Aquatic Ecology Lecture 2

What are lentic systems?

Lakes and ponds, characterized by standing water.

What are lotic systems?

Streams and rivers, characterized by flowing water.

What is laminar flow?

A smooth, orderly flow of water.

What is turbulent flow?

A chaotic, irregular flow of water.

What processes are predominant in lotic systems?

Erosion processes are predominant.

What is the significance of flow in lotic systems?

Flow enhances mixing and oxygen saturation.

How do algae differ in lentic and lotic systems?

Algae in lentic systems are mostly planktonic, while in lotic systems, they must be attached.

What are macrophytes?

Aquatic plants that can be rootless and floating or must be rooted.

What is the difference between rivers and streams?

Rivers are wider, deeper, murkier, and warmer; streams are narrower, shallower, clearer, and cooler.

What are three functions of lotic ecosystems?

Linking land and oceans, transport, and providing critical habitat, food, and shelter.

What is a drainage area?

The land area drained by all tributary streams above a chosen point in the main channel.

How is a watershed boundary determined?

By locating ridges that separate basins from adjacent closed contours.

What does the Strahler classification system measure?

Stream order, where the smallest streams are assigned 1st order.

What is a perennial stream?

A stream that flows year-round.

What is an intermittent stream?

A stream that flows at certain times of the year.

What is an ephemeral stream?

A stream that flows in response to precipitation.

What is discharge in the context of streams?

The volume of water passing through a channel per unit time.

What is the formula for calculating discharge?

Discharge Q = V × A, where V is average water velocity and A is cross-sectional area.

What is a hydrograph?

A plot of discharge against time.

What factors affect discharge on a large scale?

Storm size, groundwater, and land use.

What is stream geomorphology?

The study of the shape of streams and their interaction with the surrounding land.

What is thalweg?

The deepest part of the channel with maximum water velocity.

What is sinuosity in streams?

The ratio of stream length to valley length.

What are the methods for measuring stream discharge?

Pipet bucket for 1st order, flume for 1st-2nd order, and flowmeter/float method for >2nd order streams.

What is chemical loading in watershed management?

The determination of pollutant discharge and metal loads from concentration and flow.