APES Task 1 Notes - Ted Ma

What is the primary way humans affect the carbon cycle?

By burning fossil fuels like coal, oil, and natural gas.

What process do producers perform related to CO2 in the carbon cycle?

Producers remove CO2 from the atmosphere and generate O2.

How do consumers interact with the carbon cycle?

Consumers obtain carbon compounds by eating producers and release carbon dioxide back into the atmosphere through cellular respiration.

What are carbon sinks?

Areas where carbon can be stored and concentrated for a long time, such as the ocean, atmosphere, plants, and soil.

What is nitrogen fixation?

The process of converting atmospheric nitrogen gas (N2) into biologically usable nitrogen forms like ammonia (NH3) or nitrate (NO3).

Why is nitrogen a limiting factor in ecosystems?

Because although nitrogen makes up 80% of the atmosphere, most organisms cannot use it in its gaseous form (N2), restricting plant growth.

What are the major steps in the nitrogen cycle?

Nitrogen fixation, assimilation, ammonification, nitrification, and denitrification.

What is the role of nitrogen-fixing bacteria?

They convert atmospheric N2 into ammonia (NH3) that plants can use.

What is the significance of the phosphorus cycle?

It moves phosphorus-containing elements between sources and sinks, with major reservoirs including rocks and sediments.

How does weathering contribute to the phosphorus cycle?

Weathering of rocks releases phosphate (PO4) into soil and water, allowing it to become available to plants.

What is eutrification?

The process where extra nitrogen and phosphorus in water systems cause algal blooms, leading to oxygen depletion.

What are the soil horizons?

Layers in soil development including O Horizon, A Horizon, B Horizon, C Horizon, and D Horizon.

What does the O Horizon consist of?

Decomposing leaves, plant roots, and animal waste, providing moisture and nutrients.

What are the functions of soil in ecosystems?

Support plant growth, help with water filtration, recycle nutrients, and provide habitat.

What human activities impact the nitrogen cycle?

Fertilizer use, fossil fuel combustion, and livestock waste contributing to pollution.

What is the impact of the Green Revolution?

Increased food production, more efficient land use, and economic benefits, but also environmental issues like soil erosion and loss of biodiversity.

What are the main causes of soil erosion?

Heavy mechanization, tilling, monocropping, and deforestation.

What does monocropping lead to?

Increased efficiency initially, but decreased biodiversity and increased vulnerability to pests.

What is tiling in agriculture?

Mechanically breaking up soil for easier planting, leading to increased soil erosion and loss of organic matter.

How do synthetic fertilizers affect the environment?

They can lead to eutrophication and contribute to greenhouse gas emissions from fossil fuel use in production.

What is a key process in the carbon cycle?

Photosynthesis, where plants convert CO2 into organic matter.

What does ammonification refer to in the nitrogen cycle?

The conversion of waste and dead biomass back into ammonia (NH3) by soil bacteria.

Why is phosphorus often a limiting nutrient?

It is limited in availability within soil and water, restricting plant growth.

What contributes to acid rain?

Ammonia (NH3) gas in the atmosphere from fertilizer usage.

What is a characteristic of the B Horizon (Subsoil)?

Contains more clay and minerals leached from the A Horizon, typically has lower organic content.

How does climate affect soil formation?

Warm temperatures accelerate decomposition while high precipitation promotes weathering but can also lead to erosion.

What is the difference between porosity and permeability?

Porosity is the amount of pore space between soil particles, while permeability is the ability of water to drain through soil.

What are living organisms in soil required for?

They contribute to nutrient cycling and soil health.

What is the impact of excessive fertilizer use on crops?

Leads to less nitrogen being retained in soil for plants, which decreases growth and profit potential.

What is a disadvantage of synthetic fertilizers compared to organic fertilizers?

Synthetic fertilizers can cause eutrophication and do not add organic material back into the soil.

What is the role of decomposers in the soil?

They break down organic material, returning nutrients to the soil.

What happens during denitrification?

Bacteria convert nitrates (NO3) back into nitrogen gas (N2), which returns to the atmosphere.

How does erosion affect soil fertility?

Erosion can remove topsoil and nutrients, degrading soil quality and productivity.

What is critical to maintaining soil quality?

Managing nutrient availability, soil pH, organic matter, and aeration.

What is a consequence of agricultural mechanization?

Increased reliance on fossil fuels and reduced water retention in soil due to compaction.

What do rock and sediment reservoirs primarily store?

Phosphorus.

What factor limits plant growth in ecosystems related to phosphorus?

Limited availability in soil and water.

How is eutrophication connected to human activity?

Runoff from fertilizers introduces excess nutrients into water bodies.

What is the result of higher nitrogen levels in aquatic ecosystems?

Algal blooms that deplete oxygen, leading to dead zones where aquatic life cannot survive.

What might high soil acidity lead to?

Leaching of essential nutrients, adversely affecting soil fertility.

How do earthworms impact soil?

They enhance nutrient cycling and improve soil structure.

What can result from synthetic fertilizers negatively?

Contamination of groundwater and surface water due to leaching of nitrates.

What are key factors influencing soil formation?

Parent material, topography, climate, and soil organisms.

What does the C Horizon consist of?

Partially weathered rock that becomes mineral source for soil.

What is a major reservoir for nitrogen?

The atmosphere, which contains 78% nitrogen gas (N2).

What contributes to the fertility of soil?

Nutrient availability, organic matter, and good aeration from soil organisms.

What impact does over-farming have on soil?

It depletes nutrients without replenishment, reducing fertility.

What defines the D Horizon in soil profiles?

The unweathered rock layer beneath the soil, providing parent material.