APES Unit 8: Nutrient Pollution and Toxin Dynamics

Eutrophication

The accumulation of excess nutrients, particularly Nitrogen and Phosphorus, in water bodies, leading to rapid algal growth.

Cultural Eutrophication

The accelerated process of eutrophication caused by human activities.

Nutrient Load

Runoff containing nitrates and phosphates that enters a waterway, typically from fertilizers or wastewater.

Algal Bloom

A rapid population explosion of algae in water due to excess nutrients.

Shading

The blockage of sunlight by thick algal mats, hindering photosynthesis in submerged plants.

Decomposition

The process by which aerobic bacteria break down dead organic matter, consuming oxygen in the water.

Oxygen Depletion

The reduction of dissolved oxygen levels in water due to the high biological activity of decomposers.

Hypoxia/Dead Zone

An area with extremely low dissolved oxygen levels, unable to support aquatic life.

Dissolved Oxygen (DO)

The amount of oxygen gas available in water for aquatic organisms.

Biological Oxygen Demand (BOD)

The amount of oxygen required by bacteria to decompose organic matter in water.

Oligotrophic

Water bodies that have low nutrient levels and high water clarity.

Eutrophic

Water bodies that are rich in nutrients, often leading to low water clarity.

Bioaccumulation

The accumulation of toxins in a single organism over time.

Biomagnification

The process where toxins increase in concentration as they move up the food chain.

Persistent Organic Pollutants (POPs)

Toxic substances that resist environmental degradation and accumulate in the food chain.

10% Rule

The principle that only about 10% of energy is transferred from one trophic level to the next.

DDT

A synthetic pesticide known for its effects as an endocrine disruptor and its role in thinning bird eggshells.

Mercury (Hg)

A neurotoxin that can cause severe neurological damage and reproductive issues in aquatic life.

PCBs

Industrial chemicals that are carcinogenic and persist in the environment.

Microplastics

Small plastic particles that absorb toxins and can harm aquatic organisms.

Endocrine Disruptors

Chemicals that mimic hormones and can lead to reproductive and developmental problems in animals.

Biological Signal Blocking

When endocrine disruptors bind to cellular receptors and prevent normal hormonal functions.

Algal Suffocation Misconception

The error in thinking that algae directly suffocate fish; instead, suffocation occurs after algae die.

Bioaccumulation vs Biomagnification Misconception

The misunderstanding that these terms are interchangeable; they describe different processes related to toxins.

Eutrophication and Toxic Chemicals Misconception

The incorrect belief that eutrophication is caused by toxic chemicals rather than nutrient overload.

Phosphorus Limiting Factor

In freshwater ecosystems, phosphorus is often the nutrient that limits productivity.