Soil Organisms and Ecosystem Dynamics

The video discusses the roles of soil fauna in nutrient cycling, their differentiation by size, location, and time scale, and their feeding habits. It highlights the specialization and biodiversity of soil organisms, including microfauna, meso fauna, and macro fauna. The impact of earthworms on soil and forest ecosystems is explored, emphasizing their role as ecosystem engineers and their effects on decomposition and habitat alteration.

How do soil fauna contribute to nutrient cycling?

• By increasing the surface area of materials they feed on

• By translocating nutrients from the substrate to the soil

• By preventing the spread of microbes

• By reducing the soil's surface area

What is a key factor in differentiating soil organisms?

• Their color

• Their size and location

• Their ability to fly

• Their lifespan

Which of the following is true about microfauna?

• They live in air-filled spaces

• They are larger than mesofauna

• They live in water films in the soil

• They create their own burrows

What is a characteristic of mesofauna?

• They create their own burrows

• They live in air-filled spaces

• They are larger than macrofauna

• They live in water films

What is the primary role of macrofauna in northern soils?

• They are the main drivers of decomposition

• They play a small role in decomposition

• They only feed on plant parts

• They are inactive during the year

Which organisms are considered ecosystem engineers?

• Microfauna

• Mesofauna

• Macrofauna

• All soil organisms

How do earthworms affect the forest floor?

• By increasing the nitrogen content

• By preventing the growth of fungi

• By creating new habitats for salamanders

• By reducing the thickness of the O horizon

What impact do earthworms have on nitrogen levels in the soil?

• They increase nitrogen levels

• They have no impact on nitrogen levels

• They cause a loss of nitrogen

• They stabilize nitrogen levels

What is a consequence of earthworm activity in forest soils?

• Increased microbial associations

• Increased leaf litter

• Loss of habitat for certain species

• Stabilization of soil aggregates

How do invasive earthworms alter ecosystems?

• By reducing carbon sequestration

• By increasing the available niche for fungi

• By preventing plant regeneration

• By changing soil composition