Energy transfer and nutrient cycles Flashcards
Biomass
mass of living material in an organism
measured as mass of carbon that an organism contains or the dry mass of its tissue per unit area (kg m⁻²)
nitrogen fixation
nitrogen gas in the atmosphere is turned into nitrogen-containing compounds e.g. ammonia
some bacteria are found in root nodules of leguminous plants + form a mutualistic relationship with plants - bacteria provide nitrogen compounds + plant provides carbohydrates
other nitrogen-fixing bacteria are found in soil
ammonification
Nitrogen compounds from dead organisms and animal waste are turned into ammonia by saprobionts, which goes on to form ammonium ions.
nitrification
ammonium ions in the soil are changed into nitrogen compounds by nitrifying bacteria that can then be used by plants (nitrates)
1 types of bacteria change ammonium ions into nitrites, then another type of bacteria change nitrites into nitrates
denitrification
nitrates in the soil are converted in to nitrogen gas by denitrifying bacteria through respiration
anaerobic conditions e.g. waterlogged soils