ib biology 4.3

What is the evidence for increasing levels of CO2 in the atmosphere?

- Recent data has been easily to collect experimentally

Some animals secrete calcium carbonate (CaCO3) structures to protect themselves:

- Shells of molluscs - Hard corals exoskeletons

Methanogens are found in a variety of anoxic environments like?

- Wetlands (e.g. paddies, swamps and mangroves) - Digestive tracts of animals (e.g. cows, humans and termites) - Marine and freshwater sediments (e.g. mud in the beds of lakes) - Landfill sites (in which organic matter has been buried)

In how many different forms can carbon exist?

- atmospheric gases (CO2 and methane) - dissolved CO2 in aquatic systems - organic carbon in living organisms - carbon deposits in the lithosphere, as minerals (carbonates) or fossil fuels

In terms of the carbon cycle what three main categories of organisms carry out respiration?

- autotrophs, e.g. plants - heterotrophs, e.g. animals - saprotrophs and decomposers, e.g. fungi and bacteria

Plant initially synthesize sugars (e.g. glucose) which are then converted into other organic compounds such as?

- complex carbohydrates e.g. starch, cellulose - lipids - amino acids

Outline how peat if formed.

1. In soils organic matter, e.g, dead leaves, are digested by saprotrophic bacteria and fungi 2. Saprotrophs assimilate some carbon for growth and release as carbon dioxide during aerobic respiration 3. Anaerobic soils occur in areas where oxygen consumption by soil biota exceeds the diffusion of oxygen into the soil profile. An anerobic environment can occur in a number of soil types such as wetlands, heavy textured soils, paddy soils, organic soils poorly drained soils. However, we can't say that these environments are always anaerobic in nature. 4. Saprotrophs and methanogens are inhibited 5. When oxygen levels fall below five percent, the aerobes die and decomposition slows by as much as 90 percent. Anaerobic microorganisms take over and, in the process, produce a lot of useless organic acids and amines. The soil is now even more acidic which can prevent what bacteria is still alive from doing its job 6. Organic matter is only partially decomposed 7. Large quantities of (partially decomposed) organic matter build up 8. The organic matter is compressed to form peat

What does methane look like?

A colorless, odorless flammable gas that is the main constituent of natural gas. It is the simplest member of the alkane series of hydrocarbons.

What is natural gas?

A fossil fuel formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure over thousands of years

Methane is released into the atmosphere can be removed by?

A number of mechanisms

Carbon dioxide is what kind of product of cell respiration?

A waste product

What is anoxic condition?

Absence of free oxygen, but presence of bound oxygen

What do all autotrophs convert?

All autotrophs convert carbon dioxide (from the atmosphere or dissolved in water) or into organic compounds

What is hydrogen carbonate?

An intermediate form in the deprotonation of carbonic acid.

What is a carbon sink?

Anything that absorbs more carbon than it releases

What is a carbon source?

Anything that releases more carbon than is absorb

What are methanogens?

Archaean microorganisms that produce methane as a metabolic byproduct in anoxic conditions

What do forests act as different times?

As sources of sinks at different times.

Diffusion is a flux that moves CO2 from the atmosphere to the hydrosphere and back again. Taken together these fluxes are largest in the cycle, why is this?

Because our oceans make up 70% of the earth.

If heated dried biomass or fossilized fuels will?

Burn in the presence of oxygen

Although most autotrophs fix carbon by photosynthesis. A few are chemoautotrophs and fix carbon how?

By utilising the energy in the bonds of inorganic compounds such as hydrogen sulfide.

Between which sinks would you add a flux showing volcanoes and the weathering of rocks?

Carbon compounds in fossil fuels and CO2 in the atmosphere and hydrosphere (e.g. oceans)

Typically during ATP production is produced from?

Carbon dioxide

What is methane?

Chemical compound with the chemical formula CH4 (one atom of carbon and four atoms of hydrogen). It is the simplest alkane and the main component of natural gas

Peat is compressed and heated over millions of years and eventually becomes?

Coal

Tiny sea plants and animals died and were buried on the ocean floor. Over time, they were covered by layers of slit and sand.

Conditions are anaerobic and so decomposition is only partial

What's the essential idea?

Continued availability of carbon in ecosystems depends on carbon cycling

The cycle of sea-level changes that happened during the Carboniferous period caused?

Costal swamps to be buried promoting the formation of coal

When the animals die the soft body parts decompose, but calcium carbonate remain to form what?

Deposits on the ocean floor. The deposits are buried and compressed to eventually form limestone rock. Imprints of the hard body parts remain in rock as fossils. Limestone rock is a huge carbon

Where does CO2 from the outside of the leaf go?

Diffuses down the concentration gradient into the leaf

Organisms carry out respiration to release what?

Energy in the form of ATP

What do H+ explain?

Explains how carbon dioxide reduces the pH of water.

What are the sources of atmospheric CO2?

Factory, animals

What is CO2 necessary for?

For the calvin cycle.

Over the top summary of how coal is formed.

For the peat to become coal, it must be buried by sediment. Burial compacts the peat and, consequently, much water is squeezed out during the first stages of burial. Continued burial and the addition of heat and time cause the complex hydrocarbon compounds in the peat to break down and alter in a variety of ways. The gaseous alteration products (methane is one) are typically expelled from the deposit, and the deposit becomes more and more carbon-rich as the other elements disperse. The stages of this trend proceed from plant debris through peat, lignite (brown coal), sub-bituminous coal, bituminous coal (black coal), anthracite coal, to graphite (a pure carbon mineral). Because of the amount of squeezing and water loss that accompanies the compaction of peat after burial, it is estimated that it took 10 vertical feet of original peat material to produce 1 vertical foot of bituminous coal in eastern and western Kentucky. The peat to coal ratio is variable and dependent on the original type of peat the coal came from and the rank of the coal.

What stores carbon?

Forests, soils, oceans, and the atmosphere and this carbon moves between them in a continuous cycle. This constant movement of carbon means that forests act as sources or sinks at different times.

Where did oil and gas formation occur?

In ancient oceans

Once dried peat does what?

It burns easily and can be used as a fuel

Estimates are based on many different measurements are often published with?

Large uncertainties as a result.

Some CO2 will directly dissolve in water but what will most do?

Most will combine with water to become carbonic acid

What is most important process of methane removal?

Oxidation by hydroxyl radicals

Which processes return C to the lithosphere?

Photosynthesis, cellular respiration, decomposition.

What is the sink of atmospheric CO2?

Plants, ocean

What additional sink would you add to show the role of corals and shellfish? What additional flux would be needed?

Sink = Oceanic carbon. Shellfish and corals could be considered a sink. Phytoplankton would be considered a sink. Flux = feeding relationship between oceanic producer and consumer.

Why are fossil fuels are classified as non-renewable resources when the carbon cycle indicates they are renewed?

Takes millions of years for process to create them.

What do measurements indicate?

That the levels of atmospheric methane are increasing - it is estimated that, on average, methane persists in the atmosphere for 8.4 years

Hydroxyl radical -- neutral form of the hydroxide ion (HO-). Hydroxyl radicals are highly reactive and consequently short-lived; What is the hydroxyl radical often referred to as?

The "detergent" of the troposphere because it reacts with many pollutants

Over millions of years, the remains were buried deeper an deeper. The enormous heat and pressure turned them into oil and gas.

The mixture of different types of oil and gas is the result of complex chemical changes. Methane forms the largest part of natural gas.

What is a flux?

The process by which carbon is transferred

Where does CO2 move through in in the leaves of land plants?

Through stomatal pores

Why must plants have a constant supply of carbon dioxide (CO2)?

To continually photosynthesize.

In some environments water is unable to drain out of soils so they become waterlogged and anaerobic. This prevents the decomposition of dead organic matter forming peat deposits. Peat can be dried and burnt as fuel. How peat can be added to the carbon cycle?

Used as fuel instead of fossil fuels - alternative resource!

What does photosynthesis use CO2 for?

Uses CO2 keeping the concentration of the CO2 inside the leaf low

When is coal formed?

When deposits of peat are buried under other sediments

Is methane considered organic?

Yes even though it's a gas

Is peat a highly effective carbon sink?

Yes peat is a highly effective carbon sink, it is estimated that the world's peat contains 550 Gt of carbon

Many field stations globally use the same standardised method. All stations show

a clear upward trend with annual cycles.

Over 40 years, Charles Keeling measured atmospheric CO2 from his observatory in Mauna Loa, Hawaii, and the 'Keeling Curve' has become

an icon of climate science

methane + hydroxyl radical ->

carbon dioxide + water

The carbon dioxide information analysis centre (CDIAC) has a huge database of information regarding

carbon dioxide measurements

It is not possible to measure the size of carbon sinks and the

fluxes between them.

Ice cores are a good source of CO2 data, where researchers can analyse the CO2 concentration of air bubbles trapped

in the ice and estimate year based on the depth of the core

Both dissolved carbon dioxide and hydrogen carbonate ions are absorbed by aquatic plants and?

other autotrophs that live in water.

Not a carbides, carbonates, simple

oxides

What does partially decomposed organic matter that can be compresses to form brown soil-like form?

peat

Historical data takes more effort to collect and is more

variable in the reliability of the results produced.