Humans as the third evolutionary stage of biosphere engineering of rivers

Abstract

We examine three fundamental changes in river systems induced by innovations of the biosphere, these being: 1) the evolution of oxygenic photosynthesis; 2) the development of vascular plants with root systems; and 3) the evolution of humans. Modern river systems are associated with extensive human trace fossils that show a developing complexity from ancient civilizations, through to the gigantic metro systems beneath rivers in modern megacities. Changes induced by humans rank in scale with those caused by earlier biosphere innovations at 2.4 and 0.416 Ga, but would geologically soon revert to a "pre-human" state were humans to become extinct.

Phenomena and characteristics of barrier river reaches in the middle and lower Yangtze River, China

“…Recently, due to the influence of human activities like dam building, sand mining, and canalisation, many rivers in Europe and North America have shown an evolution towards narrowing, downcutting, tributary blocking, and main branch strengthening (Surian and Rinaldi 2003;Korpak 2007;Hudson et al 2008;Armaş et al 2012). By recognising the reasons for channel adjustment, scientists have proposed targeted remediation methods, implemented worldwide river restoration measures (Huang and Dong 1999;Duan et al 2009;Remo et al 2009;Chen and Ho 2013;Doulatyari et al 2014;Karambas and Samaras 2014;Williams et al 2014;Hajdukiewicz et al 2016), and accumulated valuable experience in maintaining river stability and restoring the aquatic ecological environment.…”

Rivers of the Anthropocene

“…Drawing together the important continuum of past, present, and future, he notes that gaining useful insight "into what people did in the past, how they act in the present, and what they are likely to do in the future" requires paying careful attention "to the complex and subtle tapestry of culture over time . " 75 Alterations to the global fluvial system associated with the onset of the Anthropocene have been profound (Syvitski et al 2005;Syvitski and Kettner 2011;Merritts et al 2011;Williams et al 2014). They have involved both direct reengineering of river systems to, for instance, "stabilize" channels, prevent active meandering, and impound water in dams; and indirect changes resulting from land use change, commonly involving such phenomena as increased sediment supply from deforestation and urbanization.…”

“…They can accurately be characterized as "organic machines" (White 1996) or "cyborg-like environments composed of an interconnected and interdependent web of natural and artificial parts" (Scarpino 1997, 5). It might even be argued that human-influenced changes to rivers globally are so great that they helped bring about a new evolutionary stage of rivers in geological terms (Williams et al 2014).…”

“…However, I argue that underground clues are imperative to understanding the techno-cultural formation of the twenty-first-century Anthropocene. The structures are so large and elaborate that they provide paleontologists with stratigraphic evidence marking human biosphere engineering (Williams et al 2014). Beneath the architecture, infrastructure, and socio-technospatial organization of Singapore's surface, there is a well-lit, air-conditioned, parallel world of movement and habitation.…”

Introduction to the Special Issue on Climate Change and Geosciences

“…The human impact on geomorphological features and processes is already evident, although it varies in degree spatially and between geomorphic domains [3]. The engineering of rivers, for example, affects geomorphological evolution [4] through changes in channel morphology and connectivity and flow ranges [5] and altered sediment deposition [6].…”