Unit 2 Biogeochemical cycles

module 4,5,8,9

biogeochemical cycles

movement of nutrient through ecosystems: Atmosphere, hydrosphere, lithosphere, biosphere

reservoir/ pool

material remian for varying amounts of time

source

reservoir that releases more than accepts; short residence time

Sink

accepts more materials than it releases: long residence time

humans affect on carbon cycle

1. exchange of carbon in steady rate

2. combustion of fossil fuels

3. deforestation

major carbon sinks

1. oceans

2. soils and bogs

3. forests and vegetation

Nitrogen cycle affects from humans

1. burning fossil fuels

2. animal waste

3. Haber- Bosch process

4. greenhouse gases

major nitrogen sinks

1. Atmosphere

2. soil organic

3. matter

4. living biomass

5. riparian buffers and wetlands

6. aquatic ecosystems

nitrogen fixation

converts N2 from atmosphere. Biotic processes——> N2 to Ammonia( NH3) abiotic ——> N2 nitrate( NO3)

nitrification

nitrifying bacteria is Ammonium ( NH4+) into nitrite( NO2-) and then into nitrate( NO3-)

assimilation

plants and algae take up either ammonium( NH4+) or nitrate( NO3-) herbivores assimilate nitrogen by eating plants and algae

mineralization

decomposers in soil and water break down biological nitrogen compounds into ammounium( NH4+)

denitrification

denitrifying bacteria in oxygen low soil and low water converts nitrate( No3-) into nitrous oxide( N2O) and eventually nitrogen gas( N2)

human affects on hydrologic cycle

1. deforestation, increased runoff

2. damning rivers, increased evaporation

3. pollution, changing nature of precipitation

major hydrologic sinks

1. oceans

2. glaciers

3. groundwater

4. lakes, rivers

5. atmosphere

6. living organisms

phosphorus cycle human affects

1. mining rocks

2. wastewater discharge

3. runoff— eutrophication, murky, alters function

phosphorus cycle

●Cycling is slow and tends to be local

●Leaching and weathering

●Cycled through food webs

●Bacterial decomposers

●Sedimentation and geological uplift

eutrophication

increase in nitrogen and or phosphorus—→affects algae growth( red tides)——> algae dies—→ bacterie decomposes——> lowers oxygen in water——> hypoxic and anoxic——> dead zones

Mono lake

ternimal lake: water picks up salt and other minerals— water evaportates those minerals are left behind

species that are specially adapted to live there

migrating birds: use the lake as a stopover

mono lake impacts

●1941: Aqueduct

●1982: half the amount of water, salinity had doubled to more than twice that of the ocean

●Exposed lakebed: dust-prone dry flat; toxic dust (PM10)

●Salt killed algae; brine shrimp had no algae to eat

●Migrating birds stayed away

●Land bridges allowed coyotes to prey on nesting birds

provisioning services

benefit to people that can be extracted from nature

regulating services

benefit provided by ecosystem processes that moderate natural phenomena

cultural services

is a non material benefit contributes to development and cultural advancement of people

supporting services

underlying natural processes that allow the earth to sustain basic life forms

provision examples

water, raw materials, food, medicinal resources

regulating services examples

pollination, erosion prevention and soil fertility, waste water treatment,

supporting services examples

habitats, photosynthesis, creation of soils

cultural service examples

recreation, mental, physical health, ecotourism, spiritual experiences

cultural ecosystem services provided by wetlands

ecotourism, wetlands used as parks to observe and enjoy unique organisms and habitat

provisioning ecosystem services provided by wetlands

water source; wetlands can remove impurities from water, this provides a drinking water source

raw materials: wetland soils are fertile, so could be used for farming.

regulating ecosystem services provided by wetlands

water regulation: wetlands store water, helps to prevent floods and provide water in droughts

supporting ecosystem services provided by wetlands

nutrient cycling: microorgsanism in wetlands can remove excess nutrients from water

photosynthesis: plants in wetlands can be an oxygen source/ carbon sink

40 percent of coastal wetlands in the lower 48 are found

Mississippi River floodwaters—huge amounts of sediment at the river’s delta

Freshwater, brackish, and salt marshes

Ecosystem services: commercial fisheries, birders, hunters, anglers, boater, outdoor enthusiasts, shipping and transit, offshore oil fields and refineries

Improving water quality, absorbing excess nutrients, replenishing aquifers, controlling erosion, dissipate storm surges.

Wetland loss: 24 square miles of wetlands each year—a football field every 100 minutes.

Natural causes: subsidence and wave erosion

Human causes: river levees, channels, canals, and dams

Drain wetlands for agriculture or urban development

w/o humans: natural wetland loss replenished by river sediments and nutrients creating new wetlands.

●Loss of storm protection

●Threatens vital fisheries, regional oyster beds, and critical nursery grounds

There are approximately one thousand miles of levees and floodgates on each side of the entire River and its tributaries.

human impacts:

-levees stop seasonal flooding

-sediments is now carried far from shore

-system of dregded canals allow saltwater intrusion

-upriver dams trap sediment

-forced drainage for agriculture and development