Week 4: Kelp ecology and diversity

Question 1

Kelp forests provide

Answer 1

1. Unique, three dimensional habitat for marine organisms
2. Refuge from predators
3. Important nursery grounds
4. Macroalgal beds can trap larvae
5. Macroalgae provide surfaces for attachment of larvae/spores
6. Important for coastal fisheries

Question 2

Kelp forests physically formed by

Answer 2

Brown macroalgae

Question 3

Why are kelp forests great habitat for animals

Answer 3

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

Question 4

Affects of kelp forests on the marine environment

Answer 4

1. Alter flow
2. Alter chemical environment
3. Increase sedimentation
4. Reduce coastal erosion

Question 5

Autogenic ecosystem engineers

Answer 5

Transform ecosystems by their own growth (e.g corals)

Question 6

Allogenic engineers

Answer 6

Alter the environment and then move on (e.g beavers)

Question 7

Decreasing light availability =

Answer 7

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

Question 8

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

Answer 8

1. Shading
2. Scouring / Sand blasting
3. Burial

Question 9

Productive and important marine habitats

Answer 9

Kelp forests

Question 10

Kelp forests are in

Answer 10

Decline

Question 11

What percentage of kelp forests may have been lost

Answer 11

50-70%

Question 12

Main human way to prevent kelp forest loss

Answer 12

Better local management and adaptation to mitigate global scale environmental change

Question 13

Autotrophs primary method for feeding

Answer 13

Photosynthesizing

Question 14

The rate of photosynthesis determines

Answer 14

Energy supply and oxygen availability to ecosystem

Question 15

Limiting factor of photosynthesis

Answer 15

Sunlight

Question 16

Sunlight penetration max depth

Answer 16

200m

Question 17

Oceans rely on transport of

Answer 17

Photosynthetic products from shallow to deeper waters

Question 18

Chemosynthesis

Answer 18

Autotrophs gain food from source of inorganic compounds to oxidise

Question 19

What are the main primary producers

Answer 19

1. Phytoplankton (90%)
2. Seaweed (2-5%)
3. Seagrass (?%)
4. Chemosynthesis (2-5%)

Question 20

Picoplankton characteristics

Answer 20

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

Question 21

Nanoplankton and Haptophytes characteristics

Answer 21

1. Major transport of carbonate to the sea floor
2. White cliffes = coccolithopores
3. Causes sea foam, major blooms
4. Haptophytes contribute 30-50% of oceanic chlorophyll standing stock

Question 22

Micro-Phytoplankton characteristics

Answer 22

1. Diatoms (50 - 200 pm)
2. Colonial or chains to 2mm long
3. Predominant in spring blooms in temperate and polar seas
4. Non-motile, prefer turbulent waters
5. Silica Frustules
6. Dinoflagellates

Question 23

Dinoflagellates are

Answer 23

Protists

Question 24

Half of dinoflagellates are

Answer 24

Autotrophs, possessing chloroplasts and the other half are non photosynthesising heterotrophs

Question 25

What are the three main groups of algae

Answer 25

1. Chlorophyta (green/chlorophyll b) 2. Phaeophyta (brown/fucoxanthin) 3. Rhodophyta (red/Phycoerythrin, Phycocyanin)

Question 26

What drives variability in ocean productivity

Answer 26

1. Temperature 2. Nitrate availability 3. Photosynthetically available radiation (PAR)

Question 27

What is liebigs law of the minimum

Answer 27

It states that productivity is not determined by the total resources, but the scarcest resource

Question 28

Limits to algal growth - nutrients

Answer 28

1. Carbon 2. Nitrogen 3. Phosphorus 4. Silicon 5. Iron

Question 29

Nutrient availability changes with

Answer 29

Latitude and Depth

Question 30

Concentration of nitrate is generally higher where

Answer 30

Towards the poles and deeper

Question 31

Limits to algal growth - light

Answer 31

1. Polar latitudes recieve less sun and therefore less Photosynthetically available radiation (PAR) 2. Low nitrate where low where there is high PAR

Question 32

Major stressors to kelp forests

Answer 32

Increasing extreme weather events