Temperate rocky reefs

Question 1

What

Answer 1

Hard substrates
Along continental shelves
Usually in temperate and subtropical areas
Complex and often with algae attached to rocks

Question 2

Kelp forest/bed

Answer 2

Rocky reefs with macroalgae
- Forest, canopy forming
- Bed shorter don’t reach surface
Highly productive

Question 3

Why is kelp important

Answer 3

Significant PP and C sequestration
Regulate recruitment of coastal species
Important for juvenile fish
Buffering and protection against waves
Production equivalent of coral reefs and tropical forests.

Question 4

True Kelp

Answer 4

Large, brown subtidal seaweeds
Very strong holdfasts
Brown algae indicates mix of pigments

Question 5

General kelp structure

Answer 5

Seaweeds lack true leaves, stems or roots.
Flat blades:
- High SA:V
- Chlorophyll concentrated here
Air filled pneumatocysts
Stipe:
- Strong flexible link between blades and holdfast
- Shock absorption
- photosynthetic
Holdfasts:
- Root like
- Don’t absorb nutrients

Question 6

Sections of rocky reef

Answer 6

Canopy:
- fronds on surface, most light and waves.
Understory:
- Fronds erect or close to bottom
- Less light and wave action
- Highest diversity of marine life
Algal turf;
- Short clumps, filaments and encrusting algae
- least of everything

Question 7

Kelp understory organisms

Answer 7

Kelp stipes, tube-forming polychaetes, bryozoans, other sessile organisms
Surf perches
Topsmelt and blue rockfish
Larvae of benthos

Question 8

Algal turf organisms

Answer 8

kelp holdfast
- small invertebrates, brittle stars, polycahetes, urchins and crabs
- many species of adult rockfish and kelp bass
Sheephead, eat crabs and urchins
Abalone, eat live kelp, drift kelp and algal turf

Question 9

Distribution of kelp beds

Answer 9

Require hard substrates
Light
need lots of dissolved inorganic nutrients
Distribution can be extended in upwelling zones

Question 10

Kelp deforestation

Answer 10

Anomalies of physical conditions push physical tolerance, El Nino, temperature or salinity
Storms remove kelp
Urchins

Question 11

Upwelling

Answer 11

Important food nutrients
Seasonal
El nino

Question 12

Phase shift

Answer 12

When urchins get out of control, initiate phase shift in kelp ecosystems
These shifts are widely distributed, sometimes reversible

Question 13

General kelp health

Answer 13

Healthy abundant kelp provides abundant detritus for urchins.
Whiplash motion deter urchins from entering forest, prevent them attaching to kelp
Any stressors for kelp can promote urchins

Question 14

Food web Alaska and north atlantic

Answer 14

Trophic cascade
Sea otter > urchin > kelp
Interannual variability in top predators can induce differences in otters, urchins and kelps
Orcas eat more otters as their food sources are declining
Cod act as otters

Question 15

California has delayed phase shifts

Answer 15

Otters were removed from Cali many years ago (between 150-200 years), yet ecosystem shifts were only apparent recently.
Many other species that could replace otters, buffer ecosystem change
We are removing these species, more urchin barriers

Question 16

black abalone

Answer 16

Eats drift kelp
Lives in low intertidal
Juveniles in rock crevices to hide
Competition for space with sea-urchins
Withering foot syndrome
Abalone density is higher in areas with high otter density.

Question 17

Withering syndrome

Answer 17

WS is a bacterial infection, prevalent in Cali warm waters, local extinctions of species
Less prevalent in cool waters of C/N Cali, more upwelling.
Infection rate thought to be largely mediated by water temp, El Nino and Climate change