Earth as a Living System

Ecosystem Functions and Ecosystem Services

4 Main Systems

• Lithosphere• Hydrosphere• Atmosphere• Biosphere

The Elements

• Biogeochemcial (element) cycles

Carbon (C )Oxygen (O)Hydrogen (H)Nitrogen (N)Phosphorus (P) Potassium (K)Sulfur (S)Calcium (Ca)Sodium (Na)

Magnesium (Mg)Manganese (Mn)Molybdenum (Mo)Cobalt (Co)Zinc (Zn)Aluminum (Al)Copper (Cu)Iron (Fe)others

Carbon (C)

Fig 5.5

© 2005 John Wiley and Sons Publishers

The Geologic Cycle

• The Geologic Cycle:– The processes responsible for formation and

change of Earth materials– Best described as a group of cycles:

• Tectonic• Hydrologic• Rock• Biogeochemical

Tectonic Cycle

• Tectonic cycle:– Involves creation and destruction of the solid

outer layer of Earth, the lithosphere

The Hydrologic Cycle

• The Hydrologic Cycle:– The transfer of water from the oceans to the

atmosphere to the land and back to the oceans. Includes:

• Evaporation of water from the oceans• Precipitation on land• Evaporation from land• Runoff from streams, rivers, and sub-surface

groundwater

The Rock Cycle

• The rock cycle:– Numerous processes that produce rocks and

soils– Depends on other cycles:

• tectonic cycle for energy • Hydrologic cycle for water

– Rock is classified as • Igneous (granite)• Sedimentary (sandstone)• Metamorphic (marble)

Biogeochemical Cycles and Life:Limiting Factors

• Macronutrients– Elements required in large amounts by all life– Include the “big six” elements that form the

fundamental building blocks of life:carbon oxygen

hydrogen phosphorusnitrogen sulfur

• Limiting factor– When chemical elements are not available at the right

times, in the right amounts, and in the right concentrations relative to each other

Fig 5.6

© 2005 John Wiley and Sons Publishers

Biosphere central to movement

The carbon cycle

Basic Carbon Facts

• Key element of life

• In its reduced form as organic c comprises 45 – 50% of the mass of all plants and animals

• Found as:• Elemental carbon (in lithosphere)• As organic carbon (e.g. C6H12O6)• As inorganic carbon

– Gaseous CO2, CO– Dissolved as HCO3, H2CO3– Carbonite minerals as FECO3, CO3, CaCO3

The carbon cycle

Atmosphere

• CO2, CH4, CO

• CO2, greenhouse gas

• Mauna Loa Curve

The Mauna Loa Curve

• During winter in the northern hemisphere, photosynthesis ceases when many plants lose their leaves, but respiration continues.

• At spring, photosynthesis resumes and atmospheric CO2 concentrations are reduced.

Terrestrial Biosphere

• Phytosphere– Trees, grass, leafs– Photosynthesis– Aerobic respiration

• GPP is around twice the size of NPP• Daily cycles, annual cycles

– Deforestation and land-use

• Soils– Upper layers

• Litter from plants, decay, becomes humus, some released as gas, or enters the ocean or waters

Vegetation

Photosynthesis:

energy (sunlight) + 6CO2 + H2O =>C6H12O6 + 6O2

Respiration:

C6H12O6 (organic matter) + 6O2 => 6CO2 + 6 H2O + energy

Hydrosphere

• Surface ocean– Organic form as plants algae– Inorganic as calcerous or HCO3

Movement• To atmosphere through diffusion, carbon partial

pressure• Photosynthesis from marine biota• Erosion• Uppwelling of cold deep water

Fig 5.16

© 2005 John Wiley and Sons Publishers

Deep Ocean

Form:– Organic form as plants algae– Inorganic as calcerous or HCO3

• Movement– Downwelling of warmer surface waters– Biopump (10%)

Lithosphere

• Crust, rocks, stones

• Movement:– Sedimentation– Erosion and ?

The Missing Carbon

• 1,9 gigatonnes carbon released from human activities are unaccounted for

• Evidence points to higher sequestration by land mass somehow than anticipated

• NASA, LANDSAT, MODIS

• Remote sensing

The carbon cycle

The Phosphorus Cycle

• The phosphorus cycle:– Involves the movement of phosphorus

throughout the biosphere and lithosphere– Important because phosphorus is an essential

element for life and often is a limiting nutrient for plant growth.

Fig 5.20

© 2005 John Wiley and Sons Publishers

The Nitrogen Cycle

• The nitrogen cycle:– Cycle responsible for moving important nitrogen

components through the biosphere and other Earth systems

– Extremely important because nitrogen is required by all living things

• Nitrogen fixation:– The process of converting inorganic, molecular

nitrogen in the atmosphere to ammonia or nitrate• Denitrification:

– The process of releasing fixed nitrogen back to molecular nitrogen

Fig 5.19

© 2005 John Wiley and Sons Publishers

Earth as a Living System

Earth itself a system of biological communities

• Biota:– All the organisms of all

species living in an area or region up to and including the biosphere

• Biosphere:1. That part of a planet

where life exists2. The planetary system

that includes and sustains life

Ecosystem

• Ecosystem:– A community of organisms and its local

nonliving environment in which matter (chemical elements) cycles and energy flows.

– Life sustained by interactions of many different organisms, functioning together, and interacting through their physical and chemical environment

– Inherently complex

Basic Characteristics of Ecosystems

• Structure – Living (Ecological Communities) – Hierarchical interactions– Non-living (physical/chemical environment)

• Processes– Cycling of chemical elements – important and complex

• Inflows, recycling, no waste in nature, interactions• Food webs

– Flow of energy• Between tropic levels

• Change– Evolution– Succession

The Community Effect

• Population: group of individuals belonging to the same species living in the same area

• Species interact directly and indirectly– Symbiosis– Competition– Predator prey

Community level interactions

• Community-level interactions– Generalists vs specialists– Niches

• Keystone species– Have large effects on it’s community or ecosystem– Its removal changes the basic nature of the

community– Ex. Sea otter

• Holistic View Needed

Change

• Evolution – change in genetic material

• Succession– The sequential change in the relative

abundances of the dominant species in a biological community converging to a climax state

Change

• Stages of Succession– Early: plants typically small with short lifecycles

(annuals…), rapid seed dispersal, environmental stabilizers.r selected, generalists

– Middle: plants typically longer lived, slower seed dispersal, and in woodland systems: larger.

– Late: plants and animal species are those associated with older, more mature ecosystem. K-selected species, niches

– “Climax”? - followed by a disturbance

Resiliency

• An ecosystem is resilient if it can maintain its functional integrity when subjected to some disturbance– Property of the system

• How to maintain?– Threshold– Keystone species– Diversity

Evolution

• The process of change over time• Biological evolution

– Change in the genetic material via– Mutations– Genetic drift– Natural selection

• Genotypes• Phenotypes

– Survival of the fittest– “fittest”?

Co-evolution

• One species is affected by the evolution of another species

• A species is affected by change in the environment

• Coevolution between environment and the economy– Insitutions e.g.

• Can you think of any examples of coevolution?

Ecosystem functions - services

Ecosystem Functions/Services

• Are the conditions and processes through which natural ecosystems and the species that make them up, sustain and fulfill human life.

• Biophysical necessities for human life provided by natural ecosystems

• Functions provide goods and services• Currently threatened by most human activities• Important (but new) conservation tool

Ecosystem functions/services

• Cover a wide range of processes and scales– Global scale

• Carbon sequestration• Global warming

– Landscape scale• Water purification• Erosion prevention

– Community scale• Crop pollination• Pest control

– Field, plot or individual person scale• Local nutrient levels • Disease and pest prevention

Ecosystem Functions and services

• Complex

• Dynamic

• Interact

• Multiple within an ecosystem

MEA approach - Ecosystem Services

Consequences of ecosystem change for human well-being

Step 1: Classification of Services

A) The MEA approach– Supporting– Provisioning– Regulating– Cultural

B) de Groot et al.– Regulation functions– Habitat functions– Production functions– Information functions

C) Goulder and Kennedy– Provision of production inputs (inputs from environment)– Sustaining plant and animal life (life support services)– Provision of existence value (Amenity services)– Provision of option value (future services)

The MEA Approach

1. Supporting– Nutrient cycling– Soil formation– Primary production

2. Provisioning– Food– Wood– Fresh water– Fuel

The MEA Approach

3. Regulating• Climate regulation• Flood prevention• Disease prevention• Water purification

4. Cultural• Aesthetic• Spiritual• Recreational• Educational

Groot et al. approach – classifying functions

1.Regulation functions – Maintenance of essential ecological processes and life support systems.

– gas regulation (UVB regulation, climate, air quality)– climate regulation (maintaining favorable climate)– disturbance prevention (Storm prevention, flood prevention)– water regulation (drainage, natural irrigation)– water supply (provision of water for consumptive use)– soil retention (maintenance of arable land)– soil formation (maintenance of productivity)– nutrient regulation (maintenance of healthy soils)– waste treatment (pollution control – detox)– Pollination (pollination of crops)– biological control (control of pests and diseases)

Ecosystem Functions - Services

2. Habitat functions– i. Refugium function (maintaining

harvested species)– ii. Nursery function

3. Production services– i. food – conversion of solar energy into

edible plants and animals, food and energy– ii. raw materials– iii.genetic resources (drugs and pharmaceuticals)– iv.medicinal resources (drugs and pharmaceuticals – and

others)– v. Ornamental resources (resources for

fashion, etc)

Ecosystem Functions - Services

4. Information functions– i. Aesthetic value (enjoyment of scenery)– ii. Recreation (travel to natural

ecosystems)– iii.Cultural and artistic information (use of nature as a

motive)– iv.Spiritual and historic information (use for religious

purpose)– v. Science and education (use for schools)

Step 2: identification

• Identify what species and processes are required to perform each service– Depends on the ecosystem– Scale issues– Separability

Step 3 Valuation

• Value the importance of those services using economic evaluation– E.g. the value of carbon sequestration– Different methods for different services