Flow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled inverte...

Where rivers enter the coastal zone, gradually varying non-uniform flow conditions develop in the channel. This section of the river is referred to as the backwater segment, and for large rivers, backwater flow extends many hundreds of kilometres upstream of the river outlet. Studies from the Mississippi River document a persistent backwater zone that influences sediment mobility throughout the...

Methane (CH4 ) fluxes from world rivers are still poorly constrained, with measurements restricted mainly to temperate climates. Additional river flux measurements, including spatio-temporal studies, are important to refine extrapolations. Here we assess the spatio-temporal variability of CH4 fluxes from the Amazon and its main tributaries, the Negro, Solimões, Madeira, Tapajós, Xingu, and Pará...

The windings of rivers have long fascinated their human observers. For example, Aboriginal legend explains the sinuous pattern of the modern Finke River (Fig. 1) as the creation of the immense and powerful Rainbow Serpent as he emerged during the Dreamtime from deep waterholes. Recently in PNAS (1), a new theory for the general origin of such sinuous flow patterns was published, which follows f...

Gregory Bateson was one of the last and most distinguished products of the school of anthropology that Haddon and Rivers created in Cambridge after the Torres Strait Expedition. Beginning his career shortly after Rivers' death, Bateson used the interwar years to create a theoretical approach that continued and deflected that of Haddon and Rivers. His major ethnography from this period, Naven, e...

1. Comparative research and generalisations in lotic ecology are challenged by the dynamic hydrology of fluvial systems. The aim of this study was to understand more fully how factors such as light, nutrients and flow can predict variation in autochthonous production and algal biomass. 2. We measured seasonal changes in percent bankfull discharge, inorganic nutrient concentrations, turbidity, i...

In previous chapters we considered the processes of advection and molecular diffusion and have seen some example problems with so called “turbulent diffusion” coefficients, where we use the same governing equations, but with larger diffusion (mixing) coefficients. In natural rivers, a host of processes lead to a non-uniform velocity field, which allows mixing to occur much faster than by molecu...

The tidal bore is a well-known phenomenon in fluid mechanics, having been observed in many rivers around the world. Two of the better known rivers where bores regularly appear are the Severn River in England [1] and the Qiantang River in China [2]. The usual circumstances in which a bore can appear develop when a tidal swell causes a difference in surface elevation in the mouth of a river or fu...

Historically, rivers have served as sources of drinking water, fisheries resources, transportation routes, irrigation supplies, and waste removal systems. Human civilization has had many major effects on rivers, dating back more than 5000 years when Egyptians built dams on the Nile to supply water for crops and human consumption. Today, management of large rivers requires a balance between huma...

1. We used field surveys to compare the density and mesohabitat-scale distribution of the native coastrange sculpin (Cottus aleuticus) and the prickly sculpin (C. asper) in coastal rivers in north-western California, U.S.A., with and without an introduced piscivorous fish, the Sacramento pikeminnow, Ptychocheilus grandis. We also measured mortality of tethered prickly sculpin in a field experim...