U.S. oil and natural gas production volumes have grown by up to 100% in key production areas between January 2017 and August 2019. Here we show that recent trends are visible from space and can be attributed to drilling, production, and gas flaring activities. By using oil and gas activity data as predictors in a multivariate regression to satellite measurements of tropospheric NO columns, observed changes in NO over time could be 2 2 attributed to NO emissions associated with drilling, production and gas flaring for three select regions: the x Permian, Bakken, and Eagle Ford basins. We find that drilling had been the dominant NO source contributing x around 80% before the downturn in drilling activity in 2015. Thereafter, NO contributions from drilling x activities and combined production and flaring activities are similar. Comparison of our top-down source attribution with a bottom-up fuel-based oil and gas NO emission inventory shows agreement within error x margins.

Plain Language Summary: U.S. oil and natural gas production volumes have grown by up to 100% in key production areas between January 2017 and August 2019. Here we show that recent trends are visible from space as increases in NO , an air pollutant that is released from combustion engines associated with the oil and 2 gas industry. For three select regions, the Permian (TX and NM), Bakken (ND), and Eagle Ford (TX) basins, we report that the trend in NO columns over time can be explained by a combination of drilling activity, 2 production numbers, and flared gas volume, which allows us to quantify the contributions from these sources to the total NO (= NO+ NO ) emissions from these areas. We find that drilling had been the dominant NO x x 2 source contributing around 80% before the downturn in drilling activity in 2015. But now, NO contributions x from drilling activities and combined production and flaring activities are similar. Both Permian and Bakken oil and gas production volumes are at an all-time high and if c urrent growth rates continue in the Eagle Ford basin, maximum production volumes will be exceeded in about 1 year.

Dixon, R.A., Barros, J., 2020. Lignin biosynthesis: old roads revisited and new roads explored. Open Biology 9, 190215.

https://doi.org/10.1098/rsob.190215 Lignin is a major component of secondarily thickened plant cell walls and is considered to be the second most abundant biopolymer on the planet. At one point believed to be the product of a highly controlled polymerization procedure involving just three potential monomeric components (monolignols), it is becoming increasingly clear that the composition of lignin is quite flexible. Furthermore, the biosynthetic pathways to the major monolignols also appear to exhibit flexibility, particularly as regards the early reactions leading to the formation of caffeic acid from coumaric acid. The operation of parallel pathways to caffeic acid occurring at the level of shikimate esters or free acids may help provide robustness to the pathway under different physiological conditions. Several features of the pathway also appear to link monolignol biosynthesis to both generation and detoxification of hydrogen peroxide, one of the oxidants responsible for creating monolignol radicals for polymerization in the apoplast. Monolignol transport to the apoplast is not well understood. It may involve passive diffusion, although this may be targeted to sites of lignin initiation/polymerization by ordered complexes of both biosynthetic enzymes on the cytosolic side of the plasma membrane and structural anchoring of proteins for monolignol oxidation and polymerization on the apoplastic side. We present several hypothetical models to illustrate these ideas and stimulate further research. These are based primarily on studies in model systems, which may or may not reflect the major lignification process in forest trees.

Dong, Z., Zhang, J., Tang, X., Liu, G., Dang, W., Liu, Y., Tao, J., Su, Z., 2020. Origin and diffusion of the over- mature transitional natural gas in multiple lithologic reservoirs: A case study of Carboniferous-Permian strata in the southeastern margin of Ordos Basin. International Journal of Coal Geology 219, 103380.

http://www.sciencedirect.com/science/article/pii/S0166516219308195 To investigate differences in gas origin and diffusion among various lithologies in the continent - marine transitional strata of the Lower Permian Shanxi Formation (P s) and Upper Carboniferous Benxi Formation 1 (C b) in the southeastern margin of Ordos Basin, 31 natural gas samples were collected from the existing 2 lithologies (including mudstone, sandstone, and coal) and their gas components and carbon and hydrogen 13 isotope compositions were measured. Remarkable diff erences in the ethane (δ C ) and carbon dioxide isotope 2