Flow aspects of research and management in aquatic

habitats focus on Average Current

Living in a Turbulent World

Paul W. Webb – SNRE, EEB Aline J. Cotel – CofE, AWRE

REALITY - Natural Flows are Characterized by Unsteady Flow = Turbulence

Measurement in Lab & Field: Acoustic Doppler Velocimetry & Particle Image Velocimetry

Turbulence is a Major Factor Affecting Aquatic Systems

… central at all scales: sediment transport and deposition, sculpting streams and rivers and shoreline topography distributing dissolved gasses and other materials

Turbulence also affects where organisms live:

Fishes choose lower turbulence habitats.

Spiny fishes (e.g. bass) more susceptible to turbulence than soft rayed fishes (e.g. minnows).

Turbulence Affects Habitat Choice and Shoreline Management Practices

strong waves weak

P = pelagic S = slow B = benthic

Depczynski, M. and D. R. Bellwood. 2005 Wave energy and spatial variability in community structure of small cryptic coral reef fishes. Marine Biology Progress Series 303: 283-293.

Depth for sheltered reefs (m

)

Weaker swimmers found in less turbulent habitats

Turbulence Affects Habitat Choices

BOTTOM LINE: Ecologist must include turbulent

flow impacts into their assessment of plant and animal

distributions and habitat functionality.

Turbulence must be built into

management recommendations.