Ecosystem 2

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Ecosystem (2)
Dr. Yi-Ching Chen Dept. of Environmental Engineer
ing Dayeh University

• Special Topics on Environmental Engineering (I)

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Definition of Ecosystem (1/8)

• An ecosystem is a natural unit consisting of all
  plants, animals and microorganisms in an area
  functioning together with all the non-living
  physical factors of the environment.

A coral reef near the Hawaiian islands is an
example of a complex marine ecosystem.
The Daintree Rainforest in Queensland, Australia.
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Definition of Ecosystem (2/8)

• An ecosystem is a dynamic and complex whole,
  interacting as an ecological unit. Some consider
  this the basic unit in ecology a structured
  functional unit in equilibrium, characterized by
  energy and matter flows between its constituent
  elements.
• The size of an ecosystem can vary widely.
  Different ecosystems are often separated by
  geographical barriers, like deserts, mountains or
  oceans, or are isolated otherwise, like lakes or
  rivers. As these borders are never rigid,
  ecosystems tend to blend into each other. As a
  result, the whole earth can be seen as a single
  ecosystem, or a lake can be divided into several
  ecosystems, depending on the scale used.

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Definition of Ecosystem (3/8)

• Most of us are confused when it comes to the
  words ecosystem and biome.  What's the
  difference? 
• There is a slight difference between the two
  words. 
• An ecosystem is much smaller than a biome. 
  Conversely, a biome can be thought of many
  similar ecosystems throughout the world grouped
  together. 
• An ecosystem can be as large as the Sahara
  Desert, or as small as a puddle or vernal pool. 

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Definition of Ecosystem (4/8)
Grasslands in the Great Sand Dunes National
Monument and Preserve

• Biomes
• Tropical Rainforests
• Savannas ?????
• Deserts
• Temperate Grasslands
• Temperate Deciduous Forests
• Coniferous Forests
• Arctic Tundra

Prairie Creek Redwoods State Park
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Definition of Ecosystem (5/8)

• Aquatic Ecosystems
• Freshwater
• Flowing Water
• Lakes
• Wetlands
• Estuaries
• Oceans
• Intertidal or littoral
• Coastal or neritic
• Coral Reefs
• Open Ocean
• Benthic

Coral Reefs are a rich, diverse and productive
ecosystems
A coastal wetland on Lake Superior, Wisconsin.
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Definition of Ecosystem (6/8)

• Managing Ecosystems means understanding and
  working with the
• Biological organisms
• Physical properties
• Functional processes

Species are the different kinds of organisms
found on the Earth.
A population comprises all the individuals of a
given species in a specific area or region at a
certain time.
Community refers to all the populations in a
specific area or region at a certain time.
Ecosystems are dynamic entities composed of the
biological community and the abiotic environment.
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Definition of Ecosystem (7/8)

• This figure depicts the strength of linkages
  between categories of ecosystem services and
  components of human well-being that are commonly
  encountered, and includes indications of the
  extent to which it is possible for socioeconomic
  factors to mediate the linkage.

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Definition of Ecosystem (8/8)

• Ecosystem ecology is the integrated study of
  biotic and abiotic components of ecosystems and
  their interactions within an ecosystem framework.
  This science examines how ecosystems work and
  relates this to their components such as
  chemicals, bedrock, soil, plants, and animals.
• A major focus of ecosystem ecology is on
  functional processes, ecological mechanisms that
  maintain the structure and services produced by
  ecosystems. These include primary productivity
  (production of biomass), decomposition, and
  trophic interactions.

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Food Webs (1/3)

• A food web is a model that shows all the possible
  feeding relationships between organisms living in
  an ecosystem.
• A food web is actually several food chains joined
  together.
• Organisms can be classified as producers first,
  second, or third order consumers or decomposers.
  

Herbivores eat only plants, Carnivores eat
only meat, and Omnivores eat both plants and
meat.
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Food Webs (2/3)
Food Chains clover ---gt worm ----gt robin ---gt
mosquitoes clover ---gt worm ----gt raccoon clover
---gt groundhog ---gt mosquitoes alder ----gt
white-tailed deer ---gt mosquitoes
Food webs
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Food Webs (3/3)
Example of Marine food webs
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Trophic Level (1/5)

• The trophic level of an organism is its position
  in a food chain, the sequence of consumption and
  energy transfer through the environment.
• In ecology, the trophic level is the position
  that an organism occupies in a food chain - what
  it eats, and what eats it.
• Levels are numbered according to how far
  particular organisms are along the chain from the
  primary producers plants at level 1, to
  herbivores (level 2), to predators (level 3), to
  carnivores or top carnivores (level 4 or 5).

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Trophic Level (2/5)

• The conversion of light energy to chemical energy
  is called gross primary production.
  (photosynthesis)
• Plants use the energy captured in photosynthesis
  for maintenance and growth.
• The energy that is accumulated in plant biomass
  is called net primary production.

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Trophic Level (3/5)
Number pyramid
Biomass pyramid
Energy pyramid
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Trophic Level (4/5)

• The Trophic Level Index (TLI) is an indicator of
  lake water quality. Four parameters are combined
  to construct the TLI total nitrogen (TN), total
  phosphorus (TP), clarity (SD) and chlorophyll a
  (Chla). 
• The parameters reflect the dynamics of the annual
  lake cycle.
• Nitrogen and phosphorus are essential plant
  nutrients. Chlorophyll a is the green pigment in
  plants used for photosynthesis.
• Algae are a natural part of any lake system, but
  large amounts of algae decrease water clarity,
  make the water look green, can form surface
  scums, reduce dissolved oxygen levels, can alter
  pH levels, and can produce unpleasant tastes and
  smells.

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Trophic Level (5/5)

• TLn -3.61 3.01 log (TN)
• TLp 0.218 2.92 log(TP)
• TLs 5.10 2.27 log(1/SD - 1/40)
• TLc 2.22 2.54 log(Chla)
• TLI ?(TLn TLp TLs TLc)/4 

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Biogeochemical Cycles

• Cycling of materials between the environment and
  organisms.
• Chemical and biological processes.
• Examples
• Water cycle (Hydrological cycle)
• Carbon cycle
• Nitrogen cycle
• Phosphorus cycle

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Water Cycle
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Carbon Cycle (1/9)

• In fact, carbon constitutes the very definition
  of life, as its presence or absence helps define
  whether a molecule is considered to be organic or
  inorganic.
• Every organism on Earth needs carbon either for
  structure, energy, or, as in the case of humans,
  for both.
• Carbon is found in forms as diverse as the gas
  carbon dioxide (CO2), and in solids like
  limestone (CaCO3), wood, plastic, diamonds, and
  graphite.

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Carbon Pools
Carbon Cycle (2/9)

• Carbon is stored on our planet in the following
  major pools
• as organic molecules in living and dead organisms
  found in the biosphere
• as the gas carbon dioxide in the atmosphere
• as organic matter in soils
• in the lithosphere as fossil fuels and
  sedimentary rock deposits such as limestone,
  dolomite and chalk
• in the oceans as dissolved atmospheric carbon
  dioxide and as calcium carbonate shells in marine
  organisms.

2/12
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Carbon Cycle (3/9)

• The movement of carbon, in its many forms,
  between the atmosphere, oceans, biosphere, and
  geosphere is described by the carbon cycle.

Carbon is exchanged between the active pools due
to various processes photosynthesis and
respiration between the land and the atmosphere,
and diffusion between the ocean and the
atmosphere.
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Carbon Cycle (4/9)
The global carbon cycle, one of the major
biogeochemical cycles, can be divided into
geological and biological components. The
geological carbon cycle operates on a time scale
of millions of years, whereas the biological
carbon cycle operates on a time scale of days to
thousands of years.
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Carbon Cycle (5/9)

• Carbon Cycle - Photosynthesis
• The simplified version of this chemical
  reaction is to utilize carbon dioxide molecules
  from the air and water molecules and the energy
  from the sun to produce a simple sugar such as
  glucose and oxygen molecules as a by product.

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Carbon Cycle (6/9)

• Carbon Cycle - Combustion/Metabolism Reaction
• Combustion occurs when any organic material
  is reacted (burned) in the presence of oxygen to
  give off the products of carbon dioxide and water
  and ENERGY.
• For metabolism, in the cells,
• a series of complex reactions
• occurs with oxygen to convert
• for example glucose sugar into
• the products of carbon dioxide
• and water and ENERGY.

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Carbon Cycle (7/9)

• Carbon Cycle - Sedimentation
• As the shelled organisms die, bits and
  pieces of the shells fall to the bottom of the
  oceans and accumulate as sediments. The carbonate
  sediments are constantly being formed and
  redissolved in the depths
• of the oceans.

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Carbon Cycle (8/9)

• Human Impacts on the Carbon Cycle - Fossil Fuels
• Humans impact the carbon cycle during the
  combustion of any type of fossil fuel, which may
  include oil, coal, or natural gas. During
  combustion in the presence of air (oxygen),
  carbon dioxide and water
• molecules are released
• into the atmosphere.

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Carbon Cycle (9/9)

• Human Impacts on the Carbon Cycle - Fossil Fuels

The Keeling curve
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O2 Cycle

• Important Processes
• -photosynthesis, respiration
• -air-water gas exchange, mixing, circulation
• Photosynthesis
• CO2 2H2O light ?CH2O O2
• Respiration
• H2O O2 CH2O ? CO2 2H2O

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Photosynthesis (1/3)

• The conversion of light energy into chemical
  energy by living organisms. The raw materials are
  carbon dioxide and water, the energy source is
  sunlight, and the end-products include glucose
  and oxygen.
• Photosynthesis occurs in two stages
• In the first phase light-dependent reactions
  or photosynthetic reactions (also called the
  Light reactions) capture the energy of light and
  use it to make high-energy molecules.
• During the second phase, the
  light-independent reactions (also called the
  Calvin-Benson Cycle, and formerly known as the
  Dark Reactions) use the high-energy molecules to
  capture carbon dioxide (CO2) and make the
  precursors of carbohydrates.

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Two Step Photosynthesis Model in a Leaf
Photosynthesis (2/3)
Step 1
Step 2
CO2
CO2 aq
CO2 ext
CO2 int
C6H12O6
Inside Leaf
Air
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Photosynthesis (3/3)

• Chlorophyll is the molecule that traps this 'most
  elusive of all powers' - and is called a
  photoreceptor. It is found in the chloroplasts of
  green plants, and is what makes green plants,
  green.

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Respiration (1/2)

• In animal physiology, respiration is the
  transport of oxygen from the ambient air to the
  tissue cells and the transport of carbon dioxide
  in the opposite direction.
• Cellular respiration the metabolic process by
  which an organism obtains energy by reacting
  oxygen with glucose to give water, carbon dioxide
  and ATP (energy).
• In unicellular organisms, simple diffusion is
  sufficient for gas exchange every cell is
  constantly bathed in the external environment,
  with only a short distance for gases to flow
  across.

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Respiration (2/2)

• Aerobic Respiration is the normal form of
  respiration. It requires oxygen and releases the
  most energy from glucose. 1Mole of Glucose
  produces 2830 Kilojoules of energy.
• Anaerobic Respiration also releases energy from
  glucose but not so much I mole of glucose will
  produce 118 Kilojoules of energy.

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Nitrogen Cycle (1/8)

• Nitrogen (N) is an essential component of DNA,
  RNA, and proteins, the building blocks of life.
• Most of the nitrogen (N2 ) in the atmosphere is
  unavailable for use by organisms. This is because
  the strong triple bond between the N atoms in N2
  molecules makes it relatively inert.
• In order for plants and animals to be able to use
  nitrogen, N2 gas must first be converted to more
  a chemically available form such as ammonium
  (NH4), nitrate (NO3-) , or organic nitrogen
  (e.g. urea - (NH3)2CO).

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Nitrogen Cycle (2/8)

• Nitrogen is an incredibly versatile element,
  existing in both inorganic and organic forms as
  well as many different oxidation states.

• Yellow arrows indicate human sources of nitrogen
  to the environment.
• Red arrows indicate microbial transformations of
  nitrogen.
• Blue arrows indicate physical forces acting on
  nitrogen.
• Green arrows indicate natural, non-microbial
  processes affecting the form and fate of
  nitrogen.

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Nitrogen Cycle (3/8)
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Nitrogen Cycle (4/8)

• Five main processes cycle nitrogen through the
  biosphere, atmosphere, and geosphere
• nitrogen fixation, nitrogen uptake
  (organismal growth), nitrogen mineralization
  (decay), nitrification, and denitrification.
• Microorganisms, particularly bacteria, play major
  roles in all of the principal nitrogen
  transformations. As microbially mediated
  processes, these nitrogen transformations tend to
  occur faster than geological processes like plate
  motion, a very slow, purely physical process that
  is a part of the carbon cycle.

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Nitrogen Cycle (5/8)

• Nitrogen Fixation N2 ?NH4 (ammonium)
• Nitrogen Uptake NH4 ? Organic N
• Nitrogen Mineralization Organic N ? NH4
• Nitrification NH4 ? NO3- (nitrates)
• DenitrificationNO3- ? N2 N2O
• Denitrification is an anaerobic process that
  is carried out by denitrifying bacteria.

NO3- (nitrates) ?   NO2- (nitrites) ?   NO ?
N2O (nitrous oxide) ?   N2
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Nitrogen Cycle (6/8)
Nitrogen States
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Nitrogen Cycle (7/8)
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Nitrogen Cycle (8/8)
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Biodiversity (1/3)

• Biodiversity is the variation of taxonomic life
  forms within a given ecosystem, biome or for the
  entire Earth. Biodiversity is often used as a
  measure of the health of biological systems.
• Variation of life at all levels of biological
  organization" .
• Biodiversity is often used as a measure of the
  health of biological systems.

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Biodiversity (2/3)

• Another definition that is often used by
  ecologists is the "totality of genes, species,
  and ecosystems of a region".
• genetic diversity - diversity of genes within a
  species. There is a genetic variability among the
  populations and the individuals of the same
  species.
• species diversity - diversity among species in an
  ecosystem. "Biodiversity hotspots" are excellent
  examples of species diversity.
• ecosystem diversity - diversity at a higher level
  of organization, the ecosystem. To do with the
  variety of ecosystems on Earth.

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Biodiversity (3/3)

• Biodiversity is usually plotted as taxonomic
  richness of a geographic area, with some
  reference to a temporal scale. Whittaker(1972)
  described three common metrics used to measure
  species-level biodiversity, encompassing
  attention to species richness or species
  evenness
• (1) Species richness
• (2) Simpson index
• (3) Shannon index

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Species richness (1/2)

• The simplest measure of biodiversity and is
  simply a count of the number of different species
  in a given area.
• Species richness is also one level of
  biodiversity known as alpha-diversity.
• High species richness for a given area denotes a
  high level of redundancy in ecosystem function,
  which further denotes the ecosystems ability to
  withstand natural disturbances by the natural
  world or man.
• It is represented in equation form as S.

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Species richness (2/2)

• In order to account for the probability of
  missing some of the actual total number of
  species present in any count based on a sample
  population, the Jackknife estimate may be
  employed
• (1) Snk(n-1)/n where S species richness
• n total number of species present in
  sample population
• k number of "unique" species (of which
  only one organism was found in sample population)
  
• or (2) S E k(n-1)/n where E the
  summation of number of species in each sample

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Simpson index (1/2)

• In ecology, it is often used to quantify the
  biodiversity of a habitat. It takes into account
  the number of species present, as well as the
  relative abundance of each species.
• The Simpson index represents the probability that
  two randomly selected individuals in the habitat
  belong to the same species.
• It is represented in equation form as D.

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Simpson index (2/2)

• The formula for the Simpson index is
• Where S is the number of species, N is the
  total percentage cover or total number of
  organisms and n is the percentage cover of a
  species or number of organisms of a species.

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Shannon index (1/2)

• It is one of several diversity indices used to
  measure diversity in categorical data.
• It is simply the Information entropy of the
  distribution, treating species as symbols and
  their relative population sizes as the
  probability.
• It is represented in equation form as H.

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Shannon index (2/2)

• The formula for the Shannon index is
• Where S is the number of species, n is the
  number of individuals in each species the
  abundance of each species, N is the total number
  of all individuals, Sni and p is the relative
  abundance of each species, calculated as the
  proportion of individuals of a given species to
  the total number of individuals in the community,
  ni/N .

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Threatened ecological communities (1/2)

• Threatened species are any species (including
  animals, plants, fungi, insects, bugs, etc.)
  which are vulnerable to extinction in the near
  future.
• The World Conservation Union (IUCN) is the
  foremost authority on threatened species, and
  treats threatened species not as a single
  category. Threatened species are also referred to
  as a red-listed species.
• A Biodiversity Action Plan (BAP) is an
  internationally recognized program addressing
  threatened species and habitats, which is
  designed to protect and restore biological
  systems.

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Threatened ecological communities (2/2)

• Critically EndangeredIf, at that time, it is
  facing an extremely high risk of extinction in
  the wild in the immediate future.
• EndangeredIf, at that time, it is not critically
  endangered and is facing a very high risk of
  extinction in the wild in the near future.
• VulnerableIf, at that time, it is not critically
  endangered or endangered, and is facing a high
  risk of extinction in the wild in the medium-term
  future.