Freshwater Ecology

Freshwater Ecology

The study of organisms in freshwater environments, including lakes, rivers, and wetlands, and their interactions with both the biotic (living) and abiotic (non-living) components of these ecosystems.

Ecosystem

A community of living organisms interacting with each other and their physical environment, including the flow of energy and cycling of nutrients.

Temporal Scale

Refers to the time frame over which ecological processes occur.

Spatial Scale

Refers to the physical area or extent of an ecological study or phenomenon.

Abiotic

Non-living components of an ecosystem, such as water, air, minerals, and sunlight, that influence the survival and growth of organisms.

Biotic

Living components of an ecosystem, including plants, animals, microorganisms, and their interactions.

Hypsographic Curves

Graphs that show the distribution of land elevation and water depth at different depths in aquatic environments.

Hydrogen Bonding (water)

A weak bond that occurs between a hydrogen atom of one water molecule and the oxygen atom of another, giving water its unique properties like high cohesion and surface tension.

Viscosity (water)

A measure of the internal friction of water, or its resistance to flow. It affects how easily organisms can move through the water. Higher viscosity means greater resistance, impacting aquatic life movement.

Inertial Forces (water)

Forces in water that resist changes to the motion of an object within the fluid, especially important in understanding water flow dynamics. These forces include inertia and momentum, influencing how organisms navigate and interact with their environment.

Reynolds Number (water)

A dimensionless number used to predict flow patterns in water, distinguishing between laminar (smooth) and turbulent flow.

Density (water/ice)

Water's density is highest at 4°C, and decreases as it freezes, which is why ice floats on water.

Temperature (water/ice)

Water has a high specific heat, meaning it can absorb a lot of heat without changing temperature, which helps regulate climates and aquatic ecosystems.

Epilimnion

The upper layer of water in a stratified lake, typically warmer and more oxygenated, above the thermocline.

Thermocline

The layer in a stratified water body where temperature changes rapidly with depth separating the warmer epilimnion from the cooler hypolimnion. It serves as a barrier to mixing between the two layers, affecting nutrient distribution and aquatic life.

Metalimnion

Another term for the thermocline layer, where there is a rapid change in temperature between the epilimnion and hypolimnion.

Hypolimnion

The deepest, coldest layer of water in a stratified lake, typically with low oxygen levels and stable temperatures.

Dimictic Lakes (seasonal cycle)

Lakes that mix twice a year, typically in spring and fall, when temperature changes cause the water to circulate throughout the lake.

Holomictic Lakes

Lakes that undergo complete mixing of their waters throughout the year. These lakes experience uniform temperatures and oxygen levels in all layers.

Warm Monomictic Lakes

A lake that mixes once a year, usually in the winter. The surface water is warmer than the bottom water.

Cold Monomictic Lakes

Lakes that mix once a year during the warmer months, typically remaining ice-covered in winter.