Eutrophication

What is the primary role of decomposers in nutrient cycling?

Decomposers break down organic matter, transforming it and making essential nutrients available to plants.

What are essential nutrients in the nutrient cycle sourced from?

Essential nutrients come from the atmosphere (like carbon) and rocks.

What form of nitrogen do plants require for protein synthesis?

Plants require nitrogen in inorganic forms such as ammonium and nitrate.

What happens to nitrogen levels in trees during the fall?

Trees recover up to 70% of nitrogen before leaves fall, leading to a decline in nitrogen and synthesis of chlorophyll.

What is decomposition?

Decomposition is the breakdown of chemical bonds in plant and animal tissues, involving processes like leaching, fragmentation, and ingestion.

Name four types of decomposers.

Fungi, bacteria, detritivores, and animals.

What experiment is used to determine the decomposition rate of leaves?

Litter Bag experiment.

What factors influence the rate of decomposition?

Quality of food source, abiotic factors like soil pH, temperature, precipitation, and molecular complexity.

How does temperature affect microbial activity in decomposition?

Low temperature and dry habitats slow down microbial activity, while warm, wet climates increase decomposition rates.

What is mineralization in the context of nutrient cycling?

Mineralization is the transformation of organic compounds, such as nitrogen, into inorganic forms.

Describe the rhizosphere.

The rhizosphere is the region of soil where plant roots function and influence soil chemistry.

What percentage of energy fixed in photosynthesis is used by rhizosphere processes?

About 50% of the energy fixed in photosynthesis is utilized by rhizosphere processes.

What defines the microbial loop in aquatic environments?

The microbial loop involves bacteria and other microorganisms that play a crucial role in nutrient cycling and energy transfer in aquatic systems.

What is eutrophication?

Eutrophication is the excess of nutrients in water bodies, leading to issues like dead zones and fish kills.

What typically leads to the 'dead zone' phenomenon in water bodies?

A lack of oxygen in the water, primarily caused by nutrient enrichment from sources like fertilizers and farm waste.

How do aquatic environments differ from terrestrial environments regarding decomposition?

Aquatic environments generally have more stable conditions for decomposition and higher accessibility for detritivores.

What role do salt marshes play in coastal ecosystems?

Salt marshes act as detrital systems, contributing to high productivity and nutrient cycling.

Explain the concept of nutrient spiraling.

Nutrient spiraling refers to the continuous transport of nutrients downstream in river systems.

What are the two forms of fertilizers mentioned in the notes?

Organic fertilizers (like manure and guano) and inorganic fertilizers (like ammonia).

What is swidden agriculture and its environmental impact?

Swidden agriculture involves cutting and burning trees to utilize their ash for nutrients, but it can lead to land abandonment and disrupted nutrient cycles.

What happens to nutrient availability in ecosystems based on primary productivity?

Low primary productivity leads to low nutrient availability in and out of the ecosystem.

What is a significant consequence of excessive nitrogen in the environment?

Excess nitrogen can kill coral and disrupt aquatic ecosystems.

How do the characteristics of terrestrial and aquatic environments affect nutrient cycling?

Terrestrial systems cycle nutrients over time, whereas aquatic systems experience both spatial and temporal nutrient cycling due to water movements.

What are two critical phases in the decomposition process?

Mineralization and immobilization are critical phases where organic compounds are transformed into inorganic forms and utilized by organisms.

What is the significance of the thermocline in aquatic environments?

The thermocline separates warmer surface waters from colder deeper waters, affecting nutrient mixing and availability.