1 - general introduction to human impacts Flashcards
how many major mass extinctions have been recognized in the Earth’s history?
5
when were the 5 major mass extinctions in the Earth’s history?
- about 450 million years ago (shortly after the evolution of the first land-based plants)
- about 350 million years ago (led to the formation of the coal forests)
- about 250 - 200 million years ago (during the Triassic period)
- 65 million years ago (the great extinction at the end of the Cretaceous Period)
extinctions per thousand species per millennium
marine defaunation
- experience less advanced than terrestrial
- due to recent industrialization of the harvesting, an era of marine wildlife decline is initiated
- if unmanaged: marine habitat alternation + climate change = marine defaunation
average declines of marine species
40-90%
Overview of human history, urban growth, development of agriculture, technology and
industry as well as corresponding links to economic growth (GDP), environmental changes and changes in land use (Modified after Costanza et al. 2007)
what’s the Anthropocene?
an era, when humans are a dominant geological force
(we have entered the Anthropocene)
Humans as a dominant geological force
- “Anthropocene” = human impacts are at least as important as natural process
- new term for new geological epoch to emphasize the central role of mankind in geology and ecology
- basic concept is that humans are now a major geological and environmental force, as important as, or more important than, natural forces
- start of this period not yet agreed, but term is widely adopted
what are changes in the atmosphere approaching? what suggestion is there?
why do we talk about the urban age?
- over half of humanity now lives in towns and cities
- by 2030 that fraction will have increased to 60 %
- Many of the global economic, social and environmental challenges have a strong urban dimension
where are the most largest cities?
- they are coastal
the UN 2030 Agenda
Paris Agreement on Climate Change
The new urban agenda - Urbanization as a tool and engine for sustainable development
when did marine resources exploitation start?
- since at least the Palaeolithic
during the Roman times marine coastal landscapes were far from pristine
what is estuarine and coastal areas degradation related to?
human population growth and impact
what about the temporal sequence of human impacts on coastal and marine ecosystems?
- the temporal sequence is distinct
(eine klare zeitliche Abfolge)
Predicted importance and direction of the different impacts
what’s, historically occurred, the oldest cause of human extinction of species?
overfishing
(MAIN HUMAN IMPACT)
impacts of fishery – direct and indirect affects
direct effect on fished species
example of direct effect on fished species
what is an effect of some fishing practices?
- damaging fishing practices have a direct effect on habitat destruction
- world oceans have been altered down to > 800 m in depth by destructive bottom trawling
- bottom trawling produces comparable effects on the deep sea floor to those generated by agricultural ploughing on land
what about indirect effects of overfishing?
- there is indirect cascading effects on ecosystems
effect of overfishing of keystone species
- alters ecosystem structure and functioning
- e.g. sea otters or oysters
impacting activities of aquaculture
pollution - how?
(MAIN HUMAN IMPACT)
- pollution from pesticides, herbicides, fertilizers and other chemicals
- urban organic pollution or from intensive farming
- thermal
- acoustic / Electromagnetic / Artificial lighting
- microplastics
pollutants entering the ocean
pollution globalisation
biomagnification
- Biomagnification is the increase in concentration of a substance, e.g a pesticide, in the tissues of organisms at successively higher levels in a food chain
- many pollutants concentrate in biological tissues along the food chain
- particular issue in marine systems because food chains are longer than on land
what are marine pollutants?
events of Petroleum hydrocarbons entering the ocean
- Exxon Valdez oil spill 1989
- 10 million gallons/ 38 million L of spilled oil
- affected 400 miles of shoreline - The Prestige sinking, 2002
- 20 million gallons of viscous fuel oil
- hundreds of miles of rugged coastline have been fouled - Persian Gulf War, 1991
- 240 million gallons of spilled oil - BP offshore drilling rig, 2010
- 200.000 gallons per day
organic enrichment and eutrophication
Global distribution of eutrophic coastal marine ecosystems (map)
what are the largest culprits (die größten Schuldigen) for pollutants entering the ocean?
Production and use of synthetic fertilizers
- since Haber-Bosch process has developed in early 20th century (Ammoniaksynthese)
- use of synthetic fertilizer has grown exponentially
what do excess nutrients lead to?
- surface water turbidity
- bottom hypoxia
Global map of hypoxic zones and OMZ’s
marine litter - plastics
(MAIN HUMAN IMPACT)
- Marine litter is human-created waste that has been discharged into the coastal or marine environment
- The term Plastic generally refers to polymers that soften on heating, and can be moulded (Plasticós = Greek for “to mold”)
global increase of plastic and micro plastic production and use
dimension and composition of plastic debris size
classification of plastic litter
classification of micro plastic
how do we fill our oceans with micro plastics?
origins are
- fibers
- granular
- plastic films
- spherules
pathway of plastic entering the oceans
plastic in the North Pacific Gyre (Nordpazifikwirbel)
- Transportation of species
- Movement of organisms to new habitats where they may harm or disturb the local ecosystem - Reaches from Japan to California, Hawaii is located near the center of the gyre.
- Water flows in a clock-wise direction
- Plastic collects on the northern edge of the gyre where water
transported by the currents builds up
Microplastics found in a range of organisms
impacts of microplastic
- physical impact
- chemical impact
indirect effects of microplastic: chemical pollution
toxic compounds in Microplastic
noise pollution (MAIN HUMAN IMPACT)
- A type of energy pollution in which distracting, irritating or damaging sounds are freely audible
- On land noise is a pervasive pollutant that directly affects the health and well-being of exposed humans and wildlife
- It can damage bridges and produce cracks in buildings.
zones of noise influence
sounds produced in the ocean may interfere with the use of sound by marine life
seismic survey
effects of seismic surveys on abundance and catch of cod and haddock
Whats ALAN?
artificial light at night
what are the reported biological effects of ALAN?
what habitats in the sea are more impacted by ALAN?
- high-shore habitats
- due to a more intense exposition to outdoor nocturnal lightings
- mostly from lamps along coastal streets and promenades,
or within harbours, ports and marinas
