Diel changes in stream benthos density on stones and artificial substrates
✍ Scribed by William P. Kovalak
- Publisher
- Springer
- Year
- 1978
- Tongue
- English
- Weight
- 654 KB
- Volume
- 58
- Category
- Article
- ISSN
- 1573-5141
No coin nor oath required. For personal study only.
✦ Synopsis
Diel changes in stream benthos density were studied by comparing faunal densities on naturally occurring stones collected at noon and at midnight and on artificial substrates (bricks) collected at 2 hr intervals for 24 hr . Over all dates and all rivers, on stones, nighttime densities were higher in 37 cases, lower in 35 cases and unchanged in three cases . The magnitude of nocturnal density increases (expressed as a proportion of daytime density) ranged between 0 .03 and 1 .o8 and the magnitude of nocturnal density decreases ranged between o .oi and o.81 . Diel density changes on bricks generally were variable and not synchronized with changes in light intensity, but in most cases (60%) densities were greater at night.
A new, accurate and rapid method to estimate the area of stone surface is also described .