Ecosystems and Biogeochemical Cycles

Flashcards of key vocabulary terms and definitions related to ecosystems and biogeochemical cycles.

Ecosystem

Includes all the organisms that live in a particular place, plus the abiotic environment in which they live.

Biogeochemical cycles

Chemicals cycling within ecosystems, affected by both biotic and abiotic processes.

Energy flow

When energy is converted to biological energy and flows through an ecosystem.

Transpiration

The gaseous form of water.

Precipitation

When water cools and falls to the surface.

Fossil fuels

Earth's reserves built up over geological time, and human burning is creating large imbalances.

Geologic cycling of CO2

Early atmosphere had high levels, combines with water to form carbonic acid, reacts with rocks, and volcanism releases it back.

Limiting nutrients

Shortest supply relative to the needs of organisms.

Nitrogen

Component of all proteins and nucleic acids.

Run off

When fertilizer overuse and runoff leads to extra nutrition, too much marine algae, and not enough oxygen for other life.

Phosphorus

Required by all organisms, occurs in nucleic acids, membranes, ATP, and exists as phosphate.

Iron as a Limiting Nutrient

When wind brings in iron-rich dust, algal populations proliferate

First Law of Thermodynamics

Energy is neither created nor destroyed; it changes forms.

Second Law of Thermodynamics

Whenever organisms use chemical-bond or light energy, some is converted to heat (entropy).

Autotrophs

Synthesize the organic compounds of their bodies from inorganic precursors.

Photoautotrophs

Light as energy source.

Chemoautotrophs

Energy from inorganic oxidation reactions

Heterotrophs

Cannot synthesize organic compounds from inorganic precursors.

Trophic cascade

Effects exerted at one level affect two or more nearby levels.

Top-down effects

When effects flow down.

Bottom-up effects

When effect flows up.

Productivity

The rate at which the organisms in the trophic level collectively synthesizes organic matter to be used for next trophic level

Primary productivity

Productivity of the primary producers, sets energy budget for an ecosystem.

Gross primary productivity (GPP)

Raw rate at which primary producers synthesize new organic matter.

Net primary productivity (NPP)

Is the GPP less the respiration of the primary producers.

Secondary productivity

Productivity of a heterotroph trophic level.

10% rule

About 10% of energy at one level made available to next level

Ecological Pyramids

Trophic relationships often depicted as pyramids.

Trophic-level interactions

effects exerted at one level affect two or more nearby levels.

Species diversity cline

biogeographic gradient in number of species correlated with latitude.

Island Biogeography

Islands have a tendency to accumulate more and more species through dispersion from mainland.