Biogeochemical Cycles life-earth-chemical cycles life-earth-chemical cycles Water cycleWater cycle Carbon cycleCarbon cycle Nitrogen cycleNitrogen cycle Phosphorus cyclePhosphorus cycle Sulfur cycleSulfur cycle

Water Cycle

How are humans affecting the water cycle?

Using large quantities of freshwater from rivers, lakes, and underground aquifers Using large quantities of freshwater from rivers, lakes, and underground aquifers Clearing vegetation and replacing it with impermeable materials (like concrete), which increases runoff Clearing vegetation and replacing it with impermeable materials (like concrete), which increases runoff Adding pollutants and excess nutrients to the water Adding pollutants and excess nutrients to the water

Water Cycle

What can people do to improve the water cycle? Water conservation Water conservation Use more permeable materials on the ground Use more permeable materials on the ground Reduce the amount of runoff and the chemicals it contains Reduce the amount of runoff and the chemicals it contains

Distillation

Carbon Cycle

Where is carbon stored?

Air – 0.037% is CO 2 Air – 0.037% is CO 2 Vegetation – during photosynthesis, plants convert CO 2 into C 6 H 12 O 6 (glucose) Vegetation – during photosynthesis, plants convert CO 2 into C 6 H 12 O 6 (glucose) Fossil fuels – plant matter that’s been subjected to heat and pressure Fossil fuels – plant matter that’s been subjected to heat and pressure Ocean – dissolves CO 2 Ocean – dissolves CO 2 Marine organisms – used to make shells Marine organisms – used to make shells Rocks – limestone is primarily CaCO 3 Rocks – limestone is primarily CaCO 3

Fossil Fuels

White Cliffs of Dover

How are humans affecting the carbon cycle?

By cutting down trees and clearing vegetation that naturally absorbs CO 2 By cutting down trees and clearing vegetation that naturally absorbs CO 2 Burning fossil fuels (especially coal) releases their stored carbon into the atmosphere Burning fossil fuels (especially coal) releases their stored carbon into the atmosphere

Effects of disrupting the carbon cycle Global Warming – more CO 2 in the atmosphere will lead to a stronger greenhouse effect Global Warming – more CO 2 in the atmosphere will lead to a stronger greenhouse effect Acidification of the oceans – more dissolved CO 2 in the water creates more carbonic acid Acidification of the oceans – more dissolved CO 2 in the water creates more carbonic acid

Nitrogen

Nitrogen 78% of the air is nitrogen (N 2 ) 78% of the air is nitrogen (N 2 ) Nitrogen is essential for organisms to make DNA, protein, amino acids, etc. Nitrogen is essential for organisms to make DNA, protein, amino acids, etc. Yet, N 2 is useless to plants and animals Yet, N 2 is useless to plants and animals

How do organisms get nitrogen? Two natural processes convert nitrogen gas into usable nitrogen: Two natural processes convert nitrogen gas into usable nitrogen: LightningLightning Nitrogen cycleNitrogen cycle

Nitrogen Cycle 5 main processes cycle nitrogen through the atmosphere, biosphere, and lithosphere: 5 main processes cycle nitrogen through the atmosphere, biosphere, and lithosphere: Nitrogen fixationNitrogen fixation NitrificationNitrification AssimilationAssimilation AmmonificationAmmonification DenitrificationDenitrification

Nitrogen Cycle

Nitrogen fixation Nitrogen fixation Bacteria (such as Rhizobium) convert gaseous nitrogen into ammonia, which is taken up by plantsBacteria (such as Rhizobium) convert gaseous nitrogen into ammonia, which is taken up by plants N 2 + 3H 2  2NH 3N 2 + 3H 2  2NH 3 Rhizobium nodules

Nitrogen Cycle

Nitrification Nitrification Ammonia in soil converted by bacteria into nitrite ions (NO 2 - ) and nitrate ions (NO 3 - )Ammonia in soil converted by bacteria into nitrite ions (NO 2 - ) and nitrate ions (NO 3 - )

Nitrogen Cycle

Assimilation Assimilation Plants use ammonia (NH 3 ), ammonium ions (NH 4 + ), and nitrate ions (NO 3 - )Plants use ammonia (NH 3 ), ammonium ions (NH 4 + ), and nitrate ions (NO 3 - ) Make DNA, amino acids, and proteinMake DNA, amino acids, and protein Animals get their nitrogen from eating plantsAnimals get their nitrogen from eating plants

Nitrogen Cycle

Ammonification Ammonification Animals excrete excess nitrogen in their urine and fecesAnimals excrete excess nitrogen in their urine and feces Additional nitrogen is added to the soil when organisms dieAdditional nitrogen is added to the soil when organisms die Decomposing bacteria and fungi convert the nitrogen in their waste into usable ammonia (NH 3 ) and ammonium ions (NH 4 + )Decomposing bacteria and fungi convert the nitrogen in their waste into usable ammonia (NH 3 ) and ammonium ions (NH 4 + )

Nitrogen Cycle

Denitrification Denitrification Bacteria in the soil convert usable ammonia (NH 3 ) and ammonium ions (NH 4 + ) back into nitrogen gas (N 2 ) and nitrous oxide gas (N 2 O)Bacteria in the soil convert usable ammonia (NH 3 ) and ammonium ions (NH 4 + ) back into nitrogen gas (N 2 ) and nitrous oxide gas (N 2 O)

Nitrogen Cycle

How are humans affecting the nitrogen cycle? Burning fuels release nitric oxide (NO) into the atmosphere Burning fuels release nitric oxide (NO) into the atmosphere Creates acid rainCreates acid rain Harms vegetation Harms vegetation Harms aquatic ecosystems Harms aquatic ecosystems Damages materials (metal, stone, etc.) Damages materials (metal, stone, etc.)

How are humans affecting the nitrogen cycle? Excess livestock waste and fertilizer adds nitrous oxide (N 2 O) to the atmosphere Excess livestock waste and fertilizer adds nitrous oxide (N 2 O) to the atmosphere N 2 O is a greenhouse gasN 2 O is a greenhouse gas May lead to global warmingMay lead to global warming

How are humans affecting the nitrogen cycle? Runoff from agricultural lands and sewage facilities adds nitrogen to aquatic ecosystems Runoff from agricultural lands and sewage facilities adds nitrogen to aquatic ecosystems Results in algal bloomsResults in algal blooms Leads to “dead zones”Leads to “dead zones”

Nitrogen Summary 1. What allows nitrogen to be used by plants? 2. How do animals get their nitrogen? 3. What makes the nitrogen cycle a cycle? 4. How are humans affecting the nitrogen cycle?

Phosphorus

Phosphorus Phosphorus is an essential nutrient for plant growth Phosphorus is an essential nutrient for plant growth It does not exist as a gas, but is mainly found in water, soil, and sediment It does not exist as a gas, but is mainly found in water, soil, and sediment

Phosphorus Cycle Phosphorus is found naturally in rocks Phosphorus is found naturally in rocks Erosion by rainfall, weathering, and runoff allows phosphorus to be available to plants Erosion by rainfall, weathering, and runoff allows phosphorus to be available to plants

Phosphorus Cycle Phosphorus is absorbed by roots in plants Phosphorus is absorbed by roots in plants Animals eat the plants and it is passed up the food chain Animals eat the plants and it is passed up the food chain Phosphorus is returned to the soil by animal excretion and decomposition Phosphorus is returned to the soil by animal excretion and decomposition

How are humans affecting the phosphorus cycle? Humans mine phosphate rocks to make fertilizers and detergents Humans mine phosphate rocks to make fertilizers and detergents Increasing erosion by removing vegetation Increasing erosion by removing vegetation Adding excess phosphorus to water from runoff from fertilizers and livestock waste Adding excess phosphorus to water from runoff from fertilizers and livestock waste

Sulfur Cycle Most sulfur is buried in rocks and minerals underground Most sulfur is buried in rocks and minerals underground Hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) are released by volcanoes Hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) are released by volcanoes

Rotorua, New Zealand (aka – “Sulfur City”)

Sulfur Cycle Sulfur is taken up by plants and is passed through the food chain Sulfur is taken up by plants and is passed through the food chain As organisms die and decompose, the sulfur then again becomes available for plants As organisms die and decompose, the sulfur then again becomes available for plants

How do humans affect the sulfur cycle? Burning coal and processing metals release SO 2 into the atmosphere Burning coal and processing metals release SO 2 into the atmosphere SO 2 reacts with water in the atmosphere to form H 2 SO 4, sulfuric acid SO 2 reacts with water in the atmosphere to form H 2 SO 4, sulfuric acid