Lecture 2

Question 1

What is the range where photosynthetic organisms access visible light?

Answer 1

400-700 nm

Question 2

What is the name for the range of light that photo synthetic organisms access?

Answer 2

Photosyntheitcally active radiation

Question 3

Whatis photosynthetically active radiation?

Answer 3

400-700 nm/the range of light that photosynthetic organism access

Question 4

What is the limit for incidence radiation?

Answer 4

1%

Question 5

Define euphotic zone

Answer 5

The zone where-photosynthesis occurs ( the surface to one percent)

Question 6

What’s the secchi depth?

Answer 6

-Depth of 10% irradiance in the waterbody

Question 7

What type of visible light is

Most absorbed by algae? Why?

Answer 7

Blue because it penetrates greater depths within the waterbody

Question 8

What is the type of chlorophyll in algae that allows them to absorb light?

Answer 8

Chlorophyll a

Question 9

Where does the euphotic zone sit in nutrient poor water?

Answer 9

Deep

Question 10

Where is the euphotic zone in nutrient rich water?

Answer 10

Shallow

Question 11

Why is the euphotic zone shallow in nutrient rich water?

Answer 11

Because the water is unclear so the range of visibility is smaller

Question 12

What is humid material?

Answer 12

The organic compounds that make up hummus(a major soil component)

Question 13

Which types of waters are influenced by their catchment, and which aren’t?

Answer 13

Fresh water-influenced by their catchment

Open ocean-no catchment

Question 14

What factors (four) influence catchment and subsequent clarity of water?

Answer 14

1. Altitude
2. Size
3. Catchment utilisation (eg farming)
4. Geology

Question 15

In what temperature water is oxygen most soluble?

Answer 15

Cold

Question 16

When is water at sterilisation?

Answer 16

100% oxygen saturation, no organism are present

Question 17

What determines tropic status?

Answer 17

Nutrient availability

Question 18

How busy is the food web when there’s one of oxygen at the BOTTOM of the water body?

Answer 18

The food web is not busy, and the lower the nutrient content

Question 19

In which two tropic status leaves can oxygen use get to high it leads to anoxic conditions at the bottom of the water bed?

Answer 19

Eutrophic and hyper eutrophic

Question 20

Define functional guild

Answer 20

Organism that exploit the same class of environmental resources in a similar way, regardless of their taxonomical position

Question 21

What is algae a generic term for? What are the two types?

Answer 21

Anything that photosynthesises in an aquatic system

Macroscopic and microscopic algae

Question 22

What are the three main limiting factors for algae in aquatic systems? Say whether they are limiting or not

Answer 22

1. Inorganic carbon-never limiting
   Inorganic nitrogen-can be limiting
   Inorganic phosphorous- can be limiting
   Sunlight- can be limiting dependant on the euphotic zone position

Question 23

What is the red field ratio?

Answer 23

The ideal ratio of carbon:nitrogen:phosphorous

106:16:1

Question 24

What are oceans and freshwater limiting in?

Answer 24

Oceans are NITROGEN LIMITING

Freshwater is PHOSPHOROUS LIMITING (with some exception)

Question 25

When is a water body nitrogen or phosphorous limiting?

Answer 25

Ratio <16 is nitrogen limited

Ratio >16 is phosphorus limiting

Question 26

What are the key types of algae?state of prokaryote or eukaryote

Answer 26

Eukaryotes:
Diatoms
Green algae
Chlorophytes
Autotrophic flagellates
Dinoflagellates
Prokaryotes:
Cyanobacteria

Question 27

Why are Cyanobacteria so efficient at photosynthesis?

Answer 27

They have two additional light pigments: phycoerythrin and phycocyanin