AP Env Sci: Freshwater Biology

Brackish or estuarine water

Water located in areas where fresh and saltwater mix, e.g. bays and estuaries

Productivity

Is the total amount of food produced by photosynthesis.

Hydrologic cycle

Aquatic systems are formed by ___, which is run by solar energy.

Transpiration

Solar energy evaporates water from a plant’s leaves.

Infiltration

When water vapors turn into heavy droplets, they precipitate and fall into the ground where they are absorbed by plants and soil life.

Runoff

Water is moved over the Earth’s surface as a small stream that will join other steams to form a lake or a river, and eventually flow into an ocean.

Watershed

Can scale between a single home, to international borders. Just as creeks drain into rivers, watersheds are always a part of a larger watershed.

Littoral zone

Shallow area of a lake, pond, or river that is near the shoreline where sunlight penetrates through the seafloor allowing for rooted plants to grow.

Limnetic zone

An open freshwater region that is too deep for rooted plants. This region extends into the depths where little light can penetrate.

Lotic habitat

• Freshwater systems that flow

  • Streams

  • Rivers

  • Creeks

Lentic habitat

• Freshwater systems that are stagnant

  • Ponds

  • Lakes

Profundal zone

• Found under the Limnetic Zone which are deep water ecosystems. Light can still penetrate efficiently for photosynthesis to occur.

  • Many living things will move through the zones to obtain the conditions they need to survive.

Thermal pollution

Rapid changes in temperature in freshwater is caused by heated industrial wastewater.

Turbidity

The measure of cloudiness in water caused by suspending particles.

Rate of flow

Is the volume or mass of a fluid that passes through a given surface per unit of time in a lake. 

Sedimentation

Eroded soil particles that settle between rocks in the bottom of a stream or river. This takes up the space for an aquatic plant to grow on, which can negatively impact a freshwater area’s ecosystem.

Depth (water)

Distance between the surface of the water and the seafloor below. Is one of the major physical factors that allow how much of sunlight can reach inside the water.

Water Hardness

A measure of how much minerals, calcium, or magnesium is dissolved in water which gives it a certain quality.

Water pH

A level which measures if the water is acidic or basic (alkaline).

Phosphates

A major nutrient needed for aquatic life. (PO₄³⁻)

Nitrates

They come from fertilizers and runoff from rainwater. (NO⁻ ₃)

Biochemical Oxygen Demand (BOD)

Factors that deplete Dissolved Oxygen.

Dissolved Oxygen (DO)

Oxygen that is mixed with the surface of the water, which helps aquatic life breathe.

Point Source Pollution

The source of pollution comes from a specific point or location.

Non-point Source Pollution

Source of pollution is more generalized and ambiguous.

Phytoplankton

Plant like; Algae that takes in forms such as desmids and diatoms.

Zooplankton

Animal-like; Takes form of rotifers and tiny crustaceans.

Eutrophication

The abnormal addition of nutrients that causes unnatural accelerated plant growth.

Index Species

Loss of certain types of organisms from streams that end up increasing the population of other species.

Benthic macroinvertebrates

A freshwater organism that lives in the deeper parts of freshwater. It is big enough to be seen without a microscope, and often is used as an indicator for polluted freshwater.

Photic Zone

Upper layer of ocean that receives enough sunlight for photosynthesis.

Aphotic zone

Deep layer of the ocean where it lacks sunlight, no photosynthesis happens here.

Chemosynthesis

Energy that is contained inside an aphotic zone, bacteria can create a new source of energy for certain aquatic that can survive in the deep ocean. (Ex. Jellyfish & Squids)

Open Ocean

Where sunlight can no longer reach the ocean bottom.

Oligotrophic

Lakes with low nutrients and productivity.

Mesotrophic

Lakes with moderate amounts of productivity.

Eutrophic

Lakes with high levels of productivity.

Freshwater Wetlands

Freshwater with low salinity. Submerged for at least part of each year, and is often characterized as being shallow enough to support vegetation.