5B Energy Transfer and Nutrient Cycles Flashcards
Biomass
The mass of living material
Mass of carbon that an organism contains or the dry mass of its tissue per unit area per unit time
How do you dry a sample of an organism?
Heat at a low temperature and weigh at regular intervals until the mass becomes constant
How much carbon is assumed to be in dry mass?
50%
GPP
Gross Primary Production- the total amount of chemical energy converted from light energy by plants, in a given area, in a given time
Approximately how much of the GPP is lost to the environment when plants respire?
50%
What is the amount of GPP lost to the environment when plants respire called?
Respiratory loss
NPP
The Net Primary Production
What is the equation for NPP?
NPP= GPP - R
How do consumers get energy?
Ingesting plant material or animals that have eaten plant material
How is energy lost in consumers?
As heat in respiration, egested as faeces
What is the equation for the net production of a consumer?
N= I- (F+R) N= net production I= Chemical energy in ingested food F= Chemical energy lost in faeces and urine R= Energy lost through respiration
What is the equation for the % efficiency of energy transfer?
% efficiency = 100 x (net production of trophic level/ net production of previous trophic level)
How do you increase the NP of livestock?
Simplify food web, reduce respiratory loss
Saprobionts
Microorganisms that feed on the remains of dead plants and animals using extra cellular digestion to break down the remains
Saprobiotic digestion
Obtaining nutrients from dead organic matter and animal waste using extra cellular digestion
Mycorrhizae
Relationships between fungi and roots of plants. Fungi made of long strands called hyphae which connect to the plant’s roots. This increases the surface area of the plant’s roots
Describe what happens during nitrogen fixation
Nitrogen gas in the atmosphere is turned into nitrogen-containing compounds by bacteria. Turns nitrogen into ammonia, which forms ammonium ions in the soil. The bacteria are found inside root nodules of leguminous plants
Describe what happens during ammonification
Nitrogen compounds from dead organisms are turned into ammonia by saprobionts which goes on to form ammonium ions
Describe what happens during nitrification
Ammonium ions in the soil are changed into nitrogen compounds that can then be used by plants (nitrates). First turn into nitrites then into nitrates.
Describe what happens during denitrification
Nitrates in the soil are converted into nitrogen gas by denitrifying bacteria. Under anaerobic conditions
Describe the 7 steps of the nitrogen cycle
Phosphate ions are released into the soil by weathering
Phosphate ions are taken into the roots
Phosphorus transferred through the food chain as animals eat plants ect
Plants and animals die, digested by saprobionts
Weathering of rocks release phosphate ions into the sea/ water sources which is taken up by aquatic producers like algae and is passed along the food chain to fish and birds
Guano returns lots of phosphate ions to the land
How are nutrients lost?
Plants take them in through the soil. Crops are harvested and they are removed from the field rather than being decomposed
Artificial fertilisers
Pure chemicals such as ammonium nitrate
Natural fertilisers
Organic matter such as manure, composed vegetables
Leaching
Water soluble compounds in the soil are washed away and end up in near by ponds and rivers
Eutrophication
The process whereby nutrients build up in water, leading to the growth of large quantities of algae. This results in the death of plants, and the decomposition of dead plant matter causes the oxygen content of the water to fall, killing aquatic organisms
Explain the process of eutrophication
Mineral ions leached from fertilised fields stimulate the rapid growth of algae in ponds and rivers
Large amounts of algae block light from reaching the plants below
Eventually the plants die because they’re unable to photosynthesise enough
Bacteria feed on the dead plant matter. The increased numbers of bacteria reduce the oxygen concentration in the water by carrying out aerobic respiration
Fish and other aquatic organisms die because there isn’t enough dissolved oxygen
