III. BIOGEOCHEMICAL CYCLES A.Overview B.The Water Cycle C.The Carbon Cycle 1. OVERVIEW

III. BIOGEOCHEMICAL CYCLESA.OverviewB.The Water CycleC.The Carbon Cycle

1. OVERVIEW

reservoirs in gigatons and exchanges in GT/year

RESERVOIRS:

Most atmospheric carbon has been transferred to the hydrosphere (dissolved CO2) and lithosphere (limestone and fossil deposits).

Dead and dissolved organic matter are other large reservoirs

The atmosphere and biosphere have some, too.


FLUXES:

Flux between hydro and atmo is still a major exchange


FLUXES:

Photosynthesis balances respiration

Volcanism balances by sedimentation and deposition

Net transfer to atmosphere is by burning of fossil fuels (7 GT) and reduction of photosynthesis by forests from deforestation (1 GT)


1. OVERVIEW 2. Change in CO2

Decrease due to terrestrial plant evolution and Carboniferous storage

- last 160,000 years (ice cores)401

280

- Since 1000: up 43% (all since 1830 – industrial revolution)

- Since 1955: 318 to 401 (April 21, 2014) – 26%

- Ocean absorption and acidification



3. Consequences – Global warming - August 2014 – warmest August on Record (since1888) - September 2014 – warmest September on record

2. Since 1860 – increase of 0.8oC – ten hottest years all since 1991



3. Consequences – Global warming 4. Correlates

-Reductions in Polar Ice

(area covered)

1979

2003Nasa.gov

Summer 2012 – Record low summer sea ice

-Reductions in Polar Ice

(thickness)

- deep sea ice depth decreased from mean of 3.1 meters in 1958 to mean of 1.8 m in 1997

Nasa.gov

- Reductions in polar ice- Reductions in glacial ice

B-15 is the size of Connecticutt (2000)

- Icebergs calving off Ross Shelf – April 2000

(B15 is 4,280 miles2 – about the size of CONNECTICUT….)

- Reductions in polar ice- Reductions in glacial ice

- Reductions in polar ice- Reductions in glacial ice- Sea level rise

- Increases in Sea Level

- Reductions in polar ice- Reductions in glacial ice- Sea level rise- Melting of Permafrost

14% of the world’s organic carbon is stored in permafrost. As the poles warm (and they are warming faster than anywhere else), this carbon may be mobilized as decomposing bacteria gear up….

This is a type of threshold response (not a gradual response), and would involve positive feedback loops…

- More big storms: March 24, 2004 – Atlantic Cyclone off Brazil.

- More big storms: March 24, 2004 – Atlantic Cyclone off Brazil. (earthobservatory.nasa.gov)

“The South Atlantic is generally not thought of by meteorologists as a place where tropical cyclones can form. The water temperatures are generally too cool and the vertical wind shear too strong. The area is so devoid of tropical storm activity that no government agency has an official warning system for storms there, which is why this storm is unnamed.”

- More big storms

“Natural disasters caused by extreme weather claimed seven times as many victims in 2003 as in the previous year and the trend is set to continue, says the world's biggest reinsurance company. (They insure insurance companies.) Munich Re said global warming would cause increasing economic damage in the future. "It is to be feared that extreme events which can be traced to climate change will have increasingly grave consequences in the future," the report said, adding that insurance premiums would rise and that clear-cut indemnity limits would be needed.”

– Reuters New Service, Feb 27, 2004

1900-2010

- Changes in Plant Growth:

Qualitative Effects:

Laurance et al. (March 2004, Nature):

- Pristine rainforests have changed composition in last 20 years, with an increase in fast-growing species and a decrease in slow growing species… probably as a result of increased CO2 availability.

- Reductions in polar ice- Reductions in glacial ice- Sea level rise- Melting of Permafrost- Stronger Storms- Effects on the Biosphere

-Changes in Reef Communities:

“Almost 15% of the world's reefs are already beyond repair thanks to global warming. Another 30% may be lost over the next 30 years.”

– (Nature, February 2004)

- Reefs are home to 25% of all marine species

- Reefs are nursery areas for the larvae and fry of commercially important fish and crustacean species

- Reefs are important storm breaks for tropical coasts


-Changes in Reef Communities:

- Changes in Species Diversity

15-37% of terrestrial species may go extinct in the next 50 years, largely because of global warming. (Thomas et al. 2004)


- Increases in Human Diseases:

UN Environmental Programme Report, Feb 21, 2005:

- Environmental change may be the cause of the resurgence of some infectious diseases.

- The fatal Nipah virus, normally found in Asian fruit bats, is believed to have crossed over to humans as the bats lost their habitats through forest fires in Sumatra and the clearance of land for palm plantations.

- Dengue fever, which was present in only nine countries in the 1970s, is now found in more than 100, most likely the result of increasing urban populations.




3. Consequences – Global warming 4. Correlates 5. Perspectives

5. Perspectives

- Canadian Environment Minister David Anderson said that global warming posed a greater long-term threat to humanity than terrorism because it could force hundreds of millions from their homes and trigger an economic catastrophe. – March 2004

World bank: “global warming requires immediate action” (2003)

- commissioned an independent panel to investigate options.

- Recommendation: “The WBG [World Bank Group] should aggressively increase investments in renewable energies by about 20 percent annually. WBG lending should concentrate on promoting the transition to renewable energy..."

-The World Bank rejected the recommendation. 2004 energy lending dedicates 6% to renewables, 94% percent to oil.

In FY 2013, the Bank provided nearly US$7 billion in energy lending, including US$2.7 billion in fossil fuels (39%), US$1.7 billion in clean energy (24%), and US$2.6 billion (38%) in “other” energy projects, such as large hydropower or transmission projects.

5. Perspectives

“We need an energy bill that encourages consumption.”

-President G. W. Bush, Sept. 23, 2002, Trenton, NJ

The Pentagon Report (2004): global warming “should be elevated beyond a scientific debate to a US national security concern.” It declares that “future wars will be fought over the issue of survival rather than religion, ideology or national honour.” – Fortune magazine – March 2004.

Senator James Inhofe, OK-R, who will be the Chairman of the Senate Committee on Environment and Public Works in 2015:

Inhofe’s top ten climate (mis)-statements



3. Consequences – Global warming 4. Correlates 5. Perspectives 6. Methane

“Globally, over 60% of total CH4 emissions come from human activities… Pound for pound, the comparative impact of CH4 on climate change is over 20 times greater than CO2 over a 100-year period.” (EPA)

6. Methane

Livestock



3. Consequences – Global warming 4. Correlates 5. Perspectives 6. Methane 7. IPCC – 2013-14 report

“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010. There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century.”

III. BIOGEOCHEMICAL CYCLESA.OverviewB.The Water CycleC.The Carbon CycleD.The Nitrogen Cycle

3900 GT

ULTIMATE RESERVOIR:

Atmosphere – N2 = 78% by volume, 75% by weight, of dry air.

FLUXES:

Atmospheric nitrogen is “fixed” by bacteria on land and in marine/aquatic systems; the N atoms are separated and H bonds, creating Ammonium ions (NH4

+).

FLUXES:

Atmospheric nitrogen is “fixed” by bacteria on land and in marine/aquatic systems; the N atoms are separated and H bonds, creating Ammonium ions (NH4

+).

Ammonium can be converted to Nitrite (NO2) and Nitrate (NO3) by nitrification; also a process only performed by certain bacteria in terrestrial and marine environments.

FLUXES:

Both ammonium and NO3 are absorbed by bacteria and plant roots, and assimilated into organic molecules.

A lot of the nitrogen is taken up by bacteria, outcompeting plant roots. Perhaps this favored plants incorporating nitrogen fixing bacteria, to escape this competition with soil bacteria.

FLUXES:

Both ammonium and NO3 are absorbed by bacteria and plant roots, and assimilated into organic molecules.

When proteins/DNA are metabolized, excess nitrogen is released as waste (NH3). This is ammonification.

FLUXES:

When proteins/DNA are metabolized, excess nitrogen is released as waste (NH3). This is ammonification.

Again, nitrifying bacteria convert this to nitrites and nitrates.

FLUXES:

Again, nitrifying bacteria convert this to nitrites and nitrates.

Besides assimilation, NO2 can be denitrified by bacteria and released an N2. This happens under anaerobic conditions, and starves soils of N.

Fixation is balanced by denitrification on land.

Fixation requires energy, supplied to Rhizobium by plant symbionts as glucose.


3900 GT

Effects of Life - Fundamental for nearly every transformation


3900 GT

Effects of Life - Fundamental for nearly every transformation

Effects of Humans: - We produce nitrogen fertilizer, and produce NOx compounds in internal combustion engines.

NEARLY EQUAL TO THE AMOUNT FIXED NATURALLY

“Fertilizing” the oceans results in a burst of production, then aerobic decomposers explode as they decomose all this new biomass…resulting in dramatic declines in oxygen, which is not replenished quickly by diffusion – especially at depth. This results in the death of other aerobic organisms, and “dead zones”

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III. BIOGEOCHEMICAL CYCLES A.Overview B.The Water Cycle C.The Carbon Cycle 1. OVERVIEW