Sequestration of CO_(2)by concrete and natural minerals-current status,future potential,and additional benefits

Concrete structures are some of the largest constructions in human civilization.Their manufacture releases CO_(2)into atmosphere,which is partially readsorbed by standing structures,and further release occurs when they are demolished.Concrete is chemically similar to basaltic minerals,both adsorb CO_(2)where they are exposed on the earth's surface.Sequestration of CO_(2)is beneficial to reduce atmospheric concentrations,and thus limit future temperature increases.Therefore,multiple options are being examined for CO_(2)sequestration.For the first time,we compare the CO_(2)sequestration capacity of these two materials.We review previous work quantifying CO_(2)sequestration capacity of both materials and for the first time,compare their potential quantitative roles.Costs of that are compiled,to the extent they have been examined.Costly grinding of these materials to small particle sizes accelerates CO_(2)sequestration,and mycorrhizae in agricultural soils might reduce the associated costs.Both these materials can improve nutrient status in agricultural soils,and limit acidification from external nitrogen fertilization.Limitations are discussed in terms of land-use and material availability,and soil pH conditions.We call for further experiments with these materials that compare CO_(2)sequestration and other biogeochemical processes in agricultural systems across climates,carried out especially where such materials are conveniently available.

Valorizing plastic waste by insect consumption

Insects first began evolving hundreds of millions of years ago,and aided by gut microbes,they have been consuming hydrocarbon polymers ever since.Few man-made plastic polymers are chemically novel,so it is reasonable that insect/microbe systems can be found or developed to degrade them rapidly.However,remediation of global plastic waste problems should involve more than just conversion into CO_(2).Some industryscale microbial enzymatic degradation of plastic polymers may yield valuable monomers,but the plastic waste starting material must be of uniform chemistry and clean.This adds cost to the process.Many insect species can be utilized for animal feed as well as human food.Some of these insects have the capability to degrade plastic polymers.However,valorizing plastic wastes by producing edible insects or useful frass has largely been overlooked.Here we assemble the current knowledge of plastic degradation rates by insects.In addition,we also show the first instance of insect degradation of polyurethane and the first identification and isolation of insect gut fungi as directly aiding insect degradation.

Arbuscular Mycorrhiza and Sustainable Agriculture

Arbuscular mycorrhizal fungi(AMF)provide benefits to most crop species via enhanced nutrient uptake,increased drought and abiotic stress resistance,and reduced effects of pathogens and pests.Much remains unclear regarding the specific mechanisms influencing these processes,and the critical roles of AMF are often overlooked in planning agroecological systems.There is growing consensus,however,around the important roles AMF play in improving plant resilience and crop yield while also enhancing the functioning of soil microbial communities.Heterogeneous practices across all scales complicate the successful integration of AMF in agroecological systems.AMF symbioses with crops are passive,or stimulated by incorporation of crop wastes in soil,soil inoculation with AMF spores,or the planting inoculated of seeds.Here we suggest that AMF can have highest beneficial impacts in areas with low levels of agrochemical inputs.We argue that areas with intensive agrochemical inputs can also be made more sustainable with AMF enhancements.