Kelp forests

Question 1

what kelp forms

Answer 1

kelp beds or kelp forests- dense aggregations of big

brown algae e.g. Pterygophora and Nereocystis

Question 2

kelp morphology

Answer 2

• Blades
• Stipe
• Holdfast
• Pneumatocyst / floats

Question 3

requirements for kelp growth (substrate, light, nutrients, temperature, water distance)

Answer 3

Substrate – hard, subtidal substrate (bedrock or big boulders)
Light – lots of light
Shallow water (20-30 m) so that light can reach young, growing kelp
Nutrients – lots of nutrients, especially nitrate, required for kelp growth Kelps also add nutrients (to this and other ecosystems) as they die and decompose
temperate waters (5-15oC)

Question 4

location of kelp forests

Answer 4

Coastal, rocky reef areas of temperate oceans throughout the world
And in deep (30->60m) tropical waters?!

Question 5

kelp growth limited by:

Answer 5

High temperatures and low nutrients

If nutrient concentrations are adequate, kelps can survive in temperatures up to 23°C

Question 6

Physical structure formed by living organisms

Answer 6

Three-dimensional habitat with several vertical layers
Canopy forming species (e.g. Nereocystis, Macrocystis)
Understory species below the canopy – other algae,
invertebrates and fishes

Question 7

Energy /

wave action

Answer 7

Nereocystis can tolerate high wave action & strong currents
– can stretch more than 38% of its length
Macrocystis prefers less energy/wave exposure & higher salinities
Plasticity of Nereocystis blades (& necks) depending on wave action

Question 8

grazing impact on kelp

Answer 8

Herbivores can damage blades as well as stipes and holdfasts so that kelps are dislodged from substrate

Grazers include:
Sea urchins (all 3 species)
Abalone
Snails
Limpets
Crabs
Fishes

Question 9

kelp is limited by competition

Answer 9

Competition can be for light, space and/or nutrients
Macrocystis can outcompete Nereocystis and will push Nereocystis into more wave-exposed areas
Both Macrocystis and Nereocystis can also be
outcompeted by other understory algal species (coralline algae, foliose red algae and other kelp species)

Question 10

kelp on water flow

Answer 10

Kelp forests alter the abiotic environment by
dampening wave strength thereby influencing water flow and associated processes of sedimentation, recruitment, and productivity

Question 11

otters

Answer 11

sea/river otters
keystone species. Sea otters find all their food and shelter in kelp forests. the urchins would over populate the kelp forests

Question 12

biological characteristics

Answer 12

biodiversity: high
biomass: high

Question 13

what is productivity

Answer 13

rate of biomass

increase in a given area

Question 14

kelp beds’ productivity?

Answer 14

are the most productive, but don’t occupy a lot of space(

Question 15

kelp as a habitat (shelter, life, holdfast

Answer 15

Kelp forests provide shelter, food, and nursery grounds for many pelagic and benthic organisms
Some organisms live on the kelp – bryozoans, hydroids, barnacles, caprellid amphipods
Many organisms live within holdfasts – brittle stars, crabs, small abalone, annelid worms, peanut worms, fishes, snails

Question 16

refuge

Answer 16

juvenile and adult fish, rockfish, use kelp forest as a refuge from predators

Question 17

impact of kelp canopies (species light)

Answer 17

Canopies reduce light and create understory
conditions favorable for species adapted to low
light intensity

Question 18

mermaid’s purse

Answer 18

an egg capsule for the developlment of catshark

Question 19

impact of epiphytes grow on kelp

Answer 19

ulva- Shading the blades decreasing photosynthesis
At high concentrations, epiphytes can decrease the
buoyancy of the floats and cause kelp to sink
Increased drag with epiphytes may lead to dislodgement of kelp

Question 20

human impacts

Answer 20

harvest of kelp for:
- consumption
agriculture (fertilizer)
mariculture (food for abalone)
-arts and craft

Question 21

human impacts

Answer 21

overhaunting keystone species: otters, sea cow
pollution
climate change- more co2 and severe storm increase sea urchins popullation

Question 22

conservation efforts:

Answer 22

No permits are required for personal, non-commercial harvest of kelp
Collection is prohibited in managed areas such as Ecological and Marine Reserves and Provincial and Federal Parks
In BC: For Nereocystis, blades may be cut no closer than 20cm from the pneumatocyst, and no harvest of the bulb or stipe is permitted

Question 23

conservation policies

Answer 23

Protection of sea otters: SARA & IUCN

Rockfish conservation areas

Abalone captive breeding & re-introduction

DFO abalone closure

Monterey Bay Aquarium & UCSD kelp cam

Question 24

nereocystis/macrocystis growth time

Answer 24

Nereocystis is an annual, Macrocystis is a perennial

Question 25

what can happen during winter storms

Answer 25

During winter storms, wave action dislodges Nereocystis

Question 26

how are tropical water surface nutrient-wise and what impact it has on kelp?

Answer 26

Because tropical surface waters are frequently
nutrient-poor and lack plankton, the water is very clear
Thus, deep-water zones in tropical regions can be euphotic (lots of light), with reasonable temperatures and adequate nutrient supply for kelp growth

Question 27

what is euphotic and how it connects to kelp growth?

Answer 27

lots of light, photosynthesis

Question 28

what nutrient specifically kelp needs for growth

Answer 28

nitrate