ENVS10011 Lecture Notes - Lecture 1: Sea Level Rise, Ecological Footprint, Carbon Fixation
17 May 2018
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WEEK 1: INTRODUCTION
Environment: the sum of physical, chemical + biological factors that affect organisms
• Most environments are harnessed to produce goods + services
o Products: food, fibre, timber + services
Ecosystems: organisms and their abiotic environments, identifiable area/space
• Organisms:
o Producers: (primary) use photosynthesis to produce biomass
▪ Autotroph: self-feeding, fix inorganic carbon + other elements
o Consumers: animals, consume biomass
▪ Heterotroph: consume biomass to produce own biomass, need energy,
C, N, S + P
o Decomposers: soil, fungi, bacteria, decompose dead biomass, heterotrophic
Photosynthesis
• Carbon dioxide + water = sugar + oxygen (in presence of sunlight)
• Uses light energy, also called carbon fixation + assimilation
Respiration
• Glucose + oxygen = water, carbon dioxide + energy
• Degrades energy rich compounds
Productivity
• Measured in grams of biomass/time/area
• Gross Primary Productivity (GPP) = Carbon fixed in plant photosynthesis
• Net Primary Productivity (NPP) = GPP – plant respiration
o Biomass produced by plants/surface area/year
• Net Ecosystem Productivity (NEP) = NPP – heterotroph respiration
• Negative productivity: where more carbon is created than fixed (carbon source)
Human Population
• Exponential growth (compound interest equation)
• Malthius, 1798: predicted problem with providing enough food for the population
• Carrying Capacity: number of individuals of a given species that an ecosystem can
support in the long term without degrading resources
o For human populations: without degrading cultural + social environments, or
degrading resources for future generations
Finite Earth
• 40% of Earth’s NPP used by humans in 1980
• Ecological Footprint: calculation of global hectares required by each person + activity
o Crops, grazing animals, timber, fishing, infrastructure + burning fossil fuels
• Currently operating in an unsustainable mode
• Ecological Foodprint: impact of diet + lifestyle – dependent on individual
Climate Change
• Atmospheric composition: mainly nitrogen + oxygen, CO2 only plays small part – only
increasing due to human activity
• GHG: traps energy radiated back from Earth into the atmosphere
o Total anthropogenic GHG doubled between 1970 + 2014
• C.C predictions: more extreme weather events, sea level rise
Document Summary
Environment: the sum of physical, chemical + biological factors that affect organisms: most environments are harnessed to produce goods + services, products: food, fibre, timber + services. Ecosystems: organisms and their abiotic environments, identifiable area/space: organisms, producers: (primary) use photosynthesis to produce biomass, autotroph: self-feeding, fix inorganic carbon + other elements, consumers: animals, consume biomass, heterotroph: consume biomass to produce own biomass, need energy, C, n, s + p: decomposers: soil, fungi, bacteria, decompose dead biomass, heterotrophic. Photosynthesis: carbon dioxide + water = sugar + oxygen (in presence of sunlight, uses light energy, also called carbon fixation + assimilation. Respiration: glucose + oxygen = water, carbon dioxide + energy, degrades energy rich compounds.
