Short-term growth and biomechanical responses of the temperate seagrass Cymodocea nodosa to CO2 enrichment

Seagrasses are often regarded as climate change 'winners' because they exhibit higher rates of photosynthesis, carbon fixation and growth when exposed to increasing levels of ocean acidification. However, questions remain whether such growth enhancement compromises the biomechanical properties of the plants, altering their vulnerability to structural damage and leaf loss. Here, we investigated the short-term (6 wk) effects of decreasing pH by CO2 enrichment on the growth, morphology and leaf-breaking force of the temperate seagrass Cymodocea nodosa. We found that the plant biomass balance under levels of acidification representative of short-term climate change projections (pH 8.04) was positive and led to an increase in leaf abundance in the shoots. However, we also found that plant biomass balance was negative under levels of acidification experienced presently (pH 8.29) and those projected over the long-term (pH 7.82). Leaf morphology (mean leaf length, thickness and width) was invariant across our imposed acidification gradient, although leaves were slightly stronger under [CO2] representative of short-term climate change. Taken together, these findings indicate that a subtle increase in growth and mechanical resistance of C. nodosa is likely to occur following short-to medium-term changes in ocean chemistry, but that these positive effects are unlikely to be maintained over the longer term. Our study emphasises the need to account for the interdependencies between environmental conditions and variations in multiple aspects of the structure and functioning of seagrass communities when considering the likely consequences of climate change.Mobility Fellowships Programme of the EuroMarine Consortium (European Commission Seventh Framework Programme) [FP7-ENV-2010.2.2.1-3]; Foundation of Science and Technology of Portugal [SFRH/BPD/119344/2016, PTDC/MAR-EST/3223/2014]; Natural Environment Research Council (NERC) through the UK Ocean Acidification Research Programme (UKOARP) [NE/H017445/1]info:eu-repo/semantics/publishedVersio

Catalysis in Plastics for the 21st Century

For this Special Issue, which is part of the Organic and Polymer Chemistry Section, we would like to present the following editorial message [...

Specific arrangements of species dominance can be more influential than evenness in maintaining ecosystem process and function

The ecological consequences of species loss are widely studied, but represent an end point of environmental forcing that is not always realised. Changes in species evenness and the rank order of dominant species are more widespread responses to directional forcing. However, despite the repercussions for ecosystem functioning such changes have received little attention. Here, we experimentally assess how the rearrangement of species dominance structure within specific levels of evenness, rather than changes in species richness and composition, affect invertebrate particle reworking and burrow ventilation behaviour - important moderators of microbial-mediated remineralisation processes in benthic environments - and associated levels of sediment nutrient release. We find that the most dominant species exert a disproportionate influence on functioning at low levels of evenness, but that changes in biomass distribution and a change in emphasis in species-environmental interactions become more important in governing system functionality as evenness increases. Our study highlights the need to consider the functional significance of alterations to community attributes, rather than to solely focus on the attainment of particular levels of diversity when safeguarding biodiversity and ecosystems that provide essential services to society

Carbon Free Energy Development and the Role of Small Modular Reactors: A Review and Decision Framework for Deployment in Developing Countries

Global energy demand is projected to continue to grow over the next two decades, especially in developing economies. An emerging energy technology with distinct advantages for growing economies is small modular nuclear reactors (SMRs). Their smaller size makes them suitable for areas with limited grid capacities and dispersed populations while enabling flexibility in generating capacity and fuel sources. They have the ability to pair well with renewable energy sources, the major source of increased energy capacity for many developing economies. Further advantages include their passive safety features, lower capital requirements, and reduced construction times. As a result, SMRs have potential for overcoming energy poverty issues for growing economies without increasing carbon emissions. This study reviews the features and viability of SMRs to meet increasing energy capacity needs and develops a decision support framework to evaluate the market conditions for SMR deployment to emerging economies. The focus is on identifying countries best suited for domestic deployment of SMRs rather than vendor countries with ongoing or future SMR development programs for export. We begin by examining the characteristics of over two hundred countries and identifying those that satisfy several necessary economic, electrical grid capacity, and nuclear security conditions. Countries satisfying these necessary conditions are then evaluated using the Analytical Hierarchy Process (AHP) using criteria related to the economic and financial conditions, infrastructure and technological framework, and governmental policies within each country. The results find that countries with increasing GDP and energy demand that possess a robust infrastructure, energy production from high GHG sources, and governmental policies favorable to foreign investment are well-suited for future SMR deployment

Cationic rhodium(I) and iridium(I) α-diimine complexes

AbstractCondensation of glyoxal with fluoroarylanilines [ArFNH2; ArF=4-C6H4F; 2,4-C6H3F2; 2,4,6-C6H2F3] generates new fluorine-substituted aryl α-diimines, ArFNCHCHNArF; ArF=4-C6H4F and 2,4,6-C6H2F3 have been structurally characterised. Displacement of acetonitrile from [M(COD)(MeCN)2][BF4] (M=Rh, Ir, COD=1,5-cyclooctadiene) with fluorine- and non-fluorine-substituted aryl α-diimines yields cationic rhodium(I) and iridium(I) complexes, that can be carbonylated to [M(CO)2(α-diimine)][BF4]

Perfect-information games with lower-semicontinuous payoffs

We prove that every multiplayer perfect-information game with bounded and lower-semicontinuous payoffs admits a subgame-perfect epsilon-equilibrium in pure strategies. This result complements Example 3 in Solan and Vieille [Solan, E., N. Vieille. 2003. Deterministic multi-player Dynkin games. J. Math. Econom. 39 911-929], which shows that a subgame-perfect epsilon-equilibrium in pure strategies need not exist when the payoffs are not lower-semicontinuous. In addition, if the range of payoffs is finite, we characterize in the form of a Folk Theorem the set of all plays and payoffs that are induced by subgame-perfect 0-equilibria in pure strategies

Connexin43 phosphorylation in brain, cardiac, endothelial and epithelial tissues

AbstractGap junctions, composed of proteins from the connexin family, allow for intercellular communication between cells in essentially all tissues. There are 21 connexin genes in the human genome and different tissues express different connexin genes. Most connexins are known to be phosphoproteins. Phosphorylation can regulate connexin assembly into gap junctions, gap junction turnover and channel gating. Given the importance of gap junctions in development, proliferation and carcinogenesis, regulation of gap junction phosphorylation in response to wounding, hypoxia and other tissue insults is proving to be critical for cellular response and return to homeostasis. Connexin43 (Cx43) is the most widely and highly expressed gap junction protein, both in cell culture models and in humans, thus more research has been done on it and more reagents to it are available. In particular, antibodies that can report Cx43 phosphorylation status have been created allowing temporal examination of specific phosphorylation events in vivo. This review is focused on the use of these antibodies in tissue in situ, predominantly looking at Cx43 phosphorylation in brain, heart, endothelium and epithelium with reference to other connexins where data is available. These data allow us to begin to correlate specific phosphorylation events with changes in cell and tissue function. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics

Anthropogenic sources of underwater sound can modify how sediment-dwelling invertebrates mediate ecosystem properties

Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with mounting levels of offshore human activity. This has the potential to alter the way in which species interact with their environment, compromising the mediation of important ecosystem properties. Here, we show that exposure to underwater broadband sound fields that resemble offshore shipping and construction activity can alter sediment-dwelling invertebrate contributions to fluid and particle transport - key processes in mediating benthic nutrient cycling. Despite high levels of intra-specific variability in physiological response, we find that changes in the behaviour of some functionally important species can be dependent on the class of broadband sound (continuous or impulsive). Our study provides evidence that exposing coastal environments to anthropogenic sound fields is likely to have much wider ecosystem consequences than are presently acknowledge