2. The Origin of Lakes

Question 1

In North America, catchment and watershed are typically used interchangeably to refer to:

Answer 1

the entire land surface that drains hydrologically into a waterbody

Question 2

In Europe, what does watershed refer to?

Answer 2

the uppermost boundary (borderline) from which water can drain into a catchment

Question 3

T/F
Groundwater flow and surface flow cannot have different patterns in the same location

Answer 3

false

Groundwater flow can follow the pattern for surface water, but it can also have subsurface flow patterns that are different because of subterranean geology

Question 4

The water cycle exists as a series of pools and fluxes.
Pools=

Fluxes=

Answer 4

Pools=
- lakes
- rivers
- snowpack
- groundwater
- ocean
- atmosphere

Fluxes=
- evapotranspiration
- runoff (rivers)
- precipitation

Question 5

What are the soil horizons?

Answer 5

O (Organic)
A (surface)
B (subsoil)
C (substratum)
R (Bedrock)

Question 6

Lakes and rivers integrate the landscapes over __(broad/narrow) spatial scales

Answer 6

broad

Question 7

Aquatic ecosystems reflect the condition of the surrounding _____

Answer 7

landscape!

Question 8

List some aspects of the surrounding landscape that could impact aquatic ecosystems

Answer 8

• vegetation
• roads
• urbanization
• dams
• agriculture

These affect the chemistry and biology of receiving waters

Question 9

Lotic systems=

Answer 9

moving water bodies having unidirectional water flow

Question 10

Lentic systems=

Answer 10

still waterbodies lacking unidirectional water flow

Question 11

Give examples of lotic vs lentic systems

Answer 11

lotic= creeks, streams, rivers

lentic= lakes, ponds, reservoirs, wetlands

Question 12

Wetlands=

Answer 12

shallow (<1m deep) waterbodies dominated by aquatic vegetation throughout

Question 13

T/F
There is no universal definition to differentiate ponds and lakes

Answer 13

true!
just ponds are smaller than lakes

Question 14

Give 3 possible definitions to differentiate ponds and lakes

Answer 14

1. ponds are shallow enough that the bottom gets light (light through whole water column)
2. Ponds freeze to the bottom (bad definition for warm climates)
3. ponds are less than 2 hectares in area

Question 15

What is the emerging definition of a pond given by Richardson et al. 2022?

Answer 15

Ponds= waterbodies that are small (less than 5 hectares), shallow (less than 5m), with less than 30% emergent vegetation

Question 16

T/F

Ponds and lakes function very similarly/ the same

Answer 16

false

small waterbodies function quite differently compared to a midsize-big lake

Question 17

Oligotrophic lakes=

Answer 17

Lakes with low primary production as a result of low nutrient (N,P) levels

Question 18

Eutrophic Lakes=

Answer 18

Lakes with high primary production as a result of high nutrient (N,P) levels’ potentially to the point where ecosystem function declines (eutrophication)

Question 19

Dystrophic Lakes=

aka:

Answer 19

aka “bog lakes”

= lakes with significant inputs of organic matter; this enables respiration to exceed photosynthesis
- shading by organic matter inhibits light penetration

Question 20

______ are volcanic lakes. Are they deep or shallow?

Answer 20

Calderas

very deep

Question 21

How does an oxbow lake form? Are they relatively shallow or deep?

Answer 21

They are a cutoff of a meander in a meandering river

Relatively shallow

Question 22

How do kettle lakes (prairie potholes) form?

Answer 22

At the base of a glacier, chunks of “dead ice” get buried by outwash. Eventually they melt, and the outwash erodes away and you’re left with kettle lakes

Question 23

T/F
Lake origin is an important determinant of lake function

Answer 23

true