4.4- water cycle, nitrogen cycle and phosphorus cycle

3 main processes of water cycle

-evaporation

-condensation

-percipitation

evaporation

heat from sun causes water at earth's surface to evaporate

condensation

as warm air rises, it cools and condenses, forming clouds (gas turning to liquid form)

precipitation

water falls back to earths surface when it rains or snows

-rain, snow, hail

run-off

after the water fall back from earth the run-off is when water moves downhill back into ocean water due to gravity

water moves through biosphere by ...

transpiration

transpiration

process where water is absorbed by the roots of plants then lose water through small pores in the leaves

water pollution

physical, biological or chemical change in water that has a bad effect on organisms or makes water unsuitable for desired uses

sources of pollution (2)

point sources and non-point sources

point source

-easy to monitor and regulate

ex. factories, power plant, oil wells, sewage treatment plants

non-point source

-difficult to monitor, regulate and treat since pollution is periodic

ex. run-off from farms, lawns, construction sites, parking lots

organisms magnify water pollutants

-pollutants that dont degrade easily stay in the environment for a long time

-ex. DDT pesticide, heavy metals (mercury) PCBs in plastic

which ones are banned in canada

-DDT and PCBs

-when they enter the water, microscopic organisms like phytoplankton take them up and collect in their cells and tissue

bioaccumulation

the process by which pollutants collect in the cells and tissues of organisms

biomagnification

the increase in concentration of pollutants in tissues of organisms that are at successively higher levels in a food chain or food web

carbon cycle

-carbon dioxide move from atmosphere to biosphere thru photosyn and cell resp, where plants take it in

-animals eat the plants, absobring the carbon into their bodies

-carbon moves back to atmosphere thru respiration (plants and animals release carbon dioxide) when organisms die and decompose

-carbon enters geosphere where remains of organisms are trapped under sediment layers. hen humans burn fossil fuels, it leads to global warming since nature cant absorb fast enough

carbon is not always used immediately

-stored in tissue of trees

-stored in decomposing remains of organisms buried deep in ground (overtime the stored carbon transfoms into carbon rich fossil fuels

how can this upset balance

humans upset this by burning fossil fuels and deforestation

-burning fossil fuels (coal, oil, natural gas) release huge amounts of carbon dioxide into the atmosphere. this greenhouse gas contributes to global warming and climate change

-cutting down trees releases stored carbon into the atmosphere as carbon dioxide

global warming

increase in average temp of earths surface

global climate change

a long term change in earths climate

-can be caused by natural factors or human activity

natural factors

-variations in greenhouse gas

-changes in ocean and atmospheric circulation

-changes in earths orbit

human activity

increase in greenhouse gases due to burning of fossil fuels

effects of excess carbon in cycle

earths surface temp: increased by between 0.56 degress and 0.92 degress in past 100 years

-this "small'' change can affect all conditions in all of earths sphere

also melting sea and land ice

example from warmer temp

-land and sea ice melts = sea level rises = coastal flooding occurs

-warmer seawater absorbs more dioxide = seawater becomes acidic = coral reefs and other ecosystems are harmed

-xtreme weather events increase = more heat waves = human illness and deaths occur

melting sea and land ice

-this lead to destruction of habitats for polar organisms, increased local flooding and release of metahnce gas (greenhouse gas) from melting permafrost

rising sea level

-some islands have gone underwater

-salt water get into the drinking water supply

-coastal flooding and destrcution of wetlands

changing ocean chemistry

-ocean becomes more acidic cu it absorbs more dioxide from air

-an acidic and warming ocean can destroy coral reefs since it dissolves the organism's shells

nitrogen cycle

-is a nutrient that cells need to build proteins

-it makes up 78% of air, but organisms cant use this form of nitrogen

-nitrogen-fixing bacteria in soil and water change nitrogen into forms that plants can use

excess nitrogen (overgrowth of algae)

-due to human activities

-burning of fossil fuels (emits nitrogen oxide gas)

-clearing of forests and grasslands

-fertilizer use

fertilizer use

-contain nitrates

-not all is used by plants, some stay in soil

-excess nitrogen in fertilizer gets carried into auwatic ecosystems when it rains

-nitrogen in waterways leads to an overgrowhtof algae (algal boom) since there is too much of the nutrient

-the algae blocks the sunlight from reaching organisms in deep water

phosphorus cycle

-a nutrient essential for growth and development of organisms

-stored in geosphere

-when rock is broken down through weathering, its released into soil + water

-plants absorb phos and animals obtain when they eat plants and animals

-decomposers return phos to soil and water as they break down dead organisms

excess phos (overgrowth of algae)

-due to human activities

-found in dishwashing and laundry detergents

-fertilizer use

fertilizer use (phos)

-similar to nitrogen, phos in run-off from agricultural fields lead to overgrowth of algae

-algae blocks sunlight from deepwater and die