Shallow-Water Subtidal Benthic Associations

Question 1

what are sediment destabilizers?

Answer 1

organisms which cause sediment to re-suspend, erode or otherwise change

Question 2

what are some examples of sediment destabilizers?

Answer 2

mobile, deposit-feeding clams
e.g. Nucula

sea cucumbers

Question 3

what are sediment stabilizers?

Answer 3

organisms which stabilise the sediment

Question 4

what are some examples of sediment stabilizers?

Answer 4

tube-building invertebrates

seagrasses

Question 5

why are where burrow feeders are present, suspension feeders are absent?

Answer 5

sediment re-suspended by burrowing, clogs up filter feeders (suffocates)

Question 6

what is kelp?

Answer 6

mainly brown algae

fucoxanthin = brown pigment

Question 7

kelp grazers

Answer 7

gastropods
gribbles
urchins

Question 8

role of gribbles in kelp forest

Answer 8

kelp grazer -

gribbles burrow through holdfasts

Question 9

role of gastropods in kelp forest

Answer 9

kelp grazer - gastropods scrape blades with radula

Question 10

role of urchins in kelp forest

Answer 10

kelp grazer - feed on new growth and holdfasts

Question 11

what natural affects kelp forests?

Answer 11

salinity 
temperature change 
storms 
seasons 
disease 
outbreaks of grazers

Question 12

kelp forest stratification

Answer 12

canopy
understory
algal turf

Question 13

roles of kelp forests

Answer 13

• dampen wave action
• provide complex environment
• reduce erosion
• influence sedimentation
• high productivity (food)

Question 14

what is a kelp holdfast?

Answer 14

anchors kelp into sediment

Question 15

what is a kelp stripe?

Answer 15

the main stalk of the kelp

Question 16

what is a kelp blade?

Answer 16

a kelp ‘leaf’

Question 17

what is a kelp frond?

Answer 17

secondary stalks of kelp coming off stripe

Question 18

fishing down the food chain kelp forest example

Answer 18

hunted otters - ecological extinction
hunted fish
-> increase in urchins as no predators
-> urchin barrens