Energy Transfer and Nutrient Cycles Flashcards
What is biomass?
-The mass of living material in an organism
How can biomass be measured?
-The mass of carbon of an atom that an organism contains
-Dry mass of its tissue per unit area
What is gross primary production (GPP)?
-The total amount of chemical energy converted from light energy by plants in a given area
What is respiratory loss(R)?
-When GPP is lost to the environment as heat when plants respire
How do you calculated net primary production (NPP)?
NPP=GPP-R
Why do consumers not store all of the plants chemical energy?
-Not all food is eaten
-Some are indigestible, excreted as faeces
-Some energy lost to environment through respiration or excretion of urine
What is net production?
-The energy left stored in the consumers biomass and is available for the next trophic level
What is the equation for net production (N)?
N=I-(F+R)
I=Chemical energy in ingested food
F=Chemical energy lost in faeces and urine
R=Energy lost through respiration
What is the equation for % efficiency of energy transfer?
net production of trophic level/net production of previous trophic level x 100
What is a trophic level?
-Each of the stages in a food chain
What is the role of saprobionts?
-Feed on the remains of dead plants and animals on their waste products
-Secrete enzymes and digest food externally and absorb the nutrients they need
What is mycorrhizae?
-When fungi form a symbiotic relationship with the roots of plants
-Hyphae connect to a plants roots and greatly increase their surface area so that they can absorb more nutrients
Occurring during the nitrogen cycle, what is nitrogen fixation?
-When nitrogen gas in the atmosphere is turned into nitrogen-containing compounds
Occurring during the nitrogen cycle, what is ammonification?
-When nitrogen compounds from dead organisms are turned into ammonia by saprobionts, which goes on to form ammonium ions
What is nitrification?
-When ammonium ions in the soil are changed into nitrogen compounds that can be used by plants (nitrates)
What is denitrification?
-When nitrates in the soil are converted into nitrogen gas by denitrifying bacteria-they use nitrates in the soil to carry out respiration and produce nitrogen gas
Describe the phosphorus cycle
-Phosphate ions in rocks are released into soil by weathering
-Phosphate ions are taken into plants through roots
-Phosphate ions are transferred through the food chain
-Phosphate ions are lost from animals in waste products
-Saprobionts break down dead plants and animals, releasing phosphates into soil for assimilation
-Weathering of rocks releases phosphates into seas, lakes and rives, these are taken up by aquatic producers
-Waste produced by sea birds (guano) contains lots of phosphate ions
What are artificial fertilisers?
-Inorganic
-Contain pure chemicals as powders or pellets
What are natural fertilisers?
-Organic matter
-Manure, composted vegetables, crop residues and sewage sludge
What is eutrophication?
-Mineral ions leached from fertilised fields stimulate rapid growth of algae
-Large amounts of algae block light from reaching plants below
-Plants die as they can’t photosynthesise enough
-Bacteria feed on dead plant matter, increased bacteria reduce O2 concentration in water
-Fish and other aquatic animals die as their isn’t enough oxygen
