EARTHSC 2EI3 Lecture Notes - Lecture 4: Algal Bloom, Eutrophication, Sewage Treatment
13 Dec 2016
School
Department
Course
Professor
EARTH SCI 2EI3: Environmental Issues
LECTURE 4: ECOSYSTEMS AND MATTER CYCLING – Sept 19, 2016
Key Concepts
- Eutrophication: what is it and its causes
- The impacts of human activity on the flow of nutrients
- Aquatic Dead Zones: what are they, examples
- Eutrophication in Lake Erie: history, sources, algae involved, issues
Q1: Which of the following statements about the eutrophication process is correct?
a. It is a natural process of nutrient enrichment
b. It is a natural process of nutrient depletion
c. It leads to reduced productivity
d. It only happens because of human activity
e. It is typically associated to micronutrients
What is Eutrophication?
- Eutrophication: the natural process of nutrient enrichment of water bodies that leads to
greater productivity
- Many bodies of water of low in nitrogen and phosphorus which restricts growth of
algae, so when it is introduced, it increases algae production
o This creates a thick algae bloom preventing sunlight from coming through
▪ Detrimental to producers
o When that algae dies, it takes oxygen to decompose of it, making the water
hypoxic
▪ Detrimental to fish and other water species
Phosphorus Cycle
- Producers take up phosphorus → consumers eat producers → producers die and
decompose → phosphates sediment into land → mined by humans
o Humans rely of phosphorus a lot for agriculture and mines and it runs off into
water
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 4: ecosystems and matter cycling sept 19, 2016. Eutrophication: what is it and its causes. The impacts of human activity on the flow of nutrients. Aquatic dead zones: what are they, examples. Eutrophication in lake erie: history, sources, algae involved, issues. Eutrophication: the natural process of nutrient enrichment of water bodies that leads to greater productivity. Bodies of waters with excessive phosphorus, where the bottom waters are hypoxic. Closest to highest population densities: agriculture and household use discharge of fertilizers. Video clip (geographic scholar): dead zone: the 2014 gulf of mexico hypoxic zone (youtube) 5052 square miles of hypoxic water caused by agricultural/fertilizer and urban runoff. Affects fishing and wildlife many die or leave the area: agricultural crops bigger yield, but affects aquatic resources. Hypoxia: when oxygen levels are so low that it can no longer sustain life in bottom or near-bottom waters. Erie is the smallest of the lakes, so most sensitive to changes around its coasts.
