Energy flow in ecosystems Flashcards
What did Ciais et al find?
There was a 30% reduction in primary production during the 2003 heatwave and this could be explained by the reduction in evapotranspiration and reduced water uptake by plants. Leaf area index also reduced with temperature rise as they shrivelled up. These temperatures could result i n carbon sinks becoming carbon sources. However, this was only data from 1 year.
What are the laws of thermodynamiccs?
First law - energy can be converted from one form to another but cannot be created or destroyed.
Second law - in closed systems energy may dissipate.
What are the levels in the food chain?
Primary producers, primary consumers, secondary consumers, tertiary consumers, quanternary consumer
What are food webs effected by?
Species richness, ecosystem productivity and stability.
What effects ecological pyramids?
Energy is lost due to respiration, decomposition, unused food, excretion and growth and immigration.
What is Lindemans Law?
The trophic transfer efficiency is 10%
What is biomass?
The mass of organisms per unit area
What is standing crop?
Bodies of living organic biomass within a unit area
What is necromass?
Dead material which is inactive within biomass.
What is primary production?
Synthesis of organic compounds by autotrophs.
What is gross primary production?
The total amount of dry matter made by a plant in photosynthesis.
What is net primary productivity?
The overall gain of matter made during photosynthesis.
Why is primary production important?
It helps to understand the health of an area, look at the maximum sustainable yield, it can be used to look at how many trees can be cut down and how carbon levels can be reduced.
What factors affect net primary production?
Weather - in winter there is less
solar radiation - it increases PP
Leaf area index - higher surface area increases PP
Temperature - optimum between 16 and 25
Water and nutrient availability - Lower NPP in swamps
Growing season - longer increases PP
Pollution - Increased pollution may effect the absorbantion ability of the leaf.
What is primary production like in beech trees compared to Norway Spruce?
Norway spruce has a longer growing seasons due to solution within the leaf which means they can function at lower temperature and so they have higher primary productivity, eventhough beech trees have bigger leaves.
