kelp forest zonation
DESCRIPTION
Kelp Forest Zonation. Canopy. Understory. Inshore (Z1). Kelp Canopy (Z2). Algal Turf. Offshore (Z3). Phyllospadix. Egregia. Macrocystis. Nereocystis. Laminaria. A. Canopy Assemblages (isopods, tubeworms, hydrozoans and bryozoans). - PowerPoint PPT PresentationTRANSCRIPT
Kelp Forest Zonation
Inshore(Z1)
Kelp Canopy(Z2)Offshore
(Z3)
Canopy
Understory
Algal Turf
Macrocystis
Laminaria
Egregia Nereocystis
Phyllospadix
A. Canopy Assemblages (isopods, tubeworms, hydrozoans and bryozoans)
B. Planktonic Assemblages (jellyfish, fish larvae, diatoms, and crustaceans).
C. Holdfast Assemblages (sea urchins, crustaceans, brittle stars, and sea anemones)
D. Horizontal Substrate Assemblages (urchins, sea stars, algae, tunicates, and bottom fish).
E. Vertical Wall Assemblages (coralline algae, anemones, cup corals, sponges, and bryozoans)
Holdfast Community
Plankton
Canopy
Vertical Wall
Horizontal Surface
Orca
Sea Otter
Kelp
Urchins
Ecological Relationships in Kelp Forests
Ecological Relationships in Kelp Forests - Aleutian Archipelago
Adak Island
Ecological Relationships in Kelp Forests - Aleutian Archipelago
1972 1997
Otter #
Ecological Relationships in Kelp Forests - Aleutian Archipelago
1972 1997
Otter #
Urchin Biomass
Ecological Relationships in Kelp Forests - Aleutian Archipelago
1972 1997
Otter #
Urchin Biomass
Grazing Intensity
Ecological Relationships in Kelp Forests - Aleutian Archipelago
1972 1997
Otter #
Urchin Biomass
Grazing Intensity
Kelp Density
Mortality of Kelp - Effect of El Niño event
Recovery of community (Ebeling et al., 1985)
Destroyed kelp (Macrocystis) canopy but left understory kelp
Original situation - Macrocystis canopy, understory kelp (Pterygophora)- urchins S. purpuratus & S. franciscanus feed in crevices on drift kelp
Reduction in drift kelp used by urchins
Urchins forage in open on understory kelp
Urchins destroy remaining kelp
Storm 1
Storm 2 Kills urchins and left bare rock
Kelp settlement and mature forest (1 year)
Mortality of Kelp - Effect of El Niño event
Other El Niño Effects
-rip up holdfasts no vegetative growth
-high water temperature retards growth
-reduction in nitrogen retards growth
General Model for Maintenance of Barrens and Kelp areas
BARRENS
High grazing activity
Low algal recruitment
Severe stormsLow nutrientWarm temperatures
Low driftabundance
Low standing stock of attached algae
Low grazing activity
High algal recruitment
Benign stormsHigh nutrientLow temperatures
High driftabundance
High standing stock of attached algae
KELP
STABLE STATES
General Model for Maintenance of Barrens and Kelp areas
Harold & Reed, 1985
Barren Ground
-little drift kelp
- created by urchin grazing
- urchins actively forage
Kelp Forest
-abundant drift kelp
- urchins remain in crevices
Recruitment of kelp
Effect of urchins due to a change in behaviour not numbers
General Model for Maintenance of Barrens and Kelp areas
Harold & Reed, 1985
Effect of urchins due to a change in behaviour not numbers
General Model for Maintenance of Barrens and Kelp areas
Harold & Reed, 1985
Kelp and other algae
Sea urchins
Sea stars
Sea otter
Small herbivorous fish & invertebrates
Drift algae & dead animals
Abalone
Sharks
Planktonic algae
Planktonic invertebrates
Sessile invertebrates
Smaller predatoryFish and invertebrates
Larger crabs
Larger fish & octopus
Kelp Forest Food Web (with otters)
Kelp and other algae
Sea urchins
Sea stars
Sea otter
Small herbivorous fish & invertebrates
Drift algae & dead animals
Abalone
Sharks
Planktonic algae
Planktonic invertebrates
Sessile invertebrates
Smaller predatoryFish and invertebrates
Larger crabs
Larger fish & octopus
Kelp Forest Food Web (without otters)
Kelp Forest Productivity
Tropical Rain Forest
Tropical Seasonal Forest
Evergreen Forest
Deciduous Forest
Kelp Forest
Boreal Forest
3.0
2.5
2.0
1.5
1.0
0.5
0
50
40
30
20
10
0
Producer BiomassKg/m2
Annual Net ProductionKg/m2/yr
Litter MassKg/m2/yr
Kelp Forest Productivity
SUSPENSION FEEDERS
MusselSoft coralBarnacle
Sea AnemoneRock Jingle
Mysid
DETRITIVORESAmphipod
Crab
PREDATORSRock greenling
Sea starCormorant
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Percent of Kelp Derived Carbon
Next timeCoral Reefs