IB Environmental systems and societies 4.1 Water Systems Key Definitions

Adhesion is the attraction between unlike substances, often involving polar or charged surfaces.

Advection is the wind-blown transport of water vapour or condensed/frozen droplets from one region to another, helping connect local hydrological cycles globally.

Carbon sequestration is the process of capturing atmospheric carbon dioxide (CO₂) and storing it in solid or liquid form.

A carbon sink is any natural or artificial system that absorbs more carbon than it releases, thus removing CO₂ from the atmosphere.

The force of attraction between molecules of the same substance (in this case, water).

Evaporation is the transformation of liquid water into vapour due to solar heating.

A flow is the movement of water between stores either as a transfer or a transformation.

Greenhouse gases are atmospheric gases that absorb infrared radiation emitted from the Earth’s surface and re-radiate it back, contributing to atmospheric warming.

Infiltration is the process by which water enters the soil from the surface.

Latent heat of vaporization is the amount of energy required to convert 1 kg of liquid to vapor without a change in temperature.

Ocean acidification is the process by which the ocean becomes more acidic due to increased levels of dissolved carbon dioxide.

pH measures hydrogen ion concentration, influencing chemical reactions in water.

Phytoplankton are microscopic organisms capable of photosynthesis

Polarity refers to the uneven distribution of electrical charge in a molecule, leading to regions of slight positive and negative charge.

Specific heat capacity is the amount of energy needed to raise the temperature of 1 gram of a substance by 1°C.

Steady-state equilibrium is the condition in which inputs equal outputs over time, even though water is continuously moving between stores.

Stores are places where water accumulates or is held temporarily, such as oceans, glaciers, lakes, or groundwater.

Stratification is a common phenomenon in aquatic ecosystems, where water forms distinct layers due to differences in temperature and density.

A thermocline is a layer in a body of water where temperature decreases sharply with depth, restricting vertical movement and mixing.

Transpiration is the release of water vapour by plants into the atmosphere.

Upwelling refers to the vertical movement of deep, cold, nutrient-rich water to the surface due to the displacement of surface waters by wind.