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Globally pervasive increases in atmospheric CO2 and nitrogen (N) deposition could have substantial effects on plant communities, either directly or mediated by their interactions with soil nutrient limitation. While the direct consequences of N enrichment on plant communities are well documented, potential interactions with rising CO2 and globally widespread phosphorus (P) limitation remain poorly understood. We investigated the consequences of simultaneous elevated CO2 (eCO2) and N and P additions on grassland biodiversity, community and functional composition in P‐limited grasslands. We exposed soil‐turf monoliths from limestone and acidic grasslands that have received >25 years of N additions (3.5 and 14 g m−2 year−1) and 11 (limestone) or 25 (acidic) years of P additions (3.5 g m−2 year−1) to eCO2 (600 ppm) for 3 years. Across both grasslands, eCO2, N and P additions significantly changed community composition. Limestone communities were more responsive to eCO2 and saw significant functional shifts resulting from eCO2–nutrient interactions. Here, legume cover tripled in response to combined eCO2 and P additions, and combined eCO2 and N treatments shifted functional dominance from grasses to sedges. We suggest that eCO2 may disproportionately benefit P acquisition by sedges by subsidising the carbon cost of locally intense root exudation at the expense of co‐occurring grasses. In contrast, the functional composition of the acidic grassland was insensitive to eCO2 and its interactions with nutrient additions. Greater diversity of P‐acquisition strategies in the limestone grassland, combined with a more functionally even and diverse community, may contribute to the stronger responses compared to the acidic grassland. Our work suggests we may see large changes in the composition and biodiversity of P‐limited grasslands in response to eCO2 and its interactions with nutrient loading, particularly where these contain a high diversity of P‐acquisition strategies or developmentally young soils with sufficient bioavailable mineral P. [ABSTRACT FROM AUTHOR]

Polar hydrogen deposits on the Moon provide evidence that its spin axis has shifted; analysis of the locations of these deposits and of the lunar figure suggests that the shift occurred as a result of changes in the Moon's moments of inertia caused by a low-density thermal anomaly beneath the Procellarum region. Polar wandering on the Moon Matthew Siegler and co-authors show that the polar hydrogen deposits detected on the Moon by orbital neutron spectroscopy pose something of a mystery: the spatial distribution of hydrogen, which is thought to arise from the presence of water ice, does not match that expected from present-day lunar temperatures. The explanation may lie in the phenomenon known as 'true polar wander', in which a reference point on a solid body rotates with respect to its spin axis. Based on an analysis of polar deposit locations and of the lunar figure, the authors suggest that the shift occurred as a result of changes in the Moon's moment of inertia caused by a low-density thermal anomaly beneath the Procellarum region. Procellarum was most geologically active early in lunar history, which would imply that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers.sup.1,2,3, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures.sup.4,5. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles.sup.6. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism.sup.7,8,9,10,11 and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history.sup.7,8,9, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon and the bombardment history of the early Solar System., Author(s): M. A. Siegler [sup.1] [sup.2] , R. S. Miller [sup.3] , J. T. Keane [sup.4] , M. Laneuville [sup.5] , D. A. Paige [sup.6] , I. Matsuyama [sup.4] , [...]

To understand young people's low levels of sun protection behaviour, 145 young people (aged 12 to 20 years) were recruited from Queensland, to participate in a one-hour focus group where they discussed issues related to sun protection and images of tanned and non-tanned people. Responses were content analysed to identify common sun protection beliefs and perceptions. Key barriers and motivators for sun protection were identified. Despite young people's awareness of the advantages of sun protection, health promotion efforts still need to focus on not only reducing beliefs about the costs of performing sun protection but also decreasing the positive view of tanned images among youth.