Class 18

Question 1

What are stromatolites?

Answer 1

They are example of mats.

Question 2

What is it called when ______ are suspended?

Answer 2

Planktonic

Question 3

What are phytoplankton?

Answer 3

Alagae and Cyanobacteria are collectively called phytoplankton.

Question 4

What are primary producers and what are they called?

Answer 4

Autotrophs are primary producers. They create complex organic molecules from simple inorganic compounds such as water, CO2 and nutrients usally via photosynthesis

Question 5

What is the Transient between the water column and mineral subsurface.

Answer 5

Benthic habitat. Noncompacted mix of organic matter that has settled from the surface.

Question 6

Which has a larger microbes presence benthic or plantonic environement?

Answer 6

Benthic.

Question 7

Do open oceans have high or low primary activity and explain why.

Answer 7

Low primary activity due to low levels of essential nutrients such as N and P

Question 8

Define DOM and POM. What is the difference?

Answer 8

DOM: dissolved organic matter, used by microbes in the environment. POM is particulate organic matter, the stage before DOM.

Question 9

What is secondary production?

Answer 9

Production of bacterial biomass. It’s the major pathway for the transfer of carbon and energy to higher trophic levels in the aquatic environment.

Question 10

How many “steps” does it take to produce fish in coastal areas compared to open ocean.

Answer 10

In the coastal area it takes 1.5 to 3.5 steps, and it takes approximately 5 steps in the open oceans. THis is because plants/photosyntic microbes are responsible for primary production, which are eaten by primary consumers and then secondary consumers (Heterotrphos and carnivores)

Question 11

What is the major source of organic matter?

Answer 11

Where there is light, the major source is photosynthetic activity from phytoplankton.

Question 12

Why does oxygen get used up quickly in the benthic habitat?

Answer 12

Because there are so much phytoplankton here, the higher the number the larger teh activity and oxygen is utilized quickly.

Question 13

Name the layers in a microbial mat:

Answer 13

Sand layer, Cyanobacteria, Oxidized iron, purple sulfur bacteria and precipitated iron sulfide.

Question 14

What separates the top layer of the microbial Matt from the bottom anaerobic zone

Answer 14

Oxidized iron

Question 15

The main goal of oxidized iron in microbial mats?

Answer 15

Prevents oxygen from going past it

Question 16

What are stromatolites?

Answer 16

Stromatolites are fossilized mats in orbit first indication of life on earth

Question 17

What prevents marine animals from thriving on Matte material?

Answer 17

Hyper -SALINE environment

Question 18

Compare lentic to lactic lakes and compare oligotrphic to eutrophic lakes

Answer 18

Lentic is standing such as ponds lakes marshes and slowly rivers. Lotic is running such as rivers streams and canals. Eutrophic is shallow but high biomass. Oligotrophic is low nutrients but they tend to be deeper

Question 19

What is the source of nutrients in lentic environments

Answer 19

Autochthonous and Allochtonous. Auto is inside the stream, and based on photosynthetic environments. Allo is source is outside the stream, runoff from urban and agricultural sties.

Question 20

Why are biofilms important in lakes and rivers?

Answer 20

They are important sources of degradation and mineralization. Biofilms also consist primarily of heterotrophic microbes.

Question 21

Nutrient rich, bottom sediments rich in organic matter, shallow, warm temp and low oxygen and increased phytoplankton and vascular aquatic plants, this all describes Eutrophic or Oligotrphic lakes?

Answer 21

Eutrophic

Question 22

Which tend to be older, Eutrophic or oligotrophic lakes?

Answer 22

Eutrophic

Question 23

Rate of respiration exceeds that of photosynthesis, it just becomes anoxic, runoff from agriculture an urban area, create an oxygen sag curve. Are all characteristics of?

Answer 23

Eutrophication system

Question 24

Oligotrophic lake input is dominated by __________

Eutrophic lake dominated by ___________

Answer 24

Oligotrophic is dominated by precipitation. Eutrophic is dominated from nutrients from surround water she.

Question 25

________ ________, is when a lake converts from oligotrophic to eutrophic due to human activities.

Answer 25

Cultural eutrophication.

Question 26

The Epilimnion, Thermocline and Hypolimnion are layers of the lake based on temperature. Describe all three layers.

Answer 26

The Epilimnion is the upper zone, intensive primary productivity that can deplete it from mineral nutrients, nutrients conditions are limited.
Thermocline: middle zone characterized by rapid change in temperature, help animals change in extreme temperatures. (This is where temp-induced stratification happens in the winter and summer)
Hypolimnion: Lowest zone, low oxygen, low temp, low light and high mineral content.

Question 27

Compare Littoral zone and Limnetic zone of the lake.

Answer 27

Littoral, planktonic community of algae and Cyanobacteria (top layer)
Limnetic zone: dominated by zoo plankton.

Question 28

Whats an example of a lake phototrophic populations?

Answer 28

Chlorobium, a green sulfur bacteria. Obligate, anaerobic photolithoautrotrophs, that synthesize bacterichlroopylls (Bchls). Chlorosome, strucutre is a unique light harvesting antenna structure.
Require H2 for photosynthesis
Grow at lower depth in water, where there is little light and oxygen.

Question 29

Lake heterotrophic populations in Neuston zone and thermocline.

Answer 29

Neuston zone, has a high level of heterotrophs, due to accumulation of proteins.
Thermocline: This layer is below the zone of highest primary productivity. Benthos, upper layer of benthos, organisms are mostly anaerobic.

Question 30

What is the fungus that lives in river and lakes. Hint, this extend thier hyphae like fishing lines.

Answer 30

Zoophagus Insidians, lives on filamentous green algae in river or lakes. Hypahea grow into mouth of the rotifer.