#nutrients

Controls Ecosystem

Increased nutrient supply in bottom-up ecosystems results in:

“Increased primary producers and subsequent trophic levels” for increased nutrient supply in bottom-up ecosystems results in. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Rates depend on temperature, moisture, substrate quality, consumer physiology, and the elemental balance between organisms and their food. These controls explain why the same process can differ among terrestrial, freshwater, and marine systems without changing its definition. The remaining alternatives—“Increased predators onl

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4

View Details

SPECIES INTERACTION

Which type of interaction occurs between two species competing for limited nutrients?

When two species draw on the same limiting nutrient, each reduces the amount available to the other. Both populations consequently experience lower growth, survival, or reproduction than they would in the other's absence, producing the (-,-) outcome of interspecific competition. Competitive effects can occur through exploitation of a shared resource or through direct interference, and their strength depends on resource supply, uptake traits, and niche overlap. Mutualism benefits both species, amensalism harms one while leaving the other unaffected, and parasitism benefits one at the other's ex

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 8-13

View Details

Ecosystem Ecology & PRODUCTIVITY

Which nutrient is NOT primarily cycled in ecosystem ecology?

Sulfur is actively and importantly cycled in ecosystems, so the keyed claim that it is not primarily cycled is scientifically incorrect. Along with carbon, nitrogen, and phosphorus, sulfur participates in a major biogeochemical cycle linking organisms, soil, rocks, water, and the atmosphere. Plants take up sulfate and incorporate it into amino acids such as cysteine and methionine; food webs transfer organic sulfur, and decomposition mineralizes it. Microbes oxidize reduced sulfur compounds or reduce sulfate under anaerobic conditions. Weathering, sea spray, volcanic emissions, decomposition,

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17

View Details

Ecosystem Efficiency and Decomposition

Decomposers convert organic matter into:

Decomposers transform organic matter into inorganic nutrients through extracellular digestion, uptake, respiration, and mineralization. Organic nitrogen can become ammonium, organic phosphorus can become phosphate, and organic carbon is largely released as CO₂ under aerobic conditions. Not all material is immediately mineralized: some enters microbial biomass, humus, dissolved organic matter, or persistent mineral-associated pools. Thus decomposition both recycles plant-available ions and stabilizes part of the detrital carbon, linking energy dissipation with nutrient conservation. Carbon and

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3

View Details