Week 4: Kelp ecology and diversity

Question 1

Kelp forests provide

Answer 1

1. Three dimensional habitat
2. Refuge from predators
3. Important nursery grounds
4. Macroalgal beds can trap larvae
5. Macroalgae provide surfaces for attachment of larvae/spores

Question 2

Why do animals find kelp forests attractive

Answer 2

1. Less competition for attachment (Benthic animals)
2. Protection above benthic boundary layer
3. Seaweeds provide food (POM, DOM)

Question 3

Alteration of flow from kelp forests causes

Answer 3

1. Entrain larvae
2. Alter chemical environment (in concert with biological activity)
3. Increase sedimentation
4. Reduce coastal erosion

Question 4

Autogenic engineers

Answer 4

Transform ecosystems by their own growth and are integral to the altered environment

Question 5

Allogenic engineers

Answer 5

Physically change biotic and abiotic materials in their habitats, and may move on

Question 6

Decreasing light availability from kelp forests equals

Answer 6

1. Smaller macroalgae and less biomass
2. Less habitat and food
   3.Depth limit: approx 1m deeper in high light environments

Question 7

Sediment on algal surfaces and in the water column can strongly impact macroalgal survival through

Answer 7

1. Shading
2. Scouring/’sand blasting’
3. Burial

Question 8

Kelp forests quickly

Answer 8

Die and grow, strongly affecting other organisms

Question 9

An estimated percent of how much kelp forests have been lost

Answer 9

50-70%

Question 10

Most autotrophs

Answer 10

Photosynthesise

Question 11

The rate of photosynthesis determines

Answer 11

Energy supply and oxygen availability to ecosystem

Question 12

Sunlight penetrates up to how deep

Answer 12

200m

Question 13

Limiting factor of photosynthesis in the ocean

Answer 13

Light

Question 14

Ocean relies on the transport of photosynthetic products from

Answer 14

surface water to deeper water

Question 15

What determines if some autotrophs chemosynthesise

Answer 15

Source of inorganic compounds to oxidize

Question 16

Main primary marine producers contributions

Answer 16

90% phytoplankton
2-5% seaweed
2-5% chemosynthesis
?% seagrass

Question 17

Picoplankton characteristics

Answer 17

1. Discovered in 1986
2. Tropics and subtropics
3. Smallest known phototroph
4. Contributes 30-80% of primary production in the worlds oligotrophic oceans

Question 18

Nanoplankton/haptophytes characteristics

Answer 18

1. Major transport of carbonate to the sea floor
2. Causes sea foam from major algal blooms
3. Haptophytes contribute 30-50% of oceanic chlorophyll standing stock

Question 19

Two main classes of micro phytoplankton

Answer 19

Diatoms, Dinoflagellates

Question 20

Diatom size

Answer 20

0.05 - 0.2 mm

Question 21

Diatoms are predominant in

Answer 21

Spring blooms, temperate and polar seas

Question 22

Dinoflagellates are

Answer 22

Protists, half of which are autotrophs possessing chloroplasts and half are non-photosynthesising heterotrophs

Question 23

Main groups of algae

Answer 23

Chlorophyta - Chlorophyll b
Ochrophyta - Fucoxanthin
Rhodophyta - Phycoerythrin, Phycocyanin

Question 24

The glue that holds the reef together

Answer 24

Crustose coralline algae (CCA)

Question 25

What drives variability in ocean productivity

Answer 25

Temperature, Nitrate, PAR (radiation, light)

Question 26

Nutrient availability changes with

Answer 26

Latitude and depth

Question 27

Concentration of nitrate at the surface is

Answer 27

Low in the tropics and increases towards the poles

Question 28

Concentration of nitrate at 1000m is generally

Answer 28

Higher since there is no photosynthesis

Question 29

Low nitrates where there is

Answer 29

High PAR (radiation, light), and vice versa

Question 30

Photic zone

Answer 30

Surface layer of the ocean which receives sunlight

Question 31

Ecosystem services kelp forests provide

Answer 31

1. Provide three dimensional habitat 2. Refuge from predators and important nursery grounds 3. Macroalgal beds can trap larvae 4. Macroalgae provide surfaces for attachment of larvae/spores 5. Important for coastal fisheries

Question 32

Major stressors to kelp forests

Answer 32

Increasing extreme weather events

Question 33

2 ecosystem engineers

Answer 33

Autogenic and allogenic