Nutrient Cycles Flashcards
Which biological molecules contain nitrogen?
Proteins, ATP, and nucleic acids.
What is the importance of the nitrogen cycle?
Microorganisms convert nitrogen gas into nitrogen containing substances which plants and animals can absorb.
What is the process of the nitrogen cycle?
1) Nitrogen fixation - bacteria in the soil converts nitrogen gas into ammonium, or it can be directly converted in the root nodules of a plant by nitrogen fixing bacteria.
2) Ammonification - Decomposeds can break down organic matter into ammonium.
3) Nitrification - Nitrifying bacteria converts the ammonium into nitrites and then into nitrates.
4) Denitrification - Conversion of nitrates back to nitrogen gas by anaerobic bacteria in waterlogged soils.
What is phosphorus used for in organisms?
DNA/RNA, ATP, phospholipid bilayer.
What is the importance of mycorrhizae?
The fungi increases the surface area of the plant for water and mineral absorption and acts as a sponge so holds water and minerals around the roots making the plant able to take up more inorganic ions.
What is the process of the Phosphorous Cycle?
1) Phosphates are washed off of rocks by weathering, distributing the phosphate into soil and water.
2) Plants take up phosphate from the soil and animals consume these plants - this embeds the phosphate into DNA. When plants and animals die and decompose, phosphate returns to the soil.
3) Organic forms of phosphate can be made accessible to plants by bacteria which break down organic matter, changing the phosphate into an inorganic form of phosphorus (mineralisation).
4) One the phosphorus is in the soil, it is transferred to oceans and can then be integrated into sediments and rock again.
What is the role of sapriobionts in decomposition?
Sapriobionts are a type of decomposer which digest dead organisms externally by secreting enzymes and then absorbing the useful products. Larger ionic molecules are broken down into smaller inorganic molecules (nitrogen cycle).
What is leaching?
When water-soluble nutrients, such as nitrates and phosphates, are washed out of the soil by rainwater. This can lead to eutrophication and an algal bloom.
What is eutrophication?
When an excess of nutrients in water bodies lead to a dense growth of plant life, especially algae.
What are the consequences of leaching?
As a result of eutrophication caused by leaching, thick algae will block the sunlight, reducing photosynthesis for aquatic plants below the surface. When algae die, decomposers break them down, using a lot of oxygen. Reduced oxygen levels lead to the death of fish and other aerobic organisms.
What are some natural fertilisiers?
Faeces, urine, bone meal.
Why would you use natural fertilisers?
Natural fertilisers contain nitrogen and phosphorus in organic forms and can slowly release nutrients as they decompose, improving long-term soil structure and fertility.
Why would you use artificial fertilisers?
Artificial fertilisers provide specific and easily absorbed nutrients which are immediately available for plants, allowing for rapid growth, and are cost-effective and easy to transport and apply.
What are some negative factors of artificial fertilisers?
The overapplication of natural fertilisers can lead to leaching and eutrophication.
What are some negative factors of natural fertilisers?
Nutrient release rate is slower in natural fertilisers compared to artificial fertilisers.
