Zoology 315: Limnology Rivers & Streams Part I Abby Popp July 24th, 2006 1. PHYSICAL ASPECTS OF STREAMS & RIVERS a. Scale b. stream order Classification system Permanent Channels c. habitats riffles pools runsd. zones water column benthic zone hyporheic zone riparian zone e. ecosystem boundaries 2. ABIOTIC FACTORS INFLUENCING STREAMS a. Flow regime discharge Q = v • A Q = m/s • m2 = m3/shydrograph Five aspects of flow regime: Magnitude: Frequency: Duration: Timing: Rate of change:Thought Question: What aspects of a stream ecosystem would be affected by the flow regime? b. formation/erosion of riversSediment transport capacity: Thought Question: What might be the effect of the following human alterations on e sediment of a river? (Consider both upstream and downstream effects) • Dams • Straightening of channels thc. Temperature Thought Q sWhy is the widest range of temperatures seen in mid-order streams? Why do you think low- and high-order streams would have small temperature ranges? ue tion: d. Light Two controls: treams: ight in large rivers: Light in small s Le. xygen sually high: Exceptions: 3. BIOTA ADAPTATIONS Species composition ps a. adaptations OU & Same major grou Adapting to life in moving fluid Adaptations to flow Small-medium streams Large riversStream food webs . feeding groups i. Shredders ii. Collector-gatherers iii. Scrapers-grazers iv. Predators bc. food webs Concerned with CARBON flow Example: Boulder Creek,