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Datasets with PANGAEA technical keyword @GROWTH

Mostrando recursos 1 - 20 de 224

  1. Comparative responses of two dominant Antarctic phytoplankton taxa to interactions between ocean acidification, warming, irradiance, and iron availability

    Xu, Kai; Fu, Feixue; Hutchins, David A
    We investigated the responses of the ecologically dominant Antarctic phytoplankton species Phaeocystis antarctica (a prymnesiophyte) and Fragilariopsis cylindrus (a diatom) to a clustered matrix of three global change variables (CO2, mixed-layer depth, and temperature) under both iron (Fe)-replete and Fe-limited conditions based roughly on the Intergovernmental Panel on Climate Change (IPCC) A2 scenario: (1) Current conditions, 39 Pa (380 ppmv) CO2, 50 µmol photons/m**2/s light, and 2°C; (2) Year 2060, 61 Pa (600 ppmv) CO2, 100 µmol photons/m**2/s light, and 4°C; (3) Year 2100, 81 Pa (800 ppmv) CO2, 150 µmol photons/m**2/s light, and 6°C. The combined interactive effects of...

  2. Offspring sensitivity to ocean acidification changes seasonally in a coastal marine fish

    Murray, Christopher S; Malvezzi, Alex; Gobler, Christopher J; Baumann, Hannes
    Experimental assessments of species vulnerabilities to ocean acidification are rapidly increasing in number, yet the potential for short- and long-term adaptation to high CO2 by contemporary marine organisms remains poorly understood. We used a novel experimental approach that combined bi-weekly sampling of a wild, spawning fish population (Atlantic silverside Menidia menidia) with standardized offspring CO2 exposure experiments and parallel pH monitoring of a coastal ecosystem. We assessed whether offspring produced at different times of the spawning season (April to July) would be similarly susceptible to elevated (1100 µatm, pHNIST = 7.77) and high CO2 levels (2300 µatm, pHNIST = 7.47)....

  3. Adaptation of a globally important coccolithophore to ocean warming and acidification

    Schlüter, Lothar; Lohbeck, Kai T; Gutowska, Magdalena A; Gröger, Joachim P; Riebesell, Ulf; Reusch, Thorsten B H

  4. Light-modulated responses of growth and photosynthetic performance to ocean acidification in the model diatom Phaeodactylum tricornutum

    Li, Yahe; Xu, Juntian; Gao, Kunshan
    Ocean acidification (OA) due to atmospheric CO2 rise is expected to influence marine primary productivity. In order to investigate the interactive effects of OA and light changes on diatoms, we grew Phaeodactylum tricornutum, under ambient (390 ppmv; LC) and elevated CO2 (1000 ppmv; HC) conditions for 80 generations, and measured its physiological performance under different light levels (60 µmol/m**2/s, LL; 200 µmol/m**2/s, ML; 460 µmol/m**2/s, HL) for another 25 generations. The specific growth rate of the HC-grown cells was higher (about 12-18%) than that of the LC-grown ones, with the highest under the ML level. With increasing light levels, the...

  5. Effect of enhanced pCO2 levels on the production of dissolved organic carbon and transparent exopolymer particles in short-term bioassay experiments

    MacGilchrist, G A; Shi, T; Tyrrell, Toby; Richier, Sophie; Moore, C M; Dumousseaud, C; Achterberg, Eric P
    It has been proposed that increasing levels of pCO2 in the surface ocean will lead to more partitioning of the organic carbon fixed by marine primary production into the dissolved rather than the particulate fraction. This process may result in enhanced accumulation of dissolved organic carbon (DOC) in the surface ocean and/or concurrent accumulation of transparent exopolymer particles (TEPs), with important implications for the functioning of the marine carbon cycle. We investigated this in shipboard bioassay experiments that considered the effect of four different pCO2 scenarios (ambient, 550, 750 and 1000 µatm) on unamended natural phytoplankton communities from a range...

  6. Strong shift from HCO3- to CO2 uptake in Emiliania huxleyi with acidification: new approach unravels acclimation versus short-term pH effects

    Kottmeier, Dorothee M; Rokitta, Sebastian D; Tortell, Philippe Daniel; Rost, Bjoern
    Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 µatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative...

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

    Cornwall, Christopher E; Boyd, Philip W; McGraw, Christina M; Hepburn, Christopher D; Pilditch, Conrad A; Morris, Jaz N; Smith, Abigail M; Hurd, Catriona L; Hofmann, Gretchen E
    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...

  8. Effects of increasing seawater carbon dioxide concentrations on chain formation of the diatom Asterionellopsis glacialis

    Barcelos e Ramos, Joana; Schulz, Kai Georg; Brownlee, Colin; Sett, Scarlett; Azevedo, Eduardo Brito
    Diatoms can occur as single cells or as chain-forming aggregates. These two strategies affect buoyancy, predator evasion, light absorption and nutrient uptake. Adjacent cells in chains establish connections through various processes that determine strength and flexibility of the bonds, and at distinct cellular locations defining colony structure. Chain length has been found to vary with temperature and nutrient availability as well as being positively correlated with growth rate. However, the potential effect of enhanced carbon dioxide (CO2) concentrations and consequent changes in seawater carbonate chemistry on chain formation is virtually unknown. Here we report on experiments with semi-continuous cultures of...

  9. The response of Antarctic sea ice algae to changes in pH and CO2

    McMinn, Andrew; Müller, Marius N; Martin, Andrew; Ryan, Ken G; Swadling, Kerrie M
    Ocean acidification substantially alters ocean carbon chemistry and hence pH but the effects on sea ice formation and the CO2 concentration in the enclosed brine channels are unknown. Microbial communities inhabiting sea ice ecosystems currently contribute 10-50% of the annual primary production of polar seas, supporting overwintering zooplankton species, especially Antarctic krill, and seeding spring phytoplankton blooms. Ocean acidification is occurring in all surface waters but the strongest effects will be experienced in polar ecosystems with significant effects on all trophic levels. Brine algae collected from McMurdo Sound (Antarctica) sea ice was incubated in situ under various carbonate chemistry conditions....

  10. Impact of elevated pCO2 on paralytic shellfish poisoning toxin content and composition in Alexandrium tamarense

    Van de Waal, Dedmer B; Eberlein, Tim; John, Uwe; Wohlrab, Sylke; Rost, Bjoern
    Ocean acidification is considered a major threat to marine ecosystems and may particularly affect primary producers. Here we investigated the impact of elevated pCO2 on paralytic shellfish poisoning toxin (PST) content and composition in two strains of Alexandrium tamarense, Alex5 and Alex2. Experiments were carried out as dilute batch to keep carbonate chemistry unaltered over time. We observed only minor changes with respect to growth and elemental composition in response to elevated pCO2. For both strains, the cellular PST content, and in particular the associated cellular toxicity, was lower in the high CO2 treatments. In addition, Alex5 showed a shift...

  11. CO2 and vitamin B12 interactions determine bioactive trace metal requirements of a subarctic Pacific diatom

    King, Andrew L; Sañudo-Wilhelmy, Sergio A; Leblanc, Karine; Hutchins, David A; Fu, Feixue
    Phytoplankton growth can be limited by numerous inorganic nutrients and organic growth factors. Using the subarctic diatom Attheya sp. in culture studies, we examined how the availability of vitamin B(12) and carbon dioxide partial pressure (pCO(2)) influences growth rate, primary productivity, cellular iron (Fe), cobalt (Co), zinc (Zn) and cadmium (Cd) quotas, and the net use efficiencies (NUEs) of these bioactive trace metals (mol C fixed per mol cellular trace metal per day). Under B(12)-replete conditions, cells grown at high pCO(2) had lower Fe, Zn and Cd quotas, and used those trace metals more efficiently in comparison with cells grown...

  12. Combined effects of CO2 and light on large and small isolates of the unicellular N2-fixing cyanobacterium Crocosphaera watsonii from the western tropical Atlantic Ocean

    Garcia, Nathan S; Fu, Feixue; Breene, Cynthia L; Yu, Elizabeth K; Bernhardt, Peter W; Mulholland, Margaret R; Hutchins, David A
    We examined the combined effects of light and pCO2 on growth, CO2-fixation and N2-fixation rates by strains of the unicellular marine N2-fixing cyanobacterium Crocosphaera watsonii with small (WH0401) and large (WH0402) cells that were isolated from the western tropical Atlantic Ocean. In low-pCO2-acclimated cultures (190 ppm) of WH0401, growth, CO2-fixation and N2-fixation rates were significantly lower than those in cultures acclimated to higher (present-day 385 ppm, or future 750 ppm) pCO2 treatments. Growth rates were not significantly different, however, in low-pCO2-acclimated cultures of WH0402 in comparison with higher pCO2 treatments. Unlike previous reports for C. watsonii (strain WH8501), N2-fixation rates...

  13. Colimitation of the unicellular photosynthetic diazotroph Crocosphaera watsonii by phosphorus, light, and carbon dioxide

    Garcia, Nathan S; Fu, Feixue; Hutchins, David A
    We describe interactive effects of total phosphorus (total P = 0.1-4.0 µmol/L; added as H2NaPO4), irradiance (40 and 150 µmol quanta/m**2/s), and the partial pressure of carbon dioxide (P-CO2; 19 and 81 Pa, i.e., 190 and 800 ppm) on growth and CO2- and dinitrogen (N-2)-fixation rates of the unicellular N-2-fixing cyanobacterium Crocosphaera watsonii (WH0003) isolated from the Pacific Ocean near Hawaii. In semicontinuous cultures of C. watsonii, elevated P-CO2 positively affected growth and CO2- and N-2-fixation rates under high light. Under low light, elevated P-CO2 positively affected growth rates at all concentrations of P, but CO2- and N-2-fixation rates were...

  14. Ocean acidification affects growth but not nutritional quality of the seaweed Fucus vesiculosus (Phaeophyceae, Fucales)

    Gutow, Lars; Rahman, Mohammed Mofizur; Bartl, Kevin; Saborowski, Reinhard; Bartsch, Inka; Wiencke, Christian
    Understanding the ecological implications of global climate change requires investigations of not only the direct effects of environmental change on species performance but also indirect effects that arise from altered species interactions. We performed CO2 perturbation experiments to investigate the effects of ocean acidification on the trophic interaction between the brown seaweed Fucus vesiculosus and the herbivorous isopod Idotea baltica. We predicted faster growth of F. vesiculosus at elevated CO2-concentrations and higher carbon content of the algal tissue. We expected that I. baltica has different consumption rates on algae that have been grown at different CO2 levels and that the...

  15. Elevated CO2 levels do not affect the shell structure of the bivalve Arctica islandica from the western Baltic

    Stemmer, Kristina; Nehrke, Gernot; Brey, Thomas
    Shells of the bivalve Arctica islandica are used to reconstruct paleo-environmental conditions (e.g. temperature) via biogeochemical proxies, i.e. biogenic components that are related closely to environmental parameters at the time of shell formation. Several studies have shown that proxies like element and isotope-ratios can be affected by shell growth and microstructure. Thus it is essential to evaluate the impact of changing environmental parameters such as high pCO2 and consequent changes in carbonate chemistry on shell properties to validate these biogeochemical proxies for a wider range of environmental conditions. Growth experiments with Arctica islandica from the Western Baltic Sea kept under...

  16. Growth rate of Mnemiopsis mccradyi and Sagitta hispida determined experimentally

    Reeve, M R; Syms, Mary Ann; Kremer, Patricia

  17. Growth rate of Theragra chalcogramma determined experimentally

    Yamashita, Yoh; Bailey, K M

  18. Growth rate of Aurelia labiata determined experimentally

    Widmer, Chad L

  19. Growth rate of Calanus pacificus and Pseudocalanus sp. determined experimentally

    Vidal, J

  20. Growth rate of Acartia omori, Calanus sinicus and Paracalanus parvus determined experimentally

    Uye, Shin-ichi; Aoto, I; Onbe, Takashi

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