flux of energy and matter Flashcards
who laid the foundations of ecological energetics
linemann 1943
attempted to quantify webs by considering the efficeny of energy transfer between trophic levels
define standing crop of biomass
the bodies of living organisms in the area
define biomass
the mass or organsims per unit of ground or volume of water
define primary productivity
the rate at which biomass is produced by photosynthetic organisms
define gross primary proudctivity
the total enegry fixation
what is net primary productivity
GPP-autotrophic respiration
what limits productivity in oceans
a shortage of nutrients, high porductivity is often observed when there is upwelling of nutrient rich waters
what are the required resources for primary production
sunlight, co2, water and soil nutrients
how does temperature act as a limiting factor for productvity
has a strong influence on photosynthetic rates
how is temp and precipitation linked
high temps are associated with high evapotranspiration
how can soil texture be a limting factor
coarse soils are associated with lower nutrient retention
sandy soils are lower in nitrogen
what is primary productivity most frequently limited by
light and nutrient availability
why is productivity high in euphotic zones
there is a high nutrient input and waters are clear allowing light to pentrate
why are areas of ocean closer to land and outershelf less productive
increased turbidity closer to land
less nutrients in the outer shelf
how does an ocean upwelling occur
- wind is parallel to the coast
- water is moved offshore and is replaced with cooler nutrent rich water from the bottom
- due to this phytoplankton bloom which supports the food chain
why is iron a limiting factor in marine environments
it is insoluable and dervied from wind blown matter
how can the insertion of iron into marine envrio reduce co2
increasing iron can cause phytoplankton blooms which take in co2 from atmosphere
what is secondary productivty
the rate of production of new biomass by heterotrophic organisms
why is energy lost through trophic levels
- not all plant biomass is consumed
- not all eaten is assmilated into biomass
- excretion
what is biogeochemistry
the study of the fluxes of elements between living and non living compartments
what happens if inputs are greater than outputs
then nutrients will accumulate in lving biomass and dead organic matter
give some examples of inputs in a nutirent budget
minerals from weathering of rock and soil
atmospheric co2 and nitrogen
minerals in wetfall
human activites
give some examples of outputs in a nutrient budget
- co2 in respiration or forest fire
methan from bacterial activity in anaerobic conditions
most dissolved plant nutrients
dead organic matter
where do aquatic systems recieve most their nutrients
stream inflow
in lakes accumulation in sediments is a major export pathway
