Lecture 2

Question 1

Main ecological role of algae

Answer 1

• Photosynthesis
• Forms base of food chain

Question 2

How much oxygen does the algae generate?

Answer 2

40-80%

Question 3

Photosynthetically active radiation (PAR)

Answer 3

400-700nm

Question 4

Chlorophyll A

Answer 4

• The most common algal pigment
• 430-662nm
• Chlorophyll A in a water sample is proportional to algal biomass

Question 5

Major nutients

Answer 5

• Carbon (C):energy and all structures
• Nitrogen (N): proteins
• Phosphorus (P): Nucleic acid

Question 6

Nutrient ratio (C:N:P)

Answer 6

106:16:1

Question 7

Stoichiometry

Answer 7

• Algae can store unused nutirents in vacoules
• Algae are either N- or P-limited
• Without light for photosynthesis, they are light-limited (never C-limited)

Question 8

Marine water is usually limited by?

Answer 8

Nitrogen

Question 9

Freshwater is usually limited by?

Answer 9

Phosphorus

Question 10

Depth

Answer 10

• Light is highest at surface
• Nutrient levels are highest at the bottom. Gets stored in sediments and leaching out. Gets trapped due to stratification

Question 11

Balance of light + nutrients =

Answer 11

Deep Chlorophyll Maxima

Question 12

Sinking rate equation

Answer 12

Vs= 2gr(3) (q’-q)/(9uf)

Question 13

Strategies to stay constant depth

Answer 13

• Be small
• Flagella
• Flat
• Protuerances
• Less dense
• Air vacoules

Question 14

Sinking rate?

Answer 14

20cm-1m a day

Question 15

Algal defenses to avoid grazing?

Answer 15

• Big, hard or colony living
• Toxicity
• Gooey protective shealth to avoid digestion
• Constitutive (always present)
• Induced/plastic (turned on or off)