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Datasets of project "Mediterranean Sea Acidification in a changing climate"

Mostrando recursos 1 - 20 de 90

  1. Decline in Coccolithophore Diversity and Impact on Coccolith Morphogenesis Along a Natural CO2 Gradient

    Ziveri, Patrizia; Passaro, Marcello; Incarbona, Alessandro; Milazzo, Marco; Rodolfo-Metalpa, Riccardo; Hall-Spencer, Jason M
    A natural pH gradient caused by marine CO2 seeps off Vulcano Island (Italy) was used to assess the effects of ocean acidification on coccolithophores, which are abundant planktonic unicellular calcifiers. Such seeps are used as natural laboratories to study the effects of ocean acidification on marine ecosystems, since they cause long-term changes in seawater carbonate chemistry and pH, exposing the organisms to elevated CO2 concentrations and therefore mimicking future scenarios. Previous work at CO2 seeps has focused exclusively on benthic organisms. Here we show progressive depletion of 27 coccolithophore species, in terms of cell concentrations and diversity, along a calcite...

  2. Land based mesocosm experiment studying the simultaneous impact of warming and acidification on the planktonic food web of the Eastern Mediterranean

    Pitta, Paraskevi; Krasakopoulou, Evangelia; Frangoulis, Constantin; Ziveri, Patrizia
    A land based mesocosm experiment focusing on the study of the simultaneous impact of warming and acidification on the planktonic food web of the Eastern Mediterranean took place in August-September 2013 at the mesocosm facilities of HCMR in Crete (CRETACOSMOS). Two different pCO2 (present day and predicted for year 2100) were applied in triplicate mesocosms of 3 m**3. This was tested in two different temperatures (ambient seawater T and ambient T plus 3°C). Twelve mesocosms in total were incubated in two large concrete tanks. Temperature was controlled by sophisticated, automated systems. A large variety of chemical, biological and biochemical variables...

  3. Projected impacts of increasing acidification and climate change in the Mediterranean Sea - model results (MedSeA Project - WP5

    Lovato, Tomas; Lazzari, Paolo; Le-Vu, Briac; Cossarini, Gianpiero; Solidoro, Cosimo; Orr, James; Vichi, Marcello
    In the framework of the MedSeA project (EU grant agreement 265103), the numerical modeling work package implemented different coupled physical-biogeochemical models to investigate the projected changes in pH, carbonate saturation states, and related carbon-system variables during the 21st century. The overall focus was on the impacts of increasing acidification and climate change on the Mediterranean Sea carbonate system. Outcomes from the work package activity can be summarized through the following highlights: - Multi-model projections point toward an average surface warming from 1 to 1.5°C in the Eastern Mediterranean, Aegean and Adriatic Sea between 2000 and 2050; - Summer surface temperature...

  4. Villefranche MedSeA mesocosm experiment 2013: perturbation studies and field studies

    Gazeau, Frédéric; Guieu, Cecile; Taillandier, Vincent; Alliouane, Samir; Giani, Michele; Sallon, Amèlie; Pedrotti, Maria-Luiza; Pitta, Paraskevi; Celussi, Mauro; Giannakourou, Antonia; Maugendre, Laure; Louis, Justine
    A joint mesocosm experiment took place in February/March 2013 in the bay of Villefranche in France as part of the european MedSeA project. Nine mesocosms (52 m**3) were deployed over a 2 weeks period and 6 different levels of pCO2 and 3 control mesocosms (about 450 µatm), were used, in order to cover the range of pCO2 anticipated for the end of the present century. During this experiment, the potential effects of these perturbations on chemistry, planktonic community composition and dynamics including: eucaryotic and prokaryotic species composition, primary production, nutrient and carbon utilization, calcification, diazotrophic nitrogen fixation, organic matter exudation...

  5. Villefranche MedSeA mesocosm experiment 2013: field studies

    Gazeau, Frédéric; Guieu, Cecile; Taillandier, Vincent; Alliouane, Samir; Giani, Michele; Sallon, Amèlie; Pedrotti, Maria-Luiza; Pitta, Paraskevi; Celussi, Mauro; Maugendre, Laure; Louis, Justine

  6. Villefranche MedSeA mesocosm experiment 2013: perturbation studies

    Gazeau, Frédéric; Guieu, Cecile; Taillandier, Vincent; Alliouane, Samir; Giani, Michele; Sallon, Amèlie; Pedrotti, Maria-Luiza; Pitta, Paraskevi; Celussi, Mauro; Giannakourou, Antonia; Maugendre, Laure; Louis, Justine

  7. Sea urchin response to rising pCO2 shows ocean acidification may fundamentally alter the chemistry of marine skeletons

    Bray, Laura; Pancucci-Papadopulou, M A; Hall-Spencer, Jason M
    Ocean acidification caused by an increase in pCO2 is expected to drastically affect marine ecosystem composition, yet there is much uncertainty about the mechanisms through which ecosystems may be affected. Here we studied sea urchins that are common and important grazers in the Mediterranean (Paracentrotus lividus and Arbacia lixula). Our study included a natural CO2 seep plus reference sites in the Aegean Sea off Greece. The distribution of A. lixula was unaffected by the low pH environment, whereas densities of P. lividus were much reduced. There was skeletal degradation in both species living in acidified waters compared to reference sites...

  8. Villefranche sur Mer: multistressors experiment March 2012

    Maugendre, Laure; Gattuso, Jean-Pierre; Louis, Justine; Anna, de Kluijver; Marro, Sophie; Soetaert, Karline; Gazeau, Frédéric; Dufour, Aurélie
    The effect of ocean warming and acidification was investigated on a natural plankton assemblage from an oligotrophic area, the bay of Villefranche (NW Mediterranean Sea). The assemblage was sampled in March 2012 and exposed to the following four treatments for 12 days: control ( 360 µatm, 14°C), elevated pCO2 ( 610 µatm, 14°C), elevated temperature ( 410 µatm, 17°C), and elevated pCO2 and temperature ( 690 µatm, 17°C). Nutrients were already depleted at the beginning of the experiment and the concentrations of chlorophyll a (chl a), heterotrophic prokaryotes and viruses decreased, under all treatments, throughout the experiment. There were no...

  9. Photosynthetic activity buffers ocean acidification in seagrass meadows

    Hendriks, Iris; Olsen, Ylva; Ramajo, L; Basso, L; Steckbauer, A; Moore, T S; Howard, J; Duarte, Carlos M
    Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5-12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (omega Ar)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and...

  10. Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent

    Apostolaki, Eugenia; Vizzini, Salvatrice; Hendriks, Iris; Olsen, Ylva
    We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and delta 13C of leaves and epiphytes were significantly lower at the low...

  11. Effects of ocean acidification on sponge communities

    Goodwin, Claire; Rodolfo-Metalpa, Riccardo; Picton, Bernard; Hall-Spencer, Jason M
    The effects of ocean acidification on lower invertebrates such as sponges may be pronounced because of their low capacity for acid-base regulation. However, so far, most studies have focused on calcifiers. We present the first study of the effects of ocean acidification on the Porifera. Sponge species composition and cover along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy) was measured at sites with normal pH (8.1-8.2), lowered pH (mean 7.8-7.9, min 7.4-7.5) and extremely low pH (6.6). There was a strong correlation between pH and both sponge cover and species composition. Crambe crambe was the only species...

  12. Seawater carbonate chemistry, thickness and carbonate elemental composition of the test of juvenile sea urchins in a laboratory experiment

    Asnaghi, Valentina; Mangialajo, Luisa; Gattuso, Jean-Pierre; Francour, Patrice; Privitera, Davide; Chiantore, Mariachiara
    Continuous anthropogenic CO2 emissions to the atmosphere and uptake by the oceans will cause a reduction of seawater pH and saturation state (Omega) of CaCO3 minerals from which marine calcifiers build their shells and skeletons. Sea urchins use the most soluble form of calcium carbonate, high-magnesium calcite, to build their skeleton, spines and grazing apparatus. In order to highlight the effects of increased pCO2 on the test thickness and carbonate elemental composition of juvenile sea urchins and potential differences in their responses linked to the diet, we performed a laboratory experiment on juvenile Paracentrotus lividus, grazing on calcifying (Corallina elongata)...

  13. Effects of Ocean Acidification and Warming on Sperm Activity and Early Life Stages of the Mediterranean Mussel (Mytilus galloprovincialis)

    Vihtakari, Mikko; Hendriks, Iris; Holding, Johnna; Renaud, Paul E; Duarte, Carlos M; Havenhand, Jon N
    Larval stages are among those most vulnerable to ocean acidification (OA). Projected atmospheric CO2 levels for the end of this century may lead to negative impacts on communities dominated by calcifying taxa with planktonic life stages. We exposed Mediterranean mussel (Mytilus galloprovincialis) sperm and early life stages to pHT levels of 8.0 (current pH) and 7.6 (2100 level) by manipulating pCO2 level (380 and 1000 ppm). Sperm activity was examined at ambient temperatures (16-17 °C) using individual males as replicates. We also assessed the effects of temperature (ambient and = 20 °C) and pH on larval size, survival, respiration and...

  14. Environmental controls on the Emiliania huxleyi calcite mass

    Horigome, Mariana Tatsumi; Ziveri, Patrizia; Grelaud, Michaël; Baumann, Karl-Heinz; Marino, Gianluca; Mortyn, P G
    Although ocean acidification is expected to impact (bio)calcification by decreasing the seawater carbonate ion concentration, [CO3]2-, there exists evidence of non-uniform response of marine calcifying plankton to low seawater [CO3]2-. This raises questions on the role of environmental factors other than acidification and on the complex physiological responses behind calcification. Here we investigate the synergistic effect of multiple environmental parameters, including temperature, nutrient (nitrate and phosphate) availability, and seawater carbonate chemistry on the coccolith calcite mass of the cosmopolitan coccolithophore Emiliania huxleyi, the most abundant species in the world ocean. We use a suite of surface (late Holocene) sediment samples...

  15. Ocean acidification and the loss of phenolic substances in marine plants

    Arnold, Thomas; Mealey, Christopher; Leahey, Hannah; Miller, A Whitman; Hall-Spencer, Jason M; Milazzo, Marco; Maers, Kelly
    Rising atmospheric CO2 often triggers the production of plant phenolics, including many that serve as herbivore deterrents, digestion reducers, antimicrobials, or ultraviolet sunscreens. Such responses are predicted by popular models of plant defense, especially resource availability models which link carbon availability to phenolic biosynthesis. CO2 availability is also increasing in the oceans, where anthropogenic emissions cause ocean acidification, decreasing seawater pH and shifting the carbonate system towards further CO2 enrichment. Such conditions tend to increase seagrass productivity but may also increase rates of grazing on these marine plants. Here we show that high CO2 / low pH conditions of OA...

  16. The morphological response of Emiliania huxleyi to seawater carbonate chemistry changes: an inter-strain comparison

    Langer, Gerald; Probert, Ian; Nehrke, Gernot; Ziveri, Patrizia
    Four strains of the coccolithophore Emiliania huxleyi (RCC1212, RCC1216, RCC1238, RCC1256) were grown in dilute batch culture at four CO2 levels ranging from ~200 µatm to ~1200 µatm. Coccolith morphology was analyzed based on scanning electron micrographs. Three of the four strains did not exhibit a change in morphology over the CO2 range tested. One strain (RCC1256) displayed an increase in the percentage of malformed coccoliths with increasing CO2 concentration. We conclude that the sensitivity of the coccolith-shaping machinery to carbonate chemistry changes is strain-specific. Although it has been shown before that carbonate chemistry related changes in growth- and calcification...

  17. Seawater carbonate chemistry and egg production, hatching and metabolic rates of a Mediterranean copepod species (Acartia clausi) in a laboratory experiment

    Zervoudaki, Soultana; Frangoulis, Constantin; Giannoudi, Louisa; Krasakopoulou, Evangelia
    This study includes the first information on the combined effect of low pH and raised temperature on egg production rate (EP), hatching success (HS), excretion and respiration of the Mediterranean copepod Acartia clausi. Adult individuals of A. clausi and fresh surface seawater were collected at a coastal station in Saronikos Gulf during April 2012. Four different conditions were applied: two different pH levels (present: 8.09 and future: 7.83) at two temperature values (present: 16°C and present+4 °C= 20°C). EP and HS success decreased significantly over the duration of exposure at future pH at both temperature conditions. However, the analysis of...

  18. Seawater carbonate chemistry and growth, calcification of Thoracosphaera heimii in a laboratory experiment

    Van de Waal, Dedmer B; John, Uwe; Ziveri, Patrizia; Reichart, Gert-Jan; Hoins, Mirja; Sluijs, Appy; Rost, Bjoern
    Ocean acidification is considered a major threat to marine ecosystems and may particularly affect calcifying organisms such as corals, foraminifera and coccolithophores. Here we investigate the impact of elevated pCO2 and lowered pH on growth and calcification in the common calcareous dinoflagellate Thoracosphaera heimii. We observe a substantial reduction in growth rate, calcification and cyst stability of T. heimii under elevated pCO2. Furthermore, transcriptomic analyses reveal CO2 sensitive regulation of many genes, particularly those being associated to inorganic carbon acquisition and calcification. Stable carbon isotope fractionation for organic carbon production increased with increasing pCO2 whereas it decreased for calcification, which...

  19. Seawater carbonate chemistry and physiological response of the Mediterranean crustose coralline alga Lithophyllum cabiochae to elevated pCO2 and temperature

    Martin, Sophie; Cohu, Stéphanie; Vignot, Céline; Zimmerman, Guillaume; Gattuso, Jean-Pierre
    The response of respiration, photosynthesis, and calcification to elevated pCO2 and temperature was investigated in isolation and in combination in the Mediterranean crustose coralline alga Lithophyllum cabiochae. Algae were maintained in aquaria during 1 year at near-ambient conditions of irradiance, at ambient or elevated temperature (+3 °C), and at ambient (ca. 400 µatm) or elevated pCO2 (ca. 700 µatm). Respiration, photosynthesis, and net calcification showed a strong seasonal pattern following the seasonal variations of temperature and irradiance, with higher rates in summer than in winter. Respiration was unaffected by pCO2 but showed a general trend of increase at elevated temperature...

  20. Seawater carbonate chemistry and calcium carbonate of Padina spp., photosynthesis of Padina pavonica in nature CO2 gradients experiment

    Johnson, Vivienne R; Russell, Bayden D; Fabricius, Katharina Elisabeth; Brownlee, Colin; Hall-Spencer, Jason M
    Predicting the impacts of ocean acidification on coastal ecosystems requires an understanding of the effects on macroalgae and their grazers, as these underpin the ecology of rocky shores. Whilst calcified coralline algae (Rhodophyta) appear to be especially vulnerable to ocean acidification, there is a lack of information concerning calcified brown algae (Phaeophyta), which are not obligate calcifiers but are still important producers of calcium carbonate and organic matter in shallow coastal waters. Here, we compare ecological shifts in subtidal rocky shore systems along CO2 gradients created by volcanic seeps in the Mediterranean and Papua New Guinea, focussing on abundant macroalgae...

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