资源环境科技发展态势分析平台

Enhanced silicate rock weathering (ERW), deployable with croplands, has potential use for atmospheric carbon dioxide (CO2) removal (CDR), which is now necessary to mitigate anthropogenic climate change(1). ERW also has possible co-benefits for improved food and soil security, and reduced ocean acidification(2-4). Here we use an integrated performance modelling approach to make an initial techno-economic assessment for 2050, quantifying how CDR potential and costs vary among nations in relation to business-as-usual energy policies and policies consistent with limiting future warming to 2 degrees Celsius(5). China, India, the USA and Brazil have great potential to help achieve average global CDR goals of 0.5 to 2gigatonnes of carbon dioxide (CO2) per year with extraction costs of approximately US$80-180 per tonne of CO2. These goals and costs are robust, regardless of future energy policies. Deployment within existing croplands offers opportunities to align agriculture and climate policy. However, success will depend upon overcoming political and social inertia to develop regulatory and incentive frameworks. We discuss the challenges and opportunities of ERW deployment, including the potential for excess industrial silicate materials (basalt mine overburden, concrete, and iron and steel slag) to obviate the need for new mining, as well as uncertainties in soil weathering rates and land-ocean transfer of weathered products.

Extensive efforts have been made to harvest energy from water in the form of raindrops(1-6), river and ocean waves(7,8), tides(9) and others(10-17). However, achieving a high density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with low water supply. An alternative, the water-droplet/solid-based triboelectric nanogenerator, has so far generated peak power densities of less than one watt per square metre, owing to the limitations imposed by interfacial effects-as seen in characterizations of the charge generation and transfer that occur at solid-liquid(1-4) or liquid-liquid(5,18) interfaces. Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene film on an indium tin oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges the originally disconnected components into a closed-loop electrical system, transforming the conventional interfacial effect into a bulk effect, and so enhancing the instantaneous power density by several orders of magnitude over equivalent devices that are limited by interfacial effects.

A device involving a polytetrafluoroethylene film, an indium tin oxide substrate and an aluminium electrode allows improved electricity generation from water droplets, which bridge the previously disconnected circuit components.

The cryo-electron microscopy structure of a phycobilisome from the red alga Porphyridium purpureum reveals how aromatic interactions between the linker proteins and the chromophores drive a unidirectional transfer of energy.

Photosynthetic organisms have developed various light-harvesting systems to adapt to their environments(1). Phycobilisomes are large light-harvesting protein complexes found in cyanobacteria and red algae(2-4), although how the energies of the chromophores within these complexes are modulated by their environment is unclear. Here we report the cryo-electron microscopy structure of a 14.7-megadalton phycobilisome with a hemiellipsoidal shape from the red alga Porphyridium purpureum. Within this complex we determine the structures of 706 protein subunits, including 528 phycoerythrin, 72 phycocyanin, 46 allophycocyanin and 60 linker proteins. In addition, 1,598 chromophores are resolved comprising 1,430 phycoerythrobilin, 48 phycourobilin and 120 phycocyanobilin molecules. The markedly improved resolution of our structure compared with that of the phycobilisome of Griffithsia pacifica(5) enabled us to build an accurate atomic model of the P. purpureum phycobilisome system. The model reveals how the linker proteins affect the microenvironment of the chromophores, and suggests that interactions of the aromatic amino acids of the linker proteins with the chromophores may be a key factor in fine-tuning the energy states of the chromophores to ensure the efficient unidirectional transfer of energy.