Top PDF CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <i>Phaeodactylum tricornutum</i>

CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <i>Phaeodactylum tricornutum</i>

CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <i>Phaeodactylum tricornutum</i>

pH conditions, leading to increased photosynthetic carbon fixation and enhanced growth rate in P. tricornutum, cells ex- posed to excessive light levels appeared to suffer more dam- age to PSII in the high compared to the L-C grown cells. Hence, ocean acidification is likely to have different impacts on cells suspended in the immediate surface layer compared to those in deeper layers of the water column, and may lead to less photosynthetic production in the upper layer of eu- photic zone. Since phytoplankton cells are also susceptible to solar UV radiation in their natural environment (Gao et al., 2007), their physiology may be synergistically affected by UV and ocean acidification (Sobrino et al., 2008). While UV-A was also found to enhance photosynthetic carbon fix- ation (Gao et al., 2007) of phytoplankton assemblages and growth of a cyanobacterium (Wu et al., 2005), the change of water column primary productivity is uncertain due to the scarce knowledge on the combined effects of acidification and solar radiation in the euphotic zone.
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CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <I>Phaeodactylum tricornutum</I>

CO<sub>2</sub>-induced seawater acidification affects physiological performance of the marine diatom <I>Phaeodactylum tricornutum</I>

Orr, J. C., Fabry, V. J., Aumont, O., Bopp, L., Doney, S. C., Feely, R. A., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Key, R. M., Lindsay, K., Maier-Reimer, E., Matear, R., Mon- fray, P., Mouchet, A., Najjar, R. G., Plattner, G. K., Rodgers, K. B., Sabine, C. L., Sarmiento, J. L., Schlitzer, R., Slater, R. D., Totterdell, I. J., Weirig, M. F., Yamanaka, Y., and Yool, A.: Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying

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Technical note: Assessing gas equilibration systems for continuous <i>p</i>CO<sub>2</sub> measurements in inland waters

Technical note: Assessing gas equilibration systems for continuous <i>p</i>CO<sub>2</sub> measurements in inland waters

available (e.g., GO8050, General Oceanics, USA). Spray- type equilibrators have been used in diverse inland water sys- tems (Raymond and Hopkinson, 2003; Zhai et al., 2005; Ma- her et al., 2013; Crawford et al., 2015; Joesoef et al., 2015). The marble-type equilibrators were developed to address the monitoring conditions specific to inland waters, such as high loads of sediments and organic matter (Frankignoulle et al., 2001; Abril et al., 2006). In the marble-type equilibrator, the pumped water flows over the surface of the marbles, which increase the air–water interface and reduce the volume of headspace air, enabling gas exchange between the flowing water and the headspace air (Frankignoulle et al., 2001; Abril et al., 2006). The equilibrated air continuously circulates in a closed loop, linking the equilibrator headspace to a gas ana- lyzer, usually an IRGA or a cavity-enhanced absorption spec- trometer (Friedrichs et al., 2010; Gonzalez-Valencia et al., 2014; Webb et al., 2016). These automatic and active equili- bration systems integrate water sampling, equilibration, and gas analysis in a loop using water or air pumps powered by external sources (Table 1). This implies that factors such as power supply and maintenance could limit the application of these equilibrator systems to continuously monitor pCO 2 in
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Coupling of heterotrophic bacteria to phytoplankton bloom development at different <i>p</i>CO<sub>2</sub> levels: a mesocosm study

Coupling of heterotrophic bacteria to phytoplankton bloom development at different <i>p</i>CO<sub>2</sub> levels: a mesocosm study

Senescent planktonic algae and aggregates are rapidly col- onized by bacteria (e.g. Smith et al., 1995; Simon et al., 2002) which have a repertoire of hydrolytic enzymes (Hoppe et al., 1993; Martinez et al., 1996) for efficient POM solu- bilisation to DOM (Smith et al., 1992; Grossart and Ploug, 2001). Even though DOM of algal origin can be rapidly used by bacteria (Grossart et al., 2006a), a seasonal accumulation of DOM in the oceanic photic zone is commonly observed (Williams, 1995) and may indicate a semi-labile nature of the released dissolved organic carbon (DOC; Søndergaard et al., 2000). A substantial fraction (25 to 35%) of DOC re- leased from phytoplankton can even resist microbial degra- dation for years (Fry et al., 1996). Alternatively to low bioavailability, temporary accumulation of POC and DOC has been explained by a “malfunctioning microbial loop”, e.g. when nutrient availability limits bacterial growth and vi- ral lysis as well as grazing the bacterial biomass (Thingstad et al., 1997; Williams, 1995). However, it has been suggested that viruses primarily influence bacterial community compo- sition, while grazers have a greater impact on total bacterial biomass (Thingstad, 2000).
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Impact of seawater <i>p</i>CO<sub>2</sub> on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with <i>Ammonia tepida</i>

Impact of seawater <i>p</i>CO<sub>2</sub> on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with <i>Ammonia tepida</i>

can be considered to increase significantly with increased [CO 2− 3 ]. At salinity 24, Sr/Ca ratios increased from 1.25 to 1.33, and from 1.34 to 1.50, for an increase of 0.8 unit pH, at 10 and 15 ◦ C, respectively. At salinity 33, Sr/Ca ra- tios increased from 1.35 to 1.47 and from 1.38 to 1.48, for the same pH increase of 0.8 unit, at 10 ◦ C and 15 ◦ C, re- spectively. These results are in good agreement with pre- vious observations made by Lea et al. (1999) (1.1±0.5% in- crease per 0.1 pH unit) and Russell et al. (2004) (1.6±0.4% increase per 0.1 pH unit) for O. universa (Fig. 7). However, these two studies also show insensitivity of Sr/Ca to pH in another planktonic foraminiferal species, G. bulloides. To explain this species-specific response, Russell et al. (2004) proposed that changes in ambient pH impact photosynthetic activity of the symbionts and hence calcification rate in O. universa. Strontium in turn is affected by the calcification rate in inorganic calcite precipitation (Nehrke et al., 2007). Since G. bulloides has no symbionts, no impact of pH was observed. Ammonia tepida, like G. bulloides, is a symbiont barren species; therefore changes in pH (or [CO 2− 3 ]) do not (only) affect Sr incorporation via an impact on symbiont ac- tivity.
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CO<sub>2</sub>(<i>ν</i><sub>2</sub>)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

CO<sub>2</sub>(<i>ν</i><sub>2</sub>)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

taking into account all processes which populate and depopulate vibrational levels: op- tical transitions, chemical sources, vibrational-vibrational and vibrational-translational energy exchange processes, and the absorption of atmospheric and solar radiation in the ro-vibrational bands. The altitude above which the LTE approximation is not appli- cable depends on the relationship between these processes and for CO 22 ) vibrational

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Effect of enhanced <i>p</i>CO<sub>2</sub> levels on the production of DOC and TEP in short-term bioassay experiments

Effect of enhanced <i>p</i>CO<sub>2</sub> levels on the production of DOC and TEP in short-term bioassay experiments

Table 1. Summary of statistically significant differences between treatments for DOC (top) and TEP (bottom). Upward pointing arrows signify a positive correlation between pCO 2 and DOC/TEP production (more DOC/TEP in the higher pCO 2 treatment) and downward pointing arrows signify a negative correlation (more DOC/TEP in the lower pCO 2 treatment). Single- headed and two-headed arrows signify statistical significance at the 95 % and 99 % confidence level respectively (using the Tukey–Kramer test statistic). – signifies that treatments were not significantly different at the 95 % confidence level.
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Temperature-dependence of the relationship between <i>p</i>CO<sub>2</sub> and dissolved organic carbon in lakes

Temperature-dependence of the relationship between <i>p</i>CO<sub>2</sub> and dissolved organic carbon in lakes

open squares represent respectively significant (p < 0.05) and non-significant (p > 0.05) lin- ear regressions between absolutes values of pCO 2 and DOC concentrations for each bin interval (n varying from 7 and 1540). The solid lines represent both fitted regression equa- tion encompassing all bins. Linear Slope ( y) = −0.04 ± 0.01x + 0.91 ± 0.28 temperature 3 ◦

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Effects of in situ CO<sub>2</sub> enrichment on structural characteristics,  photosynthesis, and growth of the Mediterranean seagrass <i>Posidonia oceanica</i>

Effects of in situ CO<sub>2</sub> enrichment on structural characteristics, photosynthesis, and growth of the Mediterranean seagrass <i>Posidonia oceanica</i>

Acknowledgements. We would like to acknowledge the following people who assisted in the laboratory, in the field, or with system engineering or maintenance: E. Beck Acain, J. Acain, J. Delille, L. van der Heijden, M. Maillot, F. Moullec, S. Schenone, L. Urbini, K. Walzy´nska. We also thank J.-J. Pangrazi, R. Patrix, and E. Tanguy for aide in construction of the enclosures. Éric Béraud, G. de Liege, D. Luquet, L. Mangialajo, S. Reynaud, and D. Robin kindly assisted in diving activities. We are grateful to C. Ferrier- Pagès and her research team for use of their PAM fluorometer. We also thank B. Kirkwood at Monterey Bay Aquarium Research Institute who advised in system design. We thank the Service d’Observation Rade de Villefranche and the Service d’Observation en Milieu Littoral for their kind permission to use Point B data. We also thank the Service National d’Analyse des Paramètres Océaniques du CO 2 for performing the determination of A T at Point B. This work was funded by the “European Free Ocean Carbon Enrichment” (eFOCE; BNP Paribas Foundation), the European Commission through the project “Mediterranean Sea Acidification in a changing climate” (MedSeA; grant agreement 265103) and the MISTRALS-MERMEX (INSU, CNRS) program.
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Effects of increased <i>p</i>CO<sub>2</sub> and temperature on trace element (Ag, Cd and Zn) bioaccumulation in the eggs of the common cuttlefish, <i>Sepia officinalis</i>

Effects of increased <i>p</i>CO<sub>2</sub> and temperature on trace element (Ag, Cd and Zn) bioaccumulation in the eggs of the common cuttlefish, <i>Sepia officinalis</i>

ume (results not shown). This implies that the seawater pCO 2 disturbed the swelling process that occurs during the last two thirds of the whole developmental period. The water intake occurred progressively with the organogenesis and enhanced the periv- itelline space that the embryo requires for its growth. The mechanistic understanding of this phenomenon is not well known in cephalopod eggs, although it was observed that

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Influence of elevated CO<sub>2</sub> concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium <i>Nodularia spumigena</i>

Influence of elevated CO<sub>2</sub> concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium <i>Nodularia spumigena</i>

quently develop in the southern Baltic Sea at this value (Kononen, 1992). The cultures were illuminated at an average intensity of 85 µmol photons m −2 s −1 under a 14/10 h light/dark cycle. To ensure identical light conditions for all bottles, their positions were shifted daily. Aggregation of cell filaments and the development of microenvironments, in which growth conditions can deviate from those in the bulk medium, was avoided by

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Spatial and temporal variation of CO<sub>2</sub> efflux along a disturbance gradient in a <i>miombo</i> woodland in Western Zambia

Spatial and temporal variation of CO<sub>2</sub> efflux along a disturbance gradient in a <i>miombo</i> woodland in Western Zambia

Fig. 1. Scheme of the site and experimental setup in Mongu (Zam- bia). The dark grey area represents the disturbed area driven by de- forestation, burning and grazing. The light grey area represents the north western corner of Kataba forest reserve, established in 1973. The measurement plots, divided into subplots of different ground cover, were established along a disturbance gradient from North to South, with plot 1 being highly disturbed, 2 and 3 being slightly disturbed (edge effects) and 4 undisturbed in the core area of the forest reserve. The prevailing wind direction was east-southeast. All plots were located within the 50% fetch of the eddy covariance tower. Wind sectors in the direction of the inventory plots, used for the comparison of eddy covariance measurements to chamber measurements are shown. Coloured triangles are given to visualize hypothesized trends of the most important abiotic and biotic param- eters.
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Microbial communities responsible for fixation of CO<sub>2</sub> revealed by using <i>mcrA</i>, <i>cbbM</i>, <i>cbbL</i>, <i>fthfs</i>, <i>fefe-hydrogenase</i> genes as molecular biomarkers in petroleum reservoirs of different temperatures

Microbial communities responsible for fixation of CO<sub>2</sub> revealed by using <i>mcrA</i>, <i>cbbM</i>, <i>cbbL</i>, <i>fthfs</i>, <i>fefe-hydrogenase</i> genes as molecular biomarkers in petroleum reservoirs of different temperatures

Similarly, the cbbM gene types were also detected with relatively higher diversity in these four samples as shown in Fig. 2, suggesting that cbbM gene could be found universally in microorganisms of oil reservoirs. The 53 clones in XJ6 sample were divided into 3 OTUs in which 38 clone (represented by cbbM-XJ6-34, 71.7 %) sequences are closely related to Rhodovulum sulfidophilum, a member of Alpha-

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A model study of the seasonal and long term North Atlantic surface <i>p</i>CO<sub>2</sub> variability

A model study of the seasonal and long term North Atlantic surface <i>p</i>CO<sub>2</sub> variability

In this study, we focus on the data sub-set from the North Atlantic basin. Figure 1 shows all the ship tracks that contain some measurements. Since the data is mainly used for comparison with the model in the seasonal time scale, we isolate regions with a good seasonal (i.e., at least 8 out of 12 months) coverage over continuous years. In addition, we also avoid regions close to the continental margins where the

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Synergism between elevated <i>p</i>CO<sub>2</sub> and temperature on the Antarctic sea ice diatom <i>Nitzschia lecointei</i>

Synergism between elevated <i>p</i>CO<sub>2</sub> and temperature on the Antarctic sea ice diatom <i>Nitzschia lecointei</i>

been suggested that maximal growth rate occurs at temper- atures above in situ levels (Fiala and Oriol, 1990; Longhi et al., 2003), which indicates that a narrow thermal win- dow generally limits Antarctic microalgae. This suggests that carbon enrichment might not be beneficial at ambient con- ditions since temperature primarily regulates growth. How- ever, ambient temperatures may become closer to the peak of the thermal window during an ocean warming event and promote the effect of carbon enrichment. Temperature is es- sential to enzyme activity and metabolic processes where the speed of reactions increases with increasing temperature. Re- sults from this study indicate that N. lecointei is more effi- cient in utilizing available resources at higher temperatures (5.1 ◦ C), which is within reasonable limits of what could
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Response of <i>Nodularia spumigena</i> to <i>p</i>CO<sub>2</sub> – Part 2: Exudation and extracellular enzyme activities

Response of <i>Nodularia spumigena</i> to <i>p</i>CO<sub>2</sub> – Part 2: Exudation and extracellular enzyme activities

For further information on gel particle size and abundance, a microscopic analysis was performed. Most cyanobacteria filaments seemed to be coated by mucus which was stained by Alcian Blue (Fig. 4a) while CSP was mostly observed as “free” particles in the seawater (Fig. 4c, d). Additionally, free TEP particles were observed (Fig. 4b). Due to methodological constraints it was not possible to quantify TEP or mucus sepa-

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Effect of CO<sub>2</sub>-related acidification on aspects of the larval development of the European lobster, <i>Homarus gammarus</i> (L.)

Effect of CO<sub>2</sub>-related acidification on aspects of the larval development of the European lobster, <i>Homarus gammarus</i> (L.)

Ovigerous females were supplied by local fishermen and held in aquaria (160×100×35 cm) at the National Lobster Hatch- ery (NLH) in Padstow, Cornwall, UK. Each aquarium was constantly supplied with aerated, filtered re-circulating sea water (T =17±1 ◦ C, S=35) pumped directly from waters ad- jacent to the NLH. Water was pre-treated in a pressurized sand filter, passed through activated carbon, and finally UV- irradiated. Adult lobsters were fed ad libitium with blue mus- sels, Mytilus edulis. Experiments were carried out between June and July 2007, to coincide with the natural hatching season (between April and September).
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Inferring regional sources and sinks of atmospheric CO<sub>2</sub> from GOSAT <i>X</i>CO<sub>2</sub> data

Inferring regional sources and sinks of atmospheric CO<sub>2</sub> from GOSAT <i>X</i>CO<sub>2</sub> data

neth, A., Bernhofer, C., Bonal, D., Chen, J., Gianelle, D., Gobron, N., Kiely, G., Kutsch, W., Lasslop, G., Law, B. E., Lindroth, A., Merbold, L., Montagnani, L., Moors, E. J., Pa- pale, D., Sottocornola, M., Vaccari, F., and Williams, C.: Global patterns of land-atmosphere fluxes of carbon dioxide, latent heat, and sensible heat derived from eddy covari- ance, satellite, and meteorological observations, J. Geophys. Res.-Biogeo., 116, G00J07,

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Synergism between elevated <i>p</i>CO<sub>2</sub> and temperature on the Antarctic sea ice diatom <i>Nitzschia lecointei</i>

Synergism between elevated <i>p</i>CO<sub>2</sub> and temperature on the Antarctic sea ice diatom <i>Nitzschia lecointei</i>

tion in photosynthesis when CO 2 is limited (see Reinfelder, 2011). It has also been sug- gested that CCMs are an evolutionary response to the change of atmospheric gases over geological time, where the ratio of O 2 and CO 2 has increased (Hopkinson et al., 2011). Carbonic anhydrase (CA) is a major CCM, catalysing the reversible dehydration of HCO − 3 into CO 2 externally at the surface of algal cells (CA ext ), or internally in the cell

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Seagrass beds as ocean acidification refuges for mussels? High resolution measurements of <i>p</i>CO<sub>2</sub> and O<sub>2</sub> in a <i>Zostera marina</i> and <i>Mytilus edulis</i> mosaic habitat

Seagrass beds as ocean acidification refuges for mussels? High resolution measurements of <i>p</i>CO<sub>2</sub> and O<sub>2</sub> in a <i>Zostera marina</i> and <i>Mytilus edulis</i> mosaic habitat

sea samples (open cell analyzer as described in SOP 3b, Dickson et al., 2007). Based on the analysis of 6 discrete water samples from Kiel Bight taken at GEOMAR (Fig. 1), we found that the measurements on the analyzer used for this study were too low by 7.5 ± 3.2 µmol kg − 1 (mean ± SD). Despite such a likely salinity dependent bias, this offset does not explain the characteristics found within the pCO 2 comparison.

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