention to the role of epiphytes.

  9. Results and perspectives of tectonomagnetic investigations in the Western Antarctic

    Directory of Open Access Journals (Sweden)

    Ihor O. Chobotok

    2009-06-01

    Full Text Available The results of long-term (1998-2005 yrs. tectonomagnetic investigations in the Western Antarctic near the location
    of Ukrainian Antarctic Station «Academic Vernadsky» are reviewed. The peculiarities of the Earth’s
    anomalous magnetic field and its dynamic temporal variations (tectonomagnetic anomalies were studied using
    the newly founded tectonomagnetic polygon. Near the Argentine Archipelago intensive tectonomagnetic effects
    up to -2.8 nT/year were determined. Their spatial-temporal structure agrees with tectonic structure elements. We
    suggest that the nature of such effects is caused by a piezomagnetic effect under the influence of stretching tectonic
    forces (few bars per year in sub-latitudinal direction. Perspectives of tectonomagnetic investigations in the
    region are discussed.

  10. Testing oils in antarctic soils

    International Nuclear Information System (INIS)

    The resident seals, whales and penguins in Antarctica's Ross Sea region have only environmentally friendly ways of getting around. In contrast, wherever humans go in the Antarctic and whatever they do, be it research, tourism or fishing, they need fuel for their planes, icebreaker ships, land vehicles and generators. Because of this, petroleum hydrocarbons are the most likely source of pollution in the Antarctic. Accidental oil spills often occur near scientific stations, where storage and refuelling of aircraft and vehicles can result in spills. Spills also occur as a consequence of drilling activities. Dr Jackie Aislabie, a microbiologist from the New Zealand government's research company Landcare Research, is leading a program aimed at understanding how oil spills impact on Antarctic soils. The properties of pristine soils were compared with oil-contaminated soil at three locations: Scott Base, Marble Point and in the Wright Valley at Bull Pass. Soils in the Scott Base area are impacted by the establishment and continuous habitation of the base over 40 years, and a hydrocarbon-contaminated site was sampled near a former storage area for drums of mixed oils. Soil sampled from Marble Point was taken from near the old Marble Point camp, which was inhabited from 1957 to about 1963. Oil stains were visible on the soil surface, and are assumed to have been there for more than 30 years. The samples selected for analysis from the Wright Valley came from a spill site near Bull Pass that occurred during seismic bore-hole drilling activities in 1985. The contamination levels ranged from below detection to just over 29,000 μg/g of soil. Descriptions and analyse results are included into a Geographic Information System and associated soils database

  11. Evaluation of Macroalgae Sulfated Polysaccharides on the Leishmania (L. amazonensis Promastigote

    Directory of Open Access Journals (Sweden)

    Marcos Hikari Toyama

    2013-03-01

    Full Text Available The sulfated polysaccharides from Solieria filiformis (Sf, Botryocladia occidentalis (Bo, Caulerpa racemosa (Cr and Gracilaria caudata (Gc were extracted and extensively purified. These compounds were then subjected to in vitro assays to evaluate the inhibition of these polysaccharides on the growth of Leishmania (L. amazonensis promastigotes. Under the same assay conditions, only three of the four sulfated polysaccharides were active against L. amazonensis, and the polysaccharide purified from Cr was the most potent (EC50 value: 34.5 μg/mL. The polysaccharides derived from Bo and Sf demonstrated moderate anti-leishmanial activity (EC50 values of 63.7 μg/mL and 137.4 μg/mL. In addition, we also performed in vitro cytotoxic assays toward peritoneal macrophages and J774 macrophages. For the in vitro cytotoxicity assay employing J774 cells, all of the sulfated polysaccharides decreased cell survival, with CC50 values of 27.3 μg/mL, 49.3 μg/mL, 73.2 μg/mL, and 99.8 μg/mL for Bo, Cr, Gc, and Sf, respectively. However, none of the sulfated polysaccharides reduced the cell growth rate of the peritoneal macrophages. These results suggest that macroalgae contain compounds with various chemical properties that can control specific pathogens. According to our results, the assayed sulfated polysaccharides were able to modulate the growth rate and cell survival of Leishmania (L. amazonensis promastigotes in in vitro assays, and these effects involved the interaction of the sulfated polysaccharides on the cell membrane of the parasites.

  12. Direct hydrothermal liquefaction of undried macroalgae Enteromorpha prolifera using acid catalysts

    International Nuclear Information System (INIS)

    Highlights: • Bio-oil from liquefaction of wet E. prolifera was as feasible as dry powder. • Adding acid catalysts could improve the flow property of bio-oil. • Alkenes in the bio-oil converted to ketones in the presence of acid catalysts. • Content of 5-methyl furfural increased in the bio-oil obtained with acid catalysts. • Esters were formed in the bio-oil when adding sulfuric acid as a catalyst. - Abstract: Direct liquefaction of macroalgae Enteromorpha prolifera without predrying treatment was performed in a batch reactor. Effects of temperature, reaction time, biomass-to-water ratio and acid catalysts (sulfuric acid and acetic acid) on liquefaction products were investigated. Raw material and liquefaction products were analyzed by elemental analysis, Fourier transform infrared (FT-IR) and gas chromatography–mass spectrometry (GC–MS). Results showed that liquefaction at 290 °C for 20 min with 1:3 biomass-to-water ratio produced the highest bio-oil yield of 28.4 wt%, and high heating value (HHV) was 29.5 MJ/kg. Main components of bio-oil were fatty acids, ketones, alkenes and 5-methyl furfural, and main components of water soluble organics (WSOs) were pyridines, carboxylic acids and glycerol. In the bio-oil obtained with acid catalysts, content of ketones significantly increased while alkenes disappeared. Content of 5-methyl furfural also increased. Flow property of bio-oils was improved in the presence of acid catalysts. Moreover, esters were formed when adding sulfuric acid

  13. Environmental radioactivity at the Peruvian Scientific Station 'Machu Picchu'. Cs-137, Ra-226, Be-7 and K-40 concentrations in antarctic samples by gamma spectrometry

    International Nuclear Information System (INIS)

    In order to continue with the Research Program in Environmental Radioactivity in the Antarctic Region initiated in 1996, the Peruvian Institute of Nuclear Energy (IPEN) participated in the 11th Scientific Expedition to Antarctica (ANTAR XI) on 2000. The main objective of this study is to evaluate environmental components for achieving a baseline study related to artificial and natural radioactivity level. For this purpose, samples of brown macro-algae (phaeophyta), lichen, moss, gramineous, soil, marine sediment, sea water and air were collected in the surrounding area of the Machu Picchu Scientific Station. The physical, radiochemical treatment and radiometric assays of the samples were done in the Environmental Control Department of the 'RACSO' Nuclear Center. The presence of anthropogenic radionuclide Cs-17, in some antarctic environmental components, confirms that this element was dispersed globally after the nuclear testing carried out in other latitudes. The environmental radiological impact in the antarctic ecosystem has been minimum due to the low levels of found radioactivity. In general, lichens seem to accumulate more Cs-137 than other biological components

  14. Production of mexican brown macroalgae fucoidan and fucosidases under an integral green technology bioproceses by the biorefinery concept

    OpenAIRE

    Rodríguez-Jasso, Rosa M.; Ruiz, Hector A.; Victorino-Jasso, Gabriela; Cervantes-Cisneros, Daniela E.; Cabello-Galindo, Alejandra; Cristóbal N Aguilar; J.A. Teixeira

    2015-01-01

    Marine ecosystem can be considered a rather exploited source of natural substances with enormous bioactive potential. In Mexico macro-algae study remain forgotten for research and economic purposes besides the high amount of this resource along the west and east coast. For that reason the Bioferinery Group of the Autonomous University of Coahuila, have been studying the biorefinery concept in order to recover high value byproducts of Mexican brown macro-algae including polysacc...

  15. KAROTENOID DARI MAKROALGAE DAN MIKROALGAE: POTENSI KESEHATAN APLIKASI DAN BIOTEKNOLOGI [Carotenoids from Macroalgae and Microalgae: Health Potential, Application and Biotechnology

    OpenAIRE

    Leenawaty Limantara3); Budhi Prasetyo1); AB. Susanto2); Helly de Fretes1)*

    2012-01-01

    Algae, both micro and macroalgae, is one of the largest producers of carotenoids. The major composition of carotenoid on algae are β-carotene, astaxanthin, luthein, zeaxanthin, cryptoxanthin, and fucoxanthin which have important roles for human health. Carotenoids were produced by several microalgae species such as Dunaliella sallina, Haemotococcus pluvialis, Chlorella pyrenoidosa, Spirulina platensis, Nannnochloropsis oculata, and also from some macroalgae species such as Kappaphycus alvarez...

  16. Ultraviolet radiation response of two heterotropy Antarctic marine bacterial

    International Nuclear Information System (INIS)

    Two Antarctic marine bacterial strains, were exposed to different irradiance of ultraviolet (UV) solar radiation using several experimental protocols and interferential filters. Results showed that both, UV-A and UV-B radiation produce deleterious effects on two tested bacterial strains. The mortality values under UVB treatments were higher than those observed under UVA treatments. UVvi strain proved to be more resistant to UV radiation than the UVps strain. (author)

  17. Allelopathic inhibition of photosynthesis in the red tide-causing marine alga, Scrippsiella trochoidea (Pyrrophyta), by the dried macroalga, Gracilaria lemaneiformis (Rhodophyta)

    Science.gov (United States)

    Ye, Changpeng; Liao, Heping; Yang, Yufeng

    2014-07-01

    The red tide-causing microalga, Scrippsiella trochoidea was co-cultured with different quantities of dried macroalga Gracilaria lemaneiformis under laboratory conditions, to characterize the allelopathic inhibition effect of the seaweed on photosynthesis of the microalga. Photosynthetic oxygen evolution was measured, and chlorophyll a (Chl a) fluorescence transient O-J-I-P (O, J, I and P point in primary photochemistry reaction curve in photosystem II) curves associated with its specific parameters were determined. A concentration-dependent inhibition of S. trochoidea was observed when the dried seaweed was added. The rate of light-saturated maximum photosynthetic oxygen evolution (Pmax) was markedly decreased, and the O-J-I-P curve coupled with its specific parameters was reduced. The inhibitory effects of the macroalga on the microalga, according to the JIP-test (the relative fluorescence analysis based on O-J-I-P curve) and the activity of oxygen evolution, include a decrease in the number of active reaction centers, the blocking-up of the electron transport chain, and the damage to the oxygen-evolving complex. This study suggests that dried G. lemaneiformis is effective in inhibiting photosynthesis of S. trochoidea, and could thus be a potential candidate for mitigating S. trochoidea blooms.

  18. Underwater Optics in Sub-Antarctic and Antarctic Coastal Ecosystems

    Science.gov (United States)

    Huovinen, Pirjo; Ramírez, Jaime; Gómez, Iván

    2016-01-01

    Understanding underwater optics in natural waters is essential in evaluating aquatic primary production and risk of UV exposure in aquatic habitats. Changing environmental conditions related with global climate change, which imply potential contrasting changes in underwater light climate further emphasize the need to gain insights into patterns related with underwater optics for more accurate future predictions. The present study evaluated penetration of solar radiation in six sub-Antarctic estuaries and fjords in Chilean North Patagonian region (39–44°S) and in an Antarctic bay (62°S). Based on vertical diffuse attenuation coefficients (Kd), derived from measurements with a submersible multichannel radiometer, average summer UV penetration depth (z1%) in these water bodies ranged 2–11 m for UV-B (313 nm), 4–27 m for UV-A (395 nm), and 7–30 m for PAR (euphotic zone). UV attenuation was strongest in the shallow Quempillén estuary, while Fildes Bay (Antarctica) exhibited the highest transparency. Optically non-homogeneous water layers and seasonal variation in transparency (lower in winter) characterized Comau Fjord and Puyuhuapi Channel. In general, multivariate analysis based on Kd values of UV and PAR wavelengths discriminated strongly Quempillén estuary and Puyuhuapi Channel from other study sites. Spatial (horizontal) variation within the estuary of Valdivia river reflected stronger attenuation in zones receiving river impact, while within Fildes Bay a lower spatial variation in water transparency could in general be related to closeness of glaciers, likely due to increased turbidity through ice-driven processes. Higher transparency and deeper UV-B penetration in proportion to UV-A/visible wavelengths observed in Fildes Bay suggests a higher risk for Antarctic ecosystems reflected by e.g. altered UV-B damage vs. photorepair under UV-A/PAR. Considering that damage repair processes often slow down under cool temperatures, adverse UV impact could be

  19. Exploring the Effects of Subfreezing Temperature and Salt Concentration on Ice Growth Inhibition of Antarctic Gram-Negative Bacterium Marinomonas Primoryensis Using Coarse-Grained Simulation.

    Science.gov (United States)

    Nguyen, Hung; Dac Van, Thanh; Tran, Nhut; Le, Ly

    2016-04-01

    The aim of this work is to study the freezing process of water molecules surrounding Antarctic Gram-negative bacterium Marinomonas primoryensis antifreeze protein (MpAFP) and the MpAFP interactions to the surface of ice crystals under various marine environments (at different NaCl concentrations of 0.3, 0.6, and 0.8 mol/l). Our result indicates that activating temperature region of MpAFPs reduced as NaCl concentration increased. Specifically, MpAFP was activated and functioned at 0.6 mol/l with temperatures equal or larger 278 K, and at 0.8 mol/l with temperatures equal or larger 270 K. Additionally, MpAFP was inhibited by ice crystal network from 268 to 274 K and solid-liquid hybrid from 276 to 282 K at 0.3 mol/l concentration. Our results shed lights on structural dynamics of MpAFP among different marine environments. PMID:26758589

  20. Shifts in soil microorganisms in response to warming are consistent across a range of Antarctic environments.

    Science.gov (United States)

    Yergeau, Etienne; Bokhorst, Stef; Kang, Sanghoon; Zhou, Jizhong; Greer, Charles W; Aerts, Rien; Kowalchuk, George A

    2012-03-01

    Because of severe abiotic limitations, Antarctic soils represent simplified systems, where microorganisms are the principal drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report highly consistent responses in microbial communities across disparate sub-Antarctic and Antarctic environments in response to 3 years of experimental field warming (+0.5 to 2 °C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio, which could result in an increase in soil respiration. Furthermore, shifts toward generalist bacterial communities following warming weakened the linkage between the bacterial taxonomic and functional richness. GeoChip microarray analyses also revealed significant warming effects on functional communities, specifically in the N-cycling microorganisms. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures. PMID:21938020

  1. Unmanned aerial optical systems for spatial monitoring of Antarctic mosses

    Science.gov (United States)

    Lucieer, Arko; Turner, Darren; Veness, Tony; Malenovsky, Zbynek; Harwin, Stephen; Wallace, Luke; Kelcey, Josh; Robinson, Sharon

    2013-04-01

    The Antarctic continent has experienced major changes in temperature, wind speed and stratospheric ozone levels during the last 50 years. In a manner similar to tree rings, old growth shoots of Antarctic mosses, the only plants on the continent, also preserve a climate record of their surrounding environment. This makes them an ideal bio-indicator of the Antarctic climate change. Spatially extensive ground sampling of mosses is laborious and time limited due to the short Antarctic growing season. Obviously, there is a need for an efficient method to monitor spatially climate change induced stress of the Antarctic moss flora. Cloudy weather and high spatial fragmentation of the moss turfs makes satellite imagery unsuitable for this task. Unmanned aerial systems (UAS), flying at low altitudes and collecting image data even under a full overcast, can, however, overcome the insufficiency of satellite remote sensing. We, therefore, developed scientific UAS, consisting of a remote-controlled micro-copter carrying on-board different remote sensing optical sensors, tailored to perform fast and cost-effective mapping of Antarctic flora at ultra-high spatial resolution (1-10 cm depending on flight altitude). A single lens reflex (SLR) camera carried by UAS acquires multi-view aerial photography, which processed by the Structure from Motion computer vision algorithm provides an accurate three-dimensional digital surface model (DSM) at ultra-high spatial resolution. DSM is the key input parameter for modelling a local seasonal snowmelt run-off, which provides mosses with the vital water supply. A lightweight multispectral camera on-board of UVS is collecting images of six selected spectral wavebands with the full-width-half-maximum (FWHM) of 10 nm. The spectral bands can be used to compute various vegetation optical indices, e.g. Difference Vegetation Index (NDVI) or Photochemical Reflectance Index (PRI), assessing the actual physiological state of polar vegetation. Recently

  2. On the manoeuvering simulation of an Antarctic hovercraft

    Science.gov (United States)

    Murao, R.; Nojiri, T.

    Since 1981 an experimental hovercraft for the Antarctic has been tested in Japan's Antarctic station Syowa. During tests on the ice field near Syowa station, it was experienced that the yaw response of this craft is very sensitive to certain ice conditions. In this report, we deal with course keeping of the craft in relative crosswinds and with the maneuvering simulation while turning. Maneuvering at large yaw angle is required to generate the effective centripetal force in turning. The trajectories based on pulse steering are obtained. The course stability is very dependent upon the friction between skirts and ground, and generally not good on smooth flat ice. It is shown, however, that the rudder automatic control provides good course stability independent of ice conditions. The trajectories obtained from the simulation show that the use of a combination of rudder control and puff ports produces quick turning.

  3. Carbonate Deposition on Antarctic Shelves

    Science.gov (United States)

    Frank, T. D.; James, N. P.; Malcolm, I.

    2011-12-01

    Limestones associated with glaciomarine deposits occur throughout the geologic record but remain poorly understood. The best-described examples formed during major ice ages of the Neoproterozoic and Late Paleozoic. Quaternary analogs on Antarctic shelves have received comparatively little study. Here, we report on the composition, spatial distribution, and stratigraphic context of carbonate sediments contained in piston cores from the Ross Sea. The goals of this work are to (1) document the nature and distribution of carbonate sediments on the Ross Sea continental shelf and (2) examine temporal relationships to Quaternary glaciation. Results will be used to develop criteria that will improve understanding of analogous deposits in the ancient record. All carbonate-rich intervals in piston cores from the Ross Rea, now housed at the Antarctic Marine Geology Research Facility at Florida State University, were examined and described in detail. Sediment samples were disaggregated and sieved into size fractions before description with paleontological analysis carried out on the coarsest size fraction (>250 microns). Carbonate-rich sediments are concentrated in the northwestern Ross Sea, along the distal margins of Mawson and Pennell Banks. Calcareous facies include a spectrum of lithologies that range from fossiliferous mud, sand, and gravel to skeletal floatstone-rudstone and bafflestone. Floatstone-rudstone and bafflestone is most abundant along western-facing slopes in areas protected from the Antarctic Coastal Current. Sand-prone facies dominate the tops of banks and mud-prone, often spicultic, facies occur in deeper areas. The carbonate factory is characterized by a low-diversity, heterozoan assemblage that is dominated by stylasterine hydrocorals, barnacles, and bryozoans. Molluscs and echinoids are present but not abundant. Planktic and benthic foraminifera are ubiquitous components of the sediment matrix, which is locally very rich in sponge spicules. Biota rarely

  4. Macroalgae - an environmental problem or a resource from an eMergy perspective?

    DEFF Research Database (Denmark)

    Seghetta, Michele; Østergård, Hanne; Bastianoni, Simone

    feedstock for bioethanol. An emergy analysis highlights the most important inputs for the bioethanol production. The growth of algae requires a considerable amount of natural resources in both systems. In particular, water is a fundamental carrier of nutrients in or out of the systems. Consequently, in both......Eutrophication is an environmental problem in a majority of shallow water basins all over the world. The flow of nutrients into the water basin leads to an undesired flowering of macroalgae and their decomposition decreases dissolved oxygen which hampers heterothrophic organisms from breathing...... systems the collected algae represent the main emergy contribution. However, also the modeled biorefinery is a critical part since it consumes significant amounts of non-renewable resources. In conclusion, at present macroalgae provide environmental problems but in future they may be used as a resource...

  5. Recent changes in macroalgae distribution patterns in the Orbetello lagoon (Italy)

    OpenAIRE

    Giovani, Andrea; Mari, Elena; Specchiulli, Antonietta; Focardi, Silvano; RENZI, Monia

    2014-01-01

    This study related recent distribution changes in seven macroalgae taxa (Acetabularia acetabulum, Chaetomorpha linum, Cladophora sp., Gracilariopsis longissima, Spyridia sp., Ulva laetevirens, Valonia aegagrophyla) to spatial (basin) and temporal (time) trophic differences in a meso-eutrophic Mediterranean coastal lagoon (Orbetello, Italy). In July 2003 and July 2009, the coverage percentage (CP) of each considered taxon was measured in 38 stations equally distributed in the Western and Easte...

  6. Biodiesel production by microalgae and macroalgae from north littoral portuguese coast

    OpenAIRE

    Carvalho, Joana; Ribeiro, André; Castro, Joana Daniela Fernandes de; Vilarinho, Cândida; Castro, F.

    2011-01-01

    Biodiesel, as an alternative fuel, has many benefits. It is biodegradable, non-toxic and compared to petroleum-based diesel, has a more favorable combustion emission profile, such as low emissions of carbon monoxide, particulate matter and unburned hydrocarbons. In brief, these merits make biodiesel a good alternative to petroleum based fuel. Biodiesel feedstocks derived from microalgae and macroalgae have emerged as one of the most promising alternative sources of lipid for use in biodiesel ...

  7. Invertebrate-mediated nutrient loading increases growth of an intertidal macroalga

    OpenAIRE

    Bracken, Matthew E. S.

    2004-01-01

    Even in nitrogen-replete ecosystems, microhabitats exist where local-scale nutrient limitation occurs. For example, coastal waters of the northeastern Pacific Ocean are characterized by high nitrate concentrations associated with upwelling. However, macroalgae living in high-zone tide pools on adjacent rocky shores are isolated from this upwelled nitrate for extended periods of time, leading to nutrient limitation. When high-intertidal pools are isolated during low tide, invertebrate-excreted...

  8. Diversity among macroalgae-consuming fishes on coral reefs: a transcontinental comparison.

    Directory of Open Access Journals (Sweden)

    Adriana Vergés

    Full Text Available Despite high diversity and abundance of nominally herbivorous fishes on coral reefs, recent studies indicate that only a small subset of taxa are capable of removing dominant macroalgae once these become established. This limited functional redundancy highlights the potential vulnerability of coral reefs to disturbance and stresses the need to assess the functional role of individual species of herbivores. However, our knowledge of species-specific patterns in macroalgal consumption is limited geographically, and there is a need to determine the extent to which patterns observed in specific reefs can be generalised at larger spatial scales. In this study, video cameras were used to quantify rates of macroalgae consumption by fishes in two coral reefs located at a similar latitude in opposite sides of Australia: the Keppel Islands in the Great Barrier Reef (eastern coast and Ningaloo Reef (western coast. The community of nominally herbivorous fish was also characterised in both systems to determine whether potential differences in the species observed feeding on macroalgae were related to spatial dissimilarities in herbivore community composition. The total number of species observed biting on the dominant brown alga Sargassum myriocystum differed dramatically among the two systems, with 23 species feeding in Ningaloo, compared with just 8 in the Keppel Islands. Strong differences were also found in the species composition and total biomass of nominally herbivorous fish, which was an order of magnitude higher in Ningaloo. However, despite such marked differences in the diversity, biomass, and community composition of resident herbivorous fishes, Sargassum consumption was dominated by only four species in both systems, with Naso unicornis and Kyphosus vaigiensis consistently emerging as dominant feeders of macroalgae.

  9. Influence of n -Hexane on in Situ Transesterification of Marine Macroalgae

    OpenAIRE

    Angel Sánchez; Rocio Maceiras; Angeles Cancela; Mónica Rodríguez

    2012-01-01

    The purpose of this work is to investigate the influence of n -hexane addition on in situ transesterification of a solid raw material for biodiesel production. Extraction and reaction of macroalgae oil has been performed simultaneously in a batch reactor adding n- hexane with the reactants. In order to analyze the influence of n -hexane on the transesterification, the reaction was also carried out with sunflower oil. The results show that the presence of n -hexane does not have an important e...

  10. Abundance and Composition of Epiphytic Bacterial and Archaeal Ammonia Oxidizers of Marine Red and Brown Macroalgae

    OpenAIRE

    Trias, R. (Rosalía); García-Lledó A. (Arantzazu); Sánchez, N.; López-Jurado, J. L.; Hallin, S. (Sara); Bañeras, Ll. (Lluís)

    2012-01-01

    Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are important for nitrogen cycling in marine ecosystems. Little is known about the diversity and abundance of these organisms on the surface of marine macroalgae, despite the algae’s potential importance to create surfaces and local oxygen-rich environments supporting ammonia oxidation at depths with low dissolved oxygen levels. We determined the abundance and composition of the epiphytic bacterial and archaeal ammonia-oxidizing communities o...

  11. The marine macroalgae of Helgoland (North Sea): an annotated list of records between 1845 and 1999

    OpenAIRE

    Bartsch, Inka; Kuhlenkamp, Ralph

    2000-01-01

    AbstractThe earliest records of marine macroalgae from Helgoland (German Bight, North Sea) are known from the middle of the 19th century. Since then 274 marine macroalgal species have been reported: 77 species of Chlorophycota; 100 species of Phaeophycota; and 97 species of Rhodophycota. Additionally 11 species were only recorded as drift and 51 species as doubtful for Helgoland. Remains of the herbarium of Paul Kuckuck, the first curator for botany at the Helgoland Biological Station between...

  12. Surface alkaline phosphatase activities of macroalgae on coral reefs of the central Great Barrier Reef, Australia

    Science.gov (United States)

    Schaffelke, B.

    2001-05-01

    Inshore reefs of the Great Barrier Reef (GBR) are subject to episodic nutrient supply, mainly by flood events, whereas midshelf reefs have a more consistent low nutrient availability. Alkaline phosphatase activity (APA) enables macroalgae to increase their phosphorus (P) supply by using organic P. APA was high (~4.0 to 15.5 µmol PO4 3- g DW-1 h-1) in species colonising predominantly inshore reefs and low (human activity, which currently is a global problem.

  13. Allelopathic Interactions between the Opportunistic Species Ulva prolifera and the Native Macroalga Gracilaria lichvoides

    OpenAIRE

    Xu, Dong; Gao, Zhengquan; Zhang, Xiaowen; Fan, Xiao; Wang, Yitao; Li, Demao; Wang, Wei; Zhuang, Zhimeng; Ye, Naihao

    2012-01-01

    Allelopathy, one type of direct plant competition, can be a potent mechanism through which plant communities are structured. The aim of this study was to determine whether allelopathic interactions occur between the opportunistic green tide-forming species Ulva prolifera and the native macroalga Gracilaria lichvoides, both of which were collected from the coastline of East China sea. In laboratory experiments, the presence of G. lichvoides at 1.25 g wet weight L−1 significantly inhibited grow...

  14. Expansion of the macroalga Caulerpa racemosa and changes in softbottom macrofaunal assemblages in Moni Bay, Cyprus

    OpenAIRE

    Argyrou, M.; Demetropoulos, A.; Hadjichristophorou, M

    1999-01-01

    The recent expansion of the Red Sea macroalga Caulerpa racemosa and its impact on the diversity and abundance of macrobenthos were examined and compared in the summers of 1992 and 1997, in Moni Bay, Cyprus. The phytobenthic community of the bay in 1992 was dominated by the seagrass Posidonia oceanica while, in 1997, the Lessepsian migrant C. racemosa became the most dominant, forming extensive mars. Changes in the vegetation system in Moni Bay have caused significant compositional changes in ...

  15. Denitrification in the Antarctic stratosphere

    Science.gov (United States)

    Salawitch, R. J.; Gobbi, G. P.; Wofsy, S. C.; Mcelroy, M. B.

    1989-01-01

    Rapid loss of ozone over Antarctica in spring requires that the abundance of gaseous nitric acid be very low. Precipitation of particulate nitric acid has been assumed to occur in association with large ice crystals, requiring significant removal of H2O and temperatures well below the frost point. However, stratospheric clouds exhibit a bimodal size distribution in the Antarctic atmosphere, with most of the nitrate concentrated in particles with radii of 1 micron or greater. It is argued here that the bimodal size distribution sets the stage for efficient denitrification, with nitrate particles either falling on their own or serving as nuclei for the condensation of ice. Denitrification can therefore occur without significant dehydration, and it is unnecessary for temperatures to drop significantly below the frost point.

  16. Preference of the Herbivorous Marine Teleost Siganus canaliculatus for Different Macroalgae

    Institute of Scientific and Technical Information of China (English)

    YOU Cuihong; ZENG Fangui; WANG Shuqi; LI Yuanyou

    2014-01-01

    The decomposition of a large amount of unexploited macroalgal resource along the coast of China often results in heavy environmental pollution. In order to pave a way of using macroalgae as the dietary ingredient of rabbitfish Siganus canaliculatus, one of a few farmed herbivorous marine teleosts in China, its preference (feeding selectivity) for different macroalgae was determined in this study. Seven seaweed species abundantly inhabiting the coast of east Guangdong Province were exposed simultaneously to rab-bitfish juveniles in laboratory (multiple-choice feeding) with their content and absolute intake assayed. It was found that the most preferred algae were Ulva prolifera, Gracilaria lemaneiformis and Chaetomorpha linum, less preferred algae were U. pertusa and Porphyra haitanensis, and least preferred ones were Sargassum fusiforme and Corallina sessilis. Such an order did not change when one to four relatively preferred seaweeds were removed. The preferred seaweeds were richer in protein and soluble sugar thus higher in energy than the least preferred. In addition, this fish was found to favor filamentous and flat algae rather than calcified ones. Ac-cordingly, the richness of nutrients and morphological characteristics determined the preference of S. canaliculatus for tested macro-algae.

  17. Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins

    Directory of Open Access Journals (Sweden)

    Natalie Heffernan

    2015-01-01

    Full Text Available Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis. Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW phlorotannins were found to have a molecular weight range equivalent to 4–12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs. These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.

  18. Responses of cyclic phosphorylation of MAPK-like proteins in intertidal macroalgae after environmental stress.

    Science.gov (United States)

    Parages, María L; Capasso, Juan M; Niell, F Xavier; Jiménez, Carlos

    2014-02-15

    The presence and activation of MAPK-like proteins in intertidal macroalgae is described in the current study. Two MAPK-like proteins of 40 and 42 kDa in size similar to p38 and JNK, of mammalian cells have been identified in six representative species of intertidal macroalgae from the Strait of Gibraltar (Southern Spain), namely in the chlorophytes Ulva rigida and Chaetomorpha aerea, the rhodophytes Corallina elongata and Jania rubens, and the phaeophytes Dictyota dichotoma and Dilophus spiralis. Phosphorylation of MAPK-like proteins was studied during semi-tidal cycles. Analysis of p38-like and JNK-like MAPKs in macroalgae protein extracts was carried out by using specific antibodies against the phosphorylated forms of both MAPKs. Protein blot analysis of samples collected from 2009 to 2011 in natural growing sites on days when either low or high tide occurred at midday, indicated that MAPK-like proteins in all species were highly phosphorylated in response to desiccation imposed by low tide or high irradiance. Phosphorylation of p38-like MAPK always preceded that of JNK-like MAPK. In addition, phosphorylation of MAPKs was fastest in rhodophytes, followed by chlorophytes and then finally phaeophytes. In the first group, phosphorylation was mostly dependent on desiccation, whereas both high irradiance and desiccation were responsible for p38-like and JNK-like phosphorylation in chlorophytes. In phaeophytes, high irradiance was mostly responsible for MAPK-like activation. PMID:24120533

  19. Role of the meiobenthos in Antarctic ecosystems

    OpenAIRE

    Vanhove, S.; Wittoeck, J; Beghyn, M.; Van Gansbeke, D.; Van Kenhove, A.; Coomans, A.; Vincx, M.

    1997-01-01

    To date meiobenthic research remained a big white spot in the systematic-ecological work on Antarctic zoobenthos. Therefore the relative importance of the meiofauna (organisms within the size range of 38-1000µm) in the Antarctic benthic community has been assessed by a combined field ecology and experimental approach. This was done in two contrasting conditions, e.g. the deep sea and low subtidal, where as to the depth of the water column the benthic characteristics were, respectively, indire...

  20. Antarctic sea ice losses drive gains in benthic carbon drawdown.

    Science.gov (United States)

    Barnes, D K A

    2015-09-21

    Climate forcing of sea-ice losses from the Arctic and West Antarctic are blueing the poles. These losses are accelerating, reducing Earth's albedo and increasing heat absorption. Subarctic forest (area expansion and increased growth) and ice-shelf losses (resulting in new phytoplankton blooms which are eaten by benthos) are the only significant described negative feedbacks acting to counteract the effects of increasing CO2 on a warming planet, together accounting for uptake of ∼10(7) tonnes of carbon per year. Most sea-ice loss to date has occurred over polar continental shelves, which are richly, but patchily, colonised by benthic animals. Most polar benthos feeds on microscopic algae (phytoplankton), which has shown increased blooms coincident with sea-ice losses. Here, growth responses of Antarctic shelf benthos to sea-ice losses and phytoplankton increases were investigated. Analysis of two decades of benthic collections showed strong increases in annual production of shelf seabed carbon in West Antarctic bryozoans. These were calculated to have nearly doubled to >2x10(5) tonnes of carbon per year since the 1980s. Annual production of bryozoans is median within wider Antarctic benthos, so upscaling to include other benthos (combined study species typically constitute ∼3% benthic biomass) suggests an increased drawdown of ∼2.9x10(6) tonnes of carbon per year. This drawdown could become sequestration because polar continental shelves are typically deeper than most modern iceberg scouring, bacterial breakdown rates are slow, and benthos is easily buried. To date, most sea-ice losses have been Arctic, so, if hyperboreal benthos shows a similar increase in drawdown, polar continental shelves would represent Earth's largest negative feedback to climate change. PMID:26394097

  1. First record of Babesia sp. in Antarctic penguins.

    Science.gov (United States)

    Montero, Estrella; González, Luis Miguel; Chaparro, Alberto; Benzal, Jesús; Bertellotti, Marcelo; Masero, José A; Colominas-Ciuró, Roger; Vidal, Virginia; Barbosa, Andrés

    2016-04-01

    This is the first reported case of Babesia sp. in Antarctic penguins, specifically a population of Chinstrap penguins (Pygoscelis antarctica) in the Vapour Col penguin rookery in Deception Island, South Shetlands, Antarctica. We collected peripheral blood from 50 adult and 30 chick Chinstrap penguins. Examination of the samples by microscopy showed intraerythrocytic forms morphologically similar to other avian Babesia species in 12 Chinstrap penguin adults and seven chicks. The estimated parasitaemias ranged from 0.25×10(-2)% to 0.75×10(-2)%. Despite the low number of parasites found in blood smears, semi-nested PCR assays yielded a 274bp fragment in 12 of the 19 positive blood samples found by microscopy. Sequencing revealed that the fragment was 97% similar to Babesia sp. 18S rRNA from Australian Little Penguins (Eudyptula minor) confirming presence of the parasite. Parasite prevalence estimated by microscopy in adults and chicks was higher (24% vs. 23.3%, respectively) than found by semi-nested PCR (16% vs. 13.3% respectively). Although sampled penguins were apparently healthy, the effect of Babesia infection in these penguins is unknown. The identification of Babesia sp. in Antarctic penguins is an important finding. Ixodes uriae, as the only tick species present in the Antarctic Peninsula, is the key to understanding the natural history of this parasite. Future work should address the transmission dynamics and pathogenicity of Babesia sp. in Chinstrap penguin as well as in other penguin species, such as Gentoo penguin (Pygoscelis papua) and Adélie penguin (Pygoscelis adeliae), present within the tick distribution range in the Antarctic Peninsula. PMID:26874670

  2. The Scientific Committee on Antarctic Research (SCAR) in the IPY 2007-2009

    Science.gov (United States)

    Kennicutt, M. C.; Wilson, T. J.; Summerhayes, C.

    2005-05-01

    variability and change in the Antarctic as a result of natural and anthropogenic forcings over the last 100,000 years. Interhemispheric Conjugacy Effects in Solar-Terrestrial and Aeronomy Research (ICESTAR) will study the interactions between and collective behavior of the many component parts of the Earth system, including the interaction between the natural environment and human society. Objectives include specification and prediction of the state of the system and assimilation and integration of data from disparate sources to understand the complex geospace environment.

  3. Health aspects of Antarctic tourism.

    Science.gov (United States)

    Prociv, P

    1998-12-01

    Increasing numbers of seaborne tourists are visiting Antarctica, with most coming from the United States (3503 in 1996-97), Germany (777), and Australia (680; cf. 356 in 1994-95 and 410 in 1995-96). The impression among travel medicine clinicians is that, each year, more prospective travelers seek advice about the health demands of this type of adventure, mostly relating to fitness for travel, exposure to extreme cold, hazards in ice and snow, and other potential health risks. This is a recent phenomenon. While a regular shipping service had been established between the Falklands and the subantarctic islands of South Georgia and the South Shetlands by 1924, the first documented tourists accompanied an Argentine expedition to the South Orkneys in 1933.1 Commercial airline flights over these islands and the Antarctic Peninsula began in 1956, from Chile, and recreational cruises to the Peninsula began in 1958. Tourist numbers subsequently grew slowly, for what was clearly an exclusive and very expensive undertaking, with few ships available for these hazardous voyages. From 1957 to 1993, 37,000 tourists visited by sea, most seeing only the Peninsula.2 The dramatic recent growth in numbers is a consequence of the collapse of the Soviet Union. The small fleet of ice-strengthened research vessels and working icebreakers, which was made redundant by withdrawal of central government support from isolated communities and military activities along the northern coast of Siberia (and from Antarctic research bases), now accounts for the bulk of charter-cruise tourism to Antarctica, at competitive prices. According to the International Association of Antarctica Tour Operators,3 7322 people traveled to Antarctica on commercially organized voyages in the 1996-97 season, and a record 10,000 shipborne visitors were expected for the 1997-98 season (November-March), traveling mainly from South America to the Peninsula on 15 ice-reinforced vessels, each carrying between 36 and 180

  4. 76 FR 9849 - Comprehensive Environmental Evaluations for Antarctic Activities

    Science.gov (United States)

    2011-02-22

    .... SUPPLEMENTARY INFORMATION: Article 3 of Annex I to the Protocol on Environmental Protection to the Antarctic... Comprehensive Environmental Evaluations for Antarctic Activities SUMMARY: The Department of State gives notice of the availability of two draft Comprehensive Environmental Evaluations (CEEs) for...

  5. Cold-acclimation limits low temperature induced photoinhibition by promoting a higher photochemical quantum yield and a more effective PSII restoration in darkness in the Antarctic rather than the Andean ecotype of Colobanthus quitensis Kunt Bartl (Cariophyllaceae

    Directory of Open Access Journals (Sweden)

    Bascuñán-Godoy Luisa

    2012-07-01

    Full Text Available Abstract Background Ecotypes of Colobanthus quitensis Kunt Bartl (Cariophyllaceae from Andes Mountains and Maritime Antarctic grow under contrasting photoinhibitory conditions, reaching differential cold tolerance upon cold acclimation. Photoinhibition depends on the extent of photodamage and recovery capability. We propose that cold acclimation increases resistance to low-temperature-induced photoinhibition, limiting photodamage and promoting recovery under cold. Therefore, the Antarctic ecotype (cold hardiest should be less photoinhibited and have better recovery from low-temperature-induced photoinhibition than the Andean ecotype. Both ecotypes were exposed to cold induced photoinhibitory treatment (PhT. Photoinhibition and recovery of photosystem II (PSII was followed by fluorescence, CO2 exchange, and immunoblotting analyses. Results The same reduction (25% in maximum PSII efficiency (Fv/Fm was observed in both cold-acclimated (CA and non-acclimated (NA plants under PhT. A full recovery was observed in CA plants of both ecotypes under dark conditions, but CA Antarctic plants recover faster than the Andean ecotype. Under PhT, CA plants maintain their quantum yield of PSII, while NA plants reduced it strongly (50% and 73% for Andean and Antarctic plants respectively. Cold acclimation induced the maintenance of PsaA and Cyt b6/f and reduced a 41% the excitation pressure in Antarctic plants, exhibiting the lowest level under PhT. xCold acclimation decreased significantly NPQs in both ecotypes, and reduced chlorophylls and D1 degradation in Andean plants under PhT. NA and CA plants were able to fully restore their normal photosynthesis, while CA Antarctic plants reached 50% higher photosynthetic rates after recovery, which was associated to electron fluxes maintenance under photoinhibitory conditions. Conclusions Cold acclimation has a greater importance on the recovery process than on limiting photodamage. Cold acclimation determined the

  6. Ionospheric irregularities at Antarctic using GPS measurements

    Indian Academy of Sciences (India)

    Sunita Tiwari; Amit Jain; Shivalika Sarkar; Sudhir Jain; A K Gwal

    2012-04-01

    The purpose of this work is to study the behaviour of the ionospheric scintillation at high latitude during geomagnetically quiet and disturbed conditions which is one of the most relevant themes in the space weather studies. Scintillation is a major problem in navigation application using GPS and in satellite communication at high latitudes. Severe amplitude fading and strong scintillation affect the reliability of GPS navigational system and satellite communication. To study the effects of the ionospheric scintillations, GPS receiver installed at Antarctic station Maitri (Geog. 70.76°S; 11.74°E) was used. The data is collected by using GISTM 4004A, NOVATEL’S GPS receiver during March 2008. Studies show that percentage occurrence of phase scintillation is well correlated with geomagnetic activity during the observation period. The result also shows that very intense scintillations can degrade GPS based location determination due to loss of lock of satellites. These findings indicate that the dependence of scintillations and irregularity occurrence on geomagnetic activity is associated with the magnetic local time (MLT). Large number of patches are reported and their activity depends on the magnetic activity index.

  7. KAROTENOID DARI MAKROALGAE DAN MIKROALGAE: POTENSI KESEHATAN APLIKASI DAN BIOTEKNOLOGI [Carotenoids from Macroalgae and Microalgae: Health Potential, Application and Biotechnology

    Directory of Open Access Journals (Sweden)

    Leenawaty Limantara3

    2012-12-01

    Full Text Available Algae, both micro and macroalgae, is one of the largest producers of carotenoids. The major composition of carotenoid on algae are β-carotene, astaxanthin, luthein, zeaxanthin, cryptoxanthin, and fucoxanthin which have important roles for human health. Carotenoids were produced by several microalgae species such as Dunaliella sallina, Haemotococcus pluvialis, Chlorella pyrenoidosa, Spirulina platensis, Nannnochloropsis oculata, and also from some macroalgae species such as Kappaphycus alvarezii, Sargassum sp, and Caulerpa sp. Carotenoids from algae has been proven as a powerful antioxidant and may prevent some degenerative diseases, cardiovascular, and cancer. Carotenoid also has been applied as a natural dye and dietary supplements. Biotechnology has been developed to increase the production of carotenoids from micro- and macroalgae. The large-scale cultivation of microalgae, either in open or closed system are shown to increase carotenoid production. During cultivation, some stress conditions can be specifically manipulated to optimize carotenoid production from microalgae.

  8. Genetic population structure in the Antarctic benthos: insights from the widespread amphipod, Orchomenella franklini.

    Directory of Open Access Journals (Sweden)

    Helena Phoenix Baird

    Full Text Available Currently there is very limited understanding of genetic population structure in the Antarctic benthos. We conducted one of the first studies of microsatellite variation in an Antarctic benthic invertebrate, using the ubiquitous amphipod Orchomenella franklini (Walker, 1903. Seven microsatellite loci were used to assess genetic structure on three spatial scales: sites (100 s of metres, locations (1-10 kilometres and regions (1000 s of kilometres sampled in East Antarctica at Casey and Davis stations. Considerable genetic diversity was revealed, which varied between the two regions and also between polluted and unpolluted sites. Genetic differentiation among all populations was highly significant (F(ST = 0.086, R(ST = 0.139, p<0.001 consistent with the brooding mode of development in O. franklini. Hierarchical AMOVA revealed that the majority of the genetic subdivision occurred across the largest geographical scale, with N(em≈1 suggesting insufficient gene flow to prevent independent evolution of the two regions, i.e., Casey and Davis are effectively isolated. Isolation by distance was detected at smaller scales and indicates that gene flow in O. franklini occurs primarily through stepping-stone dispersal. Three of the microsatellite loci showed signs of selection, providing evidence that localised adaptation may occur within the Antarctic benthos. These results provide insights into processes of speciation in Antarctic brooders, and will help inform the design of spatial management initiatives recently endorsed for the Antarctic benthos.

  9. Growth and metal bioconcentration by conspecific freshwater macroalgae cultured in industrial waste water

    Directory of Open Access Journals (Sweden)

    Michael B. Ellison

    2014-05-01

    Full Text Available The bioremediation of industrial waste water by macroalgae is a sustainable and renewable approach to the treatment of waste water produced by multiple industries. However, few studies have tested the bioremediation of complex multi-element waste streams from coal-fired power stations by live algae. This study compares the ability of three species of green freshwater macroalgae from the genus Oedogonium, isolated from different geographic regions, to grow in waste water for the bioremediation of metals. The experiments used Ash Dam water from Tarong power station in Queensland, which is contaminated by multiple metals (Al, Cd, Ni and Zn and metalloids (As and Se in excess of Australian water quality guidelines. All species had consistent growth rates in Ash Dam water, despite significant differences in their growth rates in “clean” water. A species isolated from the Ash Dam water itself was not better suited to the bioremediation of that waste water. While there were differences in the temporal pattern of the bioconcentration of metals by the three species, over the course of the experiment, all three species bioconcentrated the same elements preferentially and to a similar extent. All species bioconcentrated metals (Cu, Mn, Ni, Cd and Zn more rapidly than metalloids (As, Mo and Se. Therefore, bioremediation in situ will be most rapid and complete for metals. Overall, all three species of freshwater macroalgae had the ability to grow in waste water and bioconcentrate elements, with a consistent affinity for the key metals that are regulated by Australian and international water quality guidelines. Together, these characteristics make Oedogonium a clear target for scaled bioremediation programs across a range of geographic regions.

  10. Polyplacophora (Mollusca from reef ecosystems and associations with macroalgae on the Coast of Alagoas, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Monica Dorigo Correia

    2015-08-01

    Full Text Available ABSTRACT Brazilian marine molluscs, especially Gastropoda and Bivalvia, are relatively well studied. However, information on the class Polyplacophora is more scarce, particularly on reef-dwelling forms. This study aimed to qualitatively and quantitatively analyze aspects of polyplacophorans from reef ecosystems and their associations with macroalgae on the coast of Maceió (state of Alagoas, Brazilian Northeast. The study area included five coral reefs at Ipioca, Ponta do Prego, Ponta do Meirim, Riacho Doce and Ponta Verde, as well as two sandstone reefs, located in Guaxuma and Sereia. The samples were obtained by snorkelling along the intertidal and subtidal reef zones to a depth of up to five meters during low tides, between 2009 and 2011. In addition, the chitons associated with three macroalgae of the Ponta Verde coral reef were studied based on collections made over 12 years (from the summer of 1998 to the winter of 2009. Three replicates with an area of 25 cm2 were collected from each of the following species of macroalgal phytals: Amphiroa fragilissima (Rhodophyta, Caulerpa racemosa (Chlorophyta and Dictyota cervicornis (Phaeophyta. A total of 715 individuals (110 juveniles and 605 adults were identified, including Acanthochitona terezae Guerra, 1983, Ischnochiton striolatus (Gray, 1828 and Ischnoplax pectinata (Sowerby II, 1840. Acanthochitona terezae was found for the first time in the area. Ischnochiton striolatus was the most abundant species in the reef ecosystem and in association with macroalgae. The greatest number of individuals of all three polyplacophorans identified (adults and juveniles was found on the phytal A. fragilissima.

  11. Meteorological observatory for Antarctic data collection

    International Nuclear Information System (INIS)

    In the last years, a great number of automatic weather stations was installed in Antarctica, with the aim to examine closely the weather and climate of this region and to improve the coverage of measuring points on the Antarctic surface. In 1987 the Italian Antarctic Project started to set up a meteorological network, in an area not completely covered by other countries. Some of the activities performed by the meteorological observatory, concerning technical functions such as maintenance of the AWS's and the execution of radio soundings, or relating to scientific purposes such as validation and elaboration of collected data, are exposed. Finally, some climatological considerations on the thermal behaviour of the Antarctic troposphere such as 'coreless winter', and on the wind field, including katabatic flows in North Victoria Land are described

  12. The Antarctic cryptoendolithic ecosystem - Relevance to exobiology

    Science.gov (United States)

    Friedmann, E. I.; Ocampo-Friedmann, R.

    1984-01-01

    Cryptoendolithic microorganisms in the Antarctic desert live inside porous sandstone rocks, protected by a thin rock crust. While the rock surface is abiotic, the microclimate inside the rock is comparatively mild. These organisms may have descended from early, pre-glaciation Antarctic life forms and thus may represent the last outpost of life in a gradually deteriorating environment. Assuming that life once arose on Mars, it is conceivable that, following the loss of water, the last of surviving organisms withdrew to similar insulated microenvironments. Because such microscopic pockets have little connection with the outside environment, their detection may be difficult. The chances that the Viking lander could sample cryptoendolithic microorganisms in the Antarctic desert would be infinitesimal.

  13. Anthropogenic nitrogen impacts in littoral ecosystems: Quantification with N stable isotopes using long-living macroalgae

    OpenAIRE

    González Viana, Inés

    2015-01-01

    Coastal areas, particularly estuaries, have become the final deposits of contaminants. The utilization of the ratio of N stable isotopes (δ15N) is a useful tool to trace nutrient sources and for studying the potential risk of eutrophication of the coastal marine systems. The use of the δ15N to trace anthropogenic loadings is based on the fact that different anthropogenic sources of N alter the baseline levels of 15N in marine biota. It is generally agreed that δ15N of brown macroalgae can dis...

  14. Influence of n-Hexane on in Situ Transesterification of Marine Macroalgae

    OpenAIRE

    Angel Sánchez; Rocio Maceiras; Angeles Cancela; Mónica Rodríguez

    2012-01-01

    The purpose of this work is to investigate the influence of n-hexane addition on in situ transesterification of a solid raw material for biodiesel production. Extraction and reaction of macroalgae oil has been performed simultaneously in a batch reactor adding n-hexane with the reactants. In order to analyze the influence of n-hexane on the transesterification, the reaction was also carried out with sunflower oil. The results show that the presence of n-hexane does not have an important effec...

  15. Salt tolerance of estuarine benthic macroalgae in the Kattegat-Baltic Sea area

    DEFF Research Database (Denmark)

    Larsen, A.; Sand-Jensen, K.

    2006-01-01

    have been hampered by examination of only a few species in each study and differences in methods among studies. To permit interspecific comparisons and statistical evaluations of relations to distribution patterns we studied the ability of 44 macroalgal species from North Zealand, South Kattegat...... distribution in the inner Baltic Sea (r: 0.32). A broad tolerance and high abundance of species in the Kattegat were significantly related to the contemporary distribution of Baltic macroalgae. Nonetheless, a large proportion of the interspecific variability was unaccounted for, presumably because a range of...

  16. Antimicrobial Activity of Organic Solvent Extracts of Three Marine Macroalgae From Chilika Lake, Orissa, India

    Directory of Open Access Journals (Sweden)

    Patra, J. K.

    2009-01-01

    Full Text Available In vitro study of antibacterial activity of organic solvent extracts of three marine macroalgae viz., Chaetomorpha linum (Mell Kuetzing, Enteromorpha compressa (L Greville and Polysiphonia subtilissima Mont. showed specific activity in inhibiting the growth of three Gram-negative bacteria (Shigella flexneri, Vibrio cholerae and Escherichia coli and two Gram positive bacteria (Bacillus subtilis and Bacillus brevis. The results revealed that the chloroform and ethyl acetate extracts were active against most of the pathogens whereas methanol and ethanol extracts were active only against S. flexneri.

  17. Microsensor Studies of Oxygen and Light-Distribution in the Green Macroalga Codium Fragile

    DEFF Research Database (Denmark)

    LASSEN, C.; BEBOUT, LE; PAERL, HW; JØRGENSEN, BB

    1994-01-01

    Scalar irradiance, oxygen concentration, and oxygenic photosynthesis were measured at 0.1 mm spatial resolution within the tissue of the siphonous green macroalga Codium fragile subsp. tomentosoides (van Goer) Silva by fiber-optic scalar irradiance microsensors and oxygen microelectrodes, The...... gradient inside and around the alga. In darkness, the tissue below 0.6 mm became anoxic, and endophytic extracellular space provided an environment where anoxygenic microbial processes may occur. When illuminated at 160 mu mol photons.m(-2).s(-1), O-2 concentrations exceeded ambient levels throughout the...

  18. 海洋酸化对大型海藻生长以及磷酸盐、硝酸盐吸收利用的影响%Effects of Ocean Acidification on Growth,Phosphate and Nitrate Uptake of Macroalgae

    Institute of Scientific and Technical Information of China (English)

    于娟; 张瑜; 杨桂朋; 田延旺

    2012-01-01

    CO2浓度升高导致的海洋酸化会对大型海藻的生长、生理生态以及营养盐的吸收产生影响.本研究分析了3种pH条件下,3种大型海藻[孔石莼、萱藻、小珊瑚藻(钙化藻)]单养和混养的生长以及营养盐(磷酸盐PO34-和硝酸盐NO3-)的吸收利用情况.单养时,孔石莼、萱藻、小珊瑚藻的第10 d湿重增加百分比分别在pH 7.9、7.6、8.2条件下最多,并且小珊瑚藻在pH 7.6时的相对增长率显著低于在pH 8.2时的相对增长率.混养结果表明,低pH有利于萱藻生长,而高pH有利于小珊瑚藻生长.无论单养还是混养,3种pH条件下的培养液中PO34-、NO3-含量随时间延长而逐渐降低.在0~2 d培养液中PO34-含量急剧下降(降低了71.9%~99.0%),随后PO34-含量下降缓慢.单养时,孔石莼、萱藻、小珊瑚藻分别在pH 8.2、8.2、7.6时的PO34-吸收速率最高;孔石莼、小珊瑚藻分别在pH 8.2、7.6时的NO3-吸收速率最高.混养时,孔石莼+萱藻、孔石莼+小珊瑚藻、萱藻+小珊瑚藻分别在pH 7.6、8.2、8.2时的PO34-吸收速率最高;孔石莼+小珊瑚藻在pH 7.6时的NO3-吸收速率最高.小珊瑚藻单养在pH 7.6时的低生长以及营养盐(PO34-和NO3-)的高吸收速率结果表明,PO34-和NO3-的吸收与同化作用并不相偶联.尽管两种藻混养中的优势种并未因海洋酸化而改变,但藻的种类组成比例发生了变化.因此,自然环境中海洋酸化对不同海藻的生长和营养盐吸收的长期影响可能会导致藻群落结构的改变.%The ocean acidification caused by elevated CO2 concentration can affect the growth,physiology and ecology,and nutrient uptake of macroalgae.In this paper,the growth and nutrient(PO3-4 and NO-3) uptake of three species of macroalgae [Ulva pertusa,Scytosiphon lomentaria and Corallina pilulifera(calcified algae)] at three pHs(8.2,7.9 and 7.6) were investigated under conditions of monoculture and mixed culture

  19. First geomagnetic measurements in the Antarctic region

    Science.gov (United States)

    Raspopov, O. M.; Demina, I. M.; Meshcheryakov, V. V.

    2014-05-01

    Based on data from literature and archival sources, we have further processed and analyzed the results of geomagnetic measurements made during the 1772-1775 Second World Expedition by James Cook and the 1819-1821 overseas Antarctic Expedition by Russian mariners Bellingshausen and Lazarev. Comparison with the GUFM historical model showed that there are systematic differences in the spatial structure of both the declination and its secular variation. The results obtained can serve as a basis for the construction of regional models of the geomagnetic field for the Antarctic region.

  20. Climate Change Influences on Antarctic Bird Populations

    Science.gov (United States)

    Korczak-Abshire, Małgorzata

    2010-01-01

    Rapid changes in the major environmental variables like: temperature, wind and precipitation have occurred in the Antarctic region during the last 50 years. In this very sensitive region, even small changes can potentially lead to major environmental perturbations. Then the climate change poses a new challenge to the survival of Antarctic wildlife. As important bioindicators of changes in the ecosystem seabirds and their response to the climate perturbations have been recorded. Atmospheric warming and consequent changes in sea ice conditions have been hypothesized to differentially affect predator populations due to different predator life-history strategies and substantially altered krill recruitment dynamics.

  1. Antarctic marine bacteria versus UV-B irradiation

    International Nuclear Information System (INIS)

    The most important stages of knowledge development in Antarctic marine microbiology, from the beginning of this century, were reviewed and systematized. Multi-annual studies from 1978 to 1988 demonstrated a great variation in total and saprophytic bacterial numbers at different sites in the Antarctic. These sites included inshore waters (Admiralty Bay), open ocean waters (Drake Passage and Bransfield Strait), and the vicinity of pack-ice in Scotia Sea. Bacterial biomass, which is highly comparable to that of other organisms, combined with many times shorter bacterial generation time, (in case of saprophytic population it amounts to 17.5 h), must have profound consequences for cold marine ecosystems of the Antarctic. Higher numbers of bacteria were found in open surface waters, down to 75 m. High transparency of oceanic offshore waters causes that UV radiation (280-400 nm) penetrates to biologically effective depths to about 50 m. The UV-B sensitivity of 25 Antarctic bacterial strains from the following various habitats: coastal waters, krill stomach, krill feaces, water ice edge, water below ice and sea ice was examined. The strains were irradiated in UV-B transparent cuvettes on an optical bench with artificial UV-B (290 nm; 1.21 W. m-2 ] during 10 hours in temperature 4oC. ATP (adenosine triphosphate), number of bacterial cells, lethal effect of UV-B and survival of bacteria, total bacterial number, biovolume and changes in biochemical/physiological properties have been estimated. The results indicated a high interspecific variability in the sensitivity against UV-B. The ATP content show at the beginning of irradiation an increase (reaching typical for individual species maximum, at 0.5 to 4 hours) and afterwards a decrease to the level above zero (also characteristic of species). We hypothesize that first anabolic processes and after that catabolic processes are destroyed by UV. Survival of the bacterial strains ranged between 0 and 3.2%. Among 25 bacterial

  2. The use of the brown macroalgae, Sargassum flavicans, as a potential bioindicator of industrial nutrient enrichment

    International Nuclear Information System (INIS)

    Highlights: • The brown algae, Sargassum flavicans, was used as a successful nutrient bioindicator. • Creek sites adjacent to an industry refinery showed increased nutrient enrichment. • Higher nutrient loads in creek sites compared to adjacent oceanic sites. • Higher nutrient discharge was observed during the wet season. • δ15N values were the best endpoints to detect nutrient enrichment in the brown algae. -- Abstract: Nutrient bioindicators are increasingly being recognised as a diagnostic tool for nutrient enrichment of estuarine and marine ecosystems. Few studies, however, have focused on field translocation of bioindicator organisms to detect nutrient discharge from industrial waste. The brown macroalgae, Sargassum flavicans, was investigated as a potential bioindicator of nutrient-enriched industrial effluent originating from a nickel refinery in tropical north-eastern Australia. S. flavicans was translocated to a number of nutrient enriched creek and oceanic sites over two seasons and assessed for changes in stable isotope ratios of 15N and 13C within the plant tissue in comparison to reference sites. Nutrient uptake in macroalgae, translocated to the nutrient enriched sites adjacent to the refinery, increased 3–4-fold in δ15N, compared to reference sites. Using δ15N of translocated S. flavicans proved to be a successful method for monitoring time-integrated uptake of nitrogen, given the current lack of passive sampler technology for nutrient monitoring

  3. Polyunsaturated Fatty Acids of Marine Macroalgae: Potential for Nutritional and Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    João Varela

    2012-08-01

    Full Text Available As mammals are unable to synthesize essential polyunsaturated fatty acids (PUFA, these compounds need to be taken in through diet. Nowadays, obtaining essential PUFA in diet is becoming increasingly difficult; therefore this work investigated the suitability of using macroalgae as novel dietary sources of PUFA. Hence, 17 macroalgal species from three different phyla (Chlorophyta, Phaeophyta and Rhodophyta were analyzed and their fatty acid methyl esters (FAME profile was assessed. Each phylum presented a characteristic fatty acid signature as evidenced by clustering of PUFA profiles of algae belonging to the same phylum in a Principal Components Analysis. The major PUFA detected in all phyla were C18 and C20, namely linoleic, arachidonic and eicosapentaenoic acids. The obtained data showed that rhodophytes and phaeophytes have higher concentrations of PUFA, particularly from the n-3 series, thereby being a better source of these compounds. Moreover, rhodophytes and phaeophytes presented “healthier” ∑n-6/∑n-3 and PUFA/saturated fatty acid ratios than chlorophytes. Ulva was an exception within the Chlorophyta, as it presented high concentrations of n-3 PUFA, α-linolenic acid in particular. In conclusion, macroalgae can be considered as a potential source for large-scale production of essential PUFA with wide applications in the nutraceutical and pharmacological industries.

  4. Ocean Acidification Accelerates the Growth of Two Bloom-Forming Macroalgae.

    Science.gov (United States)

    Young, Craig S; Gobler, Christopher J

    2016-01-01

    While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). In nearly all experiments, the growth rates of Gracilaria were significantly increased by an average of 70% beyond in situ and control conditions when exposed to elevated levels of pCO2 (p0.05). The δ13C content of both Gracilaria and Ulva decreased two-to-three fold when grown under elevated pCO2 (pphotosynthesis of these algae was limited by their inorganic carbon supply. Given that eutrophication can yield elevated levels of pCO2, this study suggests that the overgrowth of macroalgae in eutrophic estuaries can be directly promoted by acidification, a process that will intensify in the coming decades. PMID:27176637

  5. Impact of seaweed beachings on dynamics of δ15N isotopic signatures in marine macroalgae

    International Nuclear Information System (INIS)

    Highlights: • Two coastal sites (COU, GM) in the Bay of Seine affected by summer seaweed beachings. • The same temporal dynamics of the algal δ15N at the two sites. • N and P concentrations in seawater of the two sites dominated by riverine sources. • A coupling between seaweed beachings and N sources of intertidal macroalgae. - Abstract: A fine-scale survey of δ15N, δ13C, tissue-N in seaweeds was conducted using samples from 17 sampling points at two sites (Grandcamp-Maisy (GM), Courseulles/Mer (COU)) along the French coast of the English Channel in 2012 and 2013. Partial triadic analysis was performed on the parameter data sets and revealed the functioning of three areas: one estuary (EstA) and two rocky areas (GM∗, COU∗). In contrast to oceanic and anthropogenic reference points similar temporal dynamics characterized δ15N signatures and N contents at GM∗ and COU∗. Nutrient dynamics were similar: the N-concentrations in seawater originated from the River Seine and local coastal rivers while P-concentrations mainly from these local rivers. δ15N at GM∗ were linked to turbidity suggesting inputs of autochthonous organic matter from large-scale summer seaweed beachings made up of a mixture of Rhodophyta, Phaeophyta and Chlorophyta species. This study highlights the coupling between seaweed beachings and nitrogen sources of intertidal macroalgae

  6. Land use, macroalgae, and a tumor-forming disease in marine turtles.

    Directory of Open Access Journals (Sweden)

    Kyle S Van Houtan

    Full Text Available Wildlife diseases are an increasing concern for endangered species conservation, but their occurrence, causes, and human influences are often unknown. We analyzed 3,939 records of stranded Hawaiian green sea turtles (Chelonia mydas over 28 years to understand fibropapillomatosis, a tumor-forming disease linked to a herpesvirus. Turtle size is a consistent risk factor and size-standardized models revealed considerable spatial and temporal variability. The disease peaked in some areas in the 1990s, in some regions rates remained constant, and elsewhere rates increased. Land use, onshore of where the turtles feed, may play a role. Elevated disease rates were clustered in watersheds with high nitrogen-footprints; an index of natural and anthropogenic factors that affect coastal eutrophication. Further analysis shows strong epidemiological links between disease rates, nitrogen-footprints, and invasive macroalgae and points to foraging ecology. These turtles now forage on invasive macroalgae, which can dominate nutrient rich waters and sequester environmental N in the amino acid arginine. Arginine is known to regulate immune activity, promote herpesviruses, and contribute to tumor formation. Our results have implications for understanding diseases in aquatic organisms, eutrophication, herpesviruses, and tumor formation.

  7. Spatially Extensive Standardized Surveys Reveal Widespread, Multi-Decadal Increase in East Antarctic Adélie Penguin Populations

    Science.gov (United States)

    Southwell, Colin; Emmerson, Louise; McKinlay, John; Newbery, Kym; Takahashi, Akinori; Kato, Akiko; Barbraud, Christophe; DeLord, Karine; Weimerskirch, Henri

    2015-01-01

    Seabirds are considered to be useful and practical indicators of the state of marine ecosystems because they integrate across changes in the lower trophic levels and the physical environment. Signals from this key group of species can indicate broad scale impacts or response to environmental change. Recent studies of penguin populations, the most commonly abundant Antarctic seabirds in the west Antarctic Peninsula and western Ross Sea, have demonstrated that physical changes in Antarctic marine environments have profound effects on biota at high trophic levels. Large populations of the circumpolar-breeding Adélie penguin occur in East Antarctica, but direct, standardized population data across much of this vast coastline have been more limited than in other Antarctic regions. We combine extensive new population survey data, new population estimation methods, and re-interpreted historical survey data to assess decadal-scale change in East Antarctic Adélie penguin breeding populations. We show that, in contrast to the west Antarctic Peninsula and western Ross Sea where breeding populations have decreased or shown variable trends over the last 30 years, East Antarctic regional populations have almost doubled in abundance since the 1980’s and have been increasing since the earliest counts in the 1960’s. The population changes are associated with five-year lagged changes in the physical environment, suggesting that the changing environment impacts primarily on the pre-breeding age classes. East Antarctic marine ecosystems have been subject to a number of changes over the last 50 years which may have influenced Adélie penguin population growth, including decadal-scale climate variation, an inferred mid-20th century sea-ice contraction, and early-to-mid 20th century exploitation of fish and whale populations. PMID:26488299

  8. Climate-dependent evolution of Antarctic ectotherms: An integrative analysis

    Science.gov (United States)

    Pörtner, Hans O.

    2006-04-01

    , and the use of lipid body stores for neutral buoyancy. Important trade-offs result from obligatory energy savings in the permanent cold: low metabolic rates support cold-compensated growth but imply narrow windows of thermal tolerance and reduced scopes for activity. The degree of thermal specialization is not uniformly defined by cold temperature but varies with life style characteristics and activity levels and associated aerobic scope. Trade-offs for the sake of cold compensated growth parallel reduced capacities for exercise performance, exacerbated by the effect of high haemolymph magnesium levels in crustaceans and, possibly, other invertebrates. High magnesium levels likely exclude the group of reptant decapod crustaceans from Antarctic waters below 0 °C. The hypothesis is developed that energy savings imposed by the permanent cold bear specific life history consequences. Due to effects of allometry, energy savings are exacerbated at small body size, favouring passive lecithotrophic larvae. At all stages of life history, reduced energy turnover for the sake of growth causes delays and low rates in other higher functions, with the result of late maturity, fecundity and offspring release, as well as extended development. As a consequence, extended life spans evolved due to life history requirements. At the same time, polar gigantism is enabled by a combination of elevated oxygen levels in cold waters, of reduced metabolism and of extended periods of growth at slow developmental rates.

  9. Contrasting Arctic and Antarctic sea ice temperatures

    Science.gov (United States)

    Vancoppenolle, Martin; Raphael, Marilyn; Rousset, Clément; Vivier, Frédéric; Moreau, Sébastien; Delille, Bruno; Tison, Jean-Louis

    2016-04-01

    Sea ice temperature affects the sea ice growth rate, heat content, permeability and habitability for ice algae. Large-scale simulations with NEMO-LIM suggest large ice temperature contrasts between the Arctic and the Antarctic sea ice. First, Antarctic sea ice proves generally warmer than in the Arctic, in particular during winter, where differences reach up to ~10°C. Second, the seasonality of temperature is different among the two hemispheres: Antarctic ice temperatures are 2-3°C higher in spring than they are in fall, whereas the opposite is true in the Arctic. These two key differences are supported by the available ice core and mass balance buoys temperature observations, and can be attributed to differences in air temperature and snow depth. As a result, the ice is found to be habitable and permeable over much larger areas and much earlier in late spring in the Antarctic as compared with the Arctic, which consequences on biogeochemical exchanges in the sea ice zone remain to be evaluated.

  10. Relevance of antarctic microbial ecosystems to exobiology

    Science.gov (United States)

    Mckay, Christopher P.

    1993-01-01

    Antarctic microbial ecosystems which provide biological and physical analogs that can be used in exobiology are studied. Since the access to extraterrestrial habitats is extremely difficult, terrestrial analogs represent the best opportunity for both formulation and preliminary testing of hypothesis about life. Antarctica, as one of few suitable environments on earth is considered to be a major locus of progress in exobiology.

  11. Genetic differentiation in the circum—Antarctic sea spider Nymphon australe (Pycnogonida; Nymphonidae)

    Science.gov (United States)

    Arango, Claudia P.; Soler-Membrives, Anna; Miller, Karen J.

    2011-03-01

    Nymphon australe Hodgson 1902 is the most abundant species of sea spiders in the Southern Ocean. The species is recognised as highly morphologically variable, circumpolar and eurybathic—which is surprising given that sea spiders lack a planktonic stage; the fertilised eggs and larvae remain attached to the ovigers of the father, and consequently have limited dispersal capacity. In this study, we investigate the genetic structure of N. australe populations around Antarctica, confronting the apparent limited dispersal ability with its recognised circumpolarity. Here we analyse mitochondrial DNA of specimens from Antarctic Peninsula, Weddell Sea and East Antarctica to determine if they represent populations of the widespread N. australe — or instead we can recognise cryptic species - and how genetically different they are. Both CO1 and 16S sequence data produced single haplotype networks for N. australe from all three Antarctic locations without indication of cryptic speciation. However, we found strong phylogeographic structure among the three Antarctic locations based on CO1 data. There was only a single shared haplotype between the Antarctic Peninsula and the East Antarctica locations, and all three regions were significantly subdivided from each other ( FST=0.28, ppopulations of N. australe separated by 10-100 s of km ( FST=0.07-0.22, pspiders life history traits indicating a limited dispersal capability. We conclude N. australe represents a single circum-Antarctic species that, despite its limited dispersal abilities, has successfully colonised large parts of the Antarctic marine ecosystem through geological history. However, clear genetic differences among and within locations indicate contemporary gene flow is limited, and that populations of N. australe around Antarctica are effectively isolated.

  12. Macroalgae blooms and δ15N in subtropical coastal lagoons from the Southeastern Gulf of California: Discrimination among agricultural, shrimp farm and sewage effluents

    International Nuclear Information System (INIS)

    Macroalgae blooms of Gracilaria vermiculophylla, Hypnea spinella and Spyridia filamentosa have been found in coastal lagoons in the SE Gulf of California. Agriculture, livestock, shrimp and poultry farms and sewage contribute anthropogenic nitrogen to the systems. The δ15N of these sources, water column and macroalgae were studied in order to identify the N supply for macroalgae blooms. δ15N of three species of macroalgae (4.3-13.6 per mille ) were enriched compared to the water column (δ15N-NO3- 3.7-6.8 per mille ), probably because of fractioning from the macroalgae. δ15N of POM (1.4-10.3 per mille ) was similar to the water column but the relationship was unclear. Depending on the site, macroalgae showed different δ15N values since some sites receive more or less influence from one given source of the associated watershed, which is reflected in the different δ15N values of the macroalgae of the same system and in the relative contributions of the sources.

  13. Neogene kinematic history of Nazca-Antarctic-Phoenix slab windows beneath Patagonia and the Antarctic Peninsula

    Science.gov (United States)

    Breitsprecher, Katrin; Thorkelson, Derek J.

    2009-01-01

    The Patagonian slab window is a subsurface tectonic feature resulting from subduction of the Nazca-Antarctic spreading-ridge system (Chile Rise) beneath southern South America. The geometry of the slab window had not been rigorously defined, in part because of the complex nature of the history of ridge subduction in the southeast Pacific region, which includes four interrelated spreading-ridge systems since 20 Ma: first, the Nazca-Phoenix ridge beneath South America, then simultaneous subduction of the Nazca-Antarctic and the northern Phoenix-Antarctic spreading-ridge systems beneath South America, and the southern Phoenix-Antarctic spreading-ridge system beneath Antarctica. Spreading-ridge paleo-geographies and rotation poles for all relevant plate pairs (Nazca, Phoenix, Antarctic, South America) are available from 20 Ma onward, and form the mathematical basis of our kinematic reconstruction of the geometry of the Patagonia and Antarctic slab windows through Neogene time. At approximately 18 Ma, the Nazca-Phoenix-Antarctic oceanic (ridge-ridge-ridge) triple junction enters the South American trench; we recognize this condition as an unstable quadruple junction. Heat flow at this junction and for some distance beneath the forearc would be considerably higher than is generally recognized in cases of ridge subduction. From 16 Ma onward, the geometry of the Patagonia slab window developed from the subduction of the trailing arms of the former oceanic triple junction. The majority of the slab window's areal extent and geometry is controlled by the highly oblique (near-parallel) subduction angle of the Nazca-Antarctic ridge system, and by the high contrast in relative convergence rates between these two plates relative to South America. The very slow convergence rate of the Antarctic slab is manifested by the shallow levels achieved by the slab edge (< 45 km); thus no point on the Antarctic slab is sufficiently deep to generate "normal" mantle-derived arc-type magmas

  14. Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China, with a special reference to the relationship of photosynthesis and CO2

    Institute of Scientific and Technical Information of China (English)

    ZOU Dinghui; GAO Kunshan

    2005-01-01

    Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents.The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petaloniafascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G.intermedia and S. hemiphyllum exhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia,exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intermedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO2 in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.

  15. Cultivation and conversion of marine macroalgae. [Gracilaria and Ulva

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J.H.; DeBusk, T.A.; Blakeslee, M.

    1984-05-01

    Research was conducted on the development of an alternative ocean energy farm concept that would not be dependent upon deep ocean water or other extraneous sources for its nutrient supply and that could be located in shallow, near shore, and protected coastal ocean areas. There are five tasks reported in this document: determination of the annual yield of Ulva in non-intensive cultures; evaluation of the effect of carbon concentration on Gracilaria and Ulva yields; evaluation of spray/mist culture of Ulva and Gracilaria; species screening for the production of petroleum replacement products; and synthesis analysis, and economic energy evaluation of culture data. An alternative concept to open ocean culture is a land-based energy production system utilizing saline waters from underground aquifers or enclosed coastal areas. Research was performed to evaluate growth and biomass production of all macroscopic algal species that could be obtained in adequate quantity in the central Florida area. A total of 42 species were grown in specially adapted burial vaults. These included 16 green algae (Garcilaria 4 weekshlorophyta), 2 brown algae (Phaeophyta), and 18 red algae (Rhodophyta). Of these, the most successful and suitable species were a strain of Gracilaria (a red seaweed) and Ulva (a green seaweed). These two species have a high carbohydrate content that may be anaerobically digested to methane gas. Well-nourished Gracilaria will double its biomass in 1 to 4 weeks, depending on the season, water flow, and other variables. After its biomass has doubled (i.e., from 2 to 4 kg/m/sup 2/) the incremental growth is harvested to return the crop to a starting density. Enrichment of the new starting crop following harvest could conceivably be accomplished onsite at the seaweed farm, but the rapid uptake and storage of nutrients by depleted seaweeds makes possible a simpler process, known as pulse fertilization.

  16. Does Antarctic glaciation cool the world?

    Directory of Open Access Journals (Sweden)

    A. Goldner

    2012-07-01

    Full Text Available In this study we compare the simulated climatic impact of adding the Antarctic Ice Sheet to the "Greenhouse World" of the Eocene and removing the Antarctic Ice Sheet from the Modern world. The Modern surface temperature anomaly (ΔT induced by Antarctic Glaciation ranges from −1.22 to −0.18 K when CO2 is dropped from 2240 to 560 ppm, whereas the Eocene ΔT is nearly constant at −0.3 K. We calculate the climate sensitivity parameter S[Antarctica] which is defined as the change in surface temperature (ΔT divided by the change in radiative forcing (ΔQAntarctica imposed by prescribing the glacial properties of Antarctica. While the ΔT associated with the imposed Antarctic properties is relatively consistent across the Eocene cases, the radiative forcing is not. This leads to a wide range of S[Antarctica], with Eocene values systematically smaller than Modern.

    This differing temperature response in Eocene and Modern is partially due to the smaller surface area of the imposed forcing over Antarctica in the Eocene and partially due to the presence of strong positive sea-ice feedbacks in the Modern. The system's response is further mediated by differing shortwave cloud feedbacks which are large and of opposite sign operating in Modern and Eocene configurations. A negative cloud feedback warms much of the Earth's surface as a large ice sheet is introduced in Antarctica in the Eocene, whereas in the Modern this cloud feedback is positive and acts to enhance cooling introduced by adding an ice sheet. Because of the importance of cloud feedbacks in determining the final temperature sensitivity of the Antarctic Ice Sheet our results are likely to be model dependent. Nevertheless, these model results show that the radiative forcing and feedbacks induced by the Antarctic Ice Sheet did not significantly decrease global mean surface temperature across

  17. Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem.

    Science.gov (United States)

    Sahade, Ricardo; Lagger, Cristian; Torre, Luciana; Momo, Fernando; Monien, Patrick; Schloss, Irene; Barnes, David K A; Servetto, Natalia; Tarantelli, Soledad; Tatián, Marcos; Zamboni, Nadia; Abele, Doris

    2015-11-01

    The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a "filter feeders-ascidian domination" to a "mixed assemblage" suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP. PMID:26702429

  18. Features and spatial distribution of circumpolar deep water in the southern Indian Ocean and the effects of Antarctic circum polar current

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The data from the Southern Ocean observations of World Ocean Circulation Experiment(WOCE)are used for analysis and illustration of the features and spatial distributions of Circumpolar Deep Water(CDW)in the southern Indian Ocean.It is learnt from the comparison among the vertical distributions of temperature/salinity/oxygen along the (30.)E, (90.)E and (145.)E sections respectively that some different features of CDW and the fronts can be found at those longitudes, and those differences can be attributed to the zonal transoceanic flow and the merizonal movement in the Circumpolar Deep Water.In fact, the zonal transoceanic flow is the main dynamic factor for the water exchange between the Pacific Ocean and the Indian Ocean or between the Atlantic Ocean and the Indian Ocean, and for the effects on the spatial distributions of the physical properties in CDW.

  19. Biogas from Marine Macroalgae: a New Environmental Technology — Life Cycle Inventory for a Further LCA

    Science.gov (United States)

    Romagnoli, Francesco; Blumberga, Dagnija; Gigli, Emanuele

    2010-01-01

    The main goal of this paper is to analyze the innovative process of production of biogas (via fermentation processes) using marine macroalgae as feedstock in a pilot project plant in Augusta (Sicily, Italy). Algae, during their growth, have the capacity to assimilate nutrients and thus subsequent harvesting of the algal biomass recovers the nutrients from biowaste sources giving the possibility to transform negative environmental externalities in positive mainly in terms of eutrophication and climate change impact categories. The paper presents a novel environmental technology for the production of biogas and 2nd generation biofuel (liquid biomethane) after an upgrading process through the use of a cryogenic technology. The paper would also like to make the first attempt at understanding the possibility to implement this innovative technology in the Latvian context. The first calculations and assumptions for the Life Cycle Inventory for a further Life Cycle Assessment are presented.

  20. Shift from coral to macroalgae dominance on a volcanically acidified reef

    Science.gov (United States)

    Enochs, I. C.; Manzello, D. P.; Donham, E. M.; Kolodziej, G.; Okano, R.; Johnston, L.; Young, C.; Iguel, J.; Edwards, C. B.; Fox, M. D.; Valentino, L.; Johnson, S.; Benavente, D.; Clark, S. J.; Carlton, R.; Burton, T.; Eynaud, Y.; Price, N. N.

    2015-12-01

    Rising anthropogenic CO2 in the atmosphere is accompanied by an increase in oceanic CO2 and a concomitant decline in seawater pH (ref. ). This phenomenon, known as ocean acidification (OA), has been experimentally shown to impact the biology and ecology of numerous animals and plants, most notably those that precipitate calcium carbonate skeletons, such as reef-building corals. Volcanically acidified water at Maug, Commonwealth of the Northern Mariana Islands (CNMI) is equivalent to near-future predictions for what coral reef ecosystems will experience worldwide due to OA. We provide the first chemical and ecological assessment of this unique site and show that acidification-related stress significantly influences the abundance and diversity of coral reef taxa, leading to the often-predicted shift from a coral to an algae-dominated state. This study provides field evidence that acidification can lead to macroalgae dominance on reefs.

  1. Macroalgae and phytoplankton as indicators of ecological status of Danish coastal waters

    DEFF Research Database (Denmark)

    Carstensen, Jacob; Krause-Jensen, Dorte; Dahl, Karsten;

    This report contributes to the development of tools that can be applied to assess the five classes of ecological status of the Water Framework Directive based on the biological quality elements phytoplankton and macroalgae. Nitrogen inputs and concentrations representing reference conditions and...... boundaries between the five ecological status classes were calculated from estimates of nitrogen inputs from Denmark to the Danish straits since 1900 combined with expert judgement of the general environmental conditions of Danish waters during different time periods. From these calculated nitrogen...... concentrations and a macroalgal model ecological status class boundaries were established for six macroalgal indicators in a number of Danish estuaries and coastal areas. Furthermore, site-specific correlations between concentrations of nitrogen and chlorophyll a were used to define reference conditions and...

  2. Onset and role of the Antarctic Circumpolar Current

    OpenAIRE

    Barker, P. F.; Threshers Barn, Whitcott Keysett, Clun, Shropshire SY7 8QE, UK; Filippelli, G. M.; Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN 46202-5132, USA; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Martin, E. E.; Department of Geological Sciences, University of Florida, Gainesville, FL 32611-2120, USA; Howard, D. S.; Department of Earth & Environmental Sciences, University of Rochester, Rochester, NY 14611, USA

    2007-01-01

    For some time, onset of the Antarctic Circumpolar Current (ACC) was considered to have caused or stabilised full Antarctic glaciation. Recently, however, the importance of the ACC in this role has been questioned. In order to understand the relationship between the ACC and Antarctic glaciation, and thence the importance of ocean circulation to palaeoclimate, we need to determine the development history of both processes. To this end, we summarise all published estimates of ACC ons...

  3. Relative Changes in Krill Abundance Inferred from Antarctic Fur Seal

    OpenAIRE

    Tao Huang; Liguang Sun; John Stark; Yuhong Wang; Zhongqi Cheng; Qichao Yang; Song Sun

    2011-01-01

    Antarctic krill Euphausia superba is a predominant species in the Southern Ocean, it is very sensitive to climate change, and it supports large stocks of fishes, seabirds, seals and whales in Antarctic marine ecosystems. Modern krill stocks have been estimated directly by net hauls and acoustic surveys; the historical krill density especially the long-term one in the Southern Ocean, however, is unknown. Here we inferred the relative krill population changes along the West Antarctic Peninsula ...

  4. On the Atmospheric Correction of Antarctic Airborne Hyperspectral Data

    OpenAIRE

    Martin Black; Andrew Fleming; Teal Riley; Graham Ferrier; Peter Fretwell; John McFee; Stephen Achal; Alejandra Umana Diaz

    2014-01-01

    The first airborne hyperspectral campaign in the Antarctic Peninsula region was carried out by the British Antarctic Survey and partners in February 2011. This paper presents an insight into the applicability of currently available radiative transfer modelling and atmospheric correction techniques for processing airborne hyperspectral data in this unique coastal Antarctic environment. Results from the Atmospheric and Topographic Correction version 4 (ATCOR-4) package reveal absolute reflectan...

  5. Surface influence on the marine and coastal Antarctic atmosphere

    OpenAIRE

    Valkonen, Teresa

    2013-01-01

    The Antarctic region plays an important role in the global climate system, and it contributes to the future of global climate through changes in regional factors, such as sea ice, atmospheric circulation patterns and moisture distribution. The aim of this thesis is to improve the understanding of the influence of the Earth surface on the marine and coastal Antarctic atmosphere. The thesis outlines the characteristics of typical phenomena of the Antarctic environment both near the surface and ...

  6. Encouraging Advances Made by Chinese Scientists in Antarctic Research

    Institute of Scientific and Technical Information of China (English)

    Zhang Qingsong

    2003-01-01

    @@ Chinese scientists began involving in the Antarctic research in 1980. As the first step, some 40 Chinese scientists were sent to Antarctic stations of Australia and other countries during the period from 1980 to 1984. Then,China established two Antarctic stations of its own, and purchased an icebreaker, enabling China to carry on its own independent research program both on land and at sea.

  7. Terrestrial age dating of antarctic meteorites

    International Nuclear Information System (INIS)

    During the last three antarctic field seasons, US and Japanese teams have collected several thousand meteorites. The terrestrial age of these objects is of interest because such knowledge enables the setting of lower bounds on the lower age of the ice sheet, provides information about ice movement, and aids understanding of the accumulation mechanism of the meteorites. Terrestrial ages can be established by measuring the decay of radioactive species produced by bombardment of cosmic rays while the objects are in space. After entering the Earth's atmosphere the meteorites essentially are completely shielded from cosmic rays. The radioactive products that exist at saturation values in space then decay exponentially toward zero activity. By the end of 1980, data will be established on 150 to 200 selected samples. With that large a data base we should have a fairly clear picture of the terrestrial age distribution of antarctic meteorites

  8. [Taxonomical status of the psychrotolerant Antarctic microorganisms].

    Science.gov (United States)

    Romanovskaia, V A; Gladka, G V; Tashireva, A A; Tashirev, A B

    2013-01-01

    The aerobic chemoorganotrophic bacteria, dominating in soils and phytocenosis of the Antarctic Region, on combination of morphological and biochemical properties belong to several taxons of Bacteria domain. Gram-negative strains 3189, 3415 (fam. Halomonadaceae, Halomonas sp.) and 3088, 3468, 3469 (fam. Moraxellaceae, Psychrobacter sp.) belong to phylum Proteobacteria, to class Gammaproteobacteria. Gram-negative strains 3294 3392 (Rhizobiales, fam. Methylobacteriaceae, Methylobacterium sp.) relate to class Alphaproteobacteria of this phylum. Gram-positive strains 3179, 3275, 3470, 3471 (fam. Microbacteriaceae, Cryobacterium sp.), 3054, 3058, 3411 (fam. Corynebacteriaceae, Corynebacterium sp.) and 3194, 3398 (fam. Micrococcaceae, Micrococcus sp.) relate to phylum Actinobacteria, class Actinobacteria. Thus, the psychrophilic and psychrotolerant Antarctic bacteria (aerobic chemoorganotrophic) isolated from phytocenosis and soils of polar region are characterized by wide taxonomic variety. PMID:24450178

  9. Macro-algae biomass and cover from nearshore regions of the Nantorium War Memorial, Waikiki, Oahu, Hawaii, 1966-2005 (NODC Accession 0040082)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Department of Zoology, University of Hawaii at Manoa, incorporated surveys of macro-algae as part of the Zoology 439L "Laboratory in Ecology" during annual...

  10. Quality Index of Subtidal Macroalgae (QISubMac): A suitable tool for ecological quality status assessment under the scope of the European Water Framework Directive.

    Science.gov (United States)

    Le Gal, A; Derrien-Courtel, S

    2015-12-15

    Despite their representativeness and importance in coastal waters, subtidal rocky bottom habitats have been under-studied. This has resulted in a lack of available indicators for subtidal hard substrate communities. However, a few indicators using subtidal macroalgae have been developed in recent years for the purpose of being implemented into the Water Framework Directive (WFD). Accordingly, a quality index of subtidal macroalgae has been defined as a French assessment tool for subtidal rocky bottom habitats in coastal waters. This approach is based on 14 metrics that consider the depth penetration, composition (sensitive, characteristic and opportunistic) and biodiversity of macroalgae assemblages and complies with WFD requirements. Three ecoregions have been defined to fit with the geographical distribution of macroalgae along the French coastline. As a test, QISubMac was used to assess the water quality of 20 water bodies. The results show that QISubMac may discriminate among different quality classes of water bodies. PMID:26555795

  11. Macro-algae Biomass and Cover from Nearshore Regions of the Natatorium War Memorial, Waikiki, Oahu, Hawaii 1966-2005 (NODC Accession 0040082)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Department of Zoology, University of Hawaii at Manoa, incorporated surveys of macro-algae as part of the Zoology 439L "Laboratory in Ecology" during annual...

  12. Accumulation of alkaline earth metals by the green macroalga Bryopsis maxima.

    Science.gov (United States)

    Takahashi, Shigekazu; Aizawa, Kyoko; Nakamura, Saki; Nakayama, Katsumi; Fujisaki, Shingo; Watanabe, Soichiro; Satoh, Hiroyuki

    2015-04-01

    Twenty-five days after the disaster at the Fukushima Daiichi nuclear power plant in 2011, we collected samples of the green macroalga Bryopsis maxima from the Pacific coast of Japan. Bryopsis maxima is a unicellular, multinuclear, siphonous green macroalga. Radiation analysis revealed that B. maxima emitted remarkably high gamma radiation of (131)I, (134)Cs, (137)Cs, and (140)Ba as fission products of (235)U. Interestingly, B. maxima contained naturally occurring radionuclides derived from (226)Ra and (228)Ra. Analysis of element content revealed that B. maxima accumulates many ocean elements, especially high quantities of the alkaline earth metals Sr (15.9 g per dry-kg) and Ba (3.79 g per dry-kg), whereas Ca content (12.5 g per dry-kg) was lower than that of Sr and only 61 % of the mean content of 70 Japanese seaweed species. Time-course analysis determined the rate of radioactive (85)Sr incorporation into thalli to be approximately 0.13 g Sr per dry-kg of thallus per day. Subcellular fractionation of B. maxima cells showed that most of the (85)Sr was localized in the soluble fraction, predominantly in the vacuole or cytosol. Given that (85)Sr radioactivity was permeable through a dialysis membrane, the (85)Sr was considered to be a form of inorganic ion and/or bound with a small molecule. Precipitation analysis with sodium sulfate showed that more than 70% of the Sr did not precipitate as SrSO4, indicating that a proportion of the Sr may bind with small molecules in B. maxima. PMID:25744028

  13. Direct evidence for coastal iodine particles from Laminaria macroalgae – linkage to emissions of molecular iodine

    Directory of Open Access Journals (Sweden)

    D. Wevill

    2004-02-01

    Full Text Available Renewal of ultrafine aerosols in the marine boundary layer may lead to repopulation of the marine distribution and ultimately determine the concentration of cloud condensation nuclei (CCN. Thus the formation of nanometre-scale particles can lead to enhanced scattering of incoming radiation and a net cooling of the atmosphere. The recent demonstration of the chamber formation of new particles from the photolytic production of condensable iodine-containing compounds from diiodomethane (CH2I2, (O'Dowd et al., 2002; Kolb, 2002; Jimenez et al., 2003a; Burkholder and Ravishankara, 2003, provides an additional mechanism to the gas-to-particle conversion of sulphuric acid formed in the photo-oxidation of dimethylsulphide for marine aerosol repopulation. CH2I2 is emitted from seaweeds (Carpenter et al., 1999, 2000 and has been suggested as an initiator of particle formation. We demonstrate here for the first time that ultrafine iodine-containing particles are produced by intertidal macroalgae exposed to ambient levels of ozone. The particle composition is very similar both to those formed in the chamber photo-oxidation of diiodomethane and in the oxidation of molecular iodine by ozone. The particles formed in all three systems are similarly aspherical and behave alike when exposed to increased humidity environments. Direct coastal boundary layer observations of molecular iodine, ultrafine particle production and iodocarbons are reported. Using a newly measured molecular iodine photolysis rate, it is shown that, if atomic iodine is involved in the observed particle bursts, it is of the order of at least 1000 times more likely to result from molecular iodine photolysis than diiodomethane photolysis. A hypothesis for molecular iodine release from intertidal macroalgae is presented and the potential importance of macroalgal iodine particles in their contribution to CCN and global radiative forcing are discussed.

  14. Emission of atmospherically significant halocarbons by naturally occurring and farmed tropical macroalgae

    Directory of Open Access Journals (Sweden)

    E. C. Leedham

    2013-01-01

    Full Text Available Current estimates of global halocarbon emissions highlight the tropical coastal environment as an important source of very short-lived (VSL biogenic halocarbons to the troposphere and stratosphere. This is due to a combination of assumed high primary productivity in tropical coastal waters and the prevalence of deep convective transport potentially capable of rapidly lifting surface emissions to the upper troposphere/lower stratosphere. However, despite this perceived importance direct measurements of tropical coastal biogenic halocarbon emissions, notably from macroalgae (seaweeds, have not been made. In light of this, we provide the first dedicated study of halocarbon production by a range of 15 common tropical macroalgal species and compare these results to those from previous studies of polar and temperate macroalgae. Variation between species was substantial; CHBr3 measured at the end of a 24 h incubation varied from 1.4 to 1129 pmol g FW−1 h−1 (FW = fresh weight of sample. We used our laboratory-determined emission rates to estimate emissions of CHBr3 and CH2Br2 (the two dominant VSL precursors of stratospheric bromine from the coastlines of Malaysia and South East Asia. We compare these values to previous top-down model estimates of emissions from these regions, and conclude that the contribution of coastal CHBr3 emissions is likely to be lower than previously assumed. The contribution of tropical aquaculture to current emission budgets is also considered. Whilst the current aquaculture contribution to halocarbon emissions in this regional is small, the potential exists for substantial increases in aquaculture to make a significant contribution to regional halocarbon budgets.

  15. Emission of atmospherically significant halocarbons by naturally occurring and farmed tropical macroalgae

    Directory of Open Access Journals (Sweden)

    E. C. Leedham

    2013-06-01

    Full Text Available Current estimates of global halocarbon emissions highlight the tropical coastal environment as an important source of very short-lived (VSL biogenic halocarbons to the troposphere and stratosphere, due to a combination of assumed high primary productivity in tropical coastal waters and the prevalence of deep convective transport, potentially capable of rapidly lifting surface emissions to the upper troposphere/lower stratosphere. However, despite this perceived importance, direct measurements of tropical coastal biogenic halocarbon emissions, notably from macroalgae (seaweeds, have not been made. In light of this, we provide the first dedicated study of halocarbon production by a range of 15 common tropical macroalgal species and compare these results to those from previous studies of polar and temperate macroalgae. Variation between species was substantial; CHBr3 production rates, measured at the end of a 24 h incubation, varied from 1.4 to 1129 pmol g FW−1 h−1 (FW = fresh weight of sample. We used our laboratory-determined emission rates to estimate emissions of CHBr3 and CH2Br2 (the two dominant VSL precursors of stratospheric bromine from the coastlines of Malaysia and elsewhere in South East Asia (SEA. We compare these values to previous top-down model estimates of emissions from these regions and, by using several emission scenarios, we calculate an annual CHBr3 emission of 40 (6–224 Mmol Br−1 yr, a value that is lower than previous estimates. The contribution of tropical aquaculture to current emission budgets is also considered. Whilst the current aquaculture contribution to halocarbon emissions in this regional is small, the potential exists for substantial increases in aquaculture to make a significant contribution to regional halocarbon budgets.

  16. Emission of atmospherically significant halocarbons by naturally occurring and farmed tropical macroalgae

    Science.gov (United States)

    Leedham, E. C.; Hughes, C.; Keng, F. S. L.; Phang, S.-M.; Malin, G.; Sturges, W. T.

    2013-06-01

    Current estimates of global halocarbon emissions highlight the tropical coastal environment as an important source of very short-lived (VSL) biogenic halocarbons to the troposphere and stratosphere, due to a combination of assumed high primary productivity in tropical coastal waters and the prevalence of deep convective transport, potentially capable of rapidly lifting surface emissions to the upper troposphere/lower stratosphere. However, despite this perceived importance, direct measurements of tropical coastal biogenic halocarbon emissions, notably from macroalgae (seaweeds), have not been made. In light of this, we provide the first dedicated study of halocarbon production by a range of 15 common tropical macroalgal species and compare these results to those from previous studies of polar and temperate macroalgae. Variation between species was substantial; CHBr3 production rates, measured at the end of a 24 h incubation, varied from 1.4 to 1129 pmol g FW-1 h-1 (FW = fresh weight of sample). We used our laboratory-determined emission rates to estimate emissions of CHBr3 and CH2Br2 (the two dominant VSL precursors of stratospheric bromine) from the coastlines of Malaysia and elsewhere in South East Asia (SEA). We compare these values to previous top-down model estimates of emissions from these regions and, by using several emission scenarios, we calculate an annual CHBr3 emission of 40 (6-224 Mmol Br-1 yr), a value that is lower than previous estimates. The contribution of tropical aquaculture to current emission budgets is also considered. Whilst the current aquaculture contribution to halocarbon emissions in this regional is small, the potential exists for substantial increases in aquaculture to make a significant contribution to regional halocarbon budgets.

  17. Antarctic terrestrial ecosystems: responses to environmental change

    OpenAIRE

    Convey, Peter

    2006-01-01

    The consequences of climate change are exciting considerable concern worldwide. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. This paper sets out to introduce contemporary ecosystems of the Antarctic, and the factors that have influenced them and their biodiversity over evolutionary timescales. Contemporary climate change processes significant to terrestrial biota, and the biological consequences of these changes seen t...

  18. Isotopic heterogeneity of East Antarctic mantle

    International Nuclear Information System (INIS)

    Isotopic heterogeneity of deep garnet-bearing mantle xenolytes of East Antarctics is studied to analyze the mechanisms of geochemical heterogeneity occurrence in the Earth mantle. Analysis of isotope data for the system 143Nd/144Nd - Sm/Nd permitted ascertaining the time of the last thermal impact on the mantle material (108-35 bill. years) for certain nodules, which is close to the age of ultra base alkali magmatism intrusion

  19. Photosynthesis in Antarctic sea ice diatoms

    OpenAIRE

    Mock, Thomas

    2003-01-01

    This thesis was conducted to apply new techniques for measuring photosynthesis in Antarctic sea ice diatoms. A systematic approach of investigations was applied to obtain precise measurements of photosynthesis under natural conditions in the field from which questions were derived for further analysis in the laboratory. In situ measurements with the tracer 14C through the entire thickness of a young sea ice floe revealed that algae are able to actively assimilate dissolved inorganic carbon un...

  20. Oil Pollution in the Antarctic Terrestrial Environment

    OpenAIRE

    Hughes, Kevin; Stallwood, Bethan

    2006-01-01

    Fuel oil has been extensively relied upon as an energy source since the earliest discovery and exploration of Antarctica. During this time oil spills have occurred, particularly around established research stations, which have had a negative impact on the terrestrial environment. Recently developed bioremediative technology, using indigenous Antarctic hydrocarbon-degrading bacteria, may be used to assist in cleaning up existing oil-contaminated land

  1. PSEUDO MAGNETIC ANOMALIES IN THE ANTARCTIC SEA

    OpenAIRE

    マツモト, タケシ; カミヌマ, カツタダ; Takeshi, MATSUMOTO; Katsutada, Kaminuma

    1988-01-01

    Pseudo magnetic anomaly in the Antarctic Sea has been calculated using the gravity data derived from altimetric geoid. Comparison of the pseudo magnetic anomaly thus calculated with the theoretical magnetic anomaly predicted from topography has been made with respect to the large fracture zones composed of short-wavelength ridges and troughs in the Southeastern Pacific, which shows that these two anomalies coincide well with each other. Gravity anomaly calculated from topography only also coi...

  2. Tephrochronology : Methodology and correlations, Antarctic Peninsula Area

    OpenAIRE

    Molén, Mats

    2012-01-01

    Abstract Methods for tephrochronology are evaluated, in the following way: Lake sediments <500 years old from three small Antarctic lakes were analysed for identification of tephras. Subsamples were analysed for a) grain size, and identification and concentration of volcanogenic grains, b) identification of tephra horizons, c) element abundance by EPMA WDS/EDS and LA-ICP-MS, and d) possible correlations between lakes and volcanoes. Volcanogenic minerals and shards were found all through th...

  3. New and rare cephalopods from the Antarctic waters

    OpenAIRE

    Kubodera,Tsunemi/Okutani,Takeshi

    1986-01-01

    Three species of Antarctic cephalopods, Grimpoteuthis antarctica n. sp., male specimens of Megaleledone senoi TAKI and Gonatus antarcticus LONNBERG are described with some considerations to their systematic status.

  4. On-site and in situ remediation technologies applicable to petroleum hydrocarbon contaminated sites in the Antarctic and Arctic

    Directory of Open Access Journals (Sweden)

    Danielle Camenzuli

    2015-09-01

    Full Text Available Petroleum hydrocarbon contaminated sites, associated with the contemporary and legacy effects of human activities, remain a serious environmental problem in the Antarctic and Arctic. The management of contaminated sites in these regions is often confounded by the logistical, environmental, legislative and financial challenges associated with operating in polar environments. In response to the need for efficient and safe methods for managing contaminated sites, several technologies have been adapted for on-site or in situ application in these regions. This article reviews six technologies which are currently being adapted or developed for the remediation of petroleum hydrocarbon contaminated sites in the Antarctic and Arctic. Bioremediation, landfarming, biopiles, phytoremediation, electrokinetic remediation and permeable reactive barriers are reviewed and discussed with respect to their advantages, limitations and potential for the long-term management of soil and groundwater contaminated with petroleum hydrocarbons in the Antarctic and Arctic. Although these technologies demonstrate potential for application in the Antarctic and Arctic, their effectiveness is dependent on site-specific factors including terrain, soil moisture and temperature, freeze–thaw processes and the indigenous microbial population. The importance of detailed site assessment prior to on-site or in situ implementation is emphasized, and it is argued that coupling of technologies represents one strategy for effective, long-term management of petroleum hydrocarbon contaminated sites in the Antarctic and Arctic.

  5. Measurements of 36Cl in Antarctic meteorites and Antarctic ice using a Van de Graaff accelerator

    International Nuclear Information System (INIS)

    Cosmic-ray produced 36Cl(tsub(1/2) = 3.0 X 105 years) has been measured in four Antarctic meteorites and one sample of Antarctic ice using a tandem Van de Graaff accelerator as an ultrasensitive mass spectrometer with the extremely low background level of 36Cl/Cl -16. Results from this ion counting technique (applied here to extraterrestrial materials for the first time) are used to support a two-stage irradiation model for the Yamato-7301and Allan Hills-76008 meteorites and to show a long terrestrial age (0.7 +- 0.1 m.y.) for Allan Hills-77002. Yamato-7304 has a terrestrial age of less than 0.1 m.y. The 36Cl content of the Antarctic ice sample from the Yamato Mountain area implies that the age of the ice cap at this site is less than one 36Cl half-life. (Auth.)

  6. Balance of the West Antarctic Ice Sheet

    Science.gov (United States)

    2002-01-01

    For several decades, measurements of the West Antarctic Ice Sheet showed it to be retreating rapidly. But new data derived from satellite-borne radar sensors show the ice sheet to be growing. Changing Antarctic ice sheets remains an area of high scientific interest, particularly in light of recent global warming concerns. These new findings are significant because scientists estimate that sea level would rise 5-6 meters (16-20 feet) if the ice sheet collapsed into the sea. Do these new measurements signal the end of the ice sheet's 10,000-year retreat? Or, are these new satellite data simply much more accurate than the sparse ice core and surface measurements that produced the previous estimates? Another possibility is that the ice accumulation may simply indicate that the ice sheet naturally expands and retreats in regular cycles. Cryologists will grapple with these questions, and many others, as they examine the new data. The image above depicts the region of West Antarctica where scientists measured ice speed. The fast-moving central ice streams are shown in red. Slower tributaries feeding the ice streams are shown in blue. Green areas depict slow-moving, stable areas. Thick black lines depict the areas that collect snowfall to feed their respective ice streams. Reference: Ian Joughin and Slawek Tulaczyk Science Jan 18 2002: 476-480. Image courtesy RADARSAT Antarctic Mapping Project

  7. Spatio-temporal distribution patterns of the invasive macroalga Sargassum muticum within a Danish Sargassum-bed

    DEFF Research Database (Denmark)

    Thomsen, M. S.; Wernberg, T.; Stæhr, P. A.;

    2006-01-01

    Sargassum muticum was first observed in Scandinavia in Limfjorden (Denmark) in 1984, where it is now the most abundant and conspicuous macroalga. Despite the ecological importance of Sargassum, few studies have described seasonal patterns within Scandinavian Sargassum beds. We quantified the dyna...... sediment stress limits Sargasum in shallow waters, and the presence of stable boulder substratum facilitate Sargassum. Competition for space from other macroalgae and herbivory are probably of minor importance....

  8. A spurious jump in the satellite record: is Antarctic sea ice really expanding?

    Directory of Open Access Journals (Sweden)

    I. Eisenman

    2014-01-01

    Full Text Available Recent estimates indicate that the Antarctic sea ice cover is expanding at a statistically significant rate with a magnitude one third as large as the rapid rate of sea ice retreat in the Arctic. However, during the mid-2000s, with several fewer years in the observational record, the trend in Antarctic sea ice extent was reported to be considerably smaller and statistically indistinguishable from zero. Here, we show that the increase in the reported trend occurred primarily due to the effect of a previously undocumented change in the way the satellite sea ice observations are processed for the widely-used Bootstrap algorithm dataset, rather than a physical increase in the rate of ice advance. Although our analysis does not definitively identify whether this undocumented change introduced an error or removed one, the resulting difference in the trends suggests that a substantial error exists in either the current dataset or the version that was used prior to the mid-2000s, and numerous studies that have relied on these observations should be reexamined to determine the sensitivity of their results to this change in the dataset. Furthermore, a number of recent studies have investigated physical mechanisms for the observed expansion of the Antarctic sea ice cover. The results of this analysis raise the possibility that this expansion may be a spurious artifact of an error in the satellite observations, and that the actual Antarctic sea ice cover may not be expanding at all.

  9. Phylogenetic analysis and in vitro culture of mosses from the Antarctic Fildes Peninsula

    Institute of Scientific and Technical Information of China (English)

    LIU Shenghao; ZHANG Zhaohui; WANG Nengfei; CONG Bailin; ZHANG Pengying; LIN Xuezheng; HUANG Xiaohang

    2014-01-01

    Molecular genetic techniques have proven very useful for initial analysis of the extent of genetic variation and dispersal in several Antarctic moss species. In the present study, the small subunit ribosomal RNA (SSU rDNA) and internal transcribed spacers of the nuclear ribosomal DNA (ITS rDNA) were sequenced in nine individuals of different mosses from the Fildes Peninsula of Antarctica. Sequence alignment showed that the extreme environment tended to increase the genetic diversity of Antarctic mosses. In addition, in our phylogenetic analysis, one previously unidentiifed Antarctic moss species was characterized by comparison with SSU and ITS rDNA sequences of known moss species. Moreover, the optimal culture medium and conditions for surface explant sterilization and protonemata induction in tissue culture of Pohlia nutans were investigated. The successful establishment of a tissue culture protocol together with the phylogenetic analysis of Antarctic mosses will provide technological support to establish an effective resource regeneration method for discovering new functional genes and gaining novel insights into the mechanisms of stress acclimation.

  10. Skip spawning as a reproductive strategy in Antarctic fish species: the Antarctic silverfish (Pleuragramma antarctica) case study

    OpenAIRE

    Eva Pisano; Stuart Hanchet; Marino Vacchi

    2015-01-01

    The Antarctic silverfish Pleuragramma antarctica (Notothenioidei, Nototheniidae) is the most abundant pelagic fish inhabiting the frigid Antarctic coastal waters. It plays relevant roles in the local ecosystems, where it is often considered a keystone species connecting lower and upper trophic levels within the coastal marine food web. Despite its ecological relevance, and although many aspects of the Antarctic silverfish biology have already been elucidated, knowledge on important components...

  11. Nuevos registros de macroalgas para el Atlántico mexicano y riqueza florística del Caribe mexicano New records of macroalgae for the Mexican Atlantic and floristic richness of the Mexican Caribbean

    Directory of Open Access Journals (Sweden)

    Neidy Pauline Cetz-Navarro

    2008-03-01

    Full Text Available Se revisaron muestras de macroalgas de un hábitat pocas veces analizado (colindante a la parte basal del tejido vivo de los corales Acropora palmata y Diploria strigosa y de una zona de México poco conocida florísticamente (parte Sur del Caribe mexicano, con base a lo cual se reporta a Corallophila verongiae (Rhodophyta, Derbesia fastigiata (Chlorophyta y Hincksia onslowensis (Phaeophyta como nuevos registros de macroalgas para la costa del Atlántico mexicano. Además, se reporta a Lophosiphonia obscura (Rhodophyta como nuevo registro para la parte costera continental del Atlántico mexicano, ya que sólo se había registrado hace más de 40 años para Arrecife Alacranes, sitio alejado aproximadamente 180 km al norte de Puerto Progreso, Yucatán. Aunque las especies de macroalgas no presentaron estructuras reproductoras, probablemente por tener crecimiento clonal y estar invadiendo tejido coralino, los caracteres morfológicos permitieron su identificación con certeza. Con excepción de la primera especie, las otras no se habían registrado creciendo sobre corales. Tomando en cuenta estos nuevos registros, el total de especies de macroalgas registradas hasta este estudio para el Caribe mexicano es de 546, incluyendo 307 Rhodophyta, 171 Chlorophyta y 68 Phaeophyta. Esta zona tropical y la costa templada de Baja California conforman las dos zonas florísticas marinas más ricas de México.Macroalgae samples from a habitat uncommonly analyzed (next to the basal part of live tissue of the corals Acropora palmata and Diploria strigosa, and from a Mexican zone barely known floristically (the southern part of the Mexican Caribbean were studied. Based on those samples, Corallophila verongiae (Rhodophyta, Derbesia fastigiata (Chlorophyta, and Hincksia onslowensis (Phaeophyta are recognized as new records for the Mexican Atlantic coast. Similarly, Lophosiphonia obscura (Rhodophyta is recognized as a new record for the continental coast of the Mexican

  12. The ARM West Antarctic Radiation Experiment (AWARE)

    Science.gov (United States)

    Lubin, Dan; Bromwich, David; Vogelmann, Andrew; Verlinde, Johannes; Russell, Lynn

    2016-04-01

    West Antarctica is one of the most rapidly warming regions on Earth, and its changing climate in both atmosphere and ocean is linked to loss of Antarctic ice mass and global sea level rise. The specific mechanisms for West Antarctic Ice Sheet (WAIS) warming are not fully understood, but are hypothesized to involve linkage between moisture from Southern Ocean storm tracks and the surface energy balance over the WAIS, and related teleconnections with subtropical and tropical meteorology. This present lack of understanding has motivated a climate science and cloud physics campaign jointly supported by the US National Science Foundation (NSF) and Department of Energy (DOE), called the Atmospheric Radiation Measurement Program (ARM) West Antarctic Radiation Experiment (AWARE). The DOE's second ARM Mobile Facility (AMF2) was deployed to McMurdo Station on Ross Island in November 2015 and will operate through December 2016. The AMF2 includes (1) cloud research radars, both scanning and zenith, operating in the Ka- and X-bands, (2) high spectral resolution and polarized micropulse lidars, and (3) a suite of shortwave and longwave broadband and spectral radiometers. A second suite of instruments is deployed at the WAIS Divide Ice Camp on the West Antarctic plateau during December 2015 and January 2016. The WAIS instrument suite provides (1) measurement of all surface energy balance components, (2) a polarized micropulse lidar and shortwave spectroradiometer, (3) microwave total water column measurement, and (4) four times daily rawinsonde launches which are the first from West Antarctica since 1967. There is a direct linkage between the WAIS instrument suite and the AMF2 at McMurdo, in that air masses originating in Southern Ocean storm tracks that are driven up over the WAIS often subsequently descend over the Ross Ice Shelf and arrive at Ross Island. Preliminary data are already illustrating the prevalence of mixed-phase clouds and their role in the surface energy balance

  13. Quality changes of Antarctic krill powder during long term storage

    DEFF Research Database (Denmark)

    Nielsen, Nina Skall; Lu, Henna Fung Sieng; Bruheim, Inge;

    2016-01-01

    Krill is a valuable sustainable resource of omega-3 fatty acids and protein, which may be processed into a krill powder for human consumption. The objective of this study was to investigate the stability of krill powder when stored for up to 12 months at room temperature. In addition, the effect...... and a concomitant decrease in antioxidants, tocopherol, and astaxanthin was observed. In addition, there was a minor decrease in phospholipids and n-3 fatty acids; however, storage at vacuum improved the oxidative stability of krill powder. Practical applications: For the use of krill powder in human nutrition......, it is important, that the quality and stability is sufficiently high to retain the nutritional value during storage. This study contributes with information about the stability during storage up to 12 months at room temperature and the effect of packaging the powder in vacuum. Antarctic krill (Euphausia superba...

  14. Geoethical Approach to Antarctic Subglacial Lakes Exploration

    Science.gov (United States)

    Talalay, Pavel; Markov, Alexey; Sysoev, Mikhail

    2014-05-01

    Antarctic subglacial aquatic environment have become of great interest to the science community because they may provide unique information about microbial evolution, the past climate of the Earth, and the formation of the Antarctic ice sheet. Nowadays it is generally recognized that a vast network of lakes, rivers, and streams exists thousands of meters beneath Antarctic Ice Sheets. Up to date only four boreholes accessed subglacial aquatic system but three of them were filled with high-toxic drilling fluid, and the subglacial water was contaminated. Two recent exploration programs proposed by UK and USA science communities anticipated direct access down to the lakes Ellsworth and Whillans, respectively, in the 2012/2013 Antarctic season. A team of British scientists and engineers engaged in the first attempt to drill into Lake Ellsworth but failed. US research team has successfully drilled through 800 m of Antarctic ice to reach a subglacial lake Whillans and retrieve water and sediment samples. Both activities used hot-water drilling technology to access lakes. Hot water is considered by the world science community as the most clean drilling fluid medium from the present point of view but it cannot solve environmental problems in total because hot-water even when heated to 90 °C, filtered to 0.2 μm, and UV treated at the surface could pick up microorganisms from near-surface snow and circulate them in great volume through the borehole. Another negative impact of hot-water circulation medium is thermal pollution of subglacial water. The new approach to Antarctic subglacial lakes exploration is presented by sampling technology with recoverable autonomous sonde which is equipped by two hot-points with heating elements located on the bottom and top sides of the sonde. All down-hole sonde components will be sterilized by combination of chemical wash, HPV and UV sterilization prior using. At the beginning of the summer season sonde is installed on the surface of the

  15. Effect of transglutaminase on yield of proteins extracted from whole Antarctic krill(Euphausia superba) by alkaline solubilization and acid precipitation method%谷氨酰胺转氨酶对碱溶酸沉法提取南极磷虾(Euphausia superba)蛋白质得率的影响

    Institute of Scientific and Technical Information of China (English)

    王灵昭; 薛长湖; 王玉明; 薛勇

    2012-01-01

    Alkaline solubilization and acid precipitation method was employed to extract proteins from whole Antarctic krill(Euphausia superba),and effect of transglutaminase on protein recovery yield was researched.Results indicated that the alkaline solubilization and acid precipitation method was good at recovering protein from whole Antarctic krill,and protein recovery yield was increased by approximate 5%,when transglutaminase was correctly applied during acid-induced protein precipitation.%通过碱溶酸沉法提取了南极磷虾蛋白质,研究了谷氨酰胺转氨酶的应用对蛋白质得率的影响。结果表明:碱溶酸沉法能够较好地回收南极磷虾蛋白质;在酸沉过程中,合理添加谷氨酰胺转氨酶能够提高蛋白质得率约5%。

  16. Yearly variation and annual cycle of total column ozone over New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), British Antarctic Survey Station and its effect on night airglow intensity of OH(8, 3) for the period 1979–2005

    Indian Academy of Sciences (India)

    P K Jana; D K Saha; D Sarkar

    2012-12-01

    A critical analysis made on the long-term monthly, seasonal, yearly variation and annual cycle of total column ozone (TCO) concentration at New Delhi (29°N,77°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station reveals more decline in yearly mean ozone concentration at Halley Bay than at New Delhi from 1979 to 2005. The nature of variations of monthly mean TCO during the months of August and September was the most identical with that of yearly mean ozone values at New Delhi and Halley Bay, respectively, for the same period. Annual cycles of TCO over these stations are completely different for the above period. The effect of O3 depletion on night airglow emission of OH(8, 3) line at New Delhi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of OH(8, 3) has also been affected due to the depletion of O3 concentration. The yearly variations and annual cycle of intensities of OH(8, 3) line for the above two stations are depicted and compared. It has been shown that the rate of decrease of intensity of OH(8, 3) line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O3 concentration.

  17. Growth and physiology of an industrially useful macroalga (Chondrus crispus), analyzed by continuous measurement of gas exchange

    International Nuclear Information System (INIS)

    A system has been developed for the continuous measurement of gas exchanges in an aquatic environment containing a liquid phase and a CO2-regulated gas phase, where the measurements take place. The method uses mass spectrometry and infrared analysis of CO2, the system being piloted in real time by a computer. New data on the behaviour of the carbonate system of water in the presence of photosynthetic or respiratory activities are presented. Evidence is obtained in particular of a strong resistance to CO2 diffusion and integration into the carbonate system in the replenishment of the HCO3- pool depleted by photosynthesis. This must be accounted for when calculating the photosynthesis or CO2 respiration rates. For the first time a photorespiration measurement is obtained on a macroalga by the 18O technique. Finally the influence of environmental parameters on the physiology and growth of an industrially useful macroalga, Chondrus crispus, is discussed

  18. Comparative Studies on Phosphorus Uptake and Growth Kinetics of the Microalga Tetraselmis subcordiformis and the Macroalga Ulva pertusa

    Institute of Scientific and Technical Information of China (English)

    NAN Chunrong; DONG Shuanglin

    2004-01-01

    Short-term uptake experiments and long-term semicontinuous culture experiments were performed under the condition of phosphorus (P) limitation to estimate and compare the P uptake and growth kinetics of the microalga Tetraselmis subcordiformis and the macroalga Ulva pertusa. Two new parameters, the maximum specific uptake rate (Vspm) and the maximal growth efficiency (β), are introduced to achieve uniformity for the comparison of nutrient uptake and growth efficiency between microalgae and macroalgae. T. subcordiformis possesses 3 times lower half saturation uptake constant, 4 times higher maximal growth rate and 20 times higher maximum specific uptake rate than U. pertusa, while U. pertusa possesses 4 times higher maximal growth efficiency than T. subcordiformis.

  19. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

    Directory of Open Access Journals (Sweden)

    R. S. Humphries

    2015-10-01

    Full Text Available The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3 concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol

  20. Persistent organochlorines in high-Antarctic fish; Persistente chlororganische Verbindungen in hochantarktischen Fischen

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, S.

    1997-11-01

    24 chlorinated hydrocarbons from different classes (PCB, HCH, DDT, Chlordane, Hexachlorobenzene and Octachlorostyrene) were analyzed in four species of high-Antarctic fish (Aethotaxis mitopteryx, Pleuragramma antarcticum, Trematomus lepidorhinus, and Chinodraco myersi). The concentrations were in the order of 1 {mu}g/kg wet weight or 10 {mu}g/kg lipid weight, respectively. Highest concentrations were measured for HCB in all species. The species showed different distribution patterns for the organochlorines studied. Compared with concentrations in fish from other regions the organochlorine levels measured in Antarctic fish are rather low. It is unlikely that the burden of organochlorines will cause any toxic effects in high-Antarctic fish yet. Nevertheless, with regard to the sensitive Antarctic ecosystem, even small concentrations carry a high risk of harm for Antarctic life. Environmental pollution in Antarctica should be observed with a monitoring program using standardized methods. For this purpose, the fish species studied are very useful as bioindicators for organochlorine contamination. (orig.) [Deutsch] 24 persistente Chlorkohlenwasserstoffe verschiedener Schadstoffgruppen (PCB, HCH, DDT, Chlordan, Hexachlorbenzol und Octachlorstyrol) wurden in vier hochantarktischen Fischarten (Aethotaxis mitopteryx, Pleuragramma antarcticum, Trematomus lepidorhinus und Chionodraco myersi). Die Konzentrationen der nachgewiesenen Schadstoffe im Ganzfisch liegen jeweils in der Groessenordnung von 1 {mu}g/kg Feuchtgewicht bzw. 10 {mu}g/kg Lipidgewicht mit erheblichen Schwankungen je nach Schadstoff und Art. Die Spezies zeigen artspezifische Schadstoffverteilungsmuster. Die Konzentrationen sind gegenueber denen in Fischen aus Gebieten mit staerkerem zivilisatorischem Einfluss eher niedrig. Die Fremstoffbelastungen der hochantarktischen Fische fuehren wahrscheinlich noch nicht zu messbaren toxischen Effekten bei den Fischen. Dennoch geht von den Schadstoffen in Hinblick auf das

  1. Wind profile radar for study of Antarctic air circulation. Progetto di un radar 'wind-profiler' per lo studio della circolazione atmosferica antartica

    Energy Technology Data Exchange (ETDEWEB)

    Ragaini, E.; Sarango, M.F.; Vasquez, E.H.

    1992-10-01

    After a brief discussion of meteorological methods used in the Antarctic, the paper gives an outline of a coordinated international research project whose objective is to set up a wind profiler radar station that would give meteorologists information regarding Antarctic atmospheric dynamics useful in their investigation of the causes and effects of the hole in the ozone layer. The radar instrumentation is to provide continuous readings of wind velocity at varying altitudes above the polar continent.

  2. Conventional and microwave pyrolysis of a macroalgae waste from the Agar–Agar industry. Prospects for bio-fuel production

    OpenAIRE

    Ferrera Lorenzo, Nuria; Fuente Alonso, Enrique; Bermúdez Menéndez, José Miguel; Suárez Ruiz, Isabel; Ruiz Bobes, Begoña

    2013-01-01

    [EN] A comparative study of the pyrolysis of a macroalgae industrial solid waste (algae meal) in an electrical conventional furnace and in a microwave furnace has been carried out. It was found that the chars obtained from both pyrolyses are similar and show good properties for performing as a solid bio-fuel and as a precursor of activated carbon. Bio-oils from conventional pyrolysis have a greater number of phenolic, pyrrole and alkane compounds whereas benzene and pyridine compounds are mor...

  3. Impact of sewage on the distribution, abundance and community structure of rocky intertidal macroalgae of the Colaba Coast, Mumbai, India

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Komarpant, D.S.

    complex mixture of nitrogenous compounds, ortho-phosphates, synthetic detergents, trace metals, residual chlorine, hydrocarbon, microorganisms and organic particulate (Andrews, 1976; Doblin and Clayton, 1995). All these compounds can have deleterious... were classified based on thallus morphology as sheet forming, filamentous, coarsely branched and calcareous forms. The significant contribution to macroalgal biomass at T1 and T3 was from coarsely branched macroalgae such as, Caulerpa spp., Laurencia...

  4. Comparison of ecological diversity and species composition of macroalgae, benthic macroinvertebrates, and fish assemblages between two tropical rocky reefs

    OpenAIRE

    Verónica C. García-Hernández; Héctor Reyes-Bonilla; Balart, Eduardo F; Eduardo Ríos-Jara; Lluch-Cota, Salvador E.; Elisa Serviere-Zaragoza

    2014-01-01

    Within the marine environment, the rocky shores are recognized for their high species diversity and particularly transitional zones represent areas of biotic mix, promoted by historical and ecological natural variations that allow the presence of taxa from different regions and which present dissimilar biological traits. An extensive survey describes the benthic macroalgae, macroinvertebrates (molluscs, crustaceans, and echinoderms), and fish assemblages at two rocky reefs, Islas Marietas and...

  5. Lipid content and fatty acid composition of Mediterranean macro-algae as dynamic factors for biodiesel production

    OpenAIRE

    Dahlia M. El Maghraby; Eman M. Fakhry

    2015-01-01

    Using the total lipid contents and fatty acid profiles, the marine macro-algae Jania rubens (Rhodophyceae), Ulva linza (Chlorophyceae) and Padina pavonica (Phaeophyceae) were evaluated for biodiesel production during the spring, summer and autumn. Seawater parameters such as pH, salinity and temperature were measured. The total lipid content varied from 1.56% (J. rubens) to 4.14% (U. linza) of dry weight, with the highest values occurring in spring. The fatty acid methyl ester profiles were a...

  6. 77 FR 5403 - Conservation of Antarctic Animals and Plants

    Science.gov (United States)

    2012-02-03

    ... From the Federal Register Online via the Government Publishing Office NATIONAL SCIENCE FOUNDATION 45 CFR Part 670 Conservation of Antarctic Animals and Plants AGENCY: National Science Foundation. ACTION: Final rule. SUMMARY: Pursuant to the Antarctic Conservation Act of 1978, The National...

  7. Biological studies in the Antarctic waters: A review

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.

    stream_size 12 stream_content_type text/plain stream_name Proc_Workshop_Antarct_Stud_1990_407.pdf.txt stream_source_info Proc_Workshop_Antarct_Stud_1990_407.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO...

  8. Laboratory study of nitrate photolysis in Antarctic snow

    DEFF Research Database (Denmark)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph;

    2014-01-01

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [" Laboratory study of nitrate photolysis in Antarc...... reproduce the stable isotopic composition of nitrate found in Antarctic snow profiles. © 2014 Author(s)....

  9. Altered developmental timing in early life stages of Antarctic krill (Euphausia superba) exposed to p,p'-DDE

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, Anita H., E-mail: anita.poulsen@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Rd, Brisbane, Qld 4108 (Australia); Kawaguchi, So, E-mail: so.kawaguchi@aad.gov.au [Australian Antarctic Division, Channel Highway, Kingston, Tas 7050 (Australia); Leppaenen, Matti T., E-mail: matti.t.leppanen@uef.fi [University of Eastern Finland, Joensuu Campus, Department of Biology, FIN-80101 (Finland); Kukkonen, Jussi V.K., E-mail: jussi.kukkonen@uef.fi [University of Eastern Finland, Joensuu Campus, Department of Biology, FIN-80101 (Finland); Bengtson Nash, Susan M., E-mail: s.bengtsonnash@griffith.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Rd, Brisbane, Qld 4108 (Australia); Griffith University, Atmospheric Environment Research Centre, Brisbane, Qld 4111 (Australia)

    2011-11-15

    Persistent organic pollutants (POPs) are persistent, toxic and bioaccumulative anthropogenic organic chemicals, capable of undergoing long range environmental transport to remote areas including the Antarctic. p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE) has been identified as a dominant POP accumulating in Antarctic krill (Euphausia superba), which is a key Southern Ocean species. This study examined the developmental toxicity of p,p'-DDE via aqueous exposure to Antarctic krill larvae. p,p'-DDE exposure was found to stimulate developmental timing in the first three larval stages of Antarctic krill, while extended monitoring of larvae after a five day exposure period had ended, revealed delayed inhibitory responses during development to the fourth larval stage. Stimulatory responses were observed from the lowest p,p'-DDE body residue tested of 10.1 {+-} 3.0 {mu}mol/kg (3.2 {+-} 0.95 mg/kg) preserved wet weight, which is comparable to findings for temperate species and an order of magnitude lower than the exposure level found to cause sublethal behavioural effects in Antarctic krill. The delayed responses included increased mortality, which had doubled in the highest p,p'-DDE treatment (95 {+-} 8.9% mortality at 20 {mu}g/L p,p'-DDE) compared to the solvent control (44 {+-} 11% mortality) 2 weeks after end of exposure. Development of surviving metanauplius larvae to calyptopis 1 larvae was delayed by 2 days in p,p'-DDE exposed larvae compared with untreated larvae. Finally, the developmental success of surviving p,p'-DDE exposed larvae was reduced by 50 to 75% compared to the solvent control (100% developmental success). The lowest observed effect concentration for all delayed effects was 1 {mu}g/L, the lowest exposure concentration tested. These findings demonstrate the importance of delayed and indirect effects of toxicant exposure. Further, the findings of this study are important for environmental risk assessment

  10. Altered developmental timing in early life stages of Antarctic krill (Euphausia superba) exposed to p,p'-DDE

    International Nuclear Information System (INIS)

    Persistent organic pollutants (POPs) are persistent, toxic and bioaccumulative anthropogenic organic chemicals, capable of undergoing long range environmental transport to remote areas including the Antarctic. p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE) has been identified as a dominant POP accumulating in Antarctic krill (Euphausia superba), which is a key Southern Ocean species. This study examined the developmental toxicity of p,p'-DDE via aqueous exposure to Antarctic krill larvae. p,p'-DDE exposure was found to stimulate developmental timing in the first three larval stages of Antarctic krill, while extended monitoring of larvae after a five day exposure period had ended, revealed delayed inhibitory responses during development to the fourth larval stage. Stimulatory responses were observed from the lowest p,p'-DDE body residue tested of 10.1 ± 3.0 μmol/kg (3.2 ± 0.95 mg/kg) preserved wet weight, which is comparable to findings for temperate species and an order of magnitude lower than the exposure level found to cause sublethal behavioural effects in Antarctic krill. The delayed responses included increased mortality, which had doubled in the highest p,p'-DDE treatment (95 ± 8.9% mortality at 20 μg/L p,p'-DDE) compared to the solvent control (44 ± 11% mortality) 2 weeks after end of exposure. Development of surviving metanauplius larvae to calyptopis 1 larvae was delayed by 2 days in p,p'-DDE exposed larvae compared with untreated larvae. Finally, the developmental success of surviving p,p'-DDE exposed larvae was reduced by 50 to 75% compared to the solvent control (100% developmental success). The lowest observed effect concentration for all delayed effects was 1 μg/L, the lowest exposure concentration tested. These findings demonstrate the importance of delayed and indirect effects of toxicant exposure. Further, the findings of this study are important for environmental risk assessment of POPs in the Southern Ocean ecosystem and strongly

  11. How much snow falls on the Antarctic ice sheet?

    Directory of Open Access Journals (Sweden)

    C. Palerme

    2014-02-01

    Full Text Available Climate models predict Antarctic precipitation to increase during the 21st century, but their present day Antarctic precipitation differs. A fully model-independent climatology of the Antarctic precipitation characteristics, such as snowfall rates and frequency, is needed to assess the models, but was not available so far. Satellite observation of precipitation by active spaceborne sensors has been possible in the polar regions since the launch of CloudSat in 2006. Here we use CloudSat products to build the first multi-year model-independent climatology of Antarctic precipitation. The mean snowfall rate from August 2006 to April 2011 is 171 mm yr−1 over the Antarctic ice sheet north of 82° S. The ECMWF ERA Interim dataset agrees well with the new satellite climatology.

  12. Variability of Antarctic Sea Ice 1979-1998

    Science.gov (United States)

    Zwally, H. Jay; Comiso, Josefino C.; Parkinson, Claire L.; Cavalieri, Donald J.; Gloersen, Per; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    The principal characteristics of the variability of Antarctic sea ice cover as previously described from satellite passive-microwave observations are also evident in a systematically-calibrated and analyzed data set for 20.2 years (1979-1998). The total Antarctic sea ice extent (concentration > 15 %) increased by 13,440 +/- 4180 sq km/year (+1.18 +/- 0.37%/decade). The area of sea ice within the extent boundary increased by 16,960 +/- 3,840 sq km/year (+1.96 +/- 0.44%/decade). Regionally, the trends in extent are positive in the Weddell Sea (1.5 +/- 0.9%/decade), Pacific Ocean (2.4 +/- 1.4%/decade), and Ross (6.9 +/- 1.1 %/decade) sectors, slightly negative in the Indian Ocean (-1.5 +/- 1.8%/decade, and strongly negative in the Bellingshausen-Amundsen Seas sector (-9.5 +/- 1.5%/decade). For the entire ice pack, small ice increases occur in all seasons with the largest increase during autumn. On a regional basis, the trends differ season to season. During summer and fall, the trends are positive or near zero in all sectors except the Bellingshausen-Amundsen Seas sector. During winter and spring, the trends are negative or near zero in all sectors except the Ross Sea, which has positive trends in all seasons. Components of interannual variability with periods of about 3 to 5 years are regionally large, but tend to counterbalance each other in the total ice pack. The interannual variability of the annual mean sea-ice extent is only 1.6% overall, compared to 5% to 9% in each of five regional sectors. Analysis of the relation between regional sea ice extents and spatially-averaged surface temperatures over the ice pack gives an overall sensitivity between winter ice cover and temperature of -0.7% change in sea ice extent per K. For summer, some regional ice extents vary positively with temperature and others negatively. The observed increase in Antarctic sea ice cover is counter to the observed decreases in the Arctic. It is also qualitatively consistent with the

  13. Emerging spatial patterns in Antarctic prokaryotes

    Directory of Open Access Journals (Sweden)

    Chun Wie eChong

    2015-09-01

    Full Text Available Recent advances in knowledge of patterns of biogeography in terrestrial eukaryotic organisms have led to a fundamental paradigm shift in understanding of the controls and history of life on land in Antarctica, and its interactions over the long term with the glaciological and geological processes that have shaped the continent. However, while it has long been recognized that the terrestrial ecosystems of Antarctica are dominated by microbes and their processes, knowledge of microbial diversity and distributions has lagged far behind that of the macroscopic eukaryote organisms. Increasing human contact with and activity in the continent is leading to risks of biological contamination and change in a region whose isolation has protected it for millions of years at least; these risks may be particularly acute for microbial communities which have, as yet, received scant recognition and attention. Even a matter apparently as straightforward as Protected Area designation in Antarctica requires robust biodiversity data which, in most parts of the continent, remain almost completely unavailable. A range of important contributing factors mean that it is now timely to reconsider the state of knowledge of Antarctic terrestrial prokaryotes. Rapid advances in molecular biological approaches are increasingly demonstrating that bacterial diversity in Antarctica may be far greater than previously thought, and that there is overlap in the environmental controls affecting both Antarctic prokaryotic and eukaryotic communities. Bacterial dispersal mechanisms and colonization patterns remain largely unaddressed, although evidence for regional evolutionary differentiation is rapidly accruing and, with this, there is increasing appreciation of patterns in regional bacterial biogeography in this large part of the globe. In this review, we set out to describe the state of knowledge of Antarctic prokaryote diversity patterns, drawing analogy with those of eukaryote

  14. Effects of Antarctic krill paste on volatile flavor components of marine surimi seafood%南极磷虾肉糜对海水鱼糜制品挥发性风味成分的影响

    Institute of Scientific and Technical Information of China (English)

    丁浩宸; 李栋芳; 张燕平; 戴志远; 许刚

    2015-01-01

    将南极磷虾肉糜分别添加到3种海水鱼糜(白姑鱼糜、带鱼糜和杂鱼糜)中制成复合鱼糜制品;采用顶空固相微萃取-气质联用(HS-SPME-GC-MS)技术结合相对气味活度值(ROAV)法,分析磷虾糜添加对海水鱼糜制品挥发性风味成分的影响.添加磷虾糜能增加鱼糜制品中挥发性成分的种类;磷虾糜中低感觉阈值的醛类和含硫化合物则能改变鱼糜制品的关键风味成分.白姑鱼糜制品中ROAV>10的关键风味成分为(E,Z)-2,6-壬二烯醛、癸醛和辛醛;而来源于磷虾糜的二甲基三硫醚和3-甲基丁醛在磷虾糜-白姑鱼糜复合鱼糜制品中的ROAV分别达到97.30和25.95,对复合鱼糜制品的整体风味贡献巨大.磷虾糜和不同海水鱼糜复合加工成的复合鱼糜制品均以虾香、甜香味为主,且具有相似的关键风味成分组成;(E,Z)-2,6-壬二烯醛、二甲基三硫醚、癸醛和3-甲基丁醛是3种复合鱼糜制品共有的特征性风味成分.%Three composite surimi seafoods were prepared with frozen marine surimi (respectively with white crodrer surimi,hairtail surimi and mix surimi) as raw material and Antarctic krill paste as auxiliary material.The volatile flavor components of samples were determined by HS-SPME-GC-MS.The effects of krill paste addition on the volatile flavor components of surimi seafoods were analyzed with ROAV.Krill paste addition could increase the amount of volatile flavor component of surimi seafoods.Furthermore,key odor components of surimi seafoods could be changed by low threshold volatile components (i.e.aldehydes and sulfur compounds) of krill paste.(E,Z)-2,6-nonadienal,decanal and octanal were the key odor components (ROAV > 10) of white crodrer surimi seafood.However,the ROAVs of dimethyl trisulfide and 3-methyl butanal,originated from krill paste,reached to 97.30 and 25.95 respectively in composite (krill paste-white crodrer surimi) surimi seafood.Therefore,the krill paste addition could

  15. Assessing environmental conditions of Antarctic footpaths to support management decisions.

    Science.gov (United States)

    Tejedo, Pablo; Benayas, Javier; Cajiao, Daniela; Albertos, Belén; Lara, Francisco; Pertierra, Luis R; Andrés-Abellán, Manuela; Wic, Consuelo; Luciáñez, Maria José; Enríquez, Natalia; Justel, Ana; Reck, Günther K

    2016-07-15

    Thousands of tourists visit certain Antarctic sites each year, generating a wide variety of environmental impacts. Scientific knowledge of human activities and their impacts can help in the effective design of management measures and impact mitigation. We present a case study from Barrientos Island in which a management measure was originally put in place with the goal of minimizing environmental impacts but resulted in new undesired impacts. Two alternative footpaths used by tourist groups were compared. Both affected extensive moss carpets that cover the middle part of the island and that are very vulnerable to trampling. The first path has been used by tourists and scientists since over a decade and is a marked route that is clearly visible. The second one was created more recently. Several physical and biological indicators were measured in order to assess the environmental conditions for both paths. Some physical variables related to human impact were lower for the first path (e.g. soil penetration resistance and secondary treads), while other biochemical and microbiological variables were higher for the second path (e.g. β-glucosidase and phosphatase activities, soil respiration). Moss communities located along the new path were also more diverse and sensitive to trampling. Soil biota (Collembola) was also more abundant and richer. These data indicate that the decision to adopt the second path did not lead to the reduction of environmental impacts as this path runs over a more vulnerable area with more outstanding biological features (e.g. microbiota activity, flora and soil fauna diversity). In addition, the adoption of a new route effectively doubles the human footprint on the island. We propose using only the original path that is less vulnerable to the impacts of trampling. Finally from this process, we identify several key issues that may be taken into account when carrying out impact assessment and environmental management decision-making in the

  16. Fast recession of a West Antarctic glacier

    OpenAIRE

    Rignot, EJ

    1998-01-01

    Satellite radar interferometry observations of Pine Island Glacier, West Antarctica, reveal that the glacier hinge-line position retreated 1.2 ± 0.3 kilometers per year between 1992 and 1996, which in turn implies that the ice thinned by 3.5 ± 0.9 meters per year. The fast recession of Pine Island Glacier, predicted to be a possible trigger for the disintegration of the West Antarctic Ice Sheet, is attributed to enhanced basal melting of the glacier floating tongue by warm ocean waters.

  17. Automatic focusing system of BSST in Antarctic

    Science.gov (United States)

    Tang, Peng-Yi; Liu, Jia-Jing; Zhang, Guang-yu; Wang, Jian

    2015-10-01

    Automatic focusing (AF) technology plays an important role in modern astronomical telescopes. Based on the focusing requirement of BSST (Bright Star Survey Telescope) in Antarctic, an AF system is set up. In this design, functions in OpenCV is used to find stars, the algorithm of area, HFD or FWHM are used to degree the focus metric by choosing. Curve fitting method is used to find focus position as the method of camera moving. All these design are suitable for unattended small telescope.

  18. Spread of Alsidium corallinum C. Ag. in a Tyrrhenian eutrophic lagoon dominated by opportunistic macroalgae

    International Nuclear Information System (INIS)

    Highlights: ► In 2007, Alsidium corallinum bloomed in Orbetello lagoon replacing other macroalgae. ► The main cause hypothesized was a transient low eutrophic level of the ecosystem. ► The results showed unusually low dissolved nitrogen in 2007. ► Dissolved N:P atomic ratio was much lower in 2007 than in the past and 2008. ► The observations suggest that the cycle of sediment OM determines vegetation cycles. - Abstract: In 2007, the Rhodophyceae Alsidium corallinum C. Ag., a marine taxon, bloomed in the eutrophic lagoon of Orbetello (Tuscany, Italy) for the first time, becoming the dominant species in spring and summer. In November, its biomass collapsed. The hypothesis examined in this study is that the bloom expressed a relatively low eutrophic level of the ecosystem after intense disposal of accumulated sedimentary organic matter (OM) by dystrophic processes in the two years preceding the bloom. To verify the hypothesis, we compared water physical–chemical variables, sediment redox (Eh) and OM, and standing crops of macroalgae and seagrass from the database of routine monitoring between 2005 and 2008. We also used dissolved nutrient data obtained in 2007 and 2008, as well as data on chlorophyll and total suspended matter in the water column during the microalgal bloom of 2007, and C, N and P content in thalli of the Chlorophycea Chaetomorpha linum and the Rhodophyceae Gracilariopsis longissima and A. corallinum obtained in 2007. In 2007, unusually low values of dissolved inorganic nitrogen (DIN) were recorded. Combined with stable values of soluble reactive phosphorus (SRPs), low DIN led to a reduction of about one order of magnitude in the DIN:SRP atomic ratio with respect to the past and to 2008. G. longissima accumulated C, N and P more than the other species and A. corallinum proved to be less demanding. Sediment OM was lower in the autumn of years characterized by dystrophy, confirming that summer dystrophic events coincided with maximum energy

  19. Direct evidence for coastal iodine particles from Laminaria macroalgae – linkage to emissions of molecular iodine

    Directory of Open Access Journals (Sweden)

    G. McFiggans

    2004-01-01

    Full Text Available Renewal of ultrafine aerosols in the marine boundary layer may lead to repopulation of the marine distribution and ultimately determine the concentration of cloud condensation nuclei (CCN. Thus the formation of nanometre-scale particles can lead to enhanced scattering of incoming radiation and a net cooling of the atmosphere. The recent demonstration of the chamber formation of new particles from the photolytic production of condensable iodine-containing compounds from diiodomethane (CH2I2, (O'Dowd et al., 2002; Kolb, 2002; Jimenez et al., 2003a; Burkholder and Ravishankara, 2003, provides an additional mechanism to the gas-to-particle conversion of sulphuric acid formed in the photo-oxidation of dimethylsulphide for marine aerosol repopulation. CH2I2 is emitted from seaweeds (Carpenter et al., 1999, 2000 and has been suggested as an initiator of particle formation. We demonstrate here for the first time that ultrafine iodine-containing particles are produced by intertidal macroalgae exposed to ambient levels of ozone. The particle composition is very similar both to those formed in the chamber photo-oxidation of diiodomethane and in the oxidation of molecular iodine by ozone. The particles formed in all three systems are similarly aspherical. When small, those formed in the molecular iodine system swell only moderately when exposed to increased humidity environments, and swell progressively less with increasing size; this behaviour occurs whether they are formed in dry or humid environments, in contrast to those in the CH2I2 system. Direct coastal boundary layer observations of molecular iodine, ultrafine particle production and iodocarbons are reported. Using a newly measured molecular iodine photolysis rate, it is shown that, if atomic iodine is involved in the observed particle bursts, it is of the order of at least 1000 times more likely to result from molecular iodine photolysis than diiodomethane photolysis. A hypothesis for molecular

  20. Macroalgas marinas afectadas por flotas de arrastre de camarón en el Mar Caribe de Colombia

    Directory of Open Access Journals (Sweden)

    Duarte Luis O.

    2005-12-01

    Full Text Available La captura acompañante, es decir, individuos que sin ser objetivo de las pesquerías son capturados por las artes de pesca, se ha convertido en un tema de preocupación mundial debido al impacto que su extracción significa para los ecosistemas. En el mar Caribe de Colombia opera una flota de pesca de arrastre dirigida al camarón que registra elevados niveles de captura acompañante. Las evaluaciones de las capturas de esta flota se han concentrado en las especies de peces principalmente y de invertebrados en menor grado, pero en la actualidad no existe un estudio que evalúe la composición taxonómica y brinde indicios sobre el efecto que tienen la pesca de arrastre en las comunidades de macroalgas, a pesar de que estas comunidades juegan un rol importante en la estructura y complejidad de los ecosistemas. Este estudio evaluó la composición taxonómica y biomasa de macroalgas registrada en muestreos a bordo de las flotas de arrastre de camarón en las zonas de pesca ubicadas al norte y sur del mar Caribe colombiano durante los meses de agosto, septiembre y octubre de 2004. Se obtuvo un total de 15 taxa de macroalgas en las dos zonas de pesca. El género más frecuente fue Sargassum, lo cual puede deberse a que su estrategia de vida pelágica y bentónica lo hace más vulnerable a la acción de las redes en los fondos. Las abundancias de algas fueron muy similares
    en ambas sitios de estudio. La biomasa de macroalgas registradas en cada lance fue mucho menor que la registrada de camarones y descartes. La evidencia que presenta este estudio sobre la existencia de macroalgas en la captura acompañante de la flota de arrastre de camarón y la acción prolongada de esta pesquería en el mar Caribe de Colombia, indican que es urgente implementar modificaciones en las redes para disminuir su efecto abrasivo sobre los fondos.

  1. A novel marine algal toxicity bioassay based on sporulation inhibition in the green macroalga Ulva pertusa (Chlorophyta)

    International Nuclear Information System (INIS)

    A 5-day aquatic toxicity test based on sporulation inhibition of the green macroalga Ulva pertusa Kjellman has been developed. Optimal test conditions determined for photon irradiance, salinity and temperature were 60-200 μmol photons m-2 s-1, 25-35%o and 15-20 deg C, respectively. Tests were conducted by exposing U. pertusa thallus disks to a reference toxicant (sodium dodecyl sulfate; SDS), metals (Cd2+, Cu2+, Zn2+, Pb2+) and elutriates of sludge collected from nine different locations. The EC50 values for SDS was 5.35 mg L-1. When four heavy metals were assayed, the NOECs were highest for lead (0.625 mg L-1) and lowest for copper (0.031 mg L-1). The EC50 values showed the following toxicity rankings: Cu2+ (0.061 mg L-1) > Cd2+ (0.326 mg L-1) > Zn2+ (0.738 mg L-1) > Pb2+ (0.877 mg L-1). The bioassay indicated also that the sporulation endpoint could be a sensitive indicator of toxicity effects of elutriates of sludge as reflected from the NOEC values equal to or lower than the lowest concentration employed (6.25%). Sporulation was significantly inhibitied in all elutriates with the greatest and least effects observed in elutriates of sludge from industrial waste (EC50 6.78%) and filtration bed (EC50 15.0%), respectively. The results of the Spearman rank correlation analysis for EC50 data versus the concentrations of toxicants in the sludge presented a significant correlation between toxicity and four heavy metals (Cd2+, Cu2+, Pb2+, Zn2+). Introduction of the concept of toxicity unit (TU) showed that these metals were the main cause of toxicity in elutriates of at least four out of nine sludge samples. Members of the order Ulvales show a wide geographic distribution and have similar reproductive characteristics, thus making it possible to apply the present test method to other algae of this taxa, elsewhere. This novel method will be a useful tool for assessing the aquatic toxicity of a wide range of toxicants, once the respective sensitivities are demonstrated

  2. Antarctic Harsh Environment as Natural Stress Model: Impact on Salivary Immunoglobulins, Transforming Growth Factor-β and Cortisol Level

    OpenAIRE

    Mishra, K. P.; Yadav, A.P.; Ganju, Lilly

    2012-01-01

    The Antarctic continent on the planet Earth is full of environmental extremes. It is considered as natural stress model. Therefore, the present study examined the effect of harsh environment on the certain salivary markers of 28th Indian Antarctic expeditioners. Thirty healthy men and women (median age 36 year; range 22–61 year) participated in this study. Parameters measured were salivary IgA (SIgA), IgM (SIgM), TGF-β and cortisol level at three different time points: (I) before leaving Indi...

  3. Longitudinal surface structures (flowstripes on Antarctic glaciers

    Directory of Open Access Journals (Sweden)

    N. F. Glasser

    2011-11-01

    Full Text Available Longitudinal surface structures (''flowstripes'' are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems (the Lambert Glacier/Amery Ice Shelf area, outlet glaciers in the Ross Sea sector, ice-shelf tributary glaciers on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1 as relatively wide flow stripes within glacier flow units and (2 as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

  4. Interhemispheric coupling and warm Antarctic interglacials

    Directory of Open Access Journals (Sweden)

    P. B. Holden

    2009-12-01

    Full Text Available Ice core evidence indicates that even though atmospheric CO2 concentrations did not exceed ~300 ppm at any point during the last 800 000 years, East Antarctica was at least ~3–4 °C warmer than pre-industrial (CO2 ~280 ppm in each of the last four interglacials. During the previous three interglacials, this anomalous warming was short lived (~3 000 years and apparently occurred before the completion of Northern Hemisphere deglaciation. Hereafter, we refer to these periods as "Warmer than Present Transients" (WPTs. We here present transient 800 kyr simulations using the intermediate complexity model GENIE-1 which suggest that WPTs could be explained as a consequence of the meltwater-forced slowdown of the Atlantic Meridional Overturning Circulation (AMOC during glacial terminations. It is well known that a slowed AMOC would increase southern Sea Surface Temperature (SST through the bipolar seesaw. Observational data supports this hypothesis, suggesting that the AMOC remained weak throughout the terminations preceding WPTs, strengthening rapidly at a time which coincides closely with peak Antarctic temperature. In order to investigate model and boundary condition uncertainty, we additionally present three ensembles of transient GENIE-1 simulations across Termination II (135 000 to 124 000 BP and three snapshot HadCM3 simulations at 130 000 Before Present (BP. These simulations together reproduce both the timing and magnitude of WPTs, and point to the potential importance of an albedo feedback associated with West Antarctic Ice Sheet (WAIS retreat.

  5. Solar power for an Antarctic rover

    Science.gov (United States)

    Lever, J. H.; Ray, L. R.; Streeter, A.; Price, A.

    2006-03-01

    Sensors mounted on mobile robots could serve a variety of science missions in Antarctica. Although weather conditions can be harsh, Antarctic snowfields offer unique conditions to facilitate long-distance robot deployment: the absence of obstacles, firm snow with high albedo, and 24 h sunlight during the summer. We have developed a four-wheel-drive, solar-powered rover that capitalizes on these advantages. Analyses and field measurements confirm that solar power reflected from Antarctic snow contributes 30-40% of the power available to a robot consisting of a five-side box of solar panels. Mobility analyses indicate that the 80 kg rover can move at 0.8 m s-1 during clear sky conditions on firm snow into a 5 m s-1 headwind, twice the speed needed to achieve the design target of 500 km in 2 weeks. Local winter tests of the chassis demonstrated good grade-climbing ability and lower than predicted rolling resistance. Tests of the completed robot occurred in Greenland in 2005.

  6. Macroalgae as 'sentinel' of trace and heavy metals in the management of coastal environment

    International Nuclear Information System (INIS)

    In continuation of the studies of the interactions of various heavy and trace metals and their radionuclides in the nearshore ecosystems of the west coast of India, the radioecology of brown seeweed Sargassum tenerrimum, a macroalgae from Tarapur coastal waters is studied and its role as a 'sentinel' of heavy and trace metals and radionuclides in controlled low level aqueous wastes from a 400 MWe BWR nuclear power plant of Tarapur is discussed. Samples of the species were detached along the holdfast, washed off detritus and epiphytes in running sea water, ovendried and homogenized. The whole thallus from holdfast to the apex was used to study the distribution and concentration of a few heavy and trace metals by atomic absorption spectroscopy and of radionuclides by gamma spectroscopy. Results of the studies on temporal distribution of trace elements, and 131I, 134Cs, 60Co, and 90Sr in thallus and its various parts are presented. Bioaccumulation of above mentioned radionuclides in the species is discussed. The turnover of 90Sr in the species was found to be a function of its alginate content and to be influenced by possible changes occurring in other constituents of the ionogenic groups and the physicochemical parameters. The biological half-life and the ecological half-life of the above four radionuclides were also determined. (M.G.B.)

  7. Using attached macroalgae to assess ecological status of British estuaries for the European Water Framework Directive.

    Science.gov (United States)

    Wilkinson, Martin; Wood, Paul; Wells, Emma; Scanlan, Clare

    2007-01-01

    The EC Water Framework Directive requires that ecological quality be assessed in transitional waters using the abundance and species composition of macroalgae. In estuaries, which form the majority of transitional waters, species composition is not a suitable measure. This arises from two features: (i) there is a continuous, natural change in species composition along the gradient of estuarine conditions which makes it difficult to know where within an estuary the species composition should be assessed, (ii) the inner estuarine macroalgal community of mat-forming species is very tolerant to both natural and anthropogenic stress and species poor which makes it insensitive to environmental variations in terms of species composition. An alternative feature is proposed based on the extent of upstream penetration of perennial fucoid algae. This proposal is founded on a series of case studies of the changes in fucoid limits, within a number of estuaries in the British Isles, consequent upon changes in pollution status over the last three decades. This also has to take into account variations of fucoid penetration owing to natural factors such as range of salinity variation and turbidity. The abundance criterion is taken to mean the absence of macroalgal blooms or "green tides", because general abundance of species is hard to quantify meaningfully in the upper estuarine mat-forming species and in the lower estuary is subject to great variation owing to the physical variability of estuary types. PMID:17084419

  8. Natural and Fukushima-derived radioactivity in macroalgae and mussels along the Japanese shoreline

    Science.gov (United States)

    Baumann, Z.; Casacuberta, N.; Baumann, H.; Masqué, P.; Fisher, N. S.

    2013-06-01

    Following the failure of the nuclear power plant in Fukushima Prefecture in March 2011, peer-reviewed publications describing radioactivity levels in organisms inhabiting coastal environments are scarce. This paper reports on elevated levels of 134Cs and 137Cs in macroalgae and mussels (up to ~ 800 Bq kg-1 dry wt.) in June 2011. Cs concentrations in biota sampled in early June 2011 were higher in areas south of Fukushima than sampled in the last third of the month north of Fukushima. Activity concentrations from 134+137Cs in organisms south of Fukushima were comparable to or lower than those from the naturally occurring 40K in the same samples. While 210Pb and 210Po concentrations were generally lower than these other radionuclides, 210Po as an α-emitter is more significant from a radiological viewpoint than γ-emitters as it can inflict greater biological damage. By applying known bioconcentration factors of Cs in biota, measured biota concentrations of Cs were also used to estimate Cs concentrations in coastal seawater to be in the range of 102-103 Bq m-3. These estimates show that, 3 months after the accident and maximal release of radioactive Cs, levels of Cs persisted in coastal waters, although at levels that were two orders of magnitude lower than at the time of release. These June coastal seawater Cs levels were four orders of magnitude above Cs concentrations off Japan prior to the Fukushima disaster.

  9. Natural and Fukushima-derived radioactivity in macroalgae and mussels along the Japanese shoreline

    Directory of Open Access Journals (Sweden)

    Z. Baumann

    2013-06-01

    Full Text Available Following the failure of the nuclear power plant in Fukushima Prefecture in March 2011, peer-reviewed publications describing radioactivity levels in organisms inhabiting coastal environments are scarce. This paper reports on elevated levels of 134Cs and 137Cs in macroalgae and mussels (up to ~ 800 Bq kg−1 dry wt. in June 2011. Cs concentrations in biota sampled in early June 2011 were higher in areas south of Fukushima than sampled in the last third of the month north of Fukushima. Activity concentrations from 134+137Cs in organisms south of Fukushima were comparable to or lower than those from the naturally occurring 40K in the same samples. While 210Pb and 210Po concentrations were generally lower than these other radionuclides, 210Po as an α-emitter is more significant from a radiological viewpoint than γ-emitters as it can inflict greater biological damage. By applying known bioconcentration factors of Cs in biota, measured biota concentrations of Cs were also used to estimate Cs concentrations in coastal seawater to be in the range of 102–103 Bq m−3. These estimates show that, 3 months after the accident and maximal release of radioactive Cs, levels of Cs persisted in coastal waters, although at levels that were two orders of magnitude lower than at the time of release. These June coastal seawater Cs levels were four orders of magnitude above Cs concentrations off Japan prior to the Fukushima disaster.

  10. Ocean Acidification Accelerates the Growth of Two Bloom-Forming Macroalgae

    Science.gov (United States)

    Young, Craig S.; Gobler, Christopher J.

    2016-01-01

    While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). In nearly all experiments, the growth rates of Gracilaria were significantly increased by an average of 70% beyond in situ and control conditions when exposed to elevated levels of pCO2 (p0.05). The δ13C content of both Gracilaria and Ulva decreased two-to-three fold when grown under elevated pCO2 (pacidification, a process that will intensify in the coming decades. PMID:27176637

  11. Bioassay development using early life stages of the marine macroalga, Ecklonia radiata

    Energy Technology Data Exchange (ETDEWEB)

    Bidwell, J.R.; Wheeler, K.D.; Roper, J. [Curtin Univ. of Technology, Perth (Australia); Burridge, T.R. [Victoria Univ. of Technology (Australia)

    1995-12-31

    A lack of standard toxicity test methods for species native to Australia has stimulated research to overcome this deficiency. In the present work, germination inhibition was utilized as an endpoint in 48h bioassays with the marine macroalga Ecklonia radiata. E radiata is often a dominant member of temperate subtidal communities in Australia and other parts of the southern hemisphere. The alga fills an ecological niche similar to that of Macrocystis pyrifera, the giant kelp which occurs in the northern hemisphere. In an adaptation of test methods used for M. pyrifera, release of E. radiata zoospores was induced in the laboratory. Settled spores were then exposed to toxicants for 48 h and germination success was determined by scoring the spores for the development of a germination tube. At 20 C, EC{sub 50} values ranging between 53.4 and 77.4 mg/L were generated in tests with hexavalent chromium (potassium chromate). The EC{sub 50} for copper (cupric chloride) was 0.53 mg/L. Sensitivity of E. radiata to metals such as copper may have significance toward assessing the environmental impacts of some antifoulant coatings used on seagoing vessels. In future studies, growth of zoospore germination tubes and comparative sensitivity of different E. radiata populations will be examined.

  12. Cu(II) binding by dried biomass of red, green and brown macroalgae.

    Science.gov (United States)

    Murphy, Vanessa; Hughes, Helen; McLoughlin, Peter

    2007-02-01

    Dried biomass of the marine macroalgae Fucus spiralis and Fucus vesiculosus (brown), Ulva spp. (comprising Ulva linza, Ulva compressa and Ulva intestinalis) and Ulva lactuca (green), Palmaria palmata and Polysiphonia lanosa (red) were studied in terms of their Cu(II) biosorption performance. This is the first study of its kind to compare Cu(II) uptake by these seaweeds in the South-East of Ireland. Potentiometric and conductimetric titrations revealed a variety of functionalities on the seaweed surface including carboxyl and amino groups, which are capable of metal binding. It was also found that, of the seaweeds investigated, F. vesiculosus contained the greatest number of acidic surface binding sites while Palmaria palmata contained the least. The metal uptake capacities of the seaweeds increased with increasing pH and kinetic behaviour followed a similar pattern for all seaweeds: a rapid initial sorption period followed by a longer equilibrium period. P. palmata reached equilibrium within 10min of exposure while F. vesiculosus required 60min. Correlation was found between the total number of acidic binding sites and the time taken to reach equilibrium. Fourier transform infra-red (FTIR) analysis of the seaweeds revealed the interaction of carboxyl, amino, sulphonate and hydroxyl groups on the seaweed surface with Cu(2+) ions while time course studies established the relative contribution of each of these groups in metal binding. PMID:17234234

  13. Biohythane production from marine macroalgae Sargassum sp. coupling dark fermentation and anaerobic digestion.

    Science.gov (United States)

    Costa, José C; Oliveira, João V; Pereira, Maria A; Alves, Maria M; Abreu, Angela A

    2015-08-01

    Potential biohythane production from Sargassum sp. was evaluated in a two stage process. In the first stage, hydrogen dark fermentation was performed by Caldicellulosiruptor saccharolyticus. Sargassum sp. concentrations (VS) of 2.5, 4.9 and 7.4gL(-1) and initial inoculum concentrations (CDW) of 0.04 and 0.09gL(-1) of C. saccharolyticus were used in substrate/inoculum ratios ranging from 28 to 123. The end products from hydrogen production process were subsequently used for biogas production. The highest hydrogen and methane production yields, 91.3±3.3Lkg(-1) and 541±10Lkg(-1), respectively, were achieved with 2.5gL(-1) of Sargassum sp. (VS) and 0.09gL(-1)of inoculum (CDW). The biogas produced contained 14-20% of hydrogen. Potential energy production from Sargassum sp. in two stage process was estimated in 242GJha(-1)yr(-1). A maximum energy supply of 600EJyr(-1) could be obtained from the ocean potential area for macroalgae production. PMID:25958149

  14. Pyrolytic characteristics and kinetics of the marine green tide macroalgae, Enteromorpha prolifera

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui; YAN Huaxiao; LIU Ming; ZHANG Congwang; QIN Song

    2011-01-01

    The marine macroalgae Enteromorpha prolifera was one of the main algal genera that occurred in the widespread green tides in Qingdao,China,during the summers of 2007,2008 and 2010.It is thus a plentiful source of biomass and could be used as a biofuel.In this study,the pyrolytic characteristics and kinetics of E.prolifera were investigated using thermogravimetric analysis (TGA)method.Cornstalk and sawdust were used as comparisons.Pyrolytic characteristics were studied using TG-DTG (thermogravimetry-derivative thermogravimetry) curves.Three stages in the pyrolytic process were determined:dehydration,dramatic weight loss and slow weight loss.E.prolifera was pyrolyzed at a lower initial temperature than the two terrestrial biomass forms.The apparent activation energy values for the three types of biomass were calculated and the mechanism functions were determined using 16 different mechanism functions,frequently used in thermal kinetics analysis.Activation energy values varied with mechanism function and the range of activation energy values for E.prolifera,cornstalk,and sawdust were 25-50 kJ/mol,60-90 kJ/mol and 120-155 kJ/mol,respectively.This indicates that E.prolifera has low thermal stability for pyrolysis and good combustion chaxacteristics.

  15. Nutrient and metal pollution of the eastern Gulf of Finland coastline: Sediments, macroalgae, microbiota.

    Science.gov (United States)

    Gubelit, Yulia; Polyak, Yulia; Dembska, Grazyna; Pazikowska-Sapota, Grazyna; Zegarowski, Lukasz; Kochura, Dmitry; Krivorotov, Denis; Podgornaya, Elena; Burova, Olga; Maazouzi, Chafik

    2016-04-15

    The anthropogenic pollution along the coastline of the eastern Gulf of Finland was studied through a range of methods, including analyses of metal contamination in water, surface sediments, accumulated algal biomass and its correlation with resistant microbiota. According to concentrations, the main pollutants in water were copper and manganese. Influence of Nuclear Power Plant was remarkable in adjacent areas and was expressed in high concentrations of molybdenum, nickel, copper and other elements in the water. Relatively high concentrations of copper, lead and zinc were found in sediments. Microbial tolerance appeared to be correlated with the concentration of the metals in sediments. Higher tolerance levels were found in sediment samples from more polluted stations. Macroalgae, which were massively developed in the coastal zone, had shown high level of metal bioaccumulation. Analyses of carbon, nitrogen and phosphorus content of algal tissues allowed the estimation of additional nutrient loading from accumulated decaying algal biomass on the coastal zone of the eastern Gulf of Finland. Mass development of algae in coastal area may contribute to accumulation of organic matter and associated metals. In our study the highest metal concentrations in sediments were found at the sites with dense and continuous layer of fresh and decaying macroalgal biomass, accompanied by hypoxic conditions. Also our study has shown that accumulated biomass may be a significant source of nutrients in the coastal ecosystem. PMID:26849344

  16. Toxicity of tire wear particle leachate to the marine macroalga, Ulva lactuca

    International Nuclear Information System (INIS)

    Tire wear particles filed from the treads of end-of-life vehicle tires have been added to sea water to examine the release of Zn and the toxicity of the resulting leachate and dilutions thereof to the marine macroalga, Ulva lactuca. Zinc release appeared to be diffusion-controlled, with a conditional rate constant of 5.4 μg[L(h)1/2]-1, and about 1.6% of total Zn was released after 120 h incubation. Exposure to increasing concentrations of leachate resulted in a non-linear reduction in the efficiency of photochemical energy conversion of U. lactuca and, with the exception of the undiluted leachate, increasing accumulation of Zn. Phototoxicity was significantly lower on exposure to equivalent concentrations of Zn added as Zn(NO3)2, suggesting that organic components of leachate are largely responsible for the overall toxicity to the alga. Given the ubiquity and abundance of TWP in urban coastal sediments, the generation, biogeochemistry and toxicity of tire leachate in the marine setting merit further attention. - Tire wear leachate is toxic to Ulva lactuca and zinc is a potential bioindicator of leachate contamination in urban marine systems.

  17. Macroalgas de riachos da Floresta Nacional de Irati, região centro-sul do Estado do Paraná, Sul do Brasil Stream macroalgae of Irati National Forest, mid-southern Paraná State, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Ciro Cesar Zanini Branco

    2008-06-01

    Full Text Available Estudos florísticos das comunidades de macroalgas lóticas no Brasil são quase que exclusivamente baseadas em material do Estado de São Paulo. Informações sobre macroalgas de riachos são virtualmente ausentes no Estado do Paraná. Considerando a carência de trabalhos sobre estes importantes produtores primários de ambientes lóticos, foi realizado um estudo mais amplo, a fim de conhecer melhor a biodiversidade das comunidades de macroalgas no Paraná. Neste contexto, o presente trabalho teve como objetivo realizar o levantamento florístico das comunidades de macroalgas da Floresta Nacional de Irati (Flona de Irati, uma unidade de conservação que protege uma área de Floresta Ombrófila Mista (Mata de Araucária. Os estudos foram desenvolvidos em 11 riachos, através de duas coletas realizadas durante os períodos de 19-21 de julho/2005 e 2-4 de fevereiro/2006. Em cada riacho foi estabelecido um segmento de 10 metros de extensão, no qual foi realizado o exame visual detalhado do substrato a fim de determinar a presença de macroalgas. Além da presença das macroalgas, as seguintes variáveis ambientais foram medidas em cada data de amostragem: temperatura, turbidez, condutividade específica, pH, oxigênio dissolvido, profundidade, nutrientes, cor da água e demanda química de oxigênio (DQO. O levantamento taxonômico resultou na identificação de 23 táxons e mostrou a dominância, em termos de número de táxons, de Chlorophyta sobre as demais divisões. O gênero Phormidium Kützing ex Gomont foi o único representado por mais de uma espécie. De modo geral, a maioria das espécies encontradas na Flona de Irati tem sido reportada em estudos prévios, entretanto, uma parte significativa das macroalgas inventariadas foi formada por táxons de ocorrência rara em riachos brasileiros ou, até mesmo, prováveis novidades para a ciência.Surveys of stream macroalgal communities in Brazil are almost exclusively based on data from S

  18. Microbial biomass and basal respiration in Sub-Antarctic and Antarctic soils in the areas of some Russian polar stations

    Directory of Open Access Journals (Sweden)

    E. Abakumov

    2014-03-01

    Full Text Available Antarctica is the unique place for pedological investigations. Soils of Antarctica have been studied intensively during the last century. Antarctic logistic provides the possibility to scientists access the terrestrial landscapes mainly in the places of polar stations. That is why the main and most detailed pedological investigations were conducted in Mc Murdo Valleys, Transantarctic Mountains, South Shetland Islands, Larsemann hills and Schirmacher Oasis. Investigations were conducted during the 53rd and 55th Russian Antarctic expeditions on the base of soil pits and samples collected in Sub-Antarctic and Antarctic regions. Soils of diverse Antarctic landscapes were studied with aim to assess the microbial biomass level, basal respiration rates and metabolic activity of microbial communities. The investigation conducted shows that soils of Antarctic are quite different in profile organization and carbon content. In general, Sub-Antarctic soils are characterized by more developed humus (sod organo-mineral horizons as well as the upper organic layer. The most developed organic layers were revealed in peat soils of King-George Island, where its thickness reach even 80 cm. These soils as well as soils under guano are characterized by the highest amount of total organic carbon (TOC 7.22–33.70%. Coastal and continental soils of Antarctic are presented by less developed Leptosols, Gleysols, Regolith and rare Ornhitosol with TOC levels about 0.37–4.67%. The metabolic ratios and basal respiration were higher in Sub-Antarctic soils than in Antarctic ones which can be interpreted as result of higher amounts of fresh organic remnants in organic and organo-mineral horizons. Also the soils of King-George island have higher portion of microbial biomass (max 1.54 mg g−1 than coastal (max 0.26 mg g−1 and continental (max 0.22 mg g−1 Antarctic soils. Sub-Antarctic soils mainly differ from Antarctic ones in increased organic layers thickness and total

  19. Functional changes due to invasive species: Food web shifts at shallow Posidonia oceanica seagrass beds colonized by the alien macroalga Caulerpa racemosa

    Science.gov (United States)

    Deudero, S.; Box, A.; Alós, J.; Arroyo, N. L.; Marbà, N.

    2011-06-01

    Multiple stable isotope analyses were used to examine the trophic shifts at faunal assemblages within the invading macroalga Caulerpa racemosa in comparison to established communities of Posidonia oceanica seagrass meadows. Sampling of macrobenthic invertebrates and their potential food sources of algal mats and seagrass meadows in Mallorca (NW Mediterranean) showed differences in species composition of faunal and primary producers among seagrass and C. racemosa. Accordingly, changes in food web structure and trophic guilds were observed, not only at species level but also at community level. The carbon and nitrogen isotope signatures of herbivores, detritivores and deposit feeders confirmed that the seagrass provided a small contribution to the macrofaunal organisms. δ 13C at the P. oceanica seagrass and at the C. racemosa assemblages differed, ranging from -6.19 to -21.20‰ and -2.67 to -31.41‰, respectively. δ 15N at the Caulerpa mats was lower (ranging from 2.64 to 10.45‰) than that at the seagrass meadows (3.51-12. 94‰). Significant differences in isotopic signatures and trophic level among trophic guilds at P. oceanica and C. racemosa were found. N fractionation at trophic guild level considerable differed between seagrass and macroalgae mats, especially for detritivores, deposit feeders, and herbivores. Filter feeders slightly differed with a relatively lower N signal at the seagrass and CR values at community level and at trophic guild level were higher in the C. racemosa invaded habitats indicating an increase in diversity of basal resource pools. C. racemosa did seem to broaden the niche diversity of the P. oceanica meadows it colonised at the base of the food web, may be due to the establishment of a new basal resource. The extent of the effects of invasive species on ecosystem functioning is a fundamental issue in conservation ecology. The observed changes in invertebrate and macrophytic composition, stable isotope signatures of concomitant

  20. Carbon dioxide effects research and assessment program. Environmental and societal consequences of a possible CO/sub 2/-induced climate change: volume II, part I. Response of the West Antarctic ice sheet to CO/sub 2/-induced climatic warming

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, C.

    1982-04-01

    The paper proposes a research plan to deal with the question of what the response of the West Antarctic Ice Sheet would be to a rise in global temperatures caused by an anthropogenic CO/sub 2/ buildup in the atmosphere. The plan is designed to answer the following questions: (1) how fast is the ice mass changing now, and why; (2) how will the boundary conditions that affect the ice sheet respond to an atmospheric temperature change and how are those boundary conditions changing now; (3) what will be the response of the ice sheet to changes in boundary conditions; and (4) what can be learned by analogy with what has happened in the past. (ACR)

  1. Antarctic Porifera database from the Spanish benthic expeditions

    OpenAIRE

    Pilar Rios; Javier Cristobo

    2014-01-01

    The information about the sponges in this dataset is derived from the samples collected during five Spanish Antarctic expeditions: Bentart 94, Bentart 95, Gebrap 96, Ciemar 99/00 and Bentart 2003. Samples were collected in the Antarctic Peninsula and Bellingshausen Sea at depths ranging from 4 to 2044 m using va­rious sampling gears.The Antarctic Porifera database from the Spanish benthic expeditions is unique as it provides in­formation for an under-explored region of the Southern Oc...

  2. Toxicity of fuel-contaminated soil to Antarctic moss and terrestrial algae.

    Science.gov (United States)

    Nydahl, Anna C; King, Catherine K; Wasley, Jane; Jolley, Dianne F; Robinson, Sharon A

    2015-09-01

    Fuel pollution is a significant problem in Antarctica, especially in areas where human activities occur, such as at scientific research stations. Despite this, there is little information on the effects of petroleum hydrocarbons on Antarctic terrestrial biota. The authors demonstrate that the Antarctic mosses Bryum pseudotriquetrum, Schistidium antarctici, and Ceratodon purpureus, and the Antarctic terrestrial alga Prasiola crispa are relatively tolerant to Special Antarctic Blend (SAB) fuel-contaminated soil (measured as total petroleum hydrocarbons). Freshly spiked soils were more toxic to all species than were aged soils containing degraded fuel, as measured by photosynthetic efficiency (variable fluorescence/maximum fluorescence [Fv/Fm]), pigment content, and visual observations. Concentrations that caused 20% inhibition ranged from 16,600 mg/kg to 53,200 mg/kg for freshly spiked soils and from 30,100 mg/kg to 56,200 mg/kg for aged soils. The photosynthetic efficiency of C. purpureus and S. antarctici was significantly inhibited by exposure to freshly spiked soils with lowest-observed-effect concentrations of 27,900 mg/kg and 40,400 mg/kg, respectively. Prasiola crispa was the most sensitive species to freshly spiked soils (Fv/Fm lowest-observed-effect concentration 6700 mg/kg), whereas the Fv/Fm of B. pseudotriquetrum was unaffected by exposure to SAB fuel even at the highest concentration tested (62,900 mg/kg). Standard toxicity test methods developed for nonvascular plants can be used in future risk assessments, and sensitivity data will contribute to the development of remediation targets for petroleum hydrocarbons to guide remediation activities in Antarctica. PMID:25891024

  3. 75 FR 22433 - Notice of Permit Applications Received Under the Antarctic Conservation Act of 1978 (Pub. L. 95-541)

    Science.gov (United States)

    2010-04-28

    ...-541), as amended by the Antarctic Science, Tourism and Conservation Act of 1996, has developed... (ASPA 121), Cape Bird, and Beaufort Island (ASPA 105) to study penguins and the effect of age... antennas will be set up at Cape Royds. Location: Cape Crozier (ASPA 124), Cape Royds (ASPA 121), Cape...

  4. Different adaptations of Chinese winter-over expeditioners during prolonged Antarctic and sub-Antarctic residence

    Science.gov (United States)

    Chen, Nan; Wu, Quan; Li, Hao; Zhang, Tao; Xu, Chengli

    2016-05-01

    Prolonged residence in Antarctica is characterized by exposure to isolated, confined, and extreme (ICE) environment. Winter-over expeditioners at research stations often exhibit a complex of psychophysiological symptoms, which varied by stations and sociocultural backgrounds. To understand the different patterns of psychophysiological responses provoked by environmental stress, we conducted a longitudinal assessment of mood and endocrine function in two groups of Chinese expeditioners who were deployed to sub-Antarctic (Great Wall Station, 62°S, N = 12) and Antarctic (Zhongshan Station, 66°S, N = 16) from December 2003 to 2005. Measures of mood, thyroid function, the levels of plasma catecholamine, and circulating interleukins were obtained at departure from China, mid-winter (Antarctica), end of winter (Antarctica), and return to China, respectively. The Zhongshan Station crew experienced significant increases in fatigue, anger, tension, confusion, and decrease in free thyroxine (FT4), norepinephrine (NE), and epinephrine (E) during the winter, increase in thyrotropin (TSH) and total triiodothyronine (TT3) when returning, whereas their counterparts at Great Wall Station only experienced increased TT3 after deployment. Moreover, compared with the Great Wall Station crew, the Zhongshan Station crew exhibited greater increase in anger, greater decrease in FT4, total thyroxine (TT4), NE and E over the winter, and greater increase in TSH when returning. Chinese expeditioners who lived and worked at the Antarctic station and the sub-Antarctic station for over a year showed different change patterns in mood and endocrine hormones. Negative mood and endocrine dysfunction were positively associated with the severity of environment. The study is a supplement to scientific knowledge on psychophysiological variation under ICE environment, which has certain applied value for the development of preventive countermeasures or interventions.

  5. Applicability of ERTS to Antarctic iceberg resources. [harvesting sea ice for fresh water

    Science.gov (United States)

    Hult, J. L. (Principal Investigator); Ostrander, N. C.

    1973-01-01

    The author has identified the following significant results. This investigation explorers the applicability of ERTS to (1) determine the Antarctic sea ice and environmental behavior that may influence the harvesting of icebergs, and (2) monitor iceberg locations, characteristics, and evolution. Imagery has shown that the potential applicability of ERTS to the research, planning, and harvesting operations can contribute importantly to the glowing promise derived from broader scope studies for the use of Antarctic icebergs to relieve a growing global thirst for fresh water. Several years of comprehensive monitoring will be necessary to characterize sea ice and environmental behavior and iceberg evolution. Live ERTS services will assist harvesting control and claiming operations and offer a means of harmonizing entitlements of iceberg resources. The valuable ERTS services will be more cost effective than other means will be easily justified and borne by the iceberg harvesting operations.

  6. Biomarkers and Microbial Fossils In Antarctic Rocks

    Science.gov (United States)

    Wierzchos, J.; Ascaso, C.

    Lithobiontic microbial communities living within Antarctic rocks are an example of survival in an extremely cold and dry environment. Any unfavourable change in ex- ternal conditions can result in the death and disappearance of microscopic organisms, and this may be followed by the appearance of trace biomarkers and microbial fossils. The extinction of these microorganisms in some zones of the Ross Desert, probably provoked by the hostile environment, might be considered a good terrestrial analogue of the first stage of the disappearance of possible life on early Mars. Granite samples from maritime Antarctica (Granite Harbour) and sandstone rocks from the continental Ross Desert were collected with the aim of searching for biomarkers and microbial fossils at the microscopic level of observation. To this end, a novel in situ applica- tion of scanning electron microscopy with backscattered electron imaging was com- bined with the simultaneous use of X-ray energy dispersive spectroscopy techniques. Our findings confirm the existence of inorganic biomarkers in the form of physico- chemically bioweathered minerals within the granitic rocks. The presence of Fe-rich diagenetic minerals, such as iron hydroxide nanocrystals and biogenic clays around chasmoendolithic hyphae and bacterial cells was also observed. Others biomarkers, including inorganic deposits such as calcium oxalates and silica accumulations, are clear signs of endolithic microorganism activity. The interior of the sandstone rocks (Ross Desert, Mt. Fleming) reveal the presence of microbial fossils of algae and other endolithic microorganisms. These microbial fossils, detected for the first time within Antarctic rocks, contain well preserved and morphologically distinguishable relics of ultrastructural cytoplasm elements, such as cell walls, chloroplast membranes, and oc- casionally, pyrenoids and traces of organic matter. These structures are similar to those observed in live cells also found in Antarctic

  7. Seaweed-Coral Interactions: Variance in Seaweed Allelopathy, Coral Susceptibility, and Potential Effects on Coral Resilience

    OpenAIRE

    Bonaldo, Roberta M.; Hay, Mark E.

    2014-01-01

    Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving allelopathic and non-allelopathic macroalgae on three, spatially grouped pairs of no-take Marine Prote...

  8. Characterization of meteorological parameters, solar radiation and effect of clouds at two antarctic sites, and comparison with satellite estimates Caracterización de parámetros meteorológicos, radiación solar y efecto de las nubes en dos sitios antárticos, y comparación con estimaciones satelitales

    Directory of Open Access Journals (Sweden)

    Eduardo A. Luccini

    2005-12-01

    Full Text Available The analysis of measurements of daily mean temperature, daily mean relative humidity and daily total solar irradiation for the period 1979-1985, at the Antarctic stations Almirante Brown (64.9ºS, 62.9ºW, 10m a.s.l., West of Antarctic Peninsula, and BelgranoII (77.9ºS, 34.6ºW, 250m a.s.l., East of Antarctic Peninsula is presented. A short-term characterization of monthly averages was established. Typical temperatures for summer and winter were 2ºC and -7ºC respectively at Brown, and -2ºC and -20ºC at BelgranoII. Relative humidity was always above 60% at both stations. Both measured parameters enter also as input variables in model calculations of the equivalent clear-sky daily total irradiation for each day, to determine the effective cloud transmittance of solar radiation. The effect of cloudiness was stronger at Brown, where an average cloud transmittance of 49% was determined, while it was of 71% at BelgranoII. Average daily irradiation of 27.4MJ/m² in December at BelgranoII is within the highest reported world-wide. Also, some days show increases in the daily irradiation over 20% than that expected for clear-sky conditions. Antarctic solar irradiation levels are considerably higher than in the Arctic. Ground-based data are compared with the satellite database from NASA Surface Meteorology and Solar Energy Data Set.Se presenta el análisis de mediciones de temperatura media diaria, humedad relativa media diaria e irradiación solar total diaria, realizadas en el periodo 1979-1985 en las Bases Antárticas Almirante Brown (64.9ºS, 62.9ºO, 10m s.n.m., Oeste de Península Antártica y BelgranoII (77.9ºS, 34.6ºO, 250m s.n.m., Este de Península Antártica. Se estableció una caracterización de corto plazo sobre medias mensuales. Las temperaturas típicas en verano e invierno fueron 2ºC y -7ºC respectivamente en Brown, y -2ºC y ‑20ºC en BelgranoII. La humedad relativa fue siempre sobre 60% en ambas estaciones. Estos dos par

  9. Potential use of green macroalgae Ulva lactuca as a feed supplement in diets on growth performance, feed utilization and body composition of the African catfish, Clarias gariepinus.

    Science.gov (United States)

    Abdel-Warith, Abdel-Wahab A; Younis, El-Sayed M I; Al-Asgah, Nasser A

    2016-05-01

    This study aimed to evaluate the effects of diet containing the green macroalgae, Ulva lactuca, on the growth performance, feed utilization and body composition of African catfish Clarias gariepinus. Four experimental diets were formulated: D1 as a control group and D2, D3 and D4 which included 10%, 20% and 30% U. lactuca meal, respectively. 180 African catfish, weighing 9.59 ± 0.43 g, and with an average length of 11.26 ± 0.21, (mean ± SE) were divided into four groups corresponding to the different feeding regimes. The final body weight of the fish showed insignificant differences (P > 0.05) between the control and fish fed D2, whereas, there was a significant difference (P catfish fed a diet with U. lactuca included at 20% and 30% levels showed poorer growth and feed utilization than the control group and fish fed diets containing 10% of U. lactuca. PMID:27081367

  10. Separation of native allophycocyanin and R-phycocyanin from marine red macroalga Polysiphonia urceolata by the polyacrylamide gel electrophoresis performed in novel buffer systems.

    Directory of Open Access Journals (Sweden)

    Yu Wang

    Full Text Available Three buffer systems of Imidazole-Acetic acid, HEPES-Imidazole/Bis-tris and Bis-tris-HEPES-MES were designed based on the principle of discontinuous polyacrylamide gel electrophoresis (PAGE for the native PAGE which could be performed in pH 7.0 and 6.5 in order to analyze and prepare the minor components of allophycocyanin (AP and R-phycocyanin (R-PC from marine red macroalga Polysiphonia urceolata. These AP and R-PC phycobiliproteins are easily denatured in alkaline environments. The obtained results demonstrated that the PAGE modes performed in the buffer systems of HEPES-Imidazole/Bis-tris and Bis-tris-HEPES-MES gave the satisfactory resolution and separation of AP and R-PC proteins. The absorption and fluorescence spectra of the AP and R-PC proteins which were prepared by the established PAGE modes proved that they maintained natural spectroscopic characteristics. The established PAGE modes may also provide useful references and selections for some other proteins that are sensitive to alkaline environments or are not effectively separated by the classical PAGE modes performed normally in alkaline buffer systems.

  11. Separation of Native Allophycocyanin and R-Phycocyanin from Marine Red Macroalga Polysiphonia urceolata by the Polyacrylamide Gel Electrophoresis Performed in Novel Buffer Systems

    Science.gov (United States)

    Wang, Yu; Gong, Xueqin; Wang, Shumei; Chen, Lixue; Sun, Li

    2014-01-01

    Three buffer systems of Imidazole−Acetic acid, HEPES−Imidazole/Bis-tris and Bis-tris−HEPES−MES were designed based on the principle of discontinuous polyacrylamide gel electrophoresis (PAGE) for the native PAGE which could be performed in pH 7.0 and 6.5 in order to analyze and prepare the minor components of allophycocyanin (AP) and R-phycocyanin (R-PC) from marine red macroalga Polysiphonia urceolata. These AP and R-PC phycobiliproteins are easily denatured in alkaline environments. The obtained results demonstrated that the PAGE modes performed in the buffer systems of HEPES−Imidazole/Bis-tris and Bis-tris−HEPES−MES gave the satisfactory resolution and separation of AP and R-PC proteins. The absorption and fluorescence spectra of the AP and R-PC proteins which were prepared by the established PAGE modes proved that they maintained natural spectroscopic characteristics. The established PAGE modes may also provide useful references and selections for some other proteins that are sensitive to alkaline environments or are not effectively separated by the classical PAGE modes performed normally in alkaline buffer systems. PMID:25166028

  12. Changes in the West Antarctic ice sheet

    International Nuclear Information System (INIS)

    The portion of the West Antarctic ice sheet that flows into the Ross Sea is thinning in some places and thickening in others. These changes are not caused by any current climatic change, but by the combination of a delayed response to the end of the last global glacial cycle and an internal instability. The near-future impact of the ice sheet on global sea level is largely due to processes internal to the movement of the ice sheet, and not so much to the threat of a possible greenhouse warming. Thus the near-term future of the ice sheet is already determined. However, too little of the ice sheet has been surveyed to predict its overall future behavior

  13. Joint Antarctic School Expedition - An International Collaboration for High School Students and Teachers on Antarctic Science

    Science.gov (United States)

    Botella, J.; Warburton, J.; Bartholow, S.; Reed, L. F.

    2014-12-01

    The Joint Antarctic School Expedition (JASE) is an international collaboration program between high school students and teachers from the United States and Chile aimed at providing the skills required for establishing the scientific international collaborations that our globalized world demands, and to develop a new approach for science education. The National Antarctic Programs of Chile and the United States worked together on a pilot program that brought high school students and teachers from both countries to Punta Arenas, Chile, in February 2014. The goals of this project included strengthening the partnership between the two countries, and building relationships between future generations of scientists, while developing the students' awareness of global scientific issues and expanding their knowledge and interest in Antarctica and polar science. A big component of the project involved the sharing by students of the acquired knowledge and experiences with the general public. JASE is based on the successful Chilean Antarctic Science Fair developed by Chile´s Antarctic Research Institute. For 10 years, small groups of Chilean students, each mentored by a teacher, perform experimental or bibliographical Antarctic research. Winning teams are awarded an expedition to the Chilean research station on King George Island. In 2014, the Chileans invited US participation in this program in order to strengthen science ties for upcoming generations. On King George Island, students have hands-on experiences conducting experiments and learning about field research. While the total number of students directly involved in the program is relatively small, the sharing of the experience by students with the general public is a novel approach to science education. Research experiences for students, like JASE, are important as they influence new direction for students in science learning, science interest, and help increase science knowledge. We will share experiences with the

  14. Organic carbon in Antarctic snow: spatial trends and possible sources

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, R.; Mahalinganathan, K.; Thamban, M.; Nair, S.

    Organic carbon records in Antarctic snow are sparse despite the fact that it is of great significance to global carbon dynamics, snow photochemistry, and air–snow exchange processes. Here, surface snow total organic carbon (TOC) along with sea...

  15. A Comparative Study of Antarctic Arctic and Himalayan Ice

    Directory of Open Access Journals (Sweden)

    R. C. Pathak

    1989-07-01

    Full Text Available Arctic, Antarctic and inaccessible lofty regions of Himalayas,which are geographically diverse areas and have been a constant source of inspiration, envisages a challenging field of study 'by early adventurers and scientists of the world. Characteristics of ice obtained at Arctic and Antarctic do not possess similar properties. Even thesalient properties of snow and ice of western and central Himalayas vary due to its differing free water content. A study has been carriedout based on recent Antarctic Expedition by Indian scientists and the data gathered along litha-tectonic regions of Himalayas and their characteristics have been compared, wkich brings out stratigraphic and metamorphic characteristics of the ice and snow. In the present paper,an analysis of the ice and snow properties of Arctic, Antarctic and Himalayan regions has been presented.

  16. Climate Prediction Center (CPC) Daily Antarctic Oscillation Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Antarctic Oscillation (AAO) is a leading teleconnection pattern in the Southern Hemisphere circulation. It is calculated as the first Empirical Orthogonal...

  17. Morphogenesis of Antarctic Paleosols: Martian Analogue

    Science.gov (United States)

    Mahaney, W. C.; Dohm, J. M.; Baker, V. R.; Newsom, Horton E.; Malloch, D.; Hancock, R. G. V.; Campbell, Iain; Sheppard, D.; Milner, M. W.

    2001-11-01

    Samples of horizons in paleosols from the Quartermain Mountains of the Antarctic Dry Valleys (Aztec and New Mountain areas) were analyzed for their physical characteristics, mineralogy, chemical composition, and microbiology to determine the accumulation and movement of salts and other soluble constituents and the presence/absence of microbial populations. Salt concentrations are of special interest because they are considered to be a function of age, derived over time, in part from nearby oceanic and high-altitude atmospheric sources. The chemical composition of ancient Miocene-age paleosols in these areas is the direct result of the deposition and weathering of airborne-influxed salts and other materials, as well as the weathering of till derived principally from local dolerite and sandstone outcrops. Paleosols nearer the coast have greater contents of Cl, whereas near the inland ice sheet, nitrogen tends to increase on a relative basis. The accumulation and vertical distribution of salts and other soluble chemical elements indicate relative amounts of movement in the profile over long periods of time, in the order of several million years. Four of the six selected subsamples from paleosol horizons in two ancient soil profiles contained nil concentrations of bacteria and fungi. However, two horizons at depths of between 3 and 8 cm, in two profiles, yielded several colonies of the fungi Beauveria bassiana and Penicillium brevicompactum, indicating very minor input of organic carbon. Beauveria bassiana is often reported in association with insects and is used commercially for the biological control of some insect pests. Penicillium species are commonly isolated from Arctic, temperate, and tropical soils and are known to utilize a wide variety of organic carbon and nitrogen compounds. The cold, dry soils of the Antarctic bear a close resemblance to various present and past martian environments where similar weathering could occur and possible microbial populations

  18. Morphological and molecular discrimination of green macroalgae Chaetomorpha aerea and C. linum

    Institute of Scientific and Technical Information of China (English)

    HUANG Bingxin; TENG Linhong; DING Lanping

    2016-01-01

    Green macroalgaeChaetomorpha aerea andC. linum are taxonomically confused. In this paper, we tried morphological and molecular analyses to separate these two species.C. aerea andC. linum can be distinguished from morphological characteritics, such as frond dimension, cells size and shape, their mean length/width ratios (LWR), and cell walls constriction. Thalli ofC. aerea attenuate basipetally, with diameter 270–500 μm at upper portion, 160–360 μm at middle portion, 100–160 μm at basal portion. For the upper part, the length of cells is less than their diameter. Cell walls usually constrict at the dissepiments, which are pellucid or colorless and give the filament beaded appearance. In contrast, thalli ofC. linum often have a constant diameter of 90–300 μm within the same individual, cell walls usually do not constrict and cells are cylindrical or barrel shaped. The LWR is larger than that ofC. aerea. Results show that the pairwise distance between two species is 3.6%–3.7% for 18S rRNA gene and 53.5%–54.3% for ITS region. In phylogeny, they distribute at distant clades, which confirms a genetic divergence at molecular level. In addition, morphological data indicates that filament diameter ofC. linum samples is highly variable, ranging from 90 μm to 300 μm. Then these two species can be considered as separate species.

  19. Characteristics of an R-phycoerythrin with two γ subunits prepared from red macroalga Polysiphonia urceolata.

    Science.gov (United States)

    Wang, Lu; Wang, Shumei; Fu, Xuejun; Sun, Li

    2015-01-01

    An R-phycoerythrin (R-PE) was isolated by gel filtrations on Sepharose CL-4B and Sephadex G-150 from the phycobiliprotein extract of the marine red macroalga Polysiphonia urceolata Grev and further purified by ion exchange chromatography on DEAE-Sepharose Fast Flow. The purified R-PE showed three absorption peaks at 498 nm, 538 nm, 566 nm and one fluorescent emission maximum at 577 nm. Although the R-PE showed a single band on the examination by native PAGE, it exhibited two very close bands at pH about 4.7 in native isoelectric focusing (IEF). Polypeptide analysis of the R-PE demonstrated that it contained four chromophore-carrying subunits, α18.2, β20.6, γ31.6 (γ'), γ34.6 (γ), and no colorless polypeptide; its subunit composition was 6α18.2:6β20.6:1 γ31.6:2γ34.6. The α and β subunits were distributed within a acidic pH range from 5.0 to 6.0 in denaturing IEF and the γ subunits were in a basic pH range from 7.6 to 8.1. These results reveal that the prepared R-PE may exist in two hexamers of γ (αβ)3 γ (αβ)3γ' and γ (αβ)3 γ'(αβ)3 γ and that the R-PE participate in the rod domain assembly of P. urceolata phycobilisomes by stacking each of its trimer (αβ)3 face-to-face with the aid of one γ subunit (γ or γ'). PMID:25781487

  20. The marine macroalgae of Helgoland (North Sea): an annotated list of records between 1845 and 1999

    Science.gov (United States)

    Bartsch, Inka; Kuhlenkamp, Ralph

    2000-12-01

    The earliest known records of marine macroalgae from Helgoland (German Bight, North Sea) date from the mid-19th century. Since then, 274 marine macroalgal species have been reported: 77 species of Chlorophycota, 100 species of Phaeophycota and 97 species of Rhodophycota. Additionally 11 species were only recorded as drift and 51 species as doubtful for Helgoland. The remains of the herbarium of Paul Kuckuck, the first curator for botany at the Helgoland Biological Station between 1892 and 1914, are still located there and consist of 173 macroalgal species from Helgoland. On comparing this 100-year-old herbarium and other old sources with recent macroalgal records, it became clear that changes in species composition have occurred. After World War II, several species such as Arthrocladia villosa, Corynophlaea crispa, Cutleria multifida, Eudesme virescens, Mesogloia vermiculata, Sporochnus pedunculatus, Antithamnion cruciatum, Apoglossum ruscifolium, Chondria dasyphylla, Helminthora divaricata, Jania rubens and Osmundea ramosissima were not found again. Other species such as Dictyota dichotoma, Leathesia difformis, Stictyosiphon soriferus, Helminthocladia calvadosii and Scinaia furcellata became very rare . Significantly, perhaps, most of these species have a heteromorphic life history with the appearance of the macroscopic phase restricted to (spring and) summer. Many new species of green algae were recorded for Helgoland after 1959, due to new substrata and the research activities of Peter Kornmann, curator for botany after 1959, and Paul-Heinz Sahling his technical assistant. Introductions of species during the considered time period were: Bonnemaisonia hamifera, Codium fragile, Mastocarpus stellatus and Sargassum muticum. Type material of the following species is located at the Marine Biological Station at Helgoland: Mikrosyphar porphyrae, Porphyra insolita and Ulva tenera.

  1. Natural and Fukushima-derived radioactivity in macroalgae and mussels along the Japanese shoreline

    Directory of Open Access Journals (Sweden)

    Z. Baumann

    2013-02-01

    Full Text Available Following the failure of the nuclear power plant in Fukushima Prefecture in March 2011, peer-reviewed publications describing radioactivity levels in organisms inhabiting coastal environments are scarce. This paper reports on elevated levels of 134Cs and 137Cs in macroalgae and mussels (up to ~ 800 Bq kg−1 dry wt. in June 2011. Cs concentrations in biota sampled in early June 2011 were higher in areas south of Fukushima than sampled in the last third of the month north of Fukushima. Radioactivity from 134+137Cs in organisms south of Fukushima were comparable to or lower than that from the naturally occuring 40K in the same samples. While 210Pb and 210Po concentrations were generally lower than these other radionuclides, 210Po as an α-emitter is more significant from a radiological viewpoint than γ-emitters as it can inflict greater biological damage. By applying known bioconcentration factors of Cs in biota, measured biota concentrations of Cs were also used to estimate Cs concentraitons in coastal seawater to be in the range of 102–103 Bq m−3. These estimates show that 3 months after the accident and maximal release of radioactive Cs, levels of Cs persisted in coastal waters, although at levels that were two orders of magnitude lower than at the time of release. These June coastal seawater Cs levels were four orders of magnitude above Cs concentrations off Japan prior to the Fukushima disaster.

  2. Nutrients' removal from aquaculture wastewater using the macroalgae Gracilaria birdiae

    Energy Technology Data Exchange (ETDEWEB)

    Marinho-Soriano, E.; Nunes, S.O.; Carneiro, M.A.A.; Pereira, D.C. [Universidade Federal do Rio Grande do Norte, Depto. de Oceanografia e Limnologia, Via Costeira, Praia de Mae Luiza, s/n, Natal, RN 59014-100 (Brazil)

    2009-02-15

    Intensive aquaculture releases large amount of nutrients into aquatic ecosystems and can lead to eutrophication of coastal waters. Studies conducted in aquaculture systems have demonstrated that the seaweeds are efficient in reducing nutrients and at the same time provides extra income, when species of economic importance are used. This study was conducted to evaluate whether Gracilaria birdiae could be cultivated efficiently for the production of useful algal biomass and removal of nutrients from shrimp pond effluents. The results obtained showed a gradual increase in biomass and relative growth rate (RGR) over the experimental period. Mean RGR between the weeks varied significantly (p < 0.01), reaching a maximum of 3.6 {+-} 0.35% d{sup -1} and a minimum of 1.6 {+-} 0.52% d{sup -1}. The mean for the whole period was 2.6% d{sup -1}. The biofiltration capacity of G. birdiae was confirmed by the significantly reduced concentration of the three nutrients analyzed (PO{sub 4}{sup 3-}, NH{sub 4}{sup +} and NO{sub 3}{sup -}) over the study period. The concentration of PO{sub 4}{sup 3-} decreased by 93.5%, NH{sub 4}{sup +} by 34% and NO{sub 3}{sup -} by 100% after the 4-week experimental period. The results obtained in this study indicated that G. birdiae can be used in aquaculture systems as a biofilter. In addition, the macroalgae biomass produced offers alternative source of raw material for the extraction of the phycocolloid agar, human food and animal feed. (author)

  3. Analyzing redox balance in a synthetic yeast platform to improve utilization of brown macroalgae as feedstock

    Directory of Open Access Journals (Sweden)

    C.A. Contador

    2015-12-01

    An analysis of the redox balance during ethanol fermentation from alginate and mannitol by Saccharomyces cerevisiae using metabolic engineering tools was carried out. To represent the strain designed for conversion of macroalgae carbohydrates to ethanol, a context-specific model was derived from the available yeast genome-scale metabolic reconstructions. Flux balance analysis and dynamic simulations were used to determine the flux distributions. The model indicates that ethanol production is determined by the activity of 4-deoxy-l-erythro-5-hexoseulose uronate (DEHU reductase (DehR and its preferences for NADH or NADPH which influences strongly the flow of cellular resources. Different scenarios were explored to determine the equilibrium between NAD(H and NADP(H that will lead to increased ethanol yields on mannitol and DEHU under anaerobic conditions. When rates of mannitol dehydrogenase and DehRNADH tend to be close to a ratio in the range 1–1.6, high growth rates and ethanol yields were predicted. The analysis shows a number of metabolic limitations that are not easily identified through experimental procedures such as quantifying the impact of the cofactor preference by DEHU reductase in the system, the low flux into the alginate catabolic pathway, and a detailed analysis of the redox balance. These results show that production of ethanol and other chemicals can be optimized if a redox balance is achieved. A possible methodology to achieve this balance is presented. This paper shows how metabolic engineering tools are essential to comprehend and overcome this limitation.

  4. Methyl Jasmonate-Induced Lipidomic and Biochemical Alterations in the Intertidal Macroalga Gracilaria dura (Gracilariaceae, Rhodophyta).

    Science.gov (United States)

    Kumari, Puja; Reddy, C R K; Jha, Bhavanath

    2015-10-01

    The role of exogenously added methyl jasmonate (MeJA), a lipid-derived signaling compound, in inducing oxidative stress in the marine red macroalga Gracilaria dura was investigated. MeJA at a concentration of 1-100 µM was a strong stimulant of reactive oxygen species (H(2)O(2), HO· and O(2) (·-)) (P phycocyanin, with a concomitant increase in phycoerythrin. The MeJA-induced oxidative burst also led to the induction of a fatty acid oxidation cascade, resulting in the synthesis of hydroxy-oxylipins and the up-regulation of the 13-lipoxygenase pathway. Electrospray ionization-mass spectrometry-based shotgun lipidomic analysis revealed that monogalactosyldiacylglycerol (a chloroplastic glycerolipid) and phosphatidylcholine (extrachloroplastidic phopholipid) were the most affected lipid classes. The degradation of 18:3-fatty acid-containing monogalactosyldiacylglycerol inferred that it provided fatty acyl chains for the biosynthesis of 13-hydroperoxylinolenic acid, which was further directed towards either the jasmonate pathway or other alternative pathways of the fatty acid oxidation cascade, analogous to higher plants. Also, G. dura modulated the lipid acyl chains in such a way that no significant change was observed in the fatty acid profile of the treated thalli as compared with those of the control, except for C16:0, C16:1 (n-9), C20:3 (n-6) and C20:4 (n-6) (P < 0.05). Furthermore, MeJA caused the accumulation of phenolic compounds and the up-regulation of enzymes involved in secondary metabolism such as polyphenol oxidase, shikimate dehydrogenase and phenylalanine ammonia-lyase, indicating a shift towards secondary metabolism as a defense strategy to combat the induced oxidative stress. PMID:26276825

  5. Characteristics of an R-phycoerythrin with two γ subunits prepared from red macroalga Polysiphonia urceolata.

    Directory of Open Access Journals (Sweden)

    Lu Wang

    Full Text Available An R-phycoerythrin (R-PE was isolated by gel filtrations on Sepharose CL-4B and Sephadex G-150 from the phycobiliprotein extract of the marine red macroalga Polysiphonia urceolata Grev and further purified by ion exchange chromatography on DEAE-Sepharose Fast Flow. The purified R-PE showed three absorption peaks at 498 nm, 538 nm, 566 nm and one fluorescent emission maximum at 577 nm. Although the R-PE showed a single band on the examination by native PAGE, it exhibited two very close bands at pH about 4.7 in native isoelectric focusing (IEF. Polypeptide analysis of the R-PE demonstrated that it contained four chromophore-carrying subunits, α18.2, β20.6, γ31.6 (γ', γ34.6 (γ, and no colorless polypeptide; its subunit composition was 6α18.2:6β20.6:1 γ31.6:2γ34.6. The α and β subunits were distributed within a acidic pH range from 5.0 to 6.0 in denaturing IEF and the γ subunits were in a basic pH range from 7.6 to 8.1. These results reveal that the prepared R-PE may exist in two hexamers of γ (αβ3 γ (αβ3γ' and γ (αβ3 γ'(αβ3 γ and that the R-PE participate in the rod domain assembly of P. urceolata phycobilisomes by stacking each of its trimer (αβ3 face-to-face with the aid of one γ subunit (γ or γ'.

  6. Ocean acidification alters the calcareous microstructure of the green macro-alga Halimeda opuntia

    Science.gov (United States)

    Wizemann, André; Meyer, Friedrich W.; Hofmann, Laurie C.; Wild, Christian; Westphal, Hildegard

    2015-09-01

    Decreases in seawater pH and carbonate saturation state ( Ω) following the continuous increase in atmospheric CO2 represent a process termed ocean acidification, which is predicted to become a main threat to marine calcifiers in the near future. Segmented, tropical, marine green macro-algae of the genus Halimeda form a calcareous skeleton that involves biotically initiated and induced calcification processes influenced by cell physiology. As Halimeda is an important habitat provider and major carbonate sediment producer in tropical shallow areas, alterations of these processes due to ocean acidification may cause changes in the skeletal microstructure that have major consequences for the alga and its environment, but related knowledge is scarce. This study used scanning electron microscopy to examine changes of the CaCO3 segment microstructure of Halimeda opuntia specimens that had been exposed to artificially elevated seawater pCO2 of ~650 µatm for 45 d. In spite of elevated seawater pCO2, the calcification of needles, located at the former utricle walls, was not reduced as frequent initiation of new needle-shaped crystals was observed. Abundance of the needles was ~22 % µm-2 higher and needle crystal dimensions ~14 % longer. However, those needles were ~42 % thinner compared with the control treatment. Moreover, lifetime cementation of the segments decreased under elevated seawater pCO2 due to a loss in micro-anhedral carbonate as indicated by significantly thinner calcified rims of central utricles (35-173 % compared with the control treatment). Decreased micro-anhedral carbonate suggests that seawater within the inter-utricular space becomes CaCO3 undersaturated ( Ω < 1) during nighttime under conditions of elevated seawater pCO2, thereby favoring CaCO3 dissolution over micro-anhedral carbonate accretion. Less-cemented segments of H. opuntia may impair the environmental success of the alga, its carbonate sediment contribution, and the temporal storage of

  7. Fundamental differences between Arctic and Antarctic ozone depletion

    OpenAIRE

    Solomon, Susan; Haskins, Jessica; Ivy, Diane J.; Min, Flora

    2014-01-01

    Fundamental differences in observed ozone depletion between the Arctic and the Antarctic are shown, clarifying distinctions between both average and extreme ozone decreases in the two hemispheres. Balloon-borne and satellite measurements in the heart of the ozone layer near 18−24 km altitude show that extreme ozone decreases often observed in the Antarctic ozone hole region have not yet been measured in the Arctic in any year, including the unusually cold Arctic spring of 2011. The data provi...

  8. Perspectives on the economic history of the Antarctic region

    OpenAIRE

    Basberg, Bjørn L.

    2005-01-01

    This paper starts out by indicating how the economic history of the Antarctic could be conceptualized, given the peculiarities of the continent and the region (no permanent population, no sovereignty in a traditional sense, extreme remoteness, rigorous climate etc.). Second, it describes the main industries throughout Antarctic history. Third, it examines the quantitative data available on economic activity in the region, suggests how we should proceed to analyse the economic a...

  9. Holocene subsurface temperature variability in the eastern Antarctic continental margin

    OpenAIRE

    Kim, J. H.; X. Crosta; Willmott, V.; Renssen, H.; J. Bonnin; Helmke, P.; Schouten, S.; Sinninghe Damsté, J.S.

    2012-01-01

    We reconstructed subsurface (similar to 45-200 m water depth) temperature variability in the eastern Antarctic continental margin during the late Holocene, using an archaeal lipid-based temperature proxy (TEX86 L). Our results reveal that subsurface temperature changes were probably positively coupled to the variability of warmer, nutrient-rich Modified Circumpolar Deep Water (MCDW, deep water of the Antarctic circumpolar current) intrusion onto the continental shelf. The TEX86 L record, in c...

  10. Obliquity-paced Pliocene West Antarctic ice sheet oscillations

    OpenAIRE

    Naish, T.; Antarctic Research Centre, Victoria University of Wellington, Kelburn Parade, PO Box 600, Wellington 6012, New Zealand; Powell, R.; Department of Geology & Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA.; Levy, R.; ANDRILL Science Management Office, University of Nebraska-Lincoln, Lincoln, USA; Wilson, G.; University of Otago, Department of Geology, PO Box 56, Leith Street, Dunedin, Otago 9001, New Zealand; Scherer, R.; Department of Geology & Environmental Geosciences, Northern Illinois University, DeKalb, Illinois 60115, USA.; Talarico, F.; Universita` di Siena, Dipartimento di Scienze delle Terra, Via Laterina 8, I-53100 Siena, Italy; Krissek, L.; Ohio State University, Department of Geological Sciences, 275 Mendenhall Lab, 125 South Oval Mall, Columbus, Ohio 43210, USA; Niessen, F.; Alfred Wegener Institute, Department of Geosciences, Postfach 12 01 6, Am Alten Hafen 26, D-27515 Bremerhaven, Germany; Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Wilson, T.; Ohio State University, Department of Geological Sciences, 275 Mendenhall Lab, 125 South Oval Mall, Columbus, Ohio 43210, USA; Carter, L.; Antarctic Research Centre, Victoria University of Wellington, Kelburn Parade, PO Box 600, Wellington 6012, New Zealand; DeConto, R.; Department of Geosciences, 233 Morrell Science Centre, University of Massachusetts, Amherst, Massachusetts 01003-9297, USA; Huybers, P.; Department of Earth and Planetary Sciences, Harvard University, Massachusetts 02138, USA; McKay, R.; Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington - New Zealand; Pollard, D.; Earth and Environmental Systems Institute, 2217 Earth-Engineering Science Bldg, University Park, PA 16802, USA

    2009-01-01

    Thirty years after oxygen isotope records frommicrofossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages1, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles2. Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the ‘warmer-than- present’ early-Pliocene epoch (̃5–3Myr ago) is needed to better constrain the possibl...

  11. Red shift, blue shift: investigating Doppler shifts, blubber thickness, and migration as explanations of seasonal variation in the tonality of Antarctic blue whale song.

    Science.gov (United States)

    Miller, Brian S; Leaper, Russell; Calderan, Susannah; Gedamke, Jason

    2014-01-01

    The song of Antarctic blue whales (Balaenoptera musculus intermedia) comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1) vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2) long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds. PMID:25229644

  12. Red shift, blue shift: investigating Doppler shifts, blubber thickness, and migration as explanations of seasonal variation in the tonality of Antarctic blue whale song.

    Directory of Open Access Journals (Sweden)

    Brian S Miller

    Full Text Available The song of Antarctic blue whales (Balaenoptera musculus intermedia comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1 vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2 long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds.

  13. Revisión crítica de los estudios sobre biogeografía de macroalgas marinas del Mediterráneo.

    OpenAIRE

    Vargas, J. M.; Real, Raimundo; Flores-Moya, Antonio; Báez, José C.

    2004-01-01

    Revisión crítica de los estudios sobre biogeografía de macroalgas marinas del Mediterráneo. Teniendo en cuenta los procedimientos metodológicos que se siguen en los estudios biogeográficos, se reconocen tres tipos básicos de aproximaciones: biogeografía descriptiva, biogeografía narrativa y biogeografía analítica. En este trabajo se analizan las aportaciones realizadas a la ficogeografía de las macroalgas marinas del mar Mediterráneo, atendiendo a cada una de las tres aproximaciones posibles....

  14. Non-destructive alpha-particle activation analysis of P, Cl, K and Ca in marine macro-alga samples using synthetic multielement reference material as comparative standard

    International Nuclear Information System (INIS)

    A Synthetic Reference Material (SyRM) composed with accurately known amounts of 12 elements has been prepared. The elemental composition of the SyRM is closely similar to that of marine macro-algae sample. The elemental composition of the SyRM was regulated by the starting materials used for the synthesis. The SyRM was used as a comparative standard for non-destructive alpha-particle activation analysis of marine macro-alga samples. P, Cl, K and Ca were determined simultaneously without correction for alpha range due to difference in the elemental composition between the analytical samples and the comparative standard. (author) 19 refs.; 4 tabs

  15. Determination of nanogram levels of lanthanoids in a marine macro-alga by neutron activation analysis combined with separation by selective precipitation

    International Nuclear Information System (INIS)

    Preseparation of lanthanoids by substoichiometric precipitation of calcium oxalate and simple radiochemical separation of lanthanoids by lanthanum oxalate have been developed. They were combined with neutron activation analysis of a marine macro-alga (Laminaria religiosa, brown alga) sample. Quantitative recovery of lanthanoids throughout the procedure was examined by radiotracer technique. Eleven lanthanoids, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Er, Yb and Lu, at 0.7-140 ng g-1 were determined with a relative standard deviation of 1-7% (n=3). Concentrations of lanthanoids in the marine macro-alga were compared with land plant and sea water. (author) 22 refs.; 1 fig.; 4 tabs

  16. Evaluation of nitrogen sources in the Urías lagoon system, Gulf of California, based on stable isotopes in macroalgae

    OpenAIRE

    María Julia Ochoa-Izaguirre; Martín Federico Soto-Jiménez

    2013-01-01

    The concentrations of chemical forms of nitrogen (N) and their isotopic composition in the water column and the 15N signals in 738 samples of macroalgae collected during one year across the Urías lagoon system (Mazatlán, Sinaloa, Mexico) were analyzed in order to study the N sources. The 15N-macroalgae premise is that they register and integrate the variability of N and may provide time-integrated information about N pollution. To validate this premise, we applied two models to predict the is...

  17. A Bivalve Proxy for Neogene Antarctic Shelf Marine Environments

    Science.gov (United States)

    Clark, N. A.; Williams, M.; Quilty, P. G.; Leng, M. J.; Zalasiewicz, J. A.; Smellie, J.; Dowsett, H. J.

    2012-12-01

    The Neogene shallow-marine successions of the Antarctic Peninsula and of the East Antarctic region preserve rich assemblages of bivalve molluscs. These bivalve molluscs provide a detailed record of palaeoseasonality in the chemical signature and morphology of their shells that can be used to assess sea temperatures and sea ice extent for the Antarctic shelf during the Pliocene. Analyses identify the following. 1) Neogene bivalves from James Ross Island, Antarctic Peninsula, comprise material of late Miocene through to late Pliocene age. Results identify warm (ca. 3-10 °C) early Pliocene sea temperatures, and cooler late Pliocene sea temperatures (ca. 0-4 °C), and flag a cooling trend which is consistent with the evolution of polar climate through this interval. 2) Neogene bivalves from the Larsemann Hills, East Antarctic, identify generally warmer than present sea temperatures (ca. 0-11 °C) in the early Pliocene consistent with data from other fossil groups of this age, including dolphins and silicoflagellates. The new data may provide significant ground truth for climate models assessing the Southern Ocean and Antarctic shelf climate.

  18. Transcriptomics and comparative analysis of three antarctic notothenioid fishes.

    Directory of Open Access Journals (Sweden)

    Seung Chul Shin

    Full Text Available For the past 10 to 13 million years, Antarctic notothenioid fish have undergone extraordinary periods of evolution and have adapted to a cold and highly oxygenated Antarctic marine environment. While these species are considered an attractive model with which to study physiology and evolutionary adaptation, they are poorly characterized at the molecular level, and sequence information is lacking. The transcriptomes of the Antarctic fishes Notothenia coriiceps, Chaenocephalus aceratus, and Pleuragramma antarcticum were obtained by 454 FLX Titanium sequencing of a normalized cDNA library. More than 1,900,000 reads were assembled in a total of 71,539 contigs. Overall, 40% of the contigs were annotated based on similarity to known protein or nucleotide sequences, and more than 50% of the predicted transcripts were validated as full-length or putative full-length cDNAs. These three Antarctic fishes shared 663 genes expressed in the brain and 1,557 genes expressed in the liver. In addition, these cold-adapted fish expressed more Ub-conjugated proteins compared to temperate fish; Ub-conjugated proteins are involved in maintaining proteins in their native state in the cold and thermally stable Antarctic environments. Our transcriptome analysis of Antarctic notothenioid fish provides an archive for future studies in molecular mechanisms of fundamental genetic questions, and can be used in evolution studies comparing other fish.

  19. Future Antarctic bed topography and its implications for ice sheet dynamics

    Directory of Open Access Journals (Sweden)

    S. Adhikari

    2014-01-01

    Full Text Available The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A~recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS is generally losing its mass since the last glacial maximum (LGM. In a sustained warming climate, the AIS is predicted to retreat at a greater pace primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA capability of the Ice Sheet System Model (ISSM to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that the past loading is relatively less important than future loading on the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS may uplift by a few meters and a few tens of meters at years 2100 and 2500 AD, respectively, and that the East Antarctic Ice Sheet (EAIS is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay approaches roughly 45 mm yr−1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is associated with the flattening of reverse bed, reduction of local sea depth, and thus the extension of grounding line (GL towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote the stability to marine portions of the ice sheet in future.

  20. Physiological adaptation of an Antarctic Na+/K+-ATPase to the cold.

    Science.gov (United States)

    Galarza-Muñoz, Gaddiel; Soto-Morales, Sonia I; Holmgren, Miguel; Rosenthal, Joshua J C

    2011-07-01

    Because enzymatic activity is strongly suppressed by the cold, polar poikilotherms face significant adaptive challenges. For example, at 0°C the catalytic activity of a typical enzyme from a temperate organism is reduced by more than 90%. Enzymes embedded in the plasma membrane, such as the Na(+)/K(+)-ATPase, may be even more susceptible to the cold because of thermal effects on the lipid bilayer. Accordingly, adaptive changes in response to the cold may include adjustments to the enzyme or the surrounding lipid environment, or synergistic changes to both. To assess the contribution of the enzyme itself, we cloned orthologous Na(+)/K(+)-ATPase α-subunits from an Antarctic (Pareledone sp.; -1.8°C) and a temperate octopus (Octopus bimaculatus; ∼18°C), and compared their turnover rates and temperature sensitivities in a heterologous expression system. The primary sequences of the two pumps were found to be highly similar (97% identity), with most differences being conservative changes involving hydrophobic residues. The physiology of the pumps was studied using an electrophysiological approach in intact Xenopus oocytes. The voltage dependence of the pumps was equivalent. However, at room temperature the maximum turnover rate of the Antarctic pump was found to be 25% higher than that of the temperate pump. In addition, the Antarctic pump exhibited a lower temperature sensitivity, leading to significantly higher relative activity at lower temperatures. Orthologous Na(+)/K(+) pumps were then isolated from two tropical and two Arctic octopus. The temperature sensitivities of these pumps closely matched those of the temperate and Antarctic pumps, respectively. Thus, reduced thermal sensitivity appears to be a common mechanism driving cold adaptation in the Na(+)/K(+)-ATPase. PMID:21653810

  1. Evaluation of soil bioremediation techniques in an aged diesel spill at the Antarctic Peninsula.

    Science.gov (United States)

    de Jesus, Hugo E; Peixoto, Raquel S; Cury, Juliano C; van Elsas, Jan D; Rosado, Alexandre S

    2015-12-01

    Many areas on the Antarctic continent already suffer from the direct and indirect influences of human activities. The main cause of contamination is petroleum hydrocarbons because this compound is used as a source of energy at the many research stations around the continent. Thus, the current study aims to evaluate treatments for bioremediation (biostimulation, bioaugmentation, and bioaugmentation + biostimulation) using soils from around the Brazilian Antarctic Station "Comandante Ferraz" (EACF), King George Island, Antarctic Peninsula. The experiment lasted for 45 days, and at the end of this period, chemical and molecular analyses were performed. Those analyses included the quantification of carbon and nitrogen, denaturing gradient gel electrophoresis (DGGE) analysis (with gradient denaturation), real-time PCR, and quantification of total hydrocarbons and polyaromatics. Molecular tests evaluated changes in the profile and quantity of the rrs genes of archaea and bacteria and also the alkB gene. The influence of the treatments tested was directly related to the type of soil used. The work confirmed that despite the extreme conditions found in Antarctic soils, the bacterial strains degraded hydrocarbons and bioremediation treatments directly influenced the microbial communities present in these soils even in short periods. Although the majority of the previous studies demonstrate that the addition of fertilizer seems to be most effective at promoting bioremediation, our results show that for some conditions, autochthonous bioaugmentation (ABA) treatment is indicated. This work highlights the importance of understanding the processes of recovery of contaminated environments in polar regions because time is crucial to the soil recovery and to choosing the appropriate treatment. PMID:26286513

  2. The Australasian Antarctic Expedition 2013-2014: Practicing 'Citizen-Science' in a Changing World

    Science.gov (United States)

    Fogwill, C. J.; Turney, C. S.

    2014-12-01

    Government funding is the cornerstone of modern science. But with declining investment in science across most of the Western World, a major challenge for society is where best to place what little resource we have. Which research questions should have the greatest priority? Nowhere are these issues more pressing than in the Antarctic, where bases have and continue to play host to 'big-science', multi-year programmes of research, locking up logistical support and costs. But in a warming world, the areas with the greatest effects of climate change aren't always near government research stations. With this in mind, in 2012 a plan was formed to visit Commonwealth Bay, a remote area off the East Antarctic Ice Sheet, where in 2010, an iceberg the size of Rhode Island, known as B09B, dramatically knocked a 60-mile long tongue of ice off the Mertz Glacier into the Southern Ocean, setting off a cascade of change. Inspired by the expeditions of the past, we advertised berths for sale to take citizen scientists south with us, harnessing their interest, experience and investment. People responded far and wide. We were oversubscribed, and the Australasian Antarctic Expedition 2013-2014 was born. With the Russian-owned MV Akademik Shokalskiy as the expedition vessel, we set out south from the New Zealand port of Bluff in late November 2013. During our journey south and on the ice we undertook a number of scientific firsts for the region actively engaging the volunteer scientists on board in projects ranging from oceanography, biology, ecology, geology and glaciaology. The expedition demostrated how private funding could support targeted programmes of research and communicate it to the wider world. Small-science research can capture the public's imagination and also reap real scientific outputs. Although it is a funding model developed in the Antarctic a hundred years ago, the beauty is it can applied anywhere in the world.

  3. Parasites of the Antarctic toothfish (Dissostichus mawsoni Norman, 1937 (Perciformes, Nototheniidae in the Pacific sector of the Antarctic

    Directory of Open Access Journals (Sweden)

    Ilya I. Gordeev

    2016-06-01

    Full Text Available The Antarctic toothfish (Dissostichus mawsoni Norman, 1937 is one of the main target species of commercial fisheries in the Antarctic. It is an endemic and is found along the shelf of Antarctica, as well as on the slopes of seamounts, underwater elevations and islands in the sub-Antarctic. It feeds on a variety of fish and cephalopods and can be an intermediate/paratenic host of some helminthes, whose final hosts are whales, seals, large rays and sharks. This article presents new data on toothfish infection in the Pacific sector of the Antarctic. Specimens were examined during commercial longline fishing in the Ross Sea and the Amundsen Sea in January–February 2013. Fourteen species of parasites were found using standard parasitological methods and genetic analysis.

  4. Development of a regional glycerol dialkyl glycerol tetraether (GDGT)-temperature calibration for Antarctic and sub-Antarctic lakes

    Science.gov (United States)

    Foster, Louise C.; Pearson, Emma J.; Juggins, Steve; Hodgson, Dominic A.; Saunders, Krystyna M.; Verleyen, Elie; Roberts, Stephen J.

    2016-01-01

    A regional network of quantitative reconstructions of past climate variability is required to test climate models. In recent studies, temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have enabled past temperature reconstructions in both marine and terrestrial environments. Nevertheless, to date these methods have not been widely applied in high latitude environments due to poor performance of the GDGT-temperature calibrations at lower temperatures. To address this we studied 32 lakes from Antarctica, the sub-Antarctic Islands and Southern Chile to: 1) quantify their GDGT composition and investigate the environmental controls on GDGT composition; and 2) develop a GDGT-temperature calibration model for inferring past temperatures from Antarctic and sub-Antarctic lakes. GDGTs were found in all 32 lakes studied and in 31 lakes branched GDGTs (brGDGTs) were the dominant compounds. Statistical analyses of brGDGT composition in relation to temperature, pH, conductivity and water depth showed that the composition of brGDGTs is strongly correlated with mean summer air temperature (MSAT). This enabled the development of the first regional brGDGT-temperature calibration for use in Antarctic and sub-Antarctic lakes using four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). A key discovery was that GDGT-IIIb is of particular importance in cold lacustrine environments. The addition of this compound significantly improved the model's performance from r2 = 0.67, RMSEP-LOO (leave-one-out) = 2.23 °C, RMSEP-H (h-block) = 2.37 °C when applying the re-calibrated global GDGT-temperature calibration to our Antarctic dataset to r2 = 0.83, RMSEP-LOO = 1.68 °C, RMSEP-H = 1.65 °C for our new Antarctic calibration. This shows that Antarctic and sub-Antarctic, and possibly other high latitude, palaeotemperature reconstructions should be based on a regional GDGT-temperature calibration where specific

  5. Effect of quorum sensing signals produced by seaweed-associated bacteria on carpospore liberation from Gracilaria dura

    OpenAIRE

    Singh, Ravindra Pal; Baghel, Ravi S.; Reddy, C. R. K.; Jha, Bhavanath

    2015-01-01

    Epiphytic and endophytic bacteria associated with green macroalgae Ulva (U. fasciata and U. lactuca) and red macroalgae Gracilaria (G. corticata and G. dura) have been identified from three different seasons to evaluate the effect of quorum sensing (QS) molecules on carpospores liberation from Gracilaria dura. The bacterial isolates belonging to the orders Bacillales, Pseudomonadales, Alteromonadales, and Vibrionales were present in all seasons, whereas Actinomycetales and Enterobacteriales w...

  6. Seaweed-coral interactions: variance in seaweed allelopathy, coral susceptibility, and potential effects on coral resilience.

    Directory of Open Access Journals (Sweden)

    Roberta M Bonaldo

    Full Text Available Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving allelopathic and non-allelopathic macroalgae on three, spatially grouped pairs of no-take Marine Protected Areas (MPAs and non-MPAs in Fiji. In non-MPAs, biomass of herbivorous fishes was 70-80% lower, macroalgal cover 4-9 fold higher, macroalgal-coral contacts 5-15 fold more frequent and 23-67 fold more extensive (measured as % of colony margin contacted by macroalgae, and coral cover 51-68% lower than in MPAs. Coral contacts with allelopathic macroalgae occurred less frequently than expected by chance across all sites, while contact with non-allelopathic macroalgae tended to occur more frequently than expected. Transplants of allelopathic macroalgae (Chlorodesmis fastigiata and Galaxaura filamentosa against coral edges inflicted damage to Acropora aspera and Pocillopora damicornis more rapidly and extensively than to Porites cylindrica and Porites lobata, which appeared more resistant to these macroalgae. Montipora digitata experienced intermediate damage. Extent of damage from macroalgal contact was independent of coral colony size for each of the 10 macroalgal-coral pairings we established. When natural contacts with Galaxaura filamentosa were removed in the field, recovery was rapid for Porites lobata, but Pocillopora damicornis did not recover and damage continued to expand. As macroalgae increase on overfished tropical reefs, allelopathy could produce feedbacks that suppress coral resilience, prevent coral recovery, and promote the stability of algal beds in habitats previously available to corals.

  7. Using SEM-EDX and ICP-OES to Investigate the Elemental Composition of Green Macroalga Vaucheria sessilis

    Directory of Open Access Journals (Sweden)

    Izabela Michalak

    2014-01-01

    Full Text Available The biomass of Vaucheria sessilis forms algal mats in many freshwaters. There is a need to find the method of algal biomass utilization. Vaucheria sessilis is a rich source of micro- and macronutrients and can be used as a soil amendment. In the paper, the elemental composition of enriched, via bioaccumulation process, macroalga was investigated. For this purpose, two independent techniques were used: scanning electron microscopy with an energy dispersive X-ray analytical system (SEMEDX and inductively coupled plasma optical emission spectroscopy (ICP-OES. The biomass was exposed to two microelemental solutions, with Cu(II and Zn(II ions. After two weeks of the experiment, macroalga accumulated 98.5 mg of Zn(II ions in 1 g of dry biomass and 68.9 mg g−1 of Cu(II ions. Micrographs performed by SEM proved that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of cells. Mappings of all cations showed that in the case of the surface of biomass (biosorption, the elements constituted aggregations and in the case of the cross section (bioaccumulation they were evenly distributed. The algal biomass with permanently bound microelements can find an application in many branches of the industry (feed, natural fertilizers, etc..

  8. Homoserine Lactones, Methyl Oligohydroxybutyrates, and Other Extracellular Metabolites of Macroalgae-Associated Bacteria of the Roseobacter Clade: Identification and Functions.

    Science.gov (United States)

    Ziesche, Lisa; Bruns, Hilke; Dogs, Marco; Wolter, Laura; Mann, Florian; Wagner-Döbler, Irene; Brinkhoff, Thorsten; Schulz, Stefan

    2015-09-21

    Twenty-four strains of marine Roseobacter clade bacteria were isolated from macroalgae and investigated for the production of quorum-sensing autoinducers, N-acylhomoserine lactones (AHLs). GC/MS analysis of the extracellular metabolites allowed us to evaluate the release of other small molecules as well. Nineteen strains produced AHLs, ranging from 3-OH-C10:0-HSL (homoserine lactone) to (2E,11Z)-C18:2-HSL, but no specific phylogenetic or ecological pattern of individual AHL occurrence was observed when cluster analysis was performed. Other identified compounds included indole, tropone, methyl esters of oligomers of 3-hydroxybutyric acid, and various amides, such as N-9-hexadecenoylalanine methyl ester (9-C16:1-NAME), a structural analogue of AHLs. Several compounds were tested for their antibacterial and antialgal activity on marine isolates likely to occur in the habitat of the macroalgae. Both AHLs and 9-C16:1-NAME showed high antialgal activity against Skeletonema costatum, whereas their antibacterial activity was low. PMID:26212108

  9. Biological validation of physical coastal waters classification along the NE Atlantic region based on rocky macroalgae distribution

    Science.gov (United States)

    Ramos, Elvira; Puente, Araceli; Juanes, José Antonio; Neto, João M.; Pedersen, Are; Bartsch, Inka; Scanlan, Clare; Wilkes, Robert; Van den Bergh, Erika; Ar Gall, Erwan; Melo, Ricardo

    2014-06-01

    A methodology to classify rocky shores along the North East Atlantic (NEA) region was developed. Previously, biotypes and the variability of environmental conditions within these were recognized based on abiotic data. A biological validation was required in order to support the ecological meaning of the physical typologies obtained. A database of intertidal macroalgae species occurring in the coastal area between Norway and the South Iberian Peninsula was generated. Semi-quantitative abundance data of the most representative macroalgal taxa were collected in three levels: common, rare or absent. Ordination and classification multivariate analyses revealed a clear latitudinal gradient in the distribution of macroalgae species resulting in two distinct groups: one northern and one southern group, separated at the coast of Brittany (France). In general, the results based on biological data coincided with the results based on physical characteristics. The ecological meaning of the coastal waters classification at a broad scale shown in this work demonstrates that it can be valuable as a practical tool for conservation and management purposes.

  10. Seasonal and spatial variation in species diversity, abundance, and element accumulation capacities of macroalgae in mangrove forests of Zhanjiang, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yubin; LI Yuan; SHI Fei; SUN Xingli; LIN Guanghui

    2014-01-01

    The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types (Avicennia marina assemblage andSonneratia apetala assemblage) in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assem-blages, of which the dominant species wereCladophoropsis zollingeriand Enteromorpha clathrat.Macroal-gal species were significantly most abundant in spring (p<0.05), followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove as-semblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in theS. apetalaassemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgaeC. zollingeri,E. clathrata, andGracilaria salicornia in theA. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.

  11. Cadmium, copper and lead in macroalgae from the Veracruz Reef System, Gulf of Mexico: Spatial distribution and rainy season variability

    International Nuclear Information System (INIS)

    Highlights: ► Cd, Cu, and Pb were determined in macroalgae from Veracruz Reefs, Gulf of Mexico. ► Mean concentrations were lower or similar to those from other coastal areas. ► Cd and Pb levels are controlled by fluvial discharge. ► Sediment scavenging also controls environmental trace metal levels. ► Pb environmental concentrations have been decreasing in the lasts two decades. -- Abstract: This study focused on the spatial distribution of trace metals in the Veracruz Reef System in the Southern Gulf of Mexico, and its variability in the early (July) and late (September) rainy season of 2008, by analyzing the concentration of Cd, Cu and Pb in benthic macroalgae. Mean concentrations are lower (Pb 295 ± 347 ng g−1, Cd 17.9 ± 15.0 ng g−1), or similar (Cu 3.4 ± 4.5 μg g−1) to those reported from other coastal areas. Cd and Pb concentrations are influenced by the discharge of the Jamapa River, evidencing a fluvial control on coastal trace metal levels. Also, Cd and Cu concentrations were lower in the late rainy season, when there is a high load of suspended sediments derived from fluvial discharge, which probably adsorb dissolved metals decreasing their bioavailability. Pb concentrations have been decreasing in the last two decades in the SGM, after the banning of leaded-gasoline in the late 20th century

  12. Unequivocal detection of ozone recovery in the Antarctic Ozone Hole through significant increases in atmospheric layers with minimum ozone

    Science.gov (United States)

    de Laat, Jos; van Weele, Michiel; van der A, Ronald

    2015-04-01

    An important new landmark in present day ozone research is presented through MLS satellite observations of significant ozone increases during the ozone hole season that are attributed unequivocally to declining ozone depleting substances. For many decades the Antarctic ozone hole has been the prime example of both the detrimental effects of human activities on our environment as well as how to construct effective and successful environmental policies. Nowadays atmospheric concentrations of ozone depleting substances are on the decline and first signs of recovery of stratospheric ozone and ozone in the Antarctic ozone hole have been observed. The claimed detection of significant recovery, however, is still subject of debate. In this talk we will discuss first current uncertainties in the assessment of ozone recovery in the Antarctic ozone hole by using multi-variate regression methods, and, secondly present an alternative approach to identify ozone hole recovery unequivocally. Even though multi-variate regression methods help to reduce uncertainties in estimates of ozone recovery, great care has to be taken in their application due to the existence of uncertainties and degrees of freedom in the choice of independent variables. We show that taking all uncertainties into account in the regressions the formal recovery of ozone in the Antarctic ozone hole cannot be established yet, though is likely before the end of the decade (before 2020). Rather than focusing on time and area averages of total ozone columns or ozone profiles, we argue that the time evolution of the probability distribution of vertically resolved ozone in the Antarctic ozone hole contains a better fingerprint for the detection of ozone recovery in the Antarctic ozone hole. The advantages of this method over more tradition methods of trend analyses based on spatio-temporal average ozone are discussed. The 10-year record of MLS satellite measurements of ozone in the Antarctic ozone hole shows a

  13. A study of extraction and characterization of alginates obtained from brown macroalgae Sargassum duplicatum and Sargassum crassifolium from Indonesia

    Directory of Open Access Journals (Sweden)

    Decky J. Indrani

    2013-06-01

    Full Text Available Background: Worldwide commercially available alginate have been used for tissue engineering purposes. The macroalgae Sargassum obtained from Indonesia have been used for various purposes, however, they have not been applied for tissue engineering scaffolds. Purpose: This study was aimed to extract alginate from the macroalgae Sargassum from Indonesia sea and to characterize in morphology, chemical element and functional groups. Methods: Macroalgae Sargassum duplicatum (S. Duplicatum and Sargassum crassifolium (S. Crassifolium were collected from Banten, Indonesia. Extraction of alginates were carried out using the alkaline extraction procedure. Scanning electron microscopy as well as X-ray Fluorescence and Fouirer Transform Infra-Red spectroscopy were used to characterize the extracted powders. Obtained data from the extracted powders were compared to those of the commercially available alginate. Results: Extraction using the alkaline method has resulted in S.duplicatum and S.crassifolium alginate powders. Alginate particles were suggested as irregular shapes with various dimension. Element components were mainly Na and Ca, whereas, minor elements were considered as negative impurities. COO- and C-O-C groups were evident in the finger print regio. The characteristics of Alginates extracted from the macroalgae S.duplicatum and S.crassifolium found similar to those of the commercially available alginate. Conclusion: Extraction obtained from the macroalgae S.duplicatum and S.crassifolium showed the typical alginate and the morphology, chemical element and functional groups were in agreement with those of the commercially available alginate.Latar belakang: Alginat dari berbagai penjuru dunia telah digunakan untuk kegunaan rekayasa jaringan. Alginat dari alga makro Sargassum yang diperoleh dari Indonesia telah digunakan untuk berbagai kegunaan, namun ini belum diterapkan untuk scaffold jaringan. Tujuan: Untuk mengekstrak alginat dari alga makro

  14. Comparative bioavailability of radionuclides in macroalgae from Black sea coastal environment

    International Nuclear Information System (INIS)

    Radionuclide and heavy metal content is measured by gamma spectroscopy and Atomic Absorption Spectroscopy in the commonest species of the Black Sea red, brown, and green macroalgae, sampled in the period 1996 - 2002. Radionuclide content was measured in ten different macrophytic algae species (five green: Cladophora vagabunda, Ulva rigida, Enteromorpha intestinal, Chaetomorpha gracilis, Bryopsis plumosa; two brown: Cystoseira crinita and Cystoseira barbata; three red: Ceramium rubrum, Callithamnium corymbosum, Corallina officinalis) from eleven sampling locations for eight consecutive years. The measured concentrations of artificial and natural gamma emitters in algae depend on the alga species. The obtained range for 137Cs in algae is 1.2 - 26 Bq/kg. The average values for the natural nuclides are 238U - 13 Bq/kg; 232Th - 6 Bq/kg and for 226Ra - 8 Bq/kg. The measured natural nuclides in the species Bryopsis plumosa are with two orders of magnitude higher than other species at the same location. Significant differences in Cs-137 concentrations were found among different species growing under similar environmental conditions at same locations, suggesting that uptake does not follow physical levels but influenced by allometric parameters and physiological mechanisms. Cs-137 content in collected sea algae follows the descending order: Ceramium rubrum , Cladophora vagabunda, Cystoseira barbata, Cystoseira crinita, Enteromorpha intestinalis, Ulva rigida, Callithamnium corymbosum, Corallina officinalis, Chaetomorpha gracilis. A comparison of the stations studied indicated that the accumulation degree is also dependent on the geomorphology of the specific area. Higher levels are obtained in the northern part of the Black Sea basin due to current circulation originating from the outflow of the rivers Danube, Dnyepr and Dnester, also at the south part of the Black sea coast. It is concluded that the general dispersion of Cs-137 results from the water circulation regime

  15. Antarctic Single Frames = Frame Level Records of Antarctica Photos: 1946 - 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Aerial photographs of Antarctica from the United States Antarctic Resource Center (USARC) and the British Antarctic Survey (BAS) are maintained in this collection....

  16. Marine macroalgae in the agronomy and potential use of floating sargassum for manure production in the San Andres and Providencia Archipelago, Colombia

    International Nuclear Information System (INIS)

    An account is made on the use of marine macroalgae in agronomy and the potential that floating Sargassum arriving to san Andres and Providencia has for this activity. This Sargassum, which has been a nuisance for the tourist economy of the islands, promises to be an excellent resource for manure production

  17. Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae: a brief theoretical discussion of likely scenarios

    Directory of Open Access Journals (Sweden)

    Paulo A. Horta

    2012-08-01

    Full Text Available Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalgae.

  18. Distribution, diversity and bioprospecting of bioactive compounds from cryptic fungal communities associated with endemic and cold-adapted macroalgae in Antarctica

    Science.gov (United States)

    We surveyed the distribution and diversity of fungi associated with eight macroalgae from Antarctica and their capability to produce bioactive compounds. The collections yielded 148 fungal isolates identified using molecular methods into 21 genera and 43 species. The most frequent taxa were Geomyces...

  19. Biogeochemical effects of macroalgae decomposition on intertidal microbenthos: a microcosm experiment

    DEFF Research Database (Denmark)

    Garcia-Robledo, Emilio; Corzo, Alfonso; Garcia de Lomas, J;

    2008-01-01

    3-, NO2-, NH4+, PO43- and SiO32-), dissolved organic carbon (DOC) and inorganic carbon (DIC) were measured in the inflowing and outflowing seawater. Vertical microprofiles of O2, pH and H2S at the sediment-water interface, sediment contents of organic matter (OM), inorganic and organic carbon (Corg......), total nitrogen (N) and inorganic nutrients were measured before and after addition of macroalgal detritus. Changes in the taxonomic composition of microphytobenthos were studied by optical microscopy and by the analysis of photosynthetic pigments. Macroalgal detritus vanished from the sediment surface...

  20. The safety band of Antarctic ice shelves

    Science.gov (United States)

    Fürst, Johannes Jakob; Durand, Gaël; Gillet-Chaulet, Fabien; Tavard, Laure; Rankl, Melanie; Braun, Matthias; Gagliardini, Olivier

    2016-05-01

    The floating ice shelves along the seaboard of the Antarctic ice sheet restrain the outflow of upstream grounded ice. Removal of these ice shelves, as shown by past ice-shelf recession and break-up, accelerates the outflow, which adds to sea-level rise. A key question in predicting future outflow is to quantify the extent of calving that might precondition other dynamic consequences and lead to loss of ice-shelf restraint. Here we delineate frontal areas that we label as `passive shelf ice’ and that can be removed without major dynamic implications, with contrasting results across the continent. The ice shelves in the Amundsen and Bellingshausen seas have limited or almost no `passive’ portion, which implies that further retreat of current ice-shelf fronts will yield important dynamic consequences. This region is particularly vulnerable as ice shelves have been thinning at high rates for two decades and as upstream grounded ice rests on a backward sloping bed, a precondition to marine ice-sheet instability. In contrast to these ice shelves, Larsen C Ice Shelf, in the Weddell Sea, exhibits a large `passive’ frontal area, suggesting that the imminent calving of a vast tabular iceberg will be unlikely to instantly produce much dynamic change.

  1. Iodine monoxide in the Antarctic snowpack

    Directory of Open Access Journals (Sweden)

    U. Platt

    2009-11-01

    Full Text Available Recent ground-based and space borne observations suggest the presence of significant amounts of iodine monoxide in the boundary layer of Antarctica, which are expected to have an impact on the ozone budget and might contribute to the formation of new airborne particles. So far, the source of these iodine radicals has been unknown. This paper presents long-term measurements of iodine monoxide at the German Antarctic research station Neumayer, which indicate that the snowpack is the main source for iodine radicals. The measurements have been performed using multi-axis differential optical absorption spectroscopy (MAX-DOAS. Using a coupled atmosphere-snowpack radiative transfer model, the comparison of the signals observed from scattered skylight and from light reflected by the snowpack yields several ppb of iodine monoxide in the upper layers of the sunlit snowpack throughout the year. Snow pit samples from Neumayer Station contain up to 700 ng/l of total iodine, representing a sufficient reservoir for these extraordinarily high IO concentrations.

  2. Iodine monoxide in the Antarctic snowpack

    Directory of Open Access Journals (Sweden)

    U. Frieß

    2010-03-01

    Full Text Available Recent ground-based and space borne observations suggest the presence of significant amounts of iodine monoxide in the boundary layer of Antarctica, which are expected to have an impact on the ozone budget and might contribute to the formation of new airborne particles. So far, the source of these iodine radicals has been unknown. This paper presents long-term measurements of iodine monoxide at the German Antarctic research station Neumayer, which indicate that high IO concentrations in the order of 50 ppb are present in the snow interstitial air. The measurements have been performed using multi-axis differential optical absorption spectroscopy (MAX-DOAS. Using a coupled atmosphere – snowpack radiative transfer model, the comparison of the signals observed from scattered skylight and from light reflected by the snowpack yields several ppb of iodine monoxide in the upper layers of the sunlit snowpack throughout the year. Snow pit samples from Neumayer Station contain up to 700 ng/l of total iodine, representing a sufficient reservoir for these extraordinarily high IO concentrations.

  3. Responses of Antarctic Oscillation to global warming

    Science.gov (United States)

    Feng, S.

    2015-12-01

    The Antarctic Oscillation (AAO) is the major annular mode dominates the spatiotemporal variability of the atmospheric circulation in the Southern Hemisphere. This study examined the sensitivity of AAO to future warming by analyzing the outputs of 34 state-of-the-art climate models participating in phase 5 of the Coupled Model Intercomparion Project (CMIP5). The model simulations include the stabilized (RCP4.5) and business as usual (RCP8.5) scenarios as well as the idealized 1% per year increase in atmospheric CO2 to quadrupling (1pctCO2) and an instantaneous quadrupling of CO2 (abrupt4xCO2). We show that the CMIP5 models on average simulate increases in the AAO in every season by 2100 under the RCP4.5 and RCP8.5 scenarios. However, due to the impacts of ozone, aerosol and land use changes, the amplitudes of the projected changes in AAO to future climate scenarios are quit different on different seasons. After the impact of ozone, aerosol and land use changes were removed; it was found that the impact of greenhouse gases (GHGs) on AAO is similar on all seasons. The increases of AAO are accelerating following the increase of GHGs. Our results are also consistent with the simulations of 1pctCO2 and abrupt4xCO2.

  4. Automated detection of Antarctic blue whale calls.

    Science.gov (United States)

    Socheleau, Francois-Xavier; Leroy, Emmanuelle; Pecci, Andres Carvallo; Samaran, Flore; Bonnel, Julien; Royer, Jean-Yves

    2015-11-01

    This paper addresses the problem of automated detection of Z-calls emitted by Antarctic blue whales (B. m. intermedia). The proposed solution is based on a subspace detector of sigmoidal-frequency signals with unknown time-varying amplitude. This detection strategy takes into account frequency variations of blue whale calls as well as the presence of other transient sounds that can interfere with Z-calls (such as airguns or other whale calls). The proposed method has been tested on more than 105 h of acoustic data containing about 2200 Z-calls (as found by an experienced human operator). This method is shown to have a correct-detection rate of up to more than 15% better than the extensible bioacoustic tool package, a spectrogram-based correlation detector commonly used to study blue whales. Because the proposed method relies on subspace detection, it does not suffer from some drawbacks of correlation-based detectors. In particular, it does not require the choice of an a priori fixed and subjective template. The analytic expression of the detection performance is also derived, which provides crucial information for higher level analyses such as animal density estimation from acoustic data. Finally, the detection threshold automatically adapts to the soundscape in order not to violate a user-specified false alarm rate. PMID:26627784

  5. Prospects for surviving climate change in Antarctic aquatic species

    Directory of Open Access Journals (Sweden)

    Peck Lloyd S

    2005-06-01

    Full Text Available Abstract Maritime Antarctic freshwater habitats are amongst the fastest changing environments on Earth. Temperatures have risen around 1°C and ice cover has dramatically decreased in 15 years. Few animal species inhabit these sites, but the fairy shrimp Branchinecta gaini typifies those that do. This species survives up to 25°C daily temperature fluctuations in summer and passes winter as eggs at temperatures down to -25°C. Its annual temperature envelope is, therefore around 50°C. This is typical of Antarctic terrestrial species, which exhibit great physiological flexibility in coping with temperature fluctuations. The rapidly changing conditions in the Maritime Antarctic are enhancing fitness in these species by increasing the time available for feeding, growth and reproduction, as well as increasing productivity in lakes. The future problem these animals face is via displacement by alien species from lower latitudes. Such invasions are now well documented from sub-Antarctic sites. In contrast the marine Antarctic environment has very stable temperatures. However, seasonality is intense with very short summers and long winter periods of low to no algal productivity. Marine animals grow slowly, have long generation times, low metabolic rates and low levels of activity. They also die at temperatures between +5°C and +10°C. Failure of oxygen supply mechanisms and loss of aerobic scope defines upper temperature limits. As temperature rises, their ability to perform work declines rapidly before lethal limits are reached, such that 50% of populations of clams and limpets cannot perform essential activities at 2–3°C, and all scallops are incapable of swimming at 2°C. Currently there is little evidence of temperature change in Antarctic marine sites. Models predict average global sea temperatures will rise by around 2°C by 2100. Such a rise would take many Antarctic marine animals beyond their survival limits. Animals have 3 mechanisms for

  6. Complex Geodetic Research in Ukrainian Antarctic Station "Academician Vernadsky" (Years 2002 - 2005, 2013-2014)

    Science.gov (United States)

    Tretyak, Kornyliy; Hlotov, Volodymyr; Holubinka, Yuriy; Marusazh, Khrystyna

    2016-06-01

    In this paper is given an information about complex geodetic research in Ukrainian Antarctic station "Academician Vernadsky". Research were carried by Lviv polytechnic scientists, during Antarctic expeditions in years 2002 - 2005, 2013, 2014. Main objectives of the studies were: (a) study of the islands glaciers surface volumes changes in Antarctic archipelago and Antarctic Peninsula using terestrial laser scaning and digital terrestrial stereophotogrammetry survey; (b) investigation of Penola strain tectonic fault, using the results of precise GNSS observations.

  7. On the Linkage between Antarctic Surface Water Stratification and Global Deep-Water Temperature

    OpenAIRE

    Keeling, R.F.; Visbeck, Martin

    2011-01-01

    The suggestion is advanced that the remarkably low static stability of Antarctic surface waters may arise from a feedback loop involving global deep-water temperatures. If deep-water temperatures are too warm, this promotes Antarctic convection, thereby strengthening the inflow of Antarctic Bottom Water into the ocean interior and cooling the deep ocean. If deep waters are too cold, this promotes Antarctic stratification allowing the deep ocean to warm because of the input of North Atlantic D...

  8. The spatial extent and dynamics of the Antarctic Cold Reversal

    Science.gov (United States)

    Pedro, Joel B.; Bostock, Helen C.; Bitz, Cecilia M.; He, Feng; Vandergoes, Marcus J.; Steig, Eric J.; Chase, Brian M.; Krause, Claire E.; Rasmussen, Sune O.; Markle, Bradley R.; Cortese, Giuseppe

    2016-01-01

    Antarctic ice cores show that a millennial-scale cooling event, the Antarctic Cold Reversal (14,700 to 13,000 years ago), interrupted the last deglaciation. The Antarctic Cold Reversal coincides with the Bølling-Allerød warm stage in the North Atlantic, providing an example of the inter-hemispheric coupling of abrupt climate change generally referred to as the bipolar seesaw. However, the ocean-atmosphere dynamics governing this coupling are debated. Here we examine the extent and expression of the Antarctic Cold Reversal in the Southern Hemisphere using a synthesis of 84 palaeoclimate records. We find that the cooling is strongest in the South Atlantic and all regions south of 40° S. At the same time, the terrestrial tropics and subtropics show abrupt hydrologic variations that are significantly correlated with North Atlantic climate changes. Our transient global climate model simulations indicate that the observed extent of Antarctic Cold Reversal cooling can be explained by enhanced northward ocean heat transport from the South to North Atlantic, amplified by the expansion and thickening of sea ice in the Southern Ocean. The hydrologic variations at lower latitudes result from an opposing enhancement of southward heat transport in the atmosphere mediated by the Hadley circulation. Our findings reconcile previous arguments about the relative dominance of ocean and atmospheric heat transports in inter-hemispheric coupling, demonstrating that the spatial pattern of past millennial-scale climate change reflects the superposition of both.

  9. Relative changes in krill abundance inferred from Antarctic fur seal.

    Directory of Open Access Journals (Sweden)

    Tao Huang

    Full Text Available Antarctic krill Euphausia superba is a predominant species in the Southern Ocean, it is very sensitive to climate change, and it supports large stocks of fishes, seabirds, seals and whales in Antarctic marine ecosystems. Modern krill stocks have been estimated directly by net hauls and acoustic surveys; the historical krill density especially the long-term one in the Southern Ocean, however, is unknown. Here we inferred the relative krill population changes along the West Antarctic Peninsula (WAP over the 20th century from the trophic level change of Antarctic fur seal Arctocephalus gazella using stable carbon (δ(13C and nitrogen (δ(15N isotopes of archival seal hairs. Since Antarctic fur seals feed preferentially on krill, the variation of δ(15N in seal hair indicates a change in the proportion of krill in the seal's diets and thus the krill availability in local seawater. For the past century, enriching fur seal δ(15N values indicated decreasing krill availability. This is agreement with direct observation for the past ∼30 years and suggests that the recently documented decline in krill populations began in the early parts of the 20th century. This novel method makes it possible to infer past krill population changes from ancient tissues of krill predators.

  10. The Antarctic ozone depletion caused by Erebus volcano gas emissions

    Science.gov (United States)

    Zuev, V. V.; Zueva, N. E.; Savelieva, E. S.; Gerasimov, V. V.

    2015-12-01

    Heterogeneous chemical reactions releasing photochemically active molecular chlorine play a key role in Antarctic stratospheric ozone destruction, resulting in the Antarctic ozone hole. Hydrogen chloride (HCl) is one of the principal components in these reactions on the surfaces of polar stratospheric clouds (PSCs). PSCs form during polar nights at extremely low temperatures (lower than -78 °C) mainly on sulfuric acid (H2SO4) aerosols, acting as condensation nuclei and formed from sulfur dioxide (SO2). However, the cause of HCl and H2SO4 high concentrations in the Antarctic stratosphere, leading to considerable springtime ozone depletion, is still not clear. Based on the NCEP/NCAR reanalysis data over the last 35 years and by using the NOAA HYSPLIT trajectory model, we show that Erebus volcano gas emissions (including HCl and SO2) can reach the Antarctic stratosphere via high-latitude cyclones with the annual average probability Pbarann. of at least ∼0.235 (23.5%). Depending on Erebus activity, this corresponds to additional annual stratospheric HCl mass of 1.0-14.3 kilotons (kt) and SO2 mass of 1.4-19.7 kt. Thus, Erebus volcano is the natural and powerful source of additional stratospheric HCl and SO2, and hence, the cause of the Antarctic ozone depletion, together with man-made chlorofluorocarbons.

  11. Antarctic ecosystems as models for extraterrestrial surface habitats

    Science.gov (United States)

    Wynn-Williams, D. D.; Edwards, H. G. M.

    2000-09-01

    Surface habitats in Antarctic deserts are near the limits of life on Earth and resemble those hypothesized for early Mars. Cyanobacteria dominate the transient riverbeds, stromatolitic sediments in ice-covered lakes, and endolithic communities in translucent rock. There is still no direct evidence of photosynthetic life on early Mars, but cyanobacteria are amongst the earliest microbes detectable in the fossil record for analogous habitats on Earth. Key biomolecules persist in Antarctic microbial habitats, even after extinction by excessive low temperatures, desiccation and UV-B stress within the Ozone Hole. Pigments (or their fossil residues), such as chlorophyll and the UV-protectants scytonemin, carotene and quinones, are good biomarkers. To show not only their presence but also their micro-spatial distribution in situ, we describe the use of FT-Raman spectroscopy with 1064 nm excitation to avoid autofluorescence from the pigments. We report not only the diversity of biomolecules that we have diagnosed from their unique Raman spectra of Antarctic cyanobacterial communities, but also their functional stratification in endolithic communities. Our analyses of Antarctic habitats show the potential of this remote, non-intrusive technique to probe for buried biomolecules on future Mars missions and in Antarctic Lake Vostok, >4 km beneath the Central Ice Sheet, with implications for the putative analogous sub-ice ocean on Europa.

  12. A geoelectrical survey above an Antarctic ice shelf

    Directory of Open Access Journals (Sweden)

    M. Pavan

    1998-06-01

    Full Text Available A geoelectrical survey was performed on the Hells Gate ice shelf (Victoria Land-Antarctic within the framework of an integrated geophysical and glaciological research program. The resistivity profiles show a similar trend, with resistivity values ranging from about 25000 W · m to 500000 W · m. These results have been interpreted as the effect of a sharp transition from "marine ice" to "continental" ice an interpretation that is consistent with the results of surface mapping. Interpreting the Vertical Electrical Soundings (VES is a complex process. In fact, the alternating layers of ice with different compositions and salt content generate great uncertainty relative to the corresponding electric stratigraphies. To solve these problems of equivalency, all the available constraints were used including the drilling thickness, seismic reflection profiles as well as radar profiles. The results were used to provide what is mainly a qualitative overview that is coherent with the glaciological hypotheses relative to the evolution and structure proposed by some researchers for this ice shelf.

  13. Thin Layer Sensory Cues Affect Antarctic Krill Swimming Kinematics

    Science.gov (United States)

    True, A. C.; Webster, D. R.; Weissburg, M. J.; Yen, J.

    2013-11-01

    A Bickley jet (laminar, planar free jet) is employed in a recirculating flume system to replicate thin shear and phytoplankton layers for krill behavioral assays. Planar laser-induced fluorescence (LIF) and particle image velocimetry (PIV) measurements quantify the spatiotemporal structure of the chemical and free shear layers, respectively, ensuring a close match to in situ hydrodynamic and biochemical conditions. Path kinematics from digitized trajectories of free-swimming Euphausia superba examine the effects of hydrodynamic sensory cues (deformation rate) and bloom level phytoplankton patches (~1000 cells/mL, Tetraselamis spp.) on krill behavior (body orientation, swimming modes and kinematics, path fracticality). Krill morphology is finely tuned for receiving and deciphering both hydrodynamic and chemical information that is vital for basic life processes such as schooling behaviors, predator/prey, and mate interactions. Changes in individual krill behavior in response to ecologically-relevant sensory cues have the potential to produce population-scale phenomena with significant ecological implications. Krill are a vital trophic link between primary producers (phytoplankton) and larger animals (seabirds, whales, fish, penguins, seals) as well as the subjects of a valuable commercial fishery in the Southern Ocean; thus quantifying krill behavioral responses to relevant sensory cues is an important step towards accurately modeling Antarctic ecosystems.

  14. Risk maps for Antarctic krill under projected Southern Ocean acidification

    Science.gov (United States)

    Kawaguchi, S.; Ishida, A.; King, R.; Raymond, B.; Waller, N.; Constable, A.; Nicol, S.; Wakita, M.; Ishimatsu, A.

    2013-09-01

    Marine ecosystems of the Southern Ocean are particularly vulnerable to ocean acidification. Antarctic krill (Euphausia superba; hereafter krill) is the key pelagic species of the region and its largest fishery resource. There is therefore concern about the combined effects of climate change, ocean acidification and an expanding fishery on krill and ultimately, their dependent predators--whales, seals and penguins. However, little is known about the sensitivity of krill to ocean acidification. Juvenile and adult krill are already exposed to variable seawater carbonate chemistry because they occupy a range of habitats and migrate both vertically and horizontally on a daily and seasonal basis. Moreover, krill eggs sink from the surface to hatch at 700-1,000m (ref. ), where the carbon dioxide partial pressure (pCO2) in sea water is already greater than it is in the atmosphere. Krill eggs sink passively and so cannot avoid these conditions. Here we describe the sensitivity of krill egg hatch rates to increased CO2, and present a circumpolar risk map of krill hatching success under projected pCO2 levels. We find that important krill habitats of the Weddell Sea and the Haakon VII Sea to the east are likely to become high-risk areas for krill recruitment within a century. Furthermore, unless CO2 emissions are mitigated, the Southern Ocean krill population could collapse by 2300 with dire consequences for the entire ecosystem.

  15. Antarctic DNA moving forward: genomic plasticity and biotechnological potential.

    Science.gov (United States)

    Martínez-Rosales, Cecilia; Fullana, Natalia; Musto, Héctor; Castro-Sowinski, Susana

    2012-06-01

    Antarctica is the coldest, driest, and windiest continent, where only cold-adapted organisms survive. It has been frequently cited as a pristine place, but it has a highly diverse microbial community that is continually seeded by nonindigenous microorganisms. In addition to the intromission of 'alien' microorganisms, global warming strongly affects microbial Antarctic communities, changing the genes (qualitatively and quantitatively) potentially available for horizontal gene transfer. Several mobile genetic elements have been described in Antarctic bacteria (including plasmids, transposons, integrons, and genomic islands), and the data support that they are actively involved in bacterial evolution in the Antarctic environment. In addition, this environment is a genomic source for the identification of novel molecules, and many investigators have used culture-dependent and culture-independent approaches to identify cold-adapted proteins. Some of them are described in this review. We also describe studies for the design of new recombinant technologies for the production of 'difficult' proteins. PMID:22360528

  16. Terrestrial 81Kr-Kr ages of Antarctic meteorites

    International Nuclear Information System (INIS)

    The production rate of 38Ar in meteorites-P(38)-has been determined, as a function of the sample's chemical composition, from 81Kr-Kr exposure ages of four eucrite falls. The cosmogenic 78Kr/83Kr ratio is used to estimate the shielding dependence of P(38). From the ''true'' 38Ar exposure ages and the apparent 81Kr-Kr exposure ages of nine Antarctic eucrite finds, terrestrial ages are calculated. The distribution of terrestrial ages of Allan Hills meteorites is discussed. Meteorites from this blue ice field have two sources: Directly deposited falls and meteorites transported to the Allan Hills inside the moving Antarctic ice sheet. During the surface residence time meteorites decompose due to weathering processes. The weathering ''half-life'' is about 1.6 x 105 a. From the different age distributions of Allan Hills and Yamato meteorites, it is concluded that meteorite concentrations of different Antarctic ice fields need different explanations. (author)

  17. Antarctic Porifera database from the Spanish benthic expeditions

    Directory of Open Access Journals (Sweden)

    Pilar Rios

    2014-04-01

    Full Text Available The information about the sponges in this dataset is derived from the samples collected during five Spanish Antarctic expeditions: Bentart 94, Bentart 95, Gebrap 96, Ciemar 99/00 and Bentart 2003. Samples were collected in the Antarctic Peninsula and Bellingshausen Sea at depths ranging from 4 to 2044 m using va­rious sampling gears.The Antarctic Porifera database from the Spanish benthic expeditions is unique as it provides in­formation for an under-explored region of the Southern Ocean (Bellingshausen Sea. It fills an information gap on Antarctic deep-sea sponges, for which there were previously very few data.This phylum is an important part of the Antarctic biota and plays a key role in the structure of the Antarctic marine benthic community due to its considerable diversity and predominance in different areas. It is often a dominant component of Southern Ocean benthic communities.The quality of the data was controlled very thoroughly with GPS systems onboard the R/V Hesperides and by checking the data against the World Porifera Database (which is part of the World Register of Marine Species, WoRMS. The data are therefore fit for completing checklists, inclusion in biodivers­ity pattern analysis and niche modelling. The authors can be contacted if any additional information is needed before carrying out detailed biodiversity or biogeographic studies.The dataset currently contains 767 occurrence data items that have been checked for systematic reliability. This database is not yet complete and the collection is growing. Specimens are stored in the author’s collection at the Spanish Institute of Oceanography (IEO in the city of Gijón (Spain. The data are available in GBIF.

  18. Antarctic Porifera database from the Spanish benthic expeditions.

    Science.gov (United States)

    Rios, Pilar; Cristobo, Javier

    2014-01-01

    THE INFORMATION ABOUT THE SPONGES IN THIS DATASET IS DERIVED FROM THE SAMPLES COLLECTED DURING FIVE SPANISH ANTARCTIC EXPEDITIONS: Bentart 94, Bentart 95, Gebrap 96, Ciemar 99/00 and Bentart 2003. Samples were collected in the Antarctic Peninsula and Bellingshausen Sea at depths ranging from 4 to 2044 m using various sampling gears. The Antarctic Porifera database from the Spanish benthic expeditions is unique as it provides information for an under-explored region of the Southern Ocean (Bellingshausen Sea). It fills an information gap on Antarctic deep-sea sponges, for which there were previously very few data. This phylum is an important part of the Antarctic biota and plays a key role in the structure of the Antarctic marine benthic community due to its considerable diversity and predominance in different areas. It is often a dominant component of Southern Ocean benthic communities. The quality of the data was controlled very thoroughly with GPS systems onboard the R/V Hesperides and by checking the data against the World Porifera Database (which is part of the World Register of Marine Species, WoRMS). The data are therefore fit for completing checklists, inclusion in biodiversity pattern analysis and niche modelling. The authors can be contacted if any additional information is needed before carrying out detailed biodiversity or biogeographic studies. The dataset currently contains 767 occurrence data items that have been checked for systematic reliability. This database is not yet complete and the collection is growing. Specimens are stored in the author's collection at the Spanish Institute of Oceanography (IEO) in the city of Gijón (Spain). The data are available in GBIF. PMID:24843257

  19. A meta-analysis of human disturbance impacts on Antarctic wildlife.

    Science.gov (United States)

    Coetzee, Bernard W T; Chown, Steven L

    2016-08-01

    Evidence-based assessments are increasingly recognized as the best-practice approach to determine appropriate conservation interventions, but such assessments of the impact of human disturbance on wildlife are rare. Human disturbance comprises anthropogenic activities that are typically non-lethal, but may cause short- and/or longer-term stress and fitness responses in wildlife. Expanding human activity in the Antarctic region is of particular concern because it increases the scope and potential for increased human disturbance to wildlife in a region that is often thought of as relatively untouched by anthropogenic influences. Here, we use a meta-analytical approach to synthesise research on human disturbance to wildlife over the last three decades in the Antarctic and sub-Antarctic region. We combine data from 62 studies across 21 species on the behavioural, physiological and population responses of wildlife to pedestrian, vehicle and research disturbances. The overall effect size indicated a small, albeit statistically significant negative effect of disturbance (-0.39; 95% CI: -0.60 to -0.18). Negative effects were found for both physiological and population responses, but no evidence was found for a significant impact on wildlife behavioural responses. Negative effects were found across pedestrian, vehicle and research disturbances. Significant and high among-study heterogeneity was found in both disturbance and response sub-groups. Among species, it remains unclear to what extent different forms of disturbance translate into negative population responses. Most current guidelines to limit wildlife disturbance impacts in Antarctica recommend that approaches be tailored to animal behavioural cues, but our work demonstrates that behavioural changes do not necessarily reflect more cryptic, and more deleterious impacts, such as changes in physiology. In consequence, we recommend that pedestrian approach guidelines in the Antarctic region be revisited. Due to the high

  20. Antarctic Ozone Hole on September 17, 2001

    Science.gov (United States)

    2002-01-01

    Satellite data show the area of this year's Antarctic ozone hole peaked at about 26 million square kilometers-roughly the size of North America-making the hole similar in size to those of the past three years, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Researchers have observed a leveling-off of the hole size and predict a slow recovery. Over the past several years the annual ozone hole over Antarctica has remained about the same in both its size and in the thickness of the ozone layer. 'This is consistent with human-produced chlorine compounds that destroy ozone reaching their peak concentrations in the atmosphere, leveling off, and now beginning a very slow decline,' said Samuel Oltmans of NOAA's Climate Monitoring and Diagnostics Laboratory, Boulder, Colo. In the near future-barring unusual events such as explosive volcanic eruptions-the severity of the ozone hole will likely remain similar to what has been seen in recent years, with year-to-year differences associated with meteorological variability. Over the longer term (30-50 years) the severity of the ozone hole in Antarctica is expected to decrease as chlorine levels in the atmosphere decline. The image above shows ozone levels on Spetember 17, 2001-the lowest levels observed this year. Dark blue colors correspond to the thinnest ozone, while light blue, green, and yellow pixels indicate progressively thicker ozone. For more information read: 2001 Ozone Hole About the Same Size as Past Three Years. Image courtesy Greg Shirah, GSFC Scientific Visualization Studio, based on data from the TOMS science team

  1. Viral distribution and activity in Antarctic waters

    Science.gov (United States)

    Guixa-Boixereu, Núria; Vaqué, Dolors; Gasol, Josep M.; Sánchez-Cámara, Jaime; Pedrós-Alió, Carlos

    Variability in abundance of virus-like particles (VLP), VLP decay rates and prokaryotic mortality due to viral infection were determined in three Antarctic areas: Bellingshausen Sea, Bransfield Strait and Gerlache Strait, during December 1995 and February 1996. VLP abundance showed very small spatial variability in the three areas (7×10 6-2×10 7 VLP ml -1). VLP abundance, on the other hand, decreased one order of magnitude from the surface to the bottom, in two stations where deep vertical profiles were sampled. Low seasonal variability in VLP abundance was found when comparing each area separately. Diel VLP variability was also very low. VLP abundance showed the lowest values when solar irradiation was maximal, in two of the three stations where diel cycles were examined. Viral decay rates (VDR) were determined using KCN in two kinds of experiments. Type 1 experiments were performed in 6 stations to determine viral decay. Type 2 experiments were carried out in 2 stations to examine the influence of temperature and organic matter concentration on viral decay. VDR was not influenced by these parameters. Prokaryotic mortality due to viral infection was always higher than that due to bacterivores in the stations where both factors of prokaryotic mortality were measured. Viral infection accounted for all the prokaryotic heterotrophic production in Bellingshausen Sea and Gerlache Strait and for half of the prokaryotic heterotrophic production in Bransfield Strait. These high values of prokaryotic mortality due to viral infection are difficult to reconcile in nature, and more work is necessary to determine the mechanisms involved in the disappearance of viruses.

  2. Microbiology and Geochemistry of Antarctic Paleosols

    Science.gov (United States)

    Mahaney, W. C.; Malloch, D.; Hancock, R. G. V.; Campbell, I. B.; Sheppard, D.

    2000-08-01

    Samples of ancient soils from horizons in paleosols from the Quartermain Mountains (Aztec and New Mountain areas of the Antarctic Dry Valleys) were analyzed for their chemical composition and microbiology to determine the accumulation and movement of salts and other soluble constituents. The salt concentrations are of special interest because they are considered to be a function of age, derived in part from nearby oceanic and high altitude atmospheric sources. The geochemistry of ancient Miocene-age paleosols in these areas is the direct result of the deposition and weathering of till, derived principally from dolerite and sandstone source rock, in association with airborne-influxed salts. Paleosols nearer the coast have greater contents of chlorine, and farther inland near the Inland Ice Sheet, nitrogen tends to increase on a relative basis. The accumulation and vertical distribution of salts and other soluble chemical elements indicate relative amounts of movement in the profile over long periods of time, to the order of several million years. Iron, both in total concentration and in the form of various extracts, indicates it can be used as a geochronometer to assess the buildup of goethite plus hematite over time in the paleosols. Trends for ferrihydrite, a partially soluble Fe-hydroxide, shows limited profile translocation that might be related to the movement of salt. Six of the eight selected subsamples from paleosol horizons in three soil profiles contained nil concentrations of bacteria and fungi. However, two horizons at depths of between three to eight centimeters yielded several colonies of the fungi Beauveria bassiana and Penicillium spp., indicating some input of organic carbon. Beauveria bassiana is often reported in association with insects and is used commercially for the biological control of some insect pests. Penicillium species are commonly isolated from Arctic, temperate and tropical soils and are known to utilize a wide variety of organic

  3. Hydrochemical characteristic of different modifications of Antarctic waters

    Science.gov (United States)

    Batrak, K. V.

    2008-06-01

    The report considers the distribution of several hydrochemical components (dissolved oxygen, mineral phosphorus, dissolved silicon, and nitrate nitrogen) depending on the disposition of different structural water modifications constituting the unified Antarctic structural type. It is shown that the character of the silicon distribution in the waters of the South Polar zone is mainly determined by large-scale circulation features. The distribution of mineral phosphorus and nitrate nitrogen is characterized by a certain patchiness related to the photosynthesis intensity. An attempt was made to follow the supply and transformation of dissolved silicon, nitrates, and phosphates in the Antarctic.

  4. A solid phase extraction based non-disruptive sampling technique to investigate the surface chemistry of macroalgae.

    Science.gov (United States)

    Cirri, Emilio; Grosser, Katharina; Pohnert, Georg

    2016-01-01

    The surface chemistry of aquatic organisms determines their biotic interactions. Metabolites in the spatially limited laminar boundary layer mediate processes, such as antifouling, allelopathy and chemical defense against herbivores. However, very few methods are available for the investigation of such surface metabolites. An approach is described in which surfaces are extracted by means of C18 solid phase material. By powdering wet algal surfaces with this material, organic compounds are adsorbed and can be easily recovered for subsequent liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS) investigations. The method is robust, picks up metabolites of a broad polarity range and is easy to handle. It is more universal compared to established solvent dipping protocols and it does not cause damage to the test organisms. A protocol is introduced for the macroalgae Fucus vesiculosus, Caulerpa taxifolia and Gracilaria vermiculophylla, but it can be easily transferred to other aquatic organisms. PMID:26795737

  5. Distributions of surface sediments surrounding the Antarctic Peninsula and its environmental significance

    Institute of Scientific and Technical Information of China (English)

    WANG Chunjuan; CHEN Zhihua; LI Chunshun; DU Dewen; YAN Shijuan; ZHU Zhiwei

    2014-01-01

    We analyzed grain size composition to provide information on the types and distributions as well as depositional varieties of marine surface sediments from the area surrounding the Antarctic Peninsula. The samples retrieved from the study area contain gravel, sand, silt and clay. As suggested by bathymetry and morphology, the study area is characterized by neritic, hemipelagic and pelagic deposits. The glacial-marine sediments can be divided into two types, residual paratill and compound paratill, which are primarily transported by glaciers and as ice-rafted debris. Ocean current effects on deposition are more obvious, and the deposit types are distributed consistently with terrain variations.

  6. Resource Limitations on Soil Microbial Activity in an Antarctic Dry Valley

    DEFF Research Database (Denmark)

    Sparrow, Asley; Gregorich, Ed; Hopkins, David; Novis, P; Elberling, Bo; Greenfield, L.G.

    2011-01-01

    Although Antarctic dry valley soils function under some of the harshest environmental conditions on the planet, there is significant biological activity concentrated in small areas in the landscape. These productive areas serve as a source of C and N in organic matter redistributed to the......, when that constraint is alleviated, the organisms are able to access a pool of stored C that they could not metabolize before. The effects of added C and N substrates on respiration rates under laboratory conditions were more rapid and significant than the response rates measured in situ. Because the...

  7. Evidence of the mid-latitude impact of Antarctic ozone depletion

    Science.gov (United States)

    Atkinson, Roger J.; Matthews, W. Andrew; Newman, Paul A.; Plumb, R. Alan

    1989-01-01

    Record low ozone values found over Australia and New Zealand during December 1987 following the record low Antarctic values of October 1987 are analyzed. The sudden decline of ozone amounts in midmonth rule out photochemical effects as a cause and permit the underlying processes to be investigated on a case study basis. Using data from ozone sondes, radiosondes, the Nimbus-7 total ozone mapping spectrometer, and meteorological analyses from the National Meteorological Center, it is argued that these low values resulted from transport of ozone-poor air from higher latitudes. Thus, it seems that the chemical destruction of ozone over Antarctica in early spring is having an impact on lower latitudes.

  8. Zinc concentrations in marine macroalgae and a lichen from western Ireland in relation to phylogenetic grouping, habitat and morphology

    International Nuclear Information System (INIS)

    Zinc concentrations in 19 species of marine macroalgae and a lichen from western Ireland (Spiddal, Co. Galway) were analysed by atomic absorption spectrophotometry. Algae were collected from a single site but occupied different shore levels and belonged to distinct phylogenetic groupings and to different (previously recognised) morphological groups. Concentrations ranged from 15-115 μg g-1 dry weight. The greatest variation in concentration occurred amongst the red algal species, containing both maximum and minimum concentrations. Zn concentrations in brown and green algae were generally lower than those in red algae. When grouped according to thallus morphology, thin, branched sheets (which consisted mainly of red algae) contained the highest Zn concentrations. In filamentous algae, Zn levels were higher than in thick-leathery or coarsely branched algae. However, all green algal species examined had similar Zn concentrations, despite their different morphologies. In brown algae, the highest Zn levels were detected in mid-shore fucoids (Fucus vesiculosus and Fucus serratus), while thicker, subtidal and low-shore brown algae (Laminaria digitata, Halydris siliquosa) exhibited lower Zn concentrations. The lowest Zn concentrations were detected in high-intertidal species (Fucus spiralis, Pelvetia canaliculata), the only marine lichen examined (Ramalina siliquosa) and a red crustose alga (Corallina officinalis). In all morphological groups, red algal representatives contained relatively higher levels of Zn, the exception being Corallina officinalis. Zn levels in 4 species from a second, estuarine site in Galway Bay exhibited the same relative differences amongst species, but were all consistently higher than in algae from Spiddal. It is concluded that Zn accumulation in macroalgae is closely related to ecological growth strategies, following a functional-form model. However, the phylogenetic origin of species which determines carbohydrate and phenol composition, and

  9. Zinc concentrations in marine macroalgae and a lichen from western Ireland in relation to phylogenetic grouping, habitat and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Stengel, Dagmar B.; Macken, Ailbhe; Morrison, Liam; Morley, Nicholas

    2004-05-01

    Zinc concentrations in 19 species of marine macroalgae and a lichen from western Ireland (Spiddal, Co. Galway) were analysed by atomic absorption spectrophotometry. Algae were collected from a single site but occupied different shore levels and belonged to distinct phylogenetic groupings and to different (previously recognised) morphological groups. Concentrations ranged from 15-115 {mu}g g{sup -1} dry weight. The greatest variation in concentration occurred amongst the red algal species, containing both maximum and minimum concentrations. Zn concentrations in brown and green algae were generally lower than those in red algae. When grouped according to thallus morphology, thin, branched sheets (which consisted mainly of red algae) contained the highest Zn concentrations. In filamentous algae, Zn levels were higher than in thick-leathery or coarsely branched algae. However, all green algal species examined had similar Zn concentrations, despite their different morphologies. In brown algae, the highest Zn levels were detected in mid-shore fucoids (Fucus vesiculosus and Fucus serratus), while thicker, subtidal and low-shore brown algae (Laminaria digitata, Halydris siliquosa) exhibited lower Zn concentrations. The lowest Zn concentrations were detected in high-intertidal species (Fucus spiralis, Pelvetia canaliculata), the only marine lichen examined (Ramalina siliquosa) and a red crustose alga (Corallina officinalis). In all morphological groups, red algal representatives contained relatively higher levels of Zn, the exception being Corallina officinalis. Zn levels in 4 species from a second, estuarine site in Galway Bay exhibited the same relative differences amongst species, but were all consistently higher than in algae from Spiddal. It is concluded that Zn accumulation in macroalgae is closely related to ecological growth strategies, following a functional-form model. However, the phylogenetic origin of species which determines carbohydrate and phenol composition

  10. Characterising Antarctic and Southern Ocean Lithosphere with Magnetic and Gravity Imaging of East Antarctic Rift Systems

    Science.gov (United States)

    Vaughan, A. P.; Kusznir, N. J.; Ferraccioli, F.; Jordan, T. A.; Purucker, M. E.; Golynsky, A. V.; Rogozhina, I.

    2012-12-01

    Since the International Geophysical Year (1957), a view has prevailed that the lithospheric structure of East Antarctica is relatively homogeneous, forming a geological block of largely cratonic nature, consisting of a mosaic of Precambrian terranes, stable since the Pan-African orogeny ~500 million years ago. Recent recognition of a continental-scale rift system cutting the East Antarctic interior indicates that this is incorrect, and has crystallised an alternative view of much more recent geological activity with important implications for tectonic reconstructions and controls on ice sheet formation and stability. The newly defined East Antarctic Rift System appears to extend from at least the South Pole to the continental margin at the Lambert Rift, a distance of 2500 km. This is comparable in scale to the well-studied East African rift system. New analysis of RadarSat data pioneered by Golynsky & Golynsky indicates that further rift zones may extend the East Antarctic Rift System into widely distributed extension zones within the continent. We have carried out a pilot study, using a newly developed gravity inversion technique with existing public domain satellite data, which shows that East Antarctica consists of distinct crustal thickness provinces with anomalously thick areas separated by thin, possibly rifted crust and overall high average thickness. Understanding the nature of crustal thickness in East Antarctica is critical because: 1) Better understanding of crustal thickness in Antarctica, especially along the ocean-continent transition (OCT), will make it possible to improve the plate reconstruction fit between Antarctica, Australia and India in Gondwana and also refine constraints on how and when these continents separated; 2) crustal thickness provinces can be used to aid supercontinent reconstructions and provide new assessments of the influence of basement architecture and mechanical properties on rifting processes; 3) tracking rift zones through

  11. Persistent organohalogen contaminant burdens in Antarctic krill (Euphausia superba) from the eastern Antarctic sector: A baseline study

    International Nuclear Information System (INIS)

    A baseline for persistent organohalogen compound (POC) accumulation in the Antarctic keystone species, Antarctic krill (Euphausia superba) has been established for a 50 deg. longitudinal range of the eastern Antarctic sector. Samples of adult krill, caught from 12 sites distributed between 30 deg. and 80 deg. E (60-70 deg. S), were analysed for > 100 organohalogen compounds including chlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated organic compounds and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs). Organochlorine pesticides dominated measured krill contaminant burdens with hexachlorobenzene (HCB) as the single most abundant compound quantified. Krill HCB concentrations were comparable to those detected at this trophic level in both the Arctic and temperate northwest Atlantic, lending support for the hypothesis that HCB will approach global equilibrium at a faster rate than other POCs. Para, para'-dichlorodiphenylethene (p,p'-DDE) was detected at notable concentrations. Measurements of DDT and its degradation products provide an important baseline for monitoring the temporal and geographical influence of renewed, DDT usage for malaria-control in affected southern hemisphere countries. In contrast to the Arctic, PCBs did not feature prominently in contaminant burdens of Antarctic krill. The major commercial polybrominated diphenyl ether (PBDE) congeners -99 and -47 were quantified at low background levels with clear concentration spikes observed at around 70 deg. E , in the vicinity of modern, active research stations. The likelihood that local anthropogenic activities are supplementing low PBDE levels, delivered otherwise primarily via long range environmental transport, is discussed. The suspected naturally occurring brominated organic compound, 2,4,6-tribromoanisole (TBA), was a ubiquitous contaminant in all samples whereas the only PCDD/Fs quantifiable were trace levels of octachlorodibenzo-p-dioxin (OCDD) and 1,2,3

  12. Thermo-Acidic Pretreatment of Beach Macroalgae from Rügen to Optimize Biomethane Production—Double Benefit with Simultaneous Bioenergy Production and Improvement of Local Beach and Waste Management

    OpenAIRE

    Yann Nicolas Barbot; Laurenz Thomsen; Roland Benz

    2015-01-01

    Eutrophication is a phenomenon which can rapidly generate masses of marine macroalgae, particularly in areas with high nutrient pollution. Washed ashore, this biomass impairs coastal tourism and negatively affects the coastal ecosystem. The present study evaluates the biochemical methane potential (BMP) of a macroalgae mix (Rügen-Mix, RM (RM = Rügen-Mix)) originating from Rügen, Germany. To improve biomethane recovery, thermo-acidic pretreatment was applied to the biomass prior to biomethanat...

  13. Vitamin D Supplementation and Immune Response to Antarctic Winter

    Science.gov (United States)

    Zwart, S. R.; Mehta, S. K.; Ploutz-Snyder, R.; Bourbeau, Y.; Locke, J. P.; Pierson, D. L.; Smith, Scott M.

    2011-01-01

    Maintaining vitamin D status without sunlight exposure is difficult without supplementation. This study was designed to better understand interrelationships between periodic cholecalciferol(vitamin D3) supplementation and immune function in Antarctic workers. The effect of 2 oral dosing regimens of vitamin D3 supplementation on vitamin D status and markers of immune function were evaluated in people in Antarctica with no ultraviolet light exposure for 6 mo. Participants were given a 2,000-IU (50 g) daily (n=15) or 10,000-IU (250 g) weekly (n=14) vitamin D3 supplement for 6 mo during a winter in Antarctica. Biological samples were collected at baseline and at 3 and 6 mo. Vitamin D intake, markers of vitamin D and bone metabolism, and latent virus reactivation were determined. After 6 mo the mean (SD) serum 25-hydroxyvitamin D3 concentration increased from 56 plus or minus 17 to 79 plus or minus 16 nmol/L and 52 plus or minus 10 to 69 plus or minus 9 nmol/L in the 2,000-IU/d and 10,000-IU/wk groups (main effect over time P less than 0.001). Participants with a greater BMI (participant BMI range = 19-43 grams per square meter) had a smaller increase in 25-hydroxyvitamin D3 after 6 mo supplementation (P less than 0.05). Participants with high serum cortisoland higher serum 25-hydroxyvitamin D3 were less likely to shed Epstein-Barr virus in saliva (P less than 0.05). The doses given raised vitamin D status in participants not exposed to sunlight for 6 mo, and the efficacy was influenced by baseline vitamin D status and BMI. The data also provide evidence that vitamin D, interacting with stress, can reduce risk of latent virus reactivation during the winter in Antarctica.

  14. A 3-D model for the Antarctic ice sheet: a sensitivity study on the glacial-interglacial contrast

    OpenAIRE

    Huybrechts, Philippe

    1990-01-01

    On the longer climatic time scales, changes in the elevation and extent of the Antarctic ice sheet have an important role in modulating global atmospheric andoceanographic processes, and contribute significantly to world-wide sea levels. In this paper, a 3-D time-dependent thermomechanical model for the entire icesheet is presented that is subsequently used to examine the effects of glacial-interglacial shifts in environmental boundary conditions on its geometry. Themodel takes into account a...

  15. On-site and in situ remediation technologies applicable to petroleum hydrocarbon contaminated sites in the Antarctic and Arctic

    OpenAIRE

    Camenzuli, Danielle; Freidman, Benjamin L.

    2015-01-01

    Petroleum hydrocarbon contaminated sites, associated with the contemporary and legacy effects of human activities, remain a serious environmental problem in the Antarctic and Arctic. The management of contaminated sites in these regions is often confounded by the logistical, environmental, legislative and financial challenges associated with operating in polar environments. In response to the need for efficient and safe methods for managing contaminated sites, several technologies have been a...

  16. Characterization of meteorological parameters, solar radiation and effect of clouds at two antarctic sites, and comparison with satellite estimates Caracterización de parámetros meteorológicos, radiación solar y efecto de las nubes en dos sitios antárticos, y comparación con estimaciones satelitales

    OpenAIRE

    Eduardo A. Luccini; Hugo Grossi Gallegos; Piacentini, Rubén D.; Canziani, Pablo O.

    2005-01-01

    The analysis of measurements of daily mean temperature, daily mean relative humidity and daily total solar irradiation for the period 1979-1985, at the Antarctic stations Almirante Brown (64.9ºS, 62.9ºW, 10m a.s.l., West of Antarctic Peninsula), and BelgranoII (77.9ºS, 34.6ºW, 250m a.s.l., East of Antarctic Peninsula) is presented. A short-term characterization of monthly averages was established. Typical temperatures for summer and winter were 2ºC and -7ºC respectively at Brown, and -2ºC and...

  17. Local scaling characteristics of Antarctic surface layer turbulence

    Directory of Open Access Journals (Sweden)

    S. Basu

    2010-03-01

    Full Text Available Over the past years, several studies have validated Nieuwstadt's local scaling hypothesis by utilizing turbulence observations from the mid-latitude, nocturnal stable boundary layers. In this work, we probe into the local scaling characteristics of polar, long-lived stable boundary layers by analyzing turbulence data from the South Pole region of the Antarctic Plateau.

  18. Evaluating Wind Power Potential in the Spanish Antarctic Base (BAE)

    International Nuclear Information System (INIS)

    The objective of the work is to model wind field in the surroundings of the Spanish Antarctic Base (BAE in the following). The need of such a work comes from the necessity of an energy source able to supply the energy demand in the BAE during the Antarctic winter. When the BAE is in operation (in the Antarctic summer) the energy supply comes from a diesel engine. In the Antarctic winter the base is closed, but the demand of energy supply is growing up every year because of the increase in the number of technical and scientific machines that remain in the BAE taking different measurements. For this purpose the top of a closed hill called Pico Radio, not perturbed by close obstacles, has been chosen as the better site for the measurements. The measurement station is made up with a sonic anemometer and a small wind generator to supply the energy needed by the sensors head heating of the anemometer. This way, it will be also used as a proof for the suitability of a wind generator in the new chosen site, under those special climatic conditions.(Author) 3 refs

  19. Pioneering work of CAS researchers in Antarctic expedition

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The first observatory at Dome A On 12 January, China scientific expedition to Antarctica succeeded for a second time in climbing up to Dome A, the highest Antarctic icecap peak. A similar feat was made by Chinese scientists about three years ago in January 2005, leaving first human footprints there.

  20. Occurrence of a taurine derivative in an antarctic glass sponge.

    Science.gov (United States)

    Carbone, Marianna; Núñez-Pons, Laura; Ciavatta, M Letizia; Castelluccio, Francesco; Avila, Conxita; Gavagnin, Margherita

    2014-04-01

    The n-butanol extract of an Antarctic hexactinellid sponge, Anoxycalyx (Scolymastra) joubini, was found to contain a taurine-conjugated anthranilic acid, never reported so far either as a natural product or by synthesis. The compound was inactive against human cancer cells in an in vitro growth inhibitory test, and also showed no antibacterial activity. PMID:24868857

  1. Microbial ecology and biogeochemistry of continental Antarctic soils

    Directory of Open Access Journals (Sweden)

    Don A Cowan

    2014-04-01

    Full Text Available The Antarctica Dry Valleys are regarded as the coldest hyperarid desert system on Earth. While a wide variety of environmental stressors including very low minimum temperatures, frequent freeze-thaw cycles and low water availability impose severe limitations to life, suitable niches for abundant microbial colonization exist. Antarctic desert soils contain much higher levels of microbial diversity than previously thought. Edaphic niches, including cryptic and refuge habitats, microbial mats and permafrost soils all harbour microbial communities which drive key biogeochemical cycling processes. For example, lithobionts (hypoliths and endoliths possess a genetic capacity for nitrogen and carbon cycling, polymer degradation and other system processes. Nitrogen fixation rates of hypoliths, as assessed through acetylene reduction assays, suggest that these communities are a significant input source for nitrogen into these oligotrophic soils. Here we review aspects of microbial diversity in Antarctic soils with an emphasis on functionality and capacity. We assess current knowledge regarding adaptations to Antarctic soil environments and highlight the current threats to Antarctic desert soil communities.

  2. An Antarctic Circumpolar Current driven by surface buoyancy forcing

    Science.gov (United States)

    Hogg, Andrew McC.

    2010-12-01

    Simulations of an idealised, but eddy-resolving, channel model of the Antarctic Circumpolar Current (ACC) are used to investigate the sensitivity of ACC transport to wind and surface buoyancy forcing. The results are consistent with theoretical predictions of the eddy-saturated limit, where transport is independent of wind stress. In this parameter regime, buoyancy forcing provides the primary control over ACC transport.

  3. Molecular evolution of hemoglobins of Antarctic fishes (Notothenioidei)

    NARCIS (Netherlands)

    Stam, W.T.; Beintema, J.J; D Avino, R.; Tamburrini, M.; di Prisco, G.

    1997-01-01

    Amino acid sequences of alpha- and beta-chains of human hemoglobin and of hemoglobins of coelacanth and 24 teleost fish species, including 11 antarctic and two temperate Notothenioidei, were analyzed using maximum parsimony. Trees were derived for the alpha- and beta-chains separately and for tandem

  4. Maneuver simulation model of an experimental hovercraft for the Antarctic

    Science.gov (United States)

    Murao, Rinichi

    Results of an investigation of a hovercraft model designed for Antarctic conditions are presented. The buoyancy characteristics, the propellant control system, and simulation model control are examined. An ACV (air cushion vehicle) model of the hovercraft is used to examine the flexibility and friction of the skirt. Simulation results are presented which show the performance of the hovercraft.

  5. A multivariate analysis of Antarctic sea ice since 1979

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes Neto, Newton de; Evangelista, Heitor [Universidade do Estado do Rio de Janeiro (Uerj), LARAMG - Laboratorio de Radioecologia e Mudancas Globais, Maracana, Rio de Janeiro, RJ (Brazil); Tanizaki-Fonseca, Kenny [Universidade do Estado do Rio de Janeiro (Uerj), LARAMG - Laboratorio de Radioecologia e Mudancas Globais, Maracana, Rio de Janeiro, RJ (Brazil); Universidade Federal Fluminense (UFF), Dept. Analise Geoambiental, Inst. de Geociencias, Niteroi, RJ (Brazil); Penello Meirelles, Margareth Simoes [Universidade do Estado do Rio de Janeiro (UERJ)/Geomatica, Maracana, Rio de Janeiro, RJ (Brazil); Garcia, Carlos Eiras [Universidade Federal do Rio Grande (FURG), Laboratorio de Oceanografia Fisica, Rio Grande, RS (Brazil)

    2012-03-15

    Recent satellite observations have shown an increase in the total extent of Antarctic sea ice, during periods when the atmosphere and oceans tend to be warmer surrounding a significant part of the continent. Despite an increase in total sea ice, regional analyses depict negative trends in the Bellingshausen-Amundsen Sea and positive trends in the Ross Sea. Although several climate parameters are believed to drive the formation of Antarctic sea ice and the local atmosphere, a descriptive mechanism that could trigger such differences in trends are still unknown. In this study we employed a multivariate analysis in order to identify the response of the Antarctic sea ice with respect to commonly utilized climate forcings/parameters, as follows: (1) The global air surface temperature, (2) The global sea surface temperature, (3) The atmospheric CO{sub 2} concentration, (4) The South Annular Mode, (5) The Nino 3, (6) The Nino (3 + 4, 7) The Nino 4, (8) The Southern Oscillation Index, (9) The Multivariate ENSO Index, (10) the Total Solar Irradiance, (11) The maximum O{sub 3} depletion area, and (12) The minimum O{sub 3} concentration over Antarctica. Our results indicate that western Antarctic sea ice is simultaneously impacted by several parameters; and that the minimum, mean, and maximum sea ice extent may respond to a separate set of climatic/geochemical parameters. (orig.)

  6. Antarctic Cenozoic climate history from sedimentary records: ANDRILL and beyond.

    Science.gov (United States)

    McKay, R M; Barrett, P J; Levy, R S; Naish, T R; Golledge, N R; Pyne, A

    2016-01-28

    Mounting evidence from models and geological data implies that the Antarctic Ice Sheet may behave in an unstable manner and retreat rapidly in response to a warming climate, which is a key factor motivating efforts to improve estimates of Antarctic ice volume contributions to future sea-level rise. Here, we review Antarctic cooling history since peak temperatures of the Middle Eocene Climatic Optimum (approx. 50 Ma) to provide a framework for future initiatives to recover sediment cores from subglacial lakes and sedimentary basins in Antarctica's continental interior. While the existing inventory of cores has yielded important insights into the biotic and climatic evolution of Antarctica, strata have numerous and often lengthy time breaks, providing a framework of 'snapshots' through time. Further cores, and more work on existing cores, are needed to reconcile Antarctic records with the more continuous 'far-field' records documenting the evolution of global ice volume and deep-sea temperature. To achieve this, we argue for an integrated portfolio of drilling and coring missions that encompasses existing methodologies using ship- and sea-ice-/ice-shelf-based drilling platforms as well as recently developed seafloor-based drilling and subglacial access systems. We conclude by reviewing key technological issues that will need to be overcome. PMID:26667911

  7. A novel Antarctic microbial endolithic community within gypsum crusts.

    Science.gov (United States)

    Hughes, Kevin A; Lawley, Blair

    2003-07-01

    A novel endolithic microbial habitat is described from a climatically extreme site at Two Step Cliffs, Alexander Island, Antarctic Peninsula (71 degrees 54'S, 68 degrees 13'W). Small endolithic colonies (endolithic communities are less extensive than those of the Dry Valleys, continental Antarctica, probably owing to only recent deglaciation (<7000 year ago). PMID:12823188

  8. Microbial ecology and biogeochemistry of continental Antarctic soils

    Science.gov (United States)

    Cowan, Don A.; Makhalanyane, Thulani P.; Dennis, Paul G.; Hopkins, David W.

    2014-01-01

    The Antarctica Dry Valleys are regarded as the coldest hyperarid desert system on Earth. While a wide variety of environmental stressors including very low minimum temperatures, frequent freeze-thaw cycles and low water availability impose severe limitations to life, suitable niches for abundant microbial colonization exist. Antarctic desert soils contain much higher levels of microbial diversity than previously thought. Edaphic niches, including cryptic and refuge habitats, microbial mats and permafrost soils all harbor microbial communities which drive key biogeochemical cycling processes. For example, lithobionts (hypoliths and endoliths) possess a genetic capacity for nitrogen and carbon cycling, polymer degradation, and other system processes. Nitrogen fixation rates of hypoliths, as assessed through acetylene reduction assays, suggest that these communities are a significant input source for nitrogen into these oligotrophic soils. Here we review aspects of microbial diversity in Antarctic soils with an emphasis on functionality and capacity. We assess current knowledge regarding adaptations to Antarctic soil environments and highlight the current threats to Antarctic desert soil communities. PMID:24782842

  9. Antarctic and Southern Ocean influences on Late Pliocene global cooling

    NARCIS (Netherlands)

    McKay, R.; Naish, T.; Carter, L.; Riesselman, C.; Dunbar, R.; Sjunneskog, C.; Winter, D.; Sangiorgi, F.; Warren, C.; Pagani, M.; Schouten, S.; Willmott, V.; Levy, R.; DeConto , R.M.; Powell, R.D.

    2012-01-01

    The influence of Antarctica and the Southern Ocean on Late Pliocene global climate reconstructions has remained ambiguous due to a lack of well-dated Antarctic-proximal, paleoenvironmental records. Here we present ice sheet, sea-surface temperature, and sea ice reconstructions from the ANDRILL AND-1

  10. Is there a distinct continental slope fauna in the Antarctic?

    Science.gov (United States)

    Kaiser, Stefanie; Griffiths, Huw J.; Barnes, David K. A.; Brandão, Simone N.; Brandt, Angelika; O'Brien, Philip E.

    2011-02-01

    The Antarctic continental slope spans the depths from the shelf break (usually between 500 and 1000 m) to ˜3000 m, is very steep, overlain by 'warm' (2-2.5 °C) Circumpolar Deep Water (CDW), and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the abyssal fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell Sea and Scotia Sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III, BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ (Ecology of the Antarctic Sea Ice Zone) II cruises as well as current databases (SOMBASE, SCAR-MarBIN), four different taxa were selected (i.e. cheilostome bryozoans, isopod and ostracod crustaceans and echinoid echinoderms) and two areas, the Weddell Sea and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations. Benthic samples were collected using Agassiz trawl, epibenthic sledge and Rauschert sled. By bathymetric definition, these data suggest that despite eurybathy in some of the groups examined and apparent similarity of physical conditions in the Antarctic, the shelf, slope and abyssal faunas were clearly separated in the Weddell Sea. However, no such separation of faunas was apparent in the Scotia Sea (except in echinoids). Using a geomorphological definition of the slope, shelf-slope-abyss similarity only changed significantly in the bryozoans. Our results did not support the presence of a homogenous and unique Antarctic slope fauna despite a high number of species being restricted to the slope. However, it remains the case that there may be

  11. Potential extinction of Antarctic endemic fungal species as a consequence of global warming

    Energy Technology Data Exchange (ETDEWEB)

    Selbmann, Laura, E-mail: selbmann@unitus.it [Department of Ecological and Biological Sciences (DEB), Universita degli Studi della Tuscia, Largo dell' Universita, 01100 Viterbo (Italy); Isola, Daniela; Fenice, Massimiliano; Zucconi, Laura [Department of Ecological and Biological Sciences (DEB), Universita degli Studi della Tuscia, Largo dell' Universita, 01100 Viterbo (Italy); Sterflinger, Katja [Department of Biotechnology, Austrian Center of Biological Resources and Applied Mycology (ACBR), University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Wien (Austria); Onofri, Silvano [Department of Ecological and Biological Sciences (DEB), Universita degli Studi della Tuscia, Largo dell' Universita, 01100 Viterbo (Italy)

    2012-11-01

    Cryomyces spp. are fungi adapted to the harsh conditions of the McMurdo Dry Valleys in the Antarctic. The structure of their cell wall is one of the main factors for their uncommon ability to survive external stressors. The cells are, in fact, embedded in a thick and strongly melanised cell wall encrusted with black rigid plaques giving a supplementary protection and making them practically impregnable and refractory even to commercial enzymes including chitinases and glucanases. The Antarctic fungus Lecanicillium muscarium CCFEE 5003, able to produce an arsenal of lytic enzymes, including chitinases and glucanases, is known for its ability to degrade the cell walls of different food spoiling and opportunistic fungi as well as plant pathogenic Oomycota. Active cells of Cryomyces spp. were cultivated in dual culture with the mycoparasitic fungus both in liquid and solid media. Light microscope observations revealed that the cell walls of Cryomyces were heavily decayed. This resulted in the release of protoplasts. Hyphae penetration was evident with both scanning and transmission electron microscope observations. Due to its ecological amplitude (i.e. temperature growth range 0-28 Degree-Sign C), the parasitic fungus could easily expand its area of distribution as a consequence of global warming by invading new areas towards the interior of the continent. The establishment of interactions with organisms living at present in border ecosystems may lead to extinction of extremely specialized and poorly competitive entities. -- Highlights: Black-Right-Pointing-Pointer We studied interactions among Antarctic fungi to evaluate the effects of global warming. Black-Right-Pointing-Pointer Cryomyces spp. was parasitized and killed by Lecanicillum muscarium in co-cultures. Black-Right-Pointing-Pointer L. muscarium lythic activities may have intriguing and new applications. Black-Right-Pointing-Pointer L. muscarium may expand its area of distribution as a consequence of global

  12. Potential extinction of Antarctic endemic fungal species as a consequence of global warming

    International Nuclear Information System (INIS)

    Cryomyces spp. are fungi adapted to the harsh conditions of the McMurdo Dry Valleys in the Antarctic. The structure of their cell wall is one of the main factors for their uncommon ability to survive external stressors. The cells are, in fact, embedded in a thick and strongly melanised cell wall encrusted with black rigid plaques giving a supplementary protection and making them practically impregnable and refractory even to commercial enzymes including chitinases and glucanases. The Antarctic fungus Lecanicillium muscarium CCFEE 5003, able to produce an arsenal of lytic enzymes, including chitinases and glucanases, is known for its ability to degrade the cell walls of different food spoiling and opportunistic fungi as well as plant pathogenic Oomycota. Active cells of Cryomyces spp. were cultivated in dual culture with the mycoparasitic fungus both in liquid and solid media. Light microscope observations revealed that the cell walls of Cryomyces were heavily decayed. This resulted in the release of protoplasts. Hyphae penetration was evident with both scanning and transmission electron microscope observations. Due to its ecological amplitude (i.e. temperature growth range 0–28 °C), the parasitic fungus could easily expand its area of distribution as a consequence of global warming by invading new areas towards the interior of the continent. The establishment of interactions with organisms living at present in border ecosystems may lead to extinction of extremely specialized and poorly competitive entities. -- Highlights: ► We studied interactions among Antarctic fungi to evaluate the effects of global warming. ► Cryomyces spp. was parasitized and killed by Lecanicillum muscarium in co-cultures. ► L. muscarium lythic activities may have intriguing and new applications. ► L. muscarium may expand its area of distribution as a consequence of global warming. ► Extinction of threatened species previously living in confined niches may occur.

  13. Vertical structure of Antarctic tropospheric ozone depletion events: characteristics and broader implications

    Directory of Open Access Journals (Sweden)

    A. E. Jones

    2010-08-01

    Full Text Available The majority of tropospheric ozone depletion event (ODE studies have focussed on time-series measurements, with comparatively few studies of the vertical component. Those that exist have almost exclusively used free-flying balloon-borne ozonesondes and almost all have been conducted in the Arctic. Here we use measurements from two separate Antarctic field experiments to examine the vertical profile of ozone during Antarctic ODEs. We use tethersonde data to probe details in the lowest few hundred meters and find considerable structure in the profiles associated with complex atmospheric layering. The profiles were all measured at wind speeds less than 7 ms−1, and on each occasion the lowest inversion height lay between 10 m and 40 m. We also use data from a free-flying ozonesonde study to select events where ozone depletion was recorded at altitudes >1 km above ground level. Using ERA-40 meteorological charts, we find that on every occasion the high altitude depletion was preceded by an atmospheric low pressure system. An examination of limited published ozonesonde data from other Antarctic stations shows this to be a consistent feature. Given the link between BrO and ODEs, we also examine ground-based and satellite BrO measurements and find a strong association between atmospheric low pressure systems and enhanced BrO that must arise in the troposphere. The results suggest that, in Antarctica, such depressions are responsible for driving high altitude ODEs and for generating the large-scale BrO clouds observed from satellites. In the Arctic, the prevailing meteorology differs from that in Antarctica, but, while a less common effect, major low pressure systems in the Arctic can also generate BrO clouds. Such depressions thus appear to be fundamental when considering the broader influence of ODEs, certainly in Antarctica, such as halogen export and the radiative influence of ozone-depleted air masses.

  14. Super-aggregations of krill and humpback whales in Wilhelmina Bay, Antarctic Peninsula.

    Directory of Open Access Journals (Sweden)

    Douglas P Nowacek

    Full Text Available Ecological relationships of krill and whales have not been explored in the Western Antarctic Peninsula (WAP, and have only rarely been studied elsewhere in the Southern Ocean. In the austral autumn we observed an extremely high density (5.1 whales per km(2 of humpback whales (Megaptera novaeangliae feeding on a super-aggregation of Antarctic krill (Euphausia superba in Wilhelmina Bay. The krill biomass was approximately 2 million tons, distributed over an area of 100 km(2 at densities of up to 2000 individuals m(-3; reports of such 'super-aggregations' of krill have been absent in the scientific literature for >20 years. Retentive circulation patterns in the Bay entrained phytoplankton and meso-zooplankton that were grazed by the krill. Tagged whales rested during daylight hours and fed intensively throughout the night as krill migrated toward the surface. We infer that the previously unstudied WAP embayments are important foraging areas for whales during autumn and, furthermore, that meso-scale variation in the distribution of whales and their prey are important features of this system. Recent decreases in the abundance of Antarctic krill around the WAP have been linked to reductions in sea ice, mediated by rapid climate change in this area. At the same time, baleen whale populations in the Southern Ocean, which feed primarily on krill, are recovering from past exploitation. Consideration of these features and the effects of climate change on krill dynamics are critical to managing both krill harvests and the recovery of baleen whales in the Southern Ocean.

  15. Influence of daylight on potential biodegradation of diesel and crude oil in Antarctic seawater

    International Nuclear Information System (INIS)

    The effects of daylight exposure on Antarctic coastal bacterial communities contaminated by diesel fuel and 'Arabian light' crude oil addition were studied in artificial mesocosms during the austral summers of 1991-1992, 1992-1993 and 1993-1994 in the Terre Adelie land area. In order to study the possible influence of photo-oxidation, two sets of experiments were conducted in covered and non-covered batches. Daily sampling allowed regular surveys of the changes of total bacterial abundance, mean cell volumes, saprophytic and hydrocarbon-utilizing bacterial communities. The results clearly revealed a significant response of the Antarctic bacterial community to crude oil addition. Two orders of magnitude increases were observed after contamination. Concomitant enrichments of saprophytic and hydrocarbon-utilizing bacteria occurred during these periods. Hydrocarbon-utilizing bacteria ranged from 0.001% of the total community before contamination to more than 80% after 2 weeks of contamination with crude oil. Chemical analysis of the residual hydrocarbon fraction after 5 weeks of contamination confirmed this potential biodegradation. Solar radiation had no measurable effect upon crude oil-contaminated seawater. In contrast, there was a clear toxic effect upon bacterial communities contaminated with diesel. Data suggest that the initial state of the bacterial communities can play a major role in the potential biodegradation. Some surface bacterial assemblages seem to demonstrate a better resistance to solar radiation than deeper ones. (author)

  16. Satellite mapping and automated feature extraction: Geographic information system-based change detection of the Antarctic coast

    Science.gov (United States)

    Kim, Kee-Tae

    Declassified Intelligence Satellite Photograph (DISP) data are important resources for measuring the geometry of the coastline of Antarctica. By using the state-of-art digital imaging technology, bundle block triangulation based on tie points and control points derived from a RADARSAT-1 Synthetic Aperture Radar (SAR) image mosaic and Ohio State University (OSU) Antarctic digital elevation model (DEM), the individual DISP images were accurately assembled into a map quality mosaic of Antarctica as it appeared in 1963. The new map is one of important benchmarks for gauging the response of the Antarctic coastline to changing climate. Automated coastline extraction algorithm design is the second theme of this dissertation. At the pre-processing stage, an adaptive neighborhood filtering was used to remove the film-grain noise while preserving edge features. At the segmentation stage, an adaptive Bayesian approach to image segmentation was used to split the DISP imagery into its homogenous regions, in which the fuzzy c-means clustering (FCM) technique and Gibbs random field (GRF) model were introduced to estimate the conditional and prior probability density functions. A Gaussian mixture model was used to estimate the reliable initial values for the FCM technique. At the post-processing stage, image object formation and labeling, removal of noisy image objects, and vectorization algorithms were sequentially applied to segmented images for extracting a vector representation of coastlines. Results were presented that demonstrate the effectiveness of the algorithm in segmenting the DISP data. In the cases of cloud cover and little contrast scenes, manual editing was carried out based on intermediate image processing and visual inspection in comparison of old paper maps. Through a geographic information system (GIS), the derived DISP coastline data were integrated with earlier and later data to assess continental scale changes in the Antarctic coast. Computing the area of

  17. Brain and sense organ anatomy and histology of the Falkland Islands mullet, Eleginops maclovinus (Eleginopidae), the sister group of the Antarctic notothenioid fishes (Perciformes: Notothenioidei).

    Science.gov (United States)

    Eastman, Joseph T; Lannoo, Michael J

    2008-01-01

    -living members of the Bathydraconini. Eye diameter is generally larger in Antarctic species but there is a phylogenetic loss of cellularity in the retina, including cone photoreceptors. Some deep-living Antarctic species have lost most of their cones. Mechanosensation is expanded in some species, most notably the nototheniid Pleuragramma antarcticum, the artedidraconid genera Dolloidraco and Pogonophryne, and the deep living members of the bathydraconid tribe Bathydraconini. Reduction in retinal cellularity, expansion of mechanoreception, and stalking are the most noteworthy departures from the morphology seen in Eleginops. These features reflect a modest depth or deep-sea effect, and they are not uniquely "Antarctic" attributes. Thus, at the level of organ system morphology, perciform brain and sensory systems are suitable for conditions on the Antarctic shelf, with only minor alterations in structure in directions exhibited by other fish groups inhabiting deep water. Notothenioids retain a relative balance among their array of senses that reflects their heritage as inshore perciforms. PMID:17902153

  18. Evaluation of the biological toxicity of lfuorine in Antarctic krill

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; LU Xiaoqi; WANG Zhangmin; QIN Liqiang; LIN Zhiqin; YUAN Linxi; ZHANG Wen; YIN Xuebin

    2014-01-01

    Antarctic krill is a potentially nutritious food source for humans, but lfuorine (F) toxicity is a matter of concern. To evaluate the toxicity of F in Antarctic krill, 30 Wistar rats were divided into three groups with different dietary regimens:a control group, a krill treatment group (150 mg·kg-1 F), and a sodium lfuoride (NaF) treatment group (150 mg·kg-1 F). After three months, F concentrations in feces, plasma, and bone were determined, and the degree of dental and skeletal lfuorosis was assessed. The F concentrations in plasma and bone from the krill treatment group were 0.167 0±0.020 4 mg.L-1 and 2 709.8±301.9 mg·kg-1, respectively, compared with 0.043 8±0.005 5 mg·L-1 and 442.4±60.7 mg·kg-1, respectively, in samples from the control group. Concentrations of F in plasma and bone in the krill treatment group were higher than in the control group, but lower than in the NaF treatment group. The degree of dental lfuorosis in the krill treatment group was moderate, compared with severe in the NaF treatment group and normal in the control group. The degree of skeletal lfuorosis did not change signiifcantly in any group. These results showed that the toxicity of F in Antarctic krill was lower than for an equivalent concentration of F in NaF, but it was toxic for rats consuming krill in large quantities. To conclude, we discuss possible reasons for the reduced toxicity of F in Antarctic krill. The present study provides a direct toxicological reference for the consideration of Antarctic krill for human consumption.

  19. Evidence for widespread endemism among Antarctic micro-organisms

    Science.gov (United States)

    Vyverman, Wim; Verleyen, Elie; Wilmotte, Annick; Hodgson, Dominic A.; Willems, Anne; Peeters, Karolien; Van de Vijver, Bart; De Wever, Aaike; Leliaert, Frederik; Sabbe, Koen

    2010-08-01

    Understanding the enormous diversity of microbes, their multiple roles in the functioning of ecosystems, and their response to large-scale environmental and climatic changes, are at the forefront of the international research agenda. In Antarctica, where terrestrial and lacustrine environments are predominantly microbial realms, an active and growing community of microbial ecologists is probing this diversity and its role in ecosystem processes. In a broader context, this work has the potential to make a significant contribution to the long-standing debate as to whether microbes are fundamentally different from macroorganisms in their biogeography. According to the ubiquity hypothesis, microbial community composition is not constrained by dispersal limitation and is solely the result of species sorting along environmental gradients. However, recent work on several groups of microalgae is challenging this view. Global analyses using morphology-based diatom inventories have demonstrated that, in addition to environmental harshness, geographical isolation underlies the strong latitudinal gradients in local and regional diversity in the Southern hemisphere. Increasing evidence points to a strong regionalization of diatom floras in the Antarctic and sub-Antarctic regions, mirroring the biogeographical regions that have been recognized for macroorganisms. Likewise, the application of molecular-phylogenetic techniques to cultured and uncultured diversity revealed a high number of Antarctic endemics among cyanobacteria and green algae. Calibration of these phylogenies suggests that several clades have an ancient evolutionary history within the Antarctic continent, possibly dating back to 330 Ma. These findings are in line with the current view on the origin of Antarctic terrestrial metazoa, including springtails, chironomids and mites, with most evidence suggesting a long history of geographic isolation on a multi-million year, even pre-Gondwana break-up timescale.

  20. A visionary and conceptual macroalgae-based third-generation bioethanol (TGB) biorefinery in Sabah, Malaysia as an underlay for renewable and sustainable development

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Chun Sheng; Lee, Keat Teong [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

    2010-02-15

    Several biofuel candidates were proposed to displace fossil fuels in order to eliminate the vulnerability of energy sector. Biodiesel and bioethanol produced from terrestrial plants have attracted the attention of the world as potential substitute. However, due to food vs. fuel competition as well as land consumption of these biofuel, they have brought much controversy and debate on their sustainability. In this respect, cultivation of macroalgae such as seaweed at sea water which does not expend arable land and fertilizers provides a possible solution for this energy issue. Carbohydrates derived from seaweeds contain hexose sugars which are suitable materials for fermentation to produce ethanol. Therefore, it is possible to produce fuel ethanol from seaweeds. The potential and prospective of seaweeds to play the role as a sustainable energy provider are demonstrated in this paper. This study offers a conceivable picture of macroalgae-based third-generation bioethanol biorefinery to stimulate the initiation of the exploration in the related field. (author)

  1. Bed topography under Antarctic outlet glaciers revealed by mass conservation and radar data

    Science.gov (United States)

    Morlighem, M.; Rignot, E. J.; Mouginot, J.; Seroussi, H. L.

    2015-12-01

    Bed topography, together with ice thickness, is an essential characteristic of glaciers and ice sheets for many glaciological applications. Despite significant technical advances, it remains challenging to measure ice thickness remotely, especially in deep troughs occupied by outlet glaciers. The method of mass conservation, that combines radar-derived ice thickness data with high-resolution InSAR-derived ice velocity vectors, provides an effective method for generating a high-resolution bed from sparse radar sounding profiles, and has been successfully applied along the coast of the Greenland Ice Sheet. Applying the same technique to the coast of the Antarctic Ice Sheet presents a number of challenges. The coverage of ice thickness data collected in Antarctica, for example, is much less comprehensive compared to Greenland, especially in the wake of NASA's Operation IceBridge (OIB) Mission in 2010-2015. Here, we combine radar sounder data collected by various centers (OIB/Center for Remote Sensing of Ice Sheets, the British Antarctic Survey and University of Texas) acquired between 1998 and 2011, with high-resolution ice motion data from interferometric SAR (ALOS PALSAR, RADARSAT-2 and Envisat ASAR) to reconstruct bed topography beneath major Antarctic outlet glaciers at an unprecedented level of detail. The results reveal some important features not known previously at that level of detail and shed light on the vulnerability of these glaciers in a warming climate. We find for example that Recovery glacier is deeper than in previous mappings and has long grooves parallel to the flow direction. Denman Glacier, East Antarctica, flow along a deep, narrow trough more than 2,000 m below sea level that extends more than 100 km inland. We find ridges and bumps in the vicinity of the grounding line of Thwaites Glacier, in the Amundsen Sea sector, that are consistent with the pattern of grounding line retreat. We have also a new mapping of the trough upstream of David

  2. Prospects for the use of macro-algae for fuel in Ireland and the UK: An overview of marine management issues

    OpenAIRE

    Roberts, T.; Upham, P

    2012-01-01

    Competing demand for land is driving biofuel and bioenergy research in various directions including macro-algae (seaweed). This paper reviews the main issues for the marine environment of cultivating and harvesting UK and Irish seaweed for biofuels/bioenergy, informed by stakeholder interviews. These showed stakeholders were sceptical of an offshore cultivation industry developing but generally considered inshore cultivation possible, while noting various practical obstacles and conditions. V...

  3. Macroalgas como biodindicadores de poluição metálica:um estudo no estuário do Tejo

    OpenAIRE

    Henriques, Bruno César Rodrigues

    2009-01-01

    The present study examinated the potencial use of macroalgae as biomonitors of the trace metal contamination of the Tagus estuary water column. The Tagus estuary lies in a region with high population, high industry and high agriculture density. In this region, the great Lisbon metropolitan area with about 3,2 million inhabitants is the area under the spotlights. The estuary receives discharges, many times without any treatment, from all this antropogenized area surrounding the estuary. This d...

  4. Subtidal eelgrass/macroalgae surveys for the proposed breakwaters at the US Coast Guard Station at Ediz Hook, Washington, March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Shreffler, D.K. [Battelle/Marine Sciences Lab., Sequim, WA (US)

    1993-05-01

    In 1993, the US Coast Guard proposed to construct two breakwaters and a debris boom to protect its existing pier and moored vessels inside Ediz Hook in Port Angeles Harbor, Washington. To assist the US Army Corps of Engineers -- Seattle District in determining the potential environmental impacts of the proposed breakwaters, Battelle/Marine Sciences Laboratory performed subtidal SCUBA surveys as specified in the Washington Department of Fisheries intermediate eelgrass/macroalgae habitat survey guidelines. The objectives of the subtidal surveys were to (1) quantify the shoot densities of eelgrass; (2) provide percent cover estimates for non-eelgrass macroalgae species; (3) develop a site map indicating the qualitative distribution of eelgrass/macroalgae species, substrate characterization, approximate depth contours, and the approximate location of the proposed project features; and (4) document the time and date of the surveys, turbidity/visibility, presence of invertebrate/vertebrate species, and anecdotal observations pertinent to habitat characterization of the project site. A total of 14 dives along 12 transects (T1--T12) were successfully completed between March 15 and March 17, 1993. Eelgrass was observed on all of the transects except T7 and T8 at the western debris barrier and T12 along the waterward margin of the existing T-pier. The vicinity of the proposed east breakwater had the highest eelgrass shoot densities (up to 89 shoots/m{sup 2}) observed by the divers. Macroalgae and invertebrate species diversity were also highest at the east breakwater site. The low eelgrass densities observed at the west debris barrier site (0 to 14 shoots/m{sup 2}) can be attributed mostly to the lack of suitable substrate. The existing layer of wood debris armoring the bottom at the west project site currently limits, and in the areas of heaviest deposition probably precludes, the growth of eelgrass. As was expected, no eelgrass was observed at the south breakwater site.

  5. Temporal pattern in the bloom-forming macroalgae Chaetomorpha linum and Ulva pertusa in seagrass beds, Swan Lake lagoon, North China

    International Nuclear Information System (INIS)

    Highlights: • We conducted an annual survey of bloom-forming macroalgae in a lagoon. • C. linum biomass reached 1712 ± 780 g DW m−2 at the northern part of the lagoon. • Macroalgae δ15N values indicated a land-based source of N enrichment to the blooms. • High nutrient concentrations near the river mouth supported the blooms. • C. linum blooms induced the loss of seagrasses and benthic filter feeders. - Abstract: Seagrasses that are distributed over a large area of the Swan Lake, Weihai, China, support a productive ecosystem. In recent years, however, frequent macroalgal blooms have changed the ecosystem structure and threatened the seagrasses. To understand the bloom-forming macroalgae we conducted a yearly field survey of Swan Lake. Results indicated that the macroalgae Chaetomorpha linum and Ulva pertusa both exhibited a much higher productivity and attained a greater maximum biomass (of 1712 ± 780 g DW m−2 and 1511 ± 555 g DW m−2, respectively) than was the case for the seagrasses. The mean annual atomic ratios of C/N, C/P and N/P in C. linum were 14.31 ± 4.45, 402.82 ± 130.25, and 28.12 ± 2.08, respectively. The δ15N values (11.09 ± 0.91‰ for C. linum; 9.27 ± 2.83‰ for U. pertusa) indicated a land-based source of N enrichment to the macroalgal blooms. High concentrations of nitrogen and phosphorus in the lagoon, particularly near the river mouth, supported the blooms

  6. Antioxidant and anti-inflammatory potential of the aqueous extract and polysaccharide fraction from brown marine macroalgae Padina sp. from Gulf of Mannar of Peninsular India

    OpenAIRE

    Nammunayathuputhenkotta Krishnankartha Praveen; Kajal Chakraborty

    2013-01-01

    Objective: To evaluate the antioxidant and anti-inflammatory potential of the aqueous extract and polysaccharide fraction from two brown marine macroalga, Padina gymnospora (P. gymnospora) and Padina tetrastomatica (P. tetrastomatica) harvested from Gulf of Mannar of peninsular India. Methods: The antioxidant activity was evaluated using different in vitro systems, viz., 1,1- diphenyl-2-picrylhydrazyl (DPPH), 2, 2′-azino-bis-3ethylbenzothiozoline-6-sulfonic acid diammonium s...

  7. At-Sea Distribution and Prey Selection of Antarctic Petrels and Commercial Krill Fisheries.

    Science.gov (United States)

    Descamps, Sébastien; Tarroux, Arnaud; Cherel, Yves; Delord, Karine; Godø, Olaf Rune; Kato, Akiko; Krafft, Bjørn A; Lorentsen, Svein-Håkon; Ropert-Coudert, Yan; Skaret, Georg; Varpe, Øystein

    2016-01-01

    Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries. In this study, we first quantified the overlap between the distribution of the Antarctic krill fisheries and the distribution of a krill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breeding and non-breeding season. We tracked birds from the world biggest Antarctic petrel colony (Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, during three consecutive seasons. The overall spatial overlap between krill fisheries and Antarctic petrels was limited but varied greatly among and within years, and was high in some periods during the non-breeding season. In a second step, we described the length frequency distribution of Antarctic krill consumed by Antarctic petrels, and compared this with results from fisheries, as well as from diet studies in other krill predators. Krill taken by Antarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctic krill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarctic predators. Overall, our results show that competition between Antarctic petrels and krill fisheries is currently likely negligible. However, if krill fisheries are to increase in the future, competition with the Antarctic petrel may occur, even with birds breeding thousands of kilometers away. PMID:27533327

  8. At-Sea Distribution and Prey Selection of Antarctic Petrels and Commercial Krill Fisheries

    Science.gov (United States)

    Descamps, Sébastien; Tarroux, Arnaud; Cherel, Yves; Delord, Karine; Godø, Olaf Rune; Kato, Akiko; Krafft, Bjørn A.; Lorentsen, Svein-Håkon; Ropert-Coudert, Yan; Skaret, Georg; Varpe, Øystein

    2016-01-01

    Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries. In this study, we first quantified the overlap between the distribution of the Antarctic krill fisheries and the distribution of a krill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breeding and non-breeding season. We tracked birds from the world biggest Antarctic petrel colony (Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, during three consecutive seasons. The overall spatial overlap between krill fisheries and Antarctic petrels was limited but varied greatly among and within years, and was high in some periods during the non-breeding season. In a second step, we described the length frequency distribution of Antarctic krill consumed by Antarctic petrels, and compared this with results from fisheries, as well as from diet studies in other krill predators. Krill taken by Antarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctic krill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarctic predators. Overall, our results show that competition between Antarctic petrels and krill fisheries is currently likely negligible. However, if krill fisheries are to increase in the future, competition with the Antarctic petrel may occur, even with birds breeding thousands of kilometers away. PMID:27533327

  9. Crystallization, preliminary X-ray diffraction studies and Raman microscopy of the major haemoglobin from the sub-Antarctic fish Eleginops maclovinus in the carbomonoxy form

    International Nuclear Information System (INIS)

    The major haemoglobin of the sub-Antarctic fish E. maclovinus is the first sub-Antarctic fish haemoglobin to be crystallized and its structural characterization will shed light on the molecular mechanisms of cold adaptation and the role of the Root effect in fish. The blood of the sub-Antarctic fish Eleginops maclovinus (Em) contains three haemoglobins. The major haemoglobin (Hb1Em) displays the Root effect, a drastic decrease in the oxygen affinity and a loss of cooperativity at acidic pH. The carbomonoxy form of HbEm1 has been crystallized in two different crystal forms, orthorhombic (Ortho) and hexagonal (Hexa), and high-resolution diffraction data have been collected for both forms (1.45 and 1.49 Å resolution, respectively). The high-frequency resonance Raman spectra collected from the two crystal forms using excitation at 514 nm were almost indistinguishable. Hb1Em is the first sub-Antarctic fish Hb to be crystallized and its structural characterization will shed light on the molecular mechanisms of cold adaptation and the role of the Root effect in fish haemoglobins

  10. Differential responses of calcifying and non-calcifying epibionts of a brown macroalga to present-day and future upwelling pCO2.

    Directory of Open Access Journals (Sweden)

    Vincent Saderne

    Full Text Available Seaweeds are key species of the Baltic Sea benthic ecosystems. They are the substratum of numerous fouling epibionts like bryozoans and tubeworms. Several of these epibionts bear calcified structures and could be impacted by the high pCO2 events of the late summer upwellings in the Baltic nearshores. Those events are expected to increase in strength and duration with global change and ocean acidification. If calcifying epibionts are impacted by transient acidification as driven by upwelling events, their increasing prevalence could cause a shift of the fouling communities toward fleshy species. The aim of the present study was to test the sensitivity of selected seaweed macrofoulers to transient elevation of pCO2 in their natural microenvironment, i.e. the boundary layer covering the thallus surface of brown seaweeds. Fragments of the macroalga Fucus serratus bearing an epibiotic community composed of the calcifiers Spirorbis spirorbis (Annelida and Electra pilosa (Bryozoa and the non-calcifier Alcyonidium hirsutum (Bryozoa were maintained for 30 days under three pCO2 conditions: natural 460 ± 59 µatm, present-day upwelling1193 ± 166 µatm and future upwelling 3150 ± 446 µatm. Only the highest pCO2 caused a significant reduction of growth rates and settlement of S. spirorbis individuals. Additionally, S. spirorbis settled juveniles exhibited enhanced calcification of 40% during daylight hours compared to dark hours, possibly reflecting a day-night alternation of an acidification-modulating effect by algal photosynthesis as opposed to an acidification-enhancing effect of algal respiration. E. pilosa colonies showed significantly increased growth rates at intermediate pCO2 (1193 µatm but no response to higher pCO2. No effect of acidification on A. hirsutum colonies growth rates was observed. The results suggest a remarkable resistance of the algal macro-epibionts to levels of acidification occurring at present day upwellings in the Baltic

  11. Decadal Trends in Abundance, Size and Condition of Antarctic Toothfish in McMurdo Sound, Antarctica, 1972-2010

    Science.gov (United States)

    Ainley, David G.; Nur, Nadav; Eastman, Joseph T.; Ballard. Grant; Parkinson, Claire L; Evans, Clive W.; DeVries, Arthur L.

    2012-01-01

    We report analyses of a dataset spanning 38 years of near-annual fishing for Antarctic toothfish Dissostichus mawsoni, using a vertical setline through the fast ice of McMurdo Sound, Antarctica, 1972-2010. This constitutes one of the longest biological time series in the Southern Ocean, and certainly the longest for any fish. Fish total length, condition and catch per unit effort (CPUE) were derived from the more than 5500 fish caught. Contrary to expectation, length-frequency was dominated by fish in the upper half of the industrial catch. The discrepancy may be due to biases in the sampling capabilities of vertical (this study) versus benthic (horizontal) fishing gear (industry long lines), related to the fact that only large Antarctic toothfish (more than 100 cm TL) are neutrally buoyant and occur in the water column. Fish length and condition increased from the early 1970s to the early 1990s and then decreased, related to sea ice cover, with lags of 8 months to 5 years, and may ultimately be related to the fishery (which targets large fish) and changes in the Southern Annular Mode through effects on toothfish main prey, Antarctic silverfish Pleuragramma antarcticum. CPUE was constant through 2001 and then decreased dramatically, likely related to the industrial fishery, which began in 1996 and which concentrates effort over the Ross Sea slope, where tagged McMurdo fish have been found. Due to limited prey choices and, therefore, close coupling among mesopredators of the Ross Sea, Antarctic toothfish included, the fishery may be altering the trophic structure of the Ross Sea.

  12. The magnetic orientation of the Antarctic amphipod Gondogeneia antarctica is cancelled by very weak radiofrequency fields.

    Science.gov (United States)

    Tomanova, K; Vacha, M

    2016-06-01

    Studies on weak man-made radiofrequency (RF) electromagnetic fields affecting animal magnetoreception aim for a better understanding of the reception mechanism and also point to a new phenomenon having possible consequences in ecology and environmental protection. RF impacts on magnetic compasses have recently been demonstrated in migratory birds and other vertebrates. We set out to investigate the effect of RF on the magnetic orientation of the Antarctic krill species Gondogeneia antarctica, a small marine crustacean widespread along the Antarctic littoral line. Here, we show that upon release, G. antarctica (held under laboratory conditions) escaped in the magnetically seaward direction along the magnetic sea-land axis (y-axis) of the home beach. However, the animals were disoriented after being exposed to RF. Orientation was lost not only in an RF field with a magnetic flux density of 20 nT, as expected according to the literature, but even under the 2 nT originally intended as a control. Our results extend recent findings of the extraordinary sensitivity of animal magnetoreception to weak RF fields in marine invertebrates. PMID:27026715

  13. Inability of stratospheric sulfate aerosol injections to preserve the West Antarctic Ice Sheet

    Science.gov (United States)

    McCusker, K. E.; Battisti, D. S.; Bitz, C. M.

    2015-06-01

    Injection of sulfate aerosols into the stratosphere has the potential to reduce the climate impacts of global warming, including sea level rise (SLR). However, changes in atmospheric and oceanic circulation that can significantly influence the rate of basal melting of Antarctic marine ice shelves and the associated SLR have not previously been considered. Here we use a fully coupled global climate model to investigate whether rapidly increasing stratospheric sulfate aerosol concentrations after a period of global warming could preserve Antarctic ice sheets by cooling subsurface ocean temperatures. We contrast this climate engineering method with an alternative strategy in which all greenhouse gases (GHG) are returned to preindustrial levels. We find that the rapid addition of a stratospheric aerosol layer does not effectively counteract surface and upper level atmospheric circulation changes caused by increasing GHGs, resulting in continued upwelling of warm water in proximity of ice shelves, especially in the vicinity of the already unstable Pine Island Glacier in West Antarctica. By contrast, removal of GHGs restores the circulation, yielding relatively cooler subsurface ocean temperatures to better preserve West Antarctica.

  14. Absence of 21st century warming on Antarctic Peninsula consistent with natural variability.

    Science.gov (United States)

    Turner, John; Lu, Hua; White, Ian; King, John C; Phillips, Tony; Hosking, J Scott; Bracegirdle, Thomas J; Marshall, Gareth J; Mulvaney, Robert; Deb, Pranab

    2016-07-21

    Since the 1950s, research stations on the Antarctic Peninsula have recorded some of the largest increases in near-surface air temperature in the Southern Hemisphere. This warming has contributed to the regional retreat of glaciers, disintegration of floating ice shelves and a 'greening' through the expansion in range of various flora. Several interlinked processes have been suggested as contributing to the warming, including stratospheric ozone depletion, local sea-ice loss, an increase in westerly winds, and changes in the strength and location of low-high-latitude atmospheric teleconnections. Here we use a stacked temperature record to show an absence of regional warming since the late 1990s. The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer. Temperatures have decreased as a consequence of a greater frequency of cold, east-to-southeasterly winds, resulting from more cyclonic conditions in the northern Weddell Sea associated with a strengthening mid-latitude jet. These circulation changes have also increased the advection of sea ice towards the east coast of the peninsula, amplifying their effects. Our findings cover only 1% of the Antarctic continent and emphasize that decadal temperature changes in this region are not primarily associated with the drivers of global temperature change but, rather, reflect the extreme natural internal variability of the regional atmospheric circulation. PMID:27443743

  15. Progress on photosynthetic carbon metabolism types in marine macroalgae%大型海藻光合碳代谢类型的研究进展

    Institute of Scientific and Technical Information of China (English)

    芦笛

    2013-01-01

    As a part of marine algae, marine macroalgae, whose edible and medicinal values are widely applied, participate in global CO2 and O2 turnover through photosynthesis. Therefore, when viewed from ecology as well as economics, the process of photosynthetic CO2 fixation and metabolism in marine macroalgae is of great significance. Up to the present, metabonomics and enzymology researches on photosynthetic carbon metabolism in marine macroalgae have proved the existence of the PEPCK-or PEPC-type C4 pathway as well as the CAM pathway in addition to the C3 pathway, although the integrality of the pathways is still unknown. Moreover, the results of photosynthetic gas exchange indicate that the photosynthetic carbon metabolism pathway in macroalgae performs the C4-like type on the whole. This situation resembles some terrestrial C3 plants with additional C4 pathway. Therefore, researches on photosynthetic carbon metabolism pathways in macroalgae remain to be explored in depth in the future.%作为海洋藻类的一部分,大型海藻通过光合作用参与了海洋对全球CO2和O2的周转,其食用和药用价值也得到了广泛应用。因此无论从生态还是经济角度来看,研究大型海藻通过光合作用对CO2进行固定和代谢的过程都具有重要意义。到目前为止,世界上对大型海藻光合碳代谢途径的研究从代谢组学和酶学角度证明了大型海藻体内除了C3途径外,还同时存在不能确定完整与否的PEPCK或PEPC类型的C4途径或CAM途径;光合气体交换的结果显示其光合碳代谢途径从整体上表现出类似C4(C4-like)类型。这种情况与一些体内存在C4途径的陆生C3植物相似。因此大型海藻光合碳代谢途径仍然有待深入研究。

  16. PROFILE: Environmental Impact Assessment Under the National Environmental Policy Act and the Protocol on Environmental Protection to the Antarctic Treaty.

    Science.gov (United States)

    Ensminger; McCold; Webb

    1999-07-01

    for activities undertaken by all Parties in Antarctica. The Protocol gives clear and strong guidance for protection of specific, valued antarctic environmental resources including intrinsic wilderness and aesthetic values, and the value of Antarctica as an area for scientific research. That guidance requires a higher standard of environmental protection for Antarctica than is required in other parts of the world. This paper shows that taken together NEPA and the Protocol call for closer examination of proposed actions and a more rigorous consideration of environmental impacts than either would alone. Three areas are identified where the EIA provisions of the Protocol could be strengthened to improve its effectiveness. First, the thresholds defined by the Protocol need to be clarified. Specifically, the meanings of the terms "minor" and "transitory" are not clear in the context of the Protocol. The use of "or" in the phrase "minor or transitory" further confuses the meaning. Second, cumulative impact assessment is called for by the Protocol but is not defined. A clear definition could reduce the chance that cumulative impacts would be given inadequate consideration. Finally, the public has limited opportunities to comment on or influence the preparation of initial or comprehensive environmental evaluations. Experience has shown that public input to environmental documents has a considerable influence on agency decision making and the quality of EIA that agencies perform.KEY WORDS: Environment; Impact assessment; Antarctica; NEPA; Protocol; Antarctic Treatyhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n1p13.html PMID:10341059

  17. Relative Changes in KrillAbundance Inferred from Antarctic Fur Seal

    OpenAIRE

    Huang, T.; Sun, L; Stark, John M.; Wang, Y.; Cheng, Z.; Yang, Q.; Sun, S.

    2011-01-01

    Antarctic krill Euphausia superba is a predominant species in the Southern Ocean, it is very sensitive to climate change, and it supports large stocks of fishes, seabirds, seals and whales in Antarctic marine ecosystems. Modern krill stocks have been estimated directly by net hauls and acoustic surveys; the historical krill density especially the long-term one in the Southern Ocean, however, is unknown. Here we inferred the relative krill population changes along the West Antarctic Peninsula ...

  18. Do Antarctic fish like it hot? What energy allocation can tell us about distribution shifts

    OpenAIRE

    Sandersfeld, Tina; Davison, William; Lamare, Miles D.; Richter, Claudio; Knust, Rainer

    2014-01-01

    Despite evidence for distribution shifts of single species and ecosystem changes as a reaction to global warming, little is known about the underlying processes. As a consequence of warming waters in the Southern Ocean, shifts in species distribution are expected with sub-Antarctic species migrating southward to high-Antarctic waters, while species from temperate regions might intrude sub-Antarctic areas. Species distribution and abundance are driven by reproduction and somatic growth, which ...

  19. Sensitivity of Antarctic fish to ocean warming - an energy budget approach

    OpenAIRE

    Sandersfeld, Tina

    2015-01-01

    Like the Arctic, the Antarctic region hosts some of the hot spots of climatic change. At the western Antarctic Peninsula, alterations of air and water temperature, pH, salinity and sea-ice regime were reported and associated shifts in species abundance and changes in food web structure have already become evident. In contrast, for most high-Antarctic regions, no climate related changes have yet been found. However, future temperature increases are also projected for these areas. Ocean warming...

  20. The South Atlantic in the Fine-Resolution Antarctic Model

    Directory of Open Access Journals (Sweden)

    D. P. Stevens

    Full Text Available The geographical area covered by the Fine-Resolution Antarctic Model (FRAM includes that part of the South Atlantic south of 24°S. A description of the dynamics and thermodynamics of this region of the model is presented. Both the mean and eddy fields in the model are in good agreement with reality, although the magnitude of the transients is somewhat reduced. The heat flux is northward and in broad agreement with many other estimates. Agulhas eddies are formed by the model and propagate westward into the Atlantic providing a mechanism for fluxing heat from the Indian Ocean. The confluence of the Brazil and Falkland currents produces a strong front and a large amount of mesoscale activity. In the less stratified regions to the south, topographic steering of the Antarctic circumpolar current is important.