Description: Free-ocean CO2 enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through interspecific relationships and food webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is, however, extremely challenging. The main goal of this paper is to provide guidelines on the general design, engineering, and sensor options required to conduct FOCE experiments. Another goal is to introduce xFOCE, a community-led initiative to promote awareness, provide resources for in situ perturbation experiments, and build a user community. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

Description: Purpose: To investigate whether cellular imaging by using ultrasmall superparamagnetic iron oxide (USPIO)–enhanced magnetic resonance (MR) imaging can allow detection and quantification of adipose tissue macrophage–related inflammation within adipose tissue in a mouse model. Materials and Methods: Experimental protocols were conducted in accordance with French government policies. Adipose tissue macrophages were detected and quantified with a 4.7-T MR imager in ob/ob obese mice on the basis of the signal variance of adipose tissue triggered by injection of P904 iron oxide nanoparticles (USPIO). Mice were either intravenously injected with 1000 μmol of iron per kilogram of body weight of P904 (10 ob/ob and 11 ob /+) or used as noninjected control animals (seven ob/ob and six ob /+). Three-dimensional T2*-weighted gradient-echo MR images were acquired 10 days after intravenous injection. MR imaging signal variance in mice was correlated to adipose tissue macrophage quantification by using monoclonal antibody to F4/80 immunostaining, to proinflammatory marker quantification by using reverse transcription polymerase chain reaction ( CCl2 , Tnf α , Emr1 ), and to P904 quantification by using electron paramagnetic resonance imaging. Quantitative data were compared by using the Mann-Whitney or Student t test, and correlations were performed by using the Pearson correlation test. Results: MR imaging measurements showed a significant increase in adipose tissue signal variance in ob/ob mice compared with ob /+ controls or noninjected animals ( P 〈 .0001), which was consistent with increased P904 uptake by adipose tissue in ob/ob mice. There was a significant and positive correlation between adipose tissue macrophage quantification at MR imaging and P904 iron oxide content ( r = 0.87, P 〈 .0001), adipose tissue macrophage–related inflammation at immunohistochemistry ( r = 0.60, P 〈 .01), and adipose tissue proinflammatory marker expression ( r = 0.55, 0.56, and 0.58 for CCl2 , Tnfα, and Emr1 , respectively; P 〈 .01). Conclusion: P904 USPIO–enhanced MR imaging is potentially a tool for noninvasive assessment of adipose tissue inflammation during experimental obesity. These results provide the basis for translation of MR imaging into clinical practice as a marker of patients at risk for metabolic syndrome. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111957/-/DC1

Description: 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 p CO 2 (~610 μatm, 14°C), elevated temperature (~410 μatm, 17°C), and elevated p CO 2 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 statistically significant effects of ocean warming and acidification, whether in isolation or combined, on the concentrations of nutrients, particulate organic matter, chl a and most of the photosynthetic pigments. Furthermore, 13 C labelling showed that the carbon transfer rates from 13 C-sodium bicarbonate into particulate organic carbon were not affected by seawater warming nor acidification. Rates of gross primary production followed the general decreasing trend of chl a concentrations and were significantly higher under elevated temperature, an effect exacerbated when combined to elevated p CO 2 level. In contrast to the other algal groups, the picophytoplankton population (cyanobacteria, mostly Synechococcus ) increased throughout the experiment and was more abundant in the warmer treatment though to a lesser extent when combined to high p CO 2 level. These results suggest that under nutrient-depleted conditions in the Mediterranean Sea, ocean acidification has a very limited impact on the plankton community and that small species will benefit from warming with a potential decrease of the export and energy transfer to higher trophic levels.