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Schrödinger [Schrödinger, E., 1944. What is Life? Cambridge University Press, Cambridge] marvelled at how the organism is able to use metabolic energy to maintain and even increase its organisation, which could not be understood in terms of classical statistical thermodynamics. Ho [Ho, M.W., 1993. The Rainbow and the Worm, The Physics of Organisms, World Scientific, Singapore; Ho, M.W., 1998a. The Rainbow and the Worm, The Physics of Organisms, 2nd (enlarged) ed., reprinted 1999, 2001, 2003 (available online from ISIS website www.i-sis.org.uk)] outlined a novel "thermodynamics of organised complexity" based on a nested dynamical structure that enables the organism to maintain its organisation and simultaneously achieve non-equilibrium and equilibrium energy transfer at maximum efficiency. This thermodynamic model of the organism is reminiscent of the dynamical structure of steady state ecosystems identified by Ulanowicz [Ulanowicz, R.E., 1983. Identifying the structure of cycling in ecosystems. Math. Biosci. 65, 210-237; Ulanowicz, R.E., 2003. Some steps towards a central theory of ecosystem dynamics. Comput. Biol. Chem. 27, 523-530]. The healthy organism excels in maintaining its organisation and keeping away from thermodynamic equilibrium--death by another name--and in reproducing and providing for future generations. In those respects, it is the ideal sustainable system. We propose therefore to explore the common features between organisms and ecosystems, to see how far we can analyse sustainable systems in agriculture, ecology and economics as organisms, and to extract indicators of the system's health or sustainability. We find that looking at sustainable systems as organisms provides fresh insights on sustainability, and offers diagnostic criteria for sustainability that reflect the system's health. In the case of ecosystems, those diagnostic criteria of health translate into properties such as biodiversity and productivity, the richness of cycles, the efficiency of energy use and minimum dissipation. In the case of economic systems, they translate into space-time differentiation or organised heterogeneity, local autonomy and sufficiency at appropriate levels, reciprocity and equality of exchange, and most of all, balancing the exploitation of natural resources--real input into the system--against the ability of the ecosystem to regenerate itself.

Food provides energy and nutrients, but its acquisition requires energy expenditure. In post-hunter-gatherer societies, extra-somatic energy has greatly expanded and intensified the catching, gathering, and production of food. Modern relations between energy, food, and health are very complex, raising serious, high-level policy challenges. Together with persistent widespread under-nutrition, over-nutrition (and sedentarism) is causing obesity and associated serious health consequences. Worldwide, agricultural activity, especially livestock production, accounts for about a fifth of total greenhouse-gas emissions, thus contributing to climate change and its adverse health consequences, including the threat to food yields in many regions. Particular policy attention should be paid to the health risks posed by the rapid worldwide growth in meat consumption, both by exacerbating climate change and by directly contributing to certain diseases. To prevent increased greenhouse-gas emissions from this production sector, both the average worldwide consumption level of animal products and the intensity of emissions from livestock production must be reduced. An international contraction and convergence strategy offers a feasible route to such a goal. The current global average meat consumption is 100 g per person per day, with about a ten-fold variation between high-consuming and low-consuming populations. 90 g per day is proposed as a working global target, shared more evenly, with not more than 50 g per day coming from red meat from ruminants (ie, cattle, sheep, goats, and other digastric grazers).

AbstractSpecies’ vulnerability to extinction is strongly impacted by their geographical range size. Formulating effective conservation strategies therefore requires a better understanding of how the ranges of the world’s species have changed in the past, and how they will change under alternative future scenarios. Here, we use reconstructions of global land use and biomes since 1700, and 16 possible climatic and socio-economic scenarios until the year 2100, to map the habitat ranges of 16,919 mammal, bird, and amphibian species through time. We estimate that species have lost an average of 18% of their natural habitat range sizes thus far, and may lose up to 23% by 2100. Our data reveal that range losses have been increasing disproportionately in relation to the area of destroyed habitat, driven by a long-term increase of land use in tropical biodiversity hotspots. The outcomes of different future climate and land use trajectories for global habitat ranges vary drastically, providing important quantitative evidence for conservation planners and policy makers of the costs and benefits of alternative pathways for the future of global biodiversity.

Theresa Marteau and colleagues argue for rapid, radical changes to the infrastructure and pricing systems that currently support unhealthy unsustainable behaviour

Microbial fuel cells are an emerging technology for converting organic substrates into electrical power. Recent research has shown that biofilms of some bacterial species are capable of self-mediated extracellular electron transfer. The prospect of exploiting this trait in photoautotrophic microbes that do not require an organic substrate has important implications for the future development of renewable solar energy technologies. Here we report on light-driven electrical power generated with biofilms grown from photosynthetic fresh water or marine species without the addition of an artificial electron-shuttling mediator. Green alga (Chlorella vulgaris, Dunaliella tertiolecta) or cyanobacteria (Synechocystis sp. PCC 6803, Synechococcus sp. WH 5701) strains were grown directly on a transparent, conductive anode (indium tin oxide-coated polyethylene terephthalate) and power generation under light and dark conditions was evaluated using a single-chamber bio-photovoltaic cell (BPV) system. Increased power outputs were observed for all strains upon illumination, with the largest light effect observed for Synechococcus (maximum 10.3 mW m−2 total power output recorded under 10 W m−2 white light). Further experiments conducted with Synechococcus and C. vulgaris showed that photosynthetic oxygen evolution rates were consistent with BPV power outputs under different light regimes (red, green and blue light), indicating a direct link between power output and photosynthetic activity. Biofilm power generation in these BPV devices was self-sustained for several weeks and was highly sensitive to ambient light levels. When connected in series, four BPVs (each 0.011 m2) generated enough power to run a commercial digital clock.

It was our hypothesis that, as a consequence of increased oxidative stress, cholesterol-derived hydroperoxides and oxysterols are increased in livers of rats exposed to ethanol. To test this we dosed Wistar rats (approximately 0.1 kg initial body weight) with ethanol chronically (rats fed a nutritionally complete liquid diet containing ethanol as 35% of total calories; sampled liver at approximately 6-7 weeks). We measured concentrations of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 alpha-OOH and 7 beta-OOH) as well as 7 alpha- and 7 beta-hydroxycholesterol (7 alpha-OH and 7 beta-OH), and 3 beta-hydroxycholest-5-en-7-one (also termed 7-ketocholesterol; 7-keto). In response to chronic alcohol feeding, there were significant elevations in the concentrations of 7 alpha-OOH (+169%, P = 0.005) and 7 beta-OOH (+199%, P = 0.011). Increases in the concentrations of hepatic 7-keto (+74%, P = 0.01) and decreases in cholesterol (-43%; P = 0.03) also occurred. In contrast, the concentrations of both 7 alpha-OH and 7 beta-OH were not significant (NS). However, when oxysterols in chronic ethanol-fed rats were expressed relative to cholesterol there were significant increases in 7-keto/cholesterol (P = 0.0006), 7 alpha-OH/cholesterol (P = 0.0018) and 7 beta-OH/cholesterol (P = 0.0047). In conclusion, this is the first report of increased 7 alpha-OOH, 7 beta-OOH, and 7-keto in liver of rats and their elevation in chronic experimental alcoholism represent evidence of increased oxidative stress.