Proterozoic rivers flowed through barren landscapes, and lacked interactions with macroscopic organisms. It is widely held that, in the absence of vegetation, fluvial systems featured barely entrenched channels that promptly widened over floodplains during floods. This hypothesis has never been tested because of an enduring lack of Precambrian fluvial-channel morphometric data. Here we show, th...

The ecology of viruses has been studied only in a limited number of rivers and streams. In light of a recent re-appraisal of the global fluvial surface area, issues such as abundance and production, host mortality and the influence of suspended particles and biofilms are addressed. Viral life cycles, potential impacts of viruses on water biochemistry and carbon flow, and viral diversity are con...

[1] Valley networks, regional drainage patterns suggesting liquid water stability at the surface, are confined to early in the history of Mars (the Noachian/Hesperian boundary and before), prior to a major climate transition to the hyperarid cold conditions of the Amazonian. Several later fluvial valley systems have been documented in specific Hesperian and Early Amazonian environments, and are...

Introduction: This investigation focused on Warrego Valles, a region of well-developed valley systems located in Thaumasia Planum of the southern highlands at ~42°S, 267°E. Some previous workers interpreted the valley systems in this area as being of fluvial origin [1-3], while others focused on sapping [4-6] or hydrothermal activity [7-10] as formative mechanisms. It is clear that no single mo...

the proposal of geomorphologic matters in relation to tourism is one of interdisciplinary research approaches that has been considered in recent years. in this manner, geomorphological sites are defined as geomorphological landforms and processes that have acquired a scenic/aesthetic, scientific, cultural/historical and/or a social/economic value due to human perception of geological, geomorpho...