biogeochemical cycles

BIOGEOCHEMICAL CYCLES

Bio - Living Geo - Earth Chemical - Matter

Describes how matter (atoms) moves through the Earth to living organisms back to the Earth and on and on...

There are as many as 25 elements found in ALL living organisms and just like energy they are cycled through the biosphere. Far and away the most abundant are CHNOPS.

Plants capture energy from sunlight for PHOTOSYNTHESIS

6CO2+ 6H2O + Energy → C6H12O6+ 6O2

Photosynthesis occurs in the chloroplasts in plant cells

O2 is converted to CO2 in the mitochondria of animal cells.

C6H12O6+ 6O2 → 6CO2+ 6H2O+ Energy (infrared)

CELLULAR RESPIRATION

COMBUSTIONAny chemical reaction in which one of the reactants is OXYGEN (aka fire) is a combustion reaction.

COMBUSTION OF CARBONIf CARBON is a reactant CO2 is always a

product.•Burning Methane CH4 + O2 → CO2 + 2H2O

•Burning Propane: C3H8+5O2→3CO2+4H2O

•Incinerating trash, yard waste•Forest fires•Combustion engines in cars•Burning coal (to generate electricity)

...just as the rings on a tree can tell us how old a tree is...

...so can Ice Core Samples tell us about the paleoclimate…

Paleo = ancient

THE ICE CORE DRILL

Ice cores are drilled in glaciers mostly in Greenland and Antarctica...

LAYERS OF ICE

Like the growth rings on a tree represent a year in the life of the tree...each layer of ice gives us a sample of the air from that season of ice accumulation.

Volcanic Ash Layer

Cutting the IceEach layer is sliced off seperately...

GASES DISSOLVED IN THE ICE

...are then measured by melting the ice and collecting and analyzing them...

ICE CORE STORAGE

GREENHOUSE GASESDue to the shape and size of their molecules and the type of chemical bonds they form, some molecules are better at trapping heat in the atmosphere.The strongest greenhouse gases are:•Water vapor (H2O)•Carbon dioxide (CO2)•Methane (CH4)

ATMOSPHERIC CARBONThe data collected from the ice cores

shows a dramatic increase in atmospheric carbon since the beginning of the Industrial Revolution in 1850.

WATER VAPORCarbon Heat Evaporation Heat Evaporation…

Additionally...the more fresh water trapped in the atmosphere the less we have available for use!

EFFECTS OF CLIMATE CHANGE• Melting Polar Sea Ice

• Change in ocean salinity• Ocean Acidification• Rising global temperatures• Rising sea levels• Receding glaciers• ALL ecosystems are affected!

MELTING POLAR SEA ICE

Predictions: How might changes in density affect the Great Ocean Conveyor Belt?

Do you think this water will STAY as salty if you’re adding glacial melt water? Is that water salty or fresh?

OCEAN ACIDIFICATION ● The ocean absorbs CO2.● When CO2 dissolves in water it makes

carbonic acid.  ● Carbonic acid decreases the ability of

many marine organisms to build and maintain their shells and skeletal structures. 

OCEAN ACIDIFICATION

Results in habitat loss & breakdown of the marine food web ☹

RISING GLOBAL TEMPERATURES

RECEDING GLACIERS

MENDENHALL GLACIER - 2013

The Meade Glacier is located here:

Here he is from space (zoomed)

Here he is on approach when we helicoptered out to visit him:

This is all glacial valley where ice once was and where glacial melt water runs into the bay...

This is what the beautiful glacier looks like up close...

THE WATER CYCLE

• ALL living organisms MUST have water to survive!

• The availability of water is determined by the water cycle and weather patterns driven by it.

THE NITROGEN CYCLE• The most abundant molecule in the air

we breathe is nitrogen!• DNA has “nitrogenous bases” ...so

anything with DNA needs nitrogen. • Nitrogen moves through the food chain

(trophic layers) in the same manner energy does: consumers get nitrogen from producers.

NITROGEN-FIXING BACTERIA

Bacteria that live in the soil and on the roots of plants that “fix” nitrogen from the atmosphere into a form that is ingestible by living organisms.

DENITRIFYING BACTERIAA second type of bacteria break down decomposing organic material and release the nitrogen back into the atmosphere restarting the cycle.

PHOSPHORUS CYCLE