SFB 1211: Earth - Evolution at the Dry Limit

水是可居住的地球的决定性特征;它是我们所知的所有生命的基本要素。生命在水资源极其有限的环境中进化，这覆盖了地球上的很大一部分，但还没有得到很好的理解。与生命相似，水驱动的过程在地球表面留下了独特的痕迹。火星是已知的唯一一个带有水驱动表面过程痕迹的行星，尽管是化石和古老的。即使在实际上没有液态水的情况下，也可能发生缓慢的表面过程，这基本上是未知的。显而易见的是，水供应量的短暂增加会在水资源极其有限的环境中留下持久的痕迹。有趣的是，地球表面进化的爆发痕迹很少与生物殖民/进化的爆发有关，反之亦然，尽管两者都与同一个触发因素有关：水。拟议第二阶段的化学研究中心地球-干限的演变的目标是深化关于地球表面过程与生物群之间相互演变关系的开创性研究。目标地区是干旱至极端干旱的系统，在这些系统中，生物区系和地球表面进程都受到水资源的严重和主要限制。在第一阶段，我们专注于阿塔卡马沙漠，在第二阶段，我们希望扩大我们的研究领域，包括纳米布沙漠;比较地球上两个最古老的沙漠的演变轨迹。在第一阶段取得的进展的基础上，我们的目标是分离出生物活动的关键指纹在（水）的可居住的地球的限制，并描述地球表面的过程中运行的（虚拟）没有液态水。我们的目标是表征阈值的生物殖民化和并发河流改造的景观，确定生物和非生物控制的地球表面系统的临界点（S），并建立详细的长期陆地气候记录地球上最古老和最干旱的地区。关于生物群定居和辐射的时间和空间信息将与景观演变及其共同驱动因素：气候有关。在第二阶段，我们的目标是建立统一的数字和概念模型的景观和生物的共同进化，并调查共同的遗传特征适应干旱环境。

Water is the defining feature of the habitable Earth; it is essential for all life as we know it. Evolution of life in extremely water-limited environments, which cover significant portions on Earth, is not well understood. Akin to life, water-driven processes leave unique marks on the Earth’s surface. Mars is the only other planet known to bear the marks of water-driven surface processes, albeit fossil and of great age. The slow surface processes that may operate even in the virtual absence of liquid water are essentially unknown. What is evident is that transient episodes of increased water availability leave long-lasting traces in extremely water-limited environments. Intriguingly those traces of bursts in Earth-surface evolution have rarely been related to bursts in biological colonization/evolution, and vice versa, although both relate to the same trigger: water. The objective of the CRC Earth – Evolution at the Dry Limit in the proposed second phase is to deepen the pioneering research on the mutual evolutionary relationships between Earth-surface processes and biota. The target areas are arid to hyper-arid systems, where both biota and Earth-surface processes are severely and predominantly limited by the availability of water. In the first phase we focussed on the Atacama Desert, in the second phase we want to expand our research area to include the Namib Desert; to compare the evolutionary trajectories of the two oldest deserts on Earth. Building on the progress made in the first phase we aim to isolate the key fingerprints of biological activity at the (water) limit of the habitable Earth, and to characterize the Earth-surface processes operating in the (virtual) absence of liquid water. We aim to characterize thresholds for biological colonization and concurrent fluvial transformation of landscapes, identify the tipping point(s) of biotically and abiotically controlled Earth-surface systems, and establish detailed long-term terrestrial climatic records of the oldest and most arid zones on Earth. Chronometric and spatial information on the colonization and radiation of biota will be related to the landscape evolution and their common driver: climate. In the second phase we aim to build unified numeric and conceptual models of landscape- and biological co-evolution, and investigate common genetic traits for adaptation to arid environments.