Many bodies in the solar system have features which could conceivably have been formed by a grazing impact with a comet or asteroid. We present the results of deterministic computer simulations of various objects striking a terrestrial planet at a grazing angle. The system is modeled using a combination of the Material Point Method (MPM) and classical planetary dynamics. The impact exhibits three distinct regimes: (i) the initial stage where rapid ejecta leaves the planet in a nearly straight line, (ii) the intermediate stage where the ejecta begins to curve in towards the planet and the trench is being created on the surface and the (iii) the long term stage where the trench is created and any paths exhibited by the ejecta are stable capture orbits. In the case of Mars, we show that a grazing impact can not only dig a trench which has the same general morphology as Valles Marineris but also can create ejecta which orbits the planet at distances comparable to those for current Martian satellites.

<p>Altered temperature and precipitation regimes particularly prolonged drought periods when combined with heat strongly affect forests in the last decades. However, neither did all trees die nor even stop growing at all sites. We are interested in the question if below ground interaction with ectomycorrhizal fungi could be partly mediating strong soil drought. For this purpose, we established sampling sites with <em>Fagus sylvatica</em>, <em>Picea abies</em> or <em>Pinus sylvestris</em> along a natural precipitation gradient of 400 km length in Bavaria (Germany). We hypothesized root associated fungal communities to reflect long-term adaptation to local edaphic and climate conditions and that the resulting tree-fungal partnerships have distinct compositional patterns.</p>