Ecosystem Structure, Carbon Cycling, and the Global Hydrological Cycle

Flashcards covering ecosystem components, functional properties, thermodynamics, Redfield ratio, carbon cycling pumps, and the global hydrological cycle based on lecture notes.

Ecosystem

A system of organisms and their physical environment, composed of all organisms in an area, the physical environment, and their biotic and abiotic interactions.

Population

Organisms of the same species living in the same habitat, characterized by the fundamental property of abundance (e.g., biomass).

Community

Coexisting populations of different species, defined by the fundamental properties of species diversity and food web structure.

Autotrophs

Organisms ("self-nourishers") that synthesize organic material from solar or chemical energy and essential inorganic elements from the atmosphere (e.g., $N_2$) and lithosphere (e.g., $P$, $S$, $Ca$).

Heterotrophs

Organisms ("nourished from others") that obtain energy and organic nutrients by consuming autotrophs or other heterotrophs.

Redfield Ratio

The relative atomic ratio of carbon, nitrogen, and phosphorus in living phytoplankton, defined as $C:N:P = 106:16:1$ (with an $N:P$ ratio of $16:1$).

Liebig's Law of the Minimum

The principle stating that growth is limited by only one nutrient at any one time: the nutrient in least supply relative to what is needed.

First Law of Thermodynamics

The law of conservation of matter and energy stating that matter and energy are neither created nor destroyed in any physical or chemical process, but merely transformed.

Second Law of Thermodynamics

The law of energy degradation (entropy) stating that energy moves from an organized, useful form to a disorganized, less useful form, and cannot be recycled to its original state of usefulness.

Marine Biological Pump

The pathway in which surface phytoplankton convert atmospheric $CO_2$ into organic carbon, which sinks into the deep ocean via sedimentation and undergoes bacterial decomposition before returning to the surface via upwelling.

Solubility Pump

The chemical exchange process where atmospheric $CO_2$ dissolves in ocean water to form carbonic acid ($H_2CO_3$), bicarbonate ($HCO_3^-$), and carbonate ($CO_3^{2-}$), which shelled organisms convert into calcium carbonate ($CaCO_3$).

Foraminiferans

Protozoa ($<0.5 accession-id\,mm$ in size) inhabiting plankton and marine sediments that feed on bacteria and produce approximately $1 \times 10^9\text{ tons}$ of $CaCO_3$ per year.

Coccolithophores

Planktonic algae that produce $1.5 \times 10^6\text{ tons}$ of $CaCO_3$ per year and form ocean surface blooms that reflect visible light.

Short-term Carbon Cycles

Carbon exchange processes that occur rapidly between the atmosphere and biosphere, such as photosynthesis and respiration.

Long-term Carbon Cycles

Carbon processes occurring over geological timescales involving rock weathering, volcanic activity, and the formation and destruction of sediments and fossil fuels.

Evaporation

The phase transition of liquid water to water vapor, occurring at a rate dependent on liquid temperature because higher thermal energy provides the energy needed to break chemical bonds.

Condensation

The phase transition of water vapor to liquid water, occurring at a rate dependent on vapor pressure and molecule collisions in an air parcel.

Vapor Pressure

A measure of the quantity of water vapor molecules present in a specific parcel of air at any given moment.

Transpiration

The conversion and release of liquid water to water vapor into the atmosphere by plants through their leaves.

Flying River

An atmospheric movement of huge quantities of water vapor over large land areas driven by wind currents and high volumes of recycled plant transpiration.

Biological Cloud Seeding

The release of volatile organic compounds by trees and plants that act as cloud condensation nuclei to promote localized cloud formation and rainfall.

Sublimation

The direct phase transition of water from a solid state (ice or snow) to a vapor state without passing through a liquid state.

Desublimation (Deposition)

The direct phase transition of water from a vapor state to a solid state without passing through a liquid state.

Residence Time

The average amount of time water or a substance spends within a specific reservoir, calculated under steady-state conditions as reservoir volume ($S$) divided by inflow or outflow rate ($I$).

Atmospheric Water Residence Time

The characteristic residence time of water in Earth's atmospheric reservoir, calculated as $0.03\,\text{years}$ or approximately $11\,\text{days}$.