Ecology, Biomass, Nutrient Cycles, and Climate Change

Vocabulary flashcards covering ecological sampling, ecosystem structure, ecological succession, plant and consumer biomass productivity, the nitrogen cycle, eutrophication, and the mechanisms and mitigation of climate change.

Line transect

A sampling method where a line is placed across a habitat and species in contact with the line are recorded to determine abundance and distribution.

Quadrat

A square frame of a given size that is randomly placed in an area being sampled to identify and count species to determine abundance.

Belt transect

A sampling technique that combines the use of a line transect and a quadrat.

Ecosystem

All the organisms living in a particular area (known as the community) along with all the non-living elements of that particular environment.

Community

All the organisms of different species living together in a particular area.

Biotic factors

Living factors, such as predators and disease, that control the distribution and abundance of organisms in a habitat.

Abiotic factors

Non-living factors, such as light levels and temperature, that control the distribution and abundance of organisms in a habitat.

Niche

The particular role of a species in its habitat, consisting of all its biotic and abiotic interactions with the environment.

Succession

The progressive change of one community of organisms into another over time.

Primary succession

Succession that occurs in an area previously devoid of life, such as a bare rock surface formed after a volcanic eruption.

Pioneer species

Species, such as lichens, adapted to survive in harsh conditions that are the first to colonise an area devoid of life.

Climax community

The final stage of succession, consisting of a self-sustaining and stable community of organisms.

Secondary succession

Succession that occurs in a previously colonised area where an existing community has been cleared (such as after a forest fire), beginning at a later stage because a soil layer is already present.

Biomass

The mass of carbon or dry mass of tissue per given area per given time, formed from synthesized plant sugars used to build biological molecules.

Gross primary productivity (GPP)

The rate at which energy is incorporated into organic molecules in plants during photosynthesis, representing the chemical energy store in plant biomass in a given area or volume in a given time.

Net primary productivity (NPP)

The rate at which energy is transferred into organic molecules that form new plant biomass, representing the chemical energy store after respiratory losses: $NPP = GPP - R$.

Net production of consumers ($N$)

The energy stored in consumer biomass, calculated as $N = I - (F + R)$, where $I$ is ingested food energy, $F$ is energy lost in faeces and urine, and $R$ represents respiratory losses.

Rhizobium

Nitrogen-fixing bacteria found in the root nodules of leguminous plants that exchange fixed nitrogen for glucose in a mutualistic relationship.

Nitrogen reductase

An enzyme operating under anaerobic conditions maintained by oxygen-absorbing proteins that reduces nitrogen gas to ammonium ions.

Nitrosomonas

Chemotrophic bacteria that oxidise ammonium ions into nitrites during the nitrogen cycle.

Nitrobacter

Bacteria that oxidise nitrites into nitrates in the presence of oxygen.

Eutrophication

A process where elevated nitrate levels cause algal blooms that block sunlight, resulting in plant death, aerobic saprobiont decomposition, oxygen depletion, and the accumulation of toxic waste.

Saprobiotic organisms

Organisms that feed on and decompose dead matter in aquatic systems, consuming dissolved oxygen in the process and contributing to hypoxia.

Global warming

A gradual increase in the average temperature of the Earth's atmosphere and surface, believed to lead to permanent changes in global climate.

Dendrochronology

The study of tree rings to provide evidence for past temperatures and climate change, based on how temperature affects annual ring growth size.

Pollen analysis in peat bogs

The study of preserved pollen grains extracted from peat bogs to infer the types of plant communities present when the peat was formed.

Greenhouse effect

The process by which infrared radiation from the Sun is trapped by atmospheric gases such as carbon dioxide and methane, warming the Earth's surface and atmosphere.

Biofuels

Fuels derived from grown plants that are considered carbon neutral because the carbon dioxide released upon combustion equals the carbon dioxide absorbed by the plants during photosynthesis.

Reforestation

The replanting of forests to increase the uptake and removal rate of atmospheric carbon dioxide through photosynthesis.