MSCI 340 - Kelp Forest Communities Overview

Define primary productivity

The rate at which energy is converted to organic substances by photosynthetic producers

What role do photoautotrophs have in an ecosystem?

They convert sunlight into energy, taking inorganic carbon and forming organic carbon

Describe Gross Primary Productivity (GPP)

The rate at which organic matter is produced from inorganic materials by photoautotrophs

Define Respiration in terms of productivity

The rate of consumption of organic matter into inorganic matter from any organism

Define Net Primary Productivty (NPP)

Then net production of organic matter by autotrophs

What is the NPP of coral reefs?

2700 gC/m^2y

What is the NPP of kelp forests?

2500 gC/m^2y

Which has a higher NPP per year? Coral reefs or kelp forests?

Coral reefs experience a higher NPP production because primary productivity occurs year round. Kelp forests are only seasonal, where their highest NPP production would occur during the winter and spring.

What are the types of algae we encounter in the kelp forest communities? (taxonomic names only)

*Rhodophyta, Chlorophyta, Phaeophyta*

Identify the different vertical layers of the kelp forest. (from top-down)

Canopy → Stipitate → Prostrate

What is a canopy kelp?

A species of kelp that forms canopies over the kelp forest. They typically grow very tall relative to other kelp and algae.

Identify the species of kelp that are considered “canopy forming” (Taxonomic names only)

*Macrocystis pyrifera, Neurocystis lutkeana, Echlonia maximia, Pegalophycos*

What is a stipitate kelp?

A species of kelp that are found in aggregations and extends a few meters above the seafloor (>1m in height)

Identify the species of kelp that are considered “stipitate” (Taxonomic names only)

*Eisenia arborea, Pterygophera californica, Lessonia*

What is prostrate kelp?

A species of kelp that lives near and along the seafloor (

Identify the species of kelp that are considered “prostrate” (Taxonomic names only)

*Laminaria spp., Costaria costata*

At what height above the seafloor are canopy assemblages found?

20 meters above the seafloor

Describe a basic food chain of kelp forest, starting from giant kelp

Giant kelp → bryozoans → nudibranchs → senoritas → lingcod

Describe an inducible defense

A type of defense that has a cost. More energy is likely to be spent investing into this defense.

Identify the conditions needed for kelp growth

Nutrient-rich waters, temperatures (no greater than 20 C), light, moderate water movement, and rocky bottoms