Types and specifications of wetlands and lakes

Question 1

Lake

Answer 1

Lentic (non flowing) environments
A body of water occupied in a basin and lacking continuity with the sea
Considerable area and deep enough to stratify

Question 2

Pond

Answer 2

small shallow body of water either formed through depression or man made
arise naturally

Question 3

Succecion

Answer 3

New species will replace original and previolusly better adapted species and on turn will be excluded.

Lake –> plants –> wetland –> woods

Question 4

Origin of lakes

Answer 4

• Glazial lake
• Ice scour lake (Ice sheet move over surface and hollow basins are formed –> filled with water)
• Tectonic lake
• Landslide Lake
• Volcanic Lake
• Solution Lakes (Dissolving of soluble rock material)

Question 5

Lake zones

Answer 5

… skizze

Littoral zone, Limnetic zone

Photic zone
Benthic zone
Profundal (aphotic) zone

Question 6

Littoral zone

Answer 6

• shallow water depth
• well lighted
• warmest zone of the lake
• diverse community (several species of algae (like diatoms), rooted and floating aquatic plants, grazing snails, Clams, Insects, Crustaceans, Fishes and amphibians)
• wave action is relevant (erosion, material transport)
• subject to fluctuating temperature and erosion of shore
• it’s a bond from shoreline to the depth where aquatic plants disappear.

Question 7

Limetic zone

Answer 7

• near-surface open water surrounded by the littoral zone
• well-lighted (like the littoral zone) above profundal zone
• dominated by plankton (phytoplankton and zooplankton)
• variety of freshwater fish
• the main photosynthetic body of the lakes
• most productive zone

Question 8

Profundal zone

Answer 8

• cold and dense region of the lake
• also called the aphotic zone where light is reduced
• located below the range of effective light penetration
• typically below the thermocline
• temperature nearly uniform
• sediments are fine particles
• benthic organisms dominate

Question 9

Benthic zone

Answer 9

• bottom area of the lake
• place where decomposition takes place
• for the profundal and benthic zones, low levels of photosynthesis result in lower levels of dissolved oxygen
• life mostly made up of bottom dwellers which get most of their food from dead and decaying organisms.
• most of the organisms are scavengers because they depend on dead flesh as their main food source
• organisms here tend to tolerate cooler temperatures

Question 10

Pelagic zone

Answer 10

• the water column of the lake
• Organisms living in the pelagic zone
  o Pelagic fish (living NOT near the bottom)
  o Plankton
  ▪ Phytoplankton
  ▪ Zooplankton
  ▪ Bacterioplankton
• Community divided into broad producer, consumer and recycler groups
• Nanoplankton (few μm) to Megaplankton (> 20cm)

Question 11

Lake communties

Answer 11

open water: Plankton and Nekton

skizze +

Question 12

Benthos

Answer 12

Primary producer: cyanobacteria, higher taxa of algae, flowering plants

Periphyton and Macrophytes

Profundal zone (dark, colder limited oxygen) is inhabited only by consumers and by chemoautotrophic bacteria. Biomass depends on amoun

Question 13

Coupling of benthic ans pelagic habtitats

Answer 13

• Deep-water fauna is largely dependent on production in euphotic zone
• Phytoplankton transported into littoral region provides food for filter-feeders, e.g. mussels
• Animals spend different life stages in benthos and in pelagic zone
• Diapause of numerous planktonic organisms

Question 14

Lake stratification

Answer 14

The thermal stratification of lakes refers to a change in the temperature at different depths in the lakes, and is due to the change in water’s density with temperature

Thre layers
* Epilimnoin: top of the lake
* Metalimion: the middle layers
* Hypolimnion: bottom layer

Question 15

Epilimnion

Answer 15

• warmer, higher pH, higher DO
• turbulently mixed
• most phytoplankton (sun)

Question 16

Metalimnion

Answer 16

• thin
• depending on everything

Question 17

Hypolimnion

Answer 17

• dense
• coldest in summer, warmest in winter (4 °)
• isolated and insufficient light

Question 18

Lake mixis

Answer 18

• During the summer, warm water, which is less dense will sit on top (epilimnion) of colder, denser, deeper water (hypolimnion).
• As winter approaches, the temperature of the surface water will drop.
• A point is reached where the density of the cooling surface water becomes greater than the density of the deep water, then the different layers will start to mix (overturn) as the dense surface water moves down under the influence of gravity.
• This process is often aided by wind, inflow floods and/or other processes (e.g. currents) that agitate the water
• Or “lake turnover” is a circulation which recharges oxygen (top -> down) and nutrients (bottom -> up) through the lake

Question 19

Type of lake mixis

Answer 19

• Amictic: never mix as they are permanently frozen.
• Meromictic: mix only partially, the deeper layers never mix either because of high water density caused by dissolved substances or because the lake is protected from wind effects.
• Holomictic: mix completely.
• Oligomictic: do not mix every year as they are large and have higher heat storing capacity, the mixing depending on specific climatic conditions.
• Monomictic: mix only once each year, either in winter or summer.
• Polymictic: mixing frequently, they are shallow tropical lakes with great wind exposure.

Question 20

Lake factors

Answer 20

• light
• Temperature
• morphometry

Question 21

Light

Answer 21

• intensity varies seasonally
• major factor of controlling temperature and potentionally photosysnthesis

Question 22

Temperature

Answer 22

• …
• solubility of gases
• biological activity

Question 23

Morphometry

Answer 23

• surface to volume ration

Question 24

Primary production and biomass of the phytoplankton