Ecosystems and Global Change

Vocabulary practice flashcards covering primary and secondary productivity, trophic interactions, ecological efficiency, bioamplification, nutrient cycles, and climate change mechanisms.

Primary productivity

The rate at which solar energy is captured and converted into chemical bonds via photosynthesis ($6\text{CO}_2 + 6\text{H}_2\text{O} + \text{sunlight} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$).

Gross primary productivity (GPP)

The total amount of solar energy that is captured by producers via photosynthesis in an ecosystem.

Net primary productivity (NPP)

The amount of solar energy remaining for producer growth and reproduction after subtracting energy required for cellular respiration ($\text{NPP} = \text{GPP} - \text{cellular respiration}$).

Gross secondary productivity (GSP)

The total amount of energy assimilated by consumers in a given area.

Net secondary productivity (NSP)

The amount of assimilated energy remaining for consumer growth and reproduction following losses to cellular respiration.

Ecological efficiency

The percentage of chemical energy transferred from one trophic level to the next in an ecosystem, calculated as $\frac{\text{Net secondary productivity}}{\text{Net primary productivity at next lower trophic level}} \times 100$.

The 10% rule

The principle stating that approximately $10\%$ of available energy at one trophic level is converted into biomass at the next level, causing energy scarcity and lower consumer populations at higher trophic levels.

Standing stock biomass

The total weight or mass of living organisms within a defined area or volume at a specific point in time.

Inverted pyramid of biomass

A biomass structure characteristic of aquatic ecosystems where standing stock biomass of producers (like phytoplankton) is smaller than consumers, supported by phytoplankton's rapid reproduction rate.

Bottom-up control

An ecosystem control mechanism in which the abundance of organisms across trophic levels is determined primarily by the abundance of primary producers.

Top-down control

An ecosystem control mechanism in which the abundance of organisms across lower trophic levels is determined by the abundance of high-level consumers.

Pisaster ochraceus

A predatory sea star that maintains species diversity in intertidal communities by controlling the population of the dominant mussel, Mytilus californianus.

DDT (dichloro-diphenyl-trichloroethane)

A synthetic insecticide used extensively in the 1950s against disease vectors, later shown to cause liver damage, reproductive impairment, and cancer in exposed organisms.

Biological amplification

The process by which fat-soluble poisons like DDT accumulate in organism tissues and become increasingly concentrated at higher trophic levels of a food web.

Silent Spring

A 1962 book authored by Rachel Carson that alerted the public to the environmental dangers of synthetic pesticides like DDT, leading to federal chemical bans and modern activism.

Haber-Bosch process

An industrial process that converts atmospheric nitrogen ($\text{N}_2$) into synthetic nitrogen fertilizers on a massive scale.

Eutrophication

The enrichment of aquatic ecosystems with excess nitrates (often from fertilizers), leading to rapid algal blooms and severe oxygen depletion.

Isotopic fingerprint of fossil fuels

The decrease in the atmospheric ${}^{13}\text{C}/{}^{12}\text{C}$ ratio caused by the burning of fossil fuels, which are naturally depleted in ${}^{13}\text{C}$.

Greenhouse effect

The atmospheric mechanism where gases such as $\text{CO}_2$, $\text{CH}_4$, $\text{N}_2\text{O}$, and water vapor trap re-radiated long-wavelength infrared (IR) heat near Earth's surface.

Mendenhall Glacier

A glacier located in Alaska that retreated by $550\,m$ ($1800\,ft$) between 2007 and 2015 as a result of global climate warming.