Biogeochemical Cycles: Phosphorus and Sulfur

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary effect of excess phosphorus (P) in water bodies?

Explosive growth of algae and cyanobacteria (correct)

Reduction in water temperature

Improved water quality

Increased biodiversity

Which of the following statements is true about sulfur (S) in the environment?

Sulfur is primarily found in the atmosphere.

Sulfur does not play a role in climate regulation.

S compounds influence precipitation acidity. (correct)

S is the most abundant element in Earth's crust.

How does sulfur contribute to the global climate balance?

Through the evolution of aerosol particles (correct)

Through producing high levels of carbon dioxide

By reducing atmospheric pressure

By increasing soil fertility

Where is sulfur commonly found in the natural environment?

In underground deposits and volcanic regions Signup and view all the answers

What oxidation states can sulfur assume?

-1, -2, 0, +1, +2, +3, +4, +5, +6 Signup and view all the answers

What is the main storage form of sulfur in the oceans?

Dissolved sulfate Signup and view all the answers

Which sulfur compound is primarily produced by algal and bacterial decay?

Dimethyl sulfide Signup and view all the answers

What is the dominant form of sulfur found in soil?

Sulfate (SO42−) Signup and view all the answers

What is the primary anthropogenic source of sulfur dioxide in the atmosphere?

Burning of fossil fuels Signup and view all the answers

Which compound is highly reactive and released during anaerobic decay?

Hydrogen sulfide Signup and view all the answers

Which process is responsible for the main annual contributions of sulfur from anthropogenic sources?

Burning fossil fuels Signup and view all the answers

What are sulfate aerosols primarily derived from?

Sea spray Signup and view all the answers

What forms of sulfur are considered when discussing the sulfur cycle's human interference?

Both organic and inorganic compounds Signup and view all the answers

What is the primary form in which phosphorus is found in the cycle?

Phosphate ion (PO43–) Signup and view all the answers

How does phosphorus enter the biological cycle from sedimentary rocks?

By weathering and acid rain Signup and view all the answers

What is a major consequence of human interference with the phosphorus cycle?

Decreased biodiversity in aquatic ecosystems Signup and view all the answers

Which cycle does the formation of nitric acid (HNO3) predominantly involve?

Nitrogen cycle Signup and view all the answers

What is the main reason phosphorus does not enter the atmosphere?

It is primarily found in solid form Signup and view all the answers

What are primary sinks for phosphorus in the biosphere?

Sedimentary rocks Signup and view all the answers

Which of the following activities does NOT contribute to the excess phosphorus in the environment?

Planting cover crops Signup and view all the answers

What is one of the key roles of producers in the phosphorus cycle?

Incorporating inorganic phosphorus into organic molecules Signup and view all the answers

Study Notes

Lecture 8: Biogeochemical Cycles

Biogeochemical cycles are the pathways by which elements and compounds move through the Earth's spheres (atmosphere, hydrosphere, lithosphere, and biosphere)
The lecture covered the phosphorus and sulfur cycles, focusing on their importance, human impacts, and consequences.

Phosphorus Cycle

Phosphorus (P) is an essential nutrient for plants and animals
It's not very common in the biosphere
Found in soil and sedimentary rocks (primary sinks)
Released slowly by weathering and acid rain
Does not enter the atmosphere
The main form of phosphorus in soil and water is phosphate ion (PO4³⁻) or hydrogen phosphate (HPO₄²⁻).
Human activities have major impacts on the phosphorus cycle
Mining phosphorus in large quantities to make fertilizers and detergents
Clear-cutting of forests reduces the available phosphorus
Runoff from agricultural and urban areas into rivers and oceans causes excess phosphorus.
Consequences of this include excessive algal growth and oxygen depletion in water bodies like red tides

Sulfur Cycle

Sulfur (S) is a minor but essential component of proteins
Sulfur compounds are significant in determining acidity of precipitation, water, and soil.
Sulfur particles and tiny air droplets can regulate the global climate.
Sulfur is commonly found in underground deposits, near natural hot springs, and volcanoes.
It exists in many oxidation states (-1, -2, 0, +1, +2, +3, +4, +5, +6).
In the lithosphere, sulfur is abundant in sedimentary rocks (e.g., iron disulfide- FeS₂, calcium sulfate- CaSO₄).
Sulfur is mobilized through slow weathering of rock material (runoff).
The main storage form of sulfur in the oceans is sulfate (SO₄²⁻).
Dimethyl sulfide (DMS) is a volatile sulfur compound produced by algal (phytoplankton) and bacterial decay in seawater.
Rivers transport a significant amount of sulfur into oceans.
In the atmosphere, carbonyl sulfide (COS) is the most abundant but inert form of sulfur, though carbon disulfide (CS₂) is more reactive.
Burning of fossil fuels is a significant human impact increasing sulfur emissions.
Consequences include acid rain, damage to buildings and vegetation, and respiratory illnesses in humans, reducing visibility, and cools cities and may offset greenhouse effect of rising CO2.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz focuses on Lecture 8 covering biogeochemical cycles, specifically the phosphorus and sulfur cycles. It discusses the movement of elements through Earth's spheres and the human impact on these essential cycles, emphasizing the importance of phosphorus as a nutrient and its consequences due to human activities.