Lecture 11 Soil Food Web, Biodiversity and Function

These flashcards cover key terms and definitions related to the Soil Food Web, Biodiversity, and Function.

Soil Food Web

A complex community of organisms living in soil that interact through the transfer of energy, nutrients, and carbon.

Autotrophs

Organisms that obtain their cellular carbon from CO2.

Heterotrophs

Organisms that obtain their carbon from pre-formed organic compounds and cannot use inorganic compounds as sources of energy.

Phototrophs

Organisms that obtain their energy from sunlight.

Chemotrophs

Organisms that obtain their energy from biochemical oxidation of inorganic elements or organic energy sources.

Microfauna

Small soil organisms, including protozoa and nematodes, that play critical roles in soil ecosystems.

Mesofauna

Soil organisms of intermediate size, such as mites and springtails, that influence soil structure and nutrient cycling.

Macrofauna

Larger soil organisms, such as earthworms and insects, that significantly affect soil formation and health.

Rhizosphere

The zone of soil influenced by living plant roots, where unique populations of microorganisms thrive due to root exudates.

Functional Redundancy

The ability of multiple species to perform the same function in an ecosystem, ensuring that important functions are maintained even if some species disappear.

Primary Producers

Organisms, mainly plants and photosynthetic microbes, that create organic matter through photosynthesis, forming the base of the soil food web.

Nutrient Cycling

The process whereby nutrients are recycled in the ecosystem, facilitated by the activities of soil organisms.

Soil Biodiversity

The variety of life in soil, including microorganisms, plants, and animals, which plays a vital role in ecosystem functions.

Decomposition

The process of breaking down organic matter, primarily carried out by fungi and bacteria.

Symbiosis

A mutually beneficial relationship between different species, significant in soil organisms like arbuscular mycorrhizal fungi and plants.

Ecosystem Goods and Services

The benefits provided by ecosystems, including soil health, which supports agriculture and biodiversity.

Bacteria

Single-celled microorganisms that play a crucial role in nutrient cycling, decomposition, and maintaining soil health. Both autotrophic and heterotrophic

Archaea

Ancient single-celled microorganisms similar to bacteria, often found in extreme environments, playing important roles in nutrient cycling, nitrification and organic matter decomposition.

Photosynthetic organisms

Algae and cyanobacteria - must reside at or near soil surface

Algae and cyanobacteria

Important colonizers in early soil formation - can add organic Carbon and Nitrogen to parent material

Fungi

heterotrophic organisms responsible for decomposition of complex macromolecules in organic matter

Benefits of fungi

1. cycle nutrients and carbon

2. form filamentous hyphae - stabilizing soil aggregates

3. Mycorrhizal fungi form symbiotic relationships with plants

Pathogenicity of fungi

produce spores prolifically (many are air-borne). Soil type, pH, water content and temperature affect the presence of soil-borne plant pathogenic fungi

Protists

Predators that consume bacteria and fungi

Protists

Single-celled organisms that can cause damping-off disease, clubroot and downy mildew

Fungicides do not work to kill _____________

Protists

Where soil organisms tend to be more abundant

soil surface and plant rhizosphere

symbionts

arbuscular mycorrhizal fungi (AMF) and nitrogen fixers