Topic 1.8: Primary Productivity

Vocabulary flashcards covering primary productivity, GPP, NPP, ecological efficiency, and limiting factors across biomes.

Primary Productivity

The rate that solar energy or light is transformed into organic compounds like glucose or cellulose through photosynthesis over a period of time.

Primary Productivity Units

Measures expressed as energy per area over time, such as kilocalories per meter squared per year.

Gross Primary Productivity (GPP)

The total amount of sunlight that plants capture and convert into energy, representing the total photosynthetic rate.

Respiration Loss

The amount of energy that plants use up for cellular respiration to fuel basic processes like internal transportation and keeping themselves running.

Net Primary Productivity (NPP)

The amount of energy that a plant is able to store as biomass after accounting for respiration loss, representing the energy left over for consumers.

Net Primary Productivity Equation

$$\text{NPP} = \text{GPP} - \text{Respiration Loss}$$

Ecological Efficiency

The portion of incoming sunlight that is captured by plants and converted into biomass.

Sunlight Capture Percentage

In most ecosystems, only about $1\%$ of incoming sunlight is captured by plants for gross primary productivity, while about $99\%$ is reflected or passes through.

Factors Determining Productivity

The three key environmental factors that contribute to high net primary productivity: water availability, warm temperatures, and nutrient availability.

Biodiversity and Productivity Trend

Ecosystems with higher primary productivity have higher plant growth, creating more food and shelter for animals and supporting a higher diversity of species.

Desert Productivity Limits

A terrestrial biome with low primary productivity due to a deficiency of water and sandy soil that holds very few nutrients.

Tundra Productivity Limits

A biome limited by extremely cold temperatures that cannot support year-round plant growth and a lack of usable liquid water due to freezing.

Open Ocean Productivity Limits

An aquatic biome that has warmth and abundant water, but suffers from low primary productivity due to a huge deficiency of nutrients and organic matter.