environmental issues
-Ecosystem: A dynamic complex of plant, animal and micro-organism communities
and their non-living environment interacting as a functional unit
•Ecosystem is also the network of interactions among the living and non-living
elements of the system.
•Research on these interactions networks showed the need to consider ecosystems
as a whole when studying nature
•The SCIENCE behind this studies is called ECOLOGY
•ECOLOGY is not a political option, neither is an etical approach to nature or social
movement
•Ecosystems have Self-organization.
•Their complexity increases without any external drive
•Higher complexity means higher resilience
-Scale in Ecosystem:
•Scale is important when dealing with complex systems
•We can find systems nested in larger ones
•Each on these leves usually have their own properties, and are usually related
through feedback relationships
•Complex system management (Conservation) should always be addressed at
different scales simultaneously
-Food chain:
•Linear network of links among different organisms showing how they are related
with each other by the food they eat
•Food chains start with producers (use radiation from the sun to make their food),
and ends at apex predators.
•Include detritivores (Earthworms) and/or decomposer species (bacteria, fungi)
• Each step is a Trophic Level
-Food web:
Energy comes from the Sun
Each step loses about 90% of the energy.
This energy loss restricts the amount of trophic steps and system complexity
A food web is a natural interconnection of food chains showing what-eats-what in
an ecological community
•It should also include non-living elements of the ecosystem
Biogeochemical cycles
-Socio-ecological- system: for human well being
An ecosystem, the management of this ecosystem by actors and organizations, and
the rules, social norms, and conventions underlying this Management
•The well-being of people all over the world, depends on the goods and services
provided by ecosystems
•Ecosystems need to be healthy to provide those goods and services
•However, most ecosystems are under pressure and overexploited
•We need a strategy for the integrated management of land, water and living
resources that places human needs at its centre.
•Management options:
–Hands off
–Adaptative management
–Natural resource management
–Command and control
–others
-Think BIG (Individual species- Ecosystem)
Marine Turtle:
-Problem: Longline fishing accidentally kills thousands of endangered sea turtles.
-Solution: Working with fishermen, trying and developing a different kind of hook,
developing a different kind of bait (fish, for example), changing the fishing depth
and the distance from the coast.
•How to liberate a captured marine turtle?
–They remove the hook with an indicated device.
–If that’s not possible, they cut the thread as close to the eye of the hook as they
can.
Planet Boundaries:
•These nine processes and systems regulate de stability and resilience of the Earth
System (interactions of land, ocean, atmosphere and life that provide conditions
upon which our societies depend
•Stratospheric ozone depletion.
•Loss of biosphere integrity (biodiversity loss and extinctions
•Chemical pollution and the release of novel entities
•Climate Change
•Ocean acidification
•Freshwater consumption and the global hydrological cycle
•Land system change
•Nitrogen and phosphorus flows to the biosphere and oceans
•Atmospheric aerosol loading
•Four of nine planetary boundaries have been crossed as a result of human
activity:
–Climate change
–Loss of biosphere integrity
–Land-system change
–Altered biogeochemical cycles
•Two of these, climate change and biosphere integrity, are "core boundaries".
Significantly altering either of these core boundaries would drive the Earth
System into a new state.
RESILIENCE: "the capacity of a system to absorb disturbance and reorganize while
undergoing change so as to still retain essentially the same function, structure,
identity, and feedbacks
•Ecosystem’s stability and capability of tolerating disturbance and restoring itself.
•If the disturbance is of enough magnitude or duration, a threshold may be
reached where the ecosystem undergoes a regime shift, possibly permanently.
•Resilience increase with ecosystem’s complexity
Planetary boundaries:
•Planetary boundaries are resilience thresholds for the Earth.
•Crossed boundaries, take the Earth to a different state.
•Stratospheric ozone depletion.
•Loss of biosphere integrity (biodiversity loss and extinctions
•Chemical pollution and the release of novel entities
•Climate Change
•Ocean acidification
•Freshwater consumption and the global hydrological cycle
•Land system change
•Nitrogen and phosphorus flows to the biosphere and oceans
•Atmospheric aerosol loading
Anthropocene:
Age of Humans. •They listed the many impacts of human activities on the planet
including:
–Human induced carbon and sulfur emissions
–Global run-off of nitrogen fertilizers.
–Species extinctions
–Coastal habitats destruction
They declared de Holocene over and the beginning of the Anthropocene
A geologic era is a subdivision of geologic time that divides an eon into smaller
units of time
Recognizing a new era:
•These signals have to be global, and found throughout the world in different
elements:
-Gacial ice
-Tree rings
-Coral growth bands
-Sea floor and lake sediments
-Other geological structures
Anthropocene boundarie:
•The most preeminent signal of the boundary was the radioactive fallout from
thermonuclear weapons tests.
• The fallout would reach the stratosphere and be evenly distributed throughout
the world in weeks after the test
• Plutonium is very scarce, but there is a fine layer in sediments and glacial ice all
over the planet.
•Thermonuclear weapons tests started in 1952 and ended in 1964 (they are tested
underground since then)
Antrhopocene signals :
•Fossil Fuels:
–The use of fossil fuels and carbon emissions has increased sharply since 1850.
–Carbon dioxide concentration exceeds 400 parts per million.
–The highest concentration in the last 65 million years
–Shift in carbon isotopes present in any material