Nitrogen Cycling Through Ecosystems

1. Nitrogen Cycling Through Ecosystems D. Kindersley Nitrogen Free Dr. Jeffrey R. Corney, Managing Director of the University of Minnesota’s Cedar Creek Ecosystem Science Reserve

2. Nutrient Cycling Energy Flow, Carbon & Oxygen Cycling J. Corney

3. The Nitrogen Cycle Elmhurst 10% of naturally occurring available nitrogen is generated by lightning. McGraw-Hill

4. Nutrient Cycling Nitrogen Cycling Through an Ecosystem ECOSYSTEM N OTHER SOURCES CONSUMERS N-cmpds N2 & NOx 1o 2o 3o PRODUCERS DECOMPOSERS N-cmpds ATMOSPHERE SOIL “SINK” NO3- &NH4+ J. Corney

5. Carbon vs. Nitrogen Cycles Carbon cycling is mostly atmosphere based. Nitrogen cycling is mostly soil based.

6. Carbon & Nitrogen Cycles Are Linked U.S. Dept of Energy

7. In the “Top Four” Elements for Life ASU Pearson

8. Roles of CARBON & NITROGEN: “Life as a House” If Carbon comprises the framing and roofing (FORM)… E Patrol …then Nitrogen comprises the appliances (FUNCTION).

9. Key Component of Life’s Molecules Amino Acids & Proteins Hemoglobin & Chlorophyll DNA & RNA Wikipedia UDEL NobelPrize.org

10. Carbon to Nitrogen (C:N) Ratios Plants ~ 25:1 Animals ~ 6:1 McGraw-Hill

11. Nitrogen Is Abundant in Atmosphere Atmospheric N2 U.S. EPA …but, N2 as a gas is relatively inert to life

12. Forms of Nitrogen Available for Life Nitrogen Free …but, only plants can absorb Nitrogen directly from the environment

13. The Nitrogen Cycle

14. Organic vs. Inorganic Nitrogen Organisms consume other organisms and excrete inorganic wastes. Organic (immobile) nutrients are stored in soil organisms and organic matter. Inorganic (mineral) nutrients are usable by plants, and are mobile in soil. USDA-NRCS Organisms take up and retain nutrients as they grow.

15. Nitrogen Cycle (zoomed in)

16. Fixing Nitrogen… Atmospheric Nitrogen Nitrogen -Fixing Bacteria N2 Nitrogen Ammonifying Bacteria

17. Getting to Nitrate… Nitrifying Bacteria Nitrosomonas Nitrobacter

18. Nutrients Need Water to Move Nutrient ions are mobile while in a solution of water. ? DK Clipart So, how do nutrients move in soil?

19. Composition of Soil PhysicalGeography.net

20. Interstitial Spaces U of Minnesota

21. Getting Nutrients to the Plants U of Georgia River Partners USDA-NRCS

22. Mychorrizhae: Plants & Fungi Together 90% of plant families have mychorrizhal associations. Agro-Genesis A symbiotic, mutualistic association between a fungus and the roots of plants.

23. Mychorrizhal Relationship Up Close Plant root Fungal hyphae USDA-NRCS Mycorrhizal structure

24. 2 Types of Mychorrizhal Relationships Plant a Globe USDA-NRCS USDA-NRCS 10% of plant families, mostly woody species (e.g. pine, oak, birch) 80% of plant families, mostly herbaceous species (e.g. grasses, forbs) Nature

25. Plant-Fungal Cellular Connection Image Nature Oxford Journal Cold Spring Harbor RHIZOSPHERE Area of soil immediately adjacent to plant roots and mychorrizhal structures.

26. Fungi Help Get Nutrients into Roots H2O H2O NO3- H2O NO3- H2O H2O NO3- NO3- NH4+ H2O H2O NO3- NO3- H2O H2O NH4+ NH4+ H2O H2O M. Harrison

27. Nutrients Move from Roots to Shoots Tutor Vista Helicon

28. J. Corney

29. Soil Organisms & Decomposition Organic Garden Dr. Jeffrey R. Corney, Managing Director of the University of Minnesota’s Cedar Creek Ecosystem Science Reserve

30. Formation of Soil Brooks-Cole

31. Soil Layers Surface Litter Top Soil Sub-Soil Rock DK Clipart USDA-NRCS

32. Cross-Section of Soil Absolute Science

33. Soil Ecosystem at Micro-level USDA-NRCS Rose & Elliot

34. Process of Decomposition of Animals McGraw-Hill

35. Process of Decomposition of Plants Brooks-Cole

36. Soil Food Chain Landscape for Life

37. Soil Food Web Brooks-Cole

38. Bacteria, Fungi, & Actinomycetes USDA-NRCS USDA-NRCS USDA-NRCS USDA-NRCS Decompose material, mineralize nutrients, fix nitrogen, help aggregate soil particles.

39. Annual Microbial Activity by Season USDA-NRCS

40. Protozoans USDA-NRCS BLM Mauby Consume bacteria and fungi, releasing nutrients when excrete wastes.

41. Nematodes & Springtails TAMU USDA-NRCS Rodale USDA-NRCS Consume bacteria, fungi, and protozoans, releasing nutrients when excrete wastes.

42. Mites, Sowbugs, Millipedes USDA-NRCS EcoLibrary USDA-NRCS Shred plant litter and consume detritus, increasing ability for microbes to decompose material.

43. Ants, Beetles, Spiders, Centipedes Discover Life USDA-NRCS Predators that eat other consumers, controlling populations and excreting nutrients.

44. Earthworms: “Soil Aerators” Cary Institute Science Daily WORM Mix soil layers, redistributing nutrients throughout soil, and aerate the soil.

45. Gophers & Ants: “Earth Movers” Move nutrient poor sub-layers of soil to the surface, helping enrich soil layers.

46. Soil Organisms By-the-Numbers 1 gram of soil USDA-NRCS

47. Soil Organisms By Type of Ecosystem USDA-NRCS

48. Soil Biodiversity by Ecosystem USDA-NRCS

49. Fun Facts About Soil A single spade full of rich garden soil contains more species of organisms than can be found above ground in the entire Amazon rain forest. One cup of soil may hold as many bacteria as there are people on Earth. The weight of all the bacteria in one acre of soil can equal the weight of a cow. A teaspoon of soil from a coniferous forest may hold tens of miles of fungi. The air in the upper 8 inches of a well-drained soil is completely renewed about every hour. The plants growing in a 2-acre field can have more than 30,000 miles of roots, greater than the circumference of the Earth. Mature trees can have as many as 5 million active root tips. SOURCE: USDA-NRCS The tips of small plant roots move through the soil with a twisting screw-like motion.  Mature trees can have as many as 5 million active root tips. A single spade full of rich garden soil contains more species of organisms than can be found above ground in the entire Amazon rain forest. Although the soil surface appears solid, air moves freely in and out of it. The air in the upper 8 inches of a well-drained soil is completely renewed about every hour. The plants growing in a 2-acre wheat field can have more than 30,000 miles of roots, greater than the circumference of the Earth. The wonderful "earthy" smell of newly plowed ground is believed to result from chemicals produced by micro-organisms.  One of these chemicals, called geosmin, is produced by actinomycetes, organisms that have some properties of both bacteria and fungi. Soil can act as either a sink or a source of greenhouse gases.  An estimated 30 percent of the carbon dioxide, 70 percent of the methane, and 90 percent of the nitrous oxide released to the atmosphere each year pass through the soil. It takes about 4,000 to 6,000 pounds of crop residue per year to maintain the content of organic matter in a soil. Modern farming practices that minimize soil disturbance (plowing) and return plant residues to the soil, such as no-till farming and crop rotations, are slowly rebuilding the Nation's stock of soil organic matter. Of the carbon returned to the soil as plant residue, about 5 to 15 percent become tied up in the bodies of organisms and 60 to 75 percent is respired as carbon dioxide back to the atmosphere. Only 10 to 25 percent is converted to humus in the soil. “We know more about the movement of celestial bodies than about the soil underfoot.”---Leonardo Da Vinci, circa 1500's “Every time you take a step in a mature Oregon forest, your foot is being supported on the backs of 16,000 invertebrates held up by an average total of 120,000 legs.” –Dr. Andrew Moldenke, Oregon State University. Even in agricultural soils, more than a thousand arthropod legs support your every step. One cup of soil may hold as many bacteria as there are people on Earth. Bacteria and actinomycetes are exceedingly tiny. Yet, because of their tremendous numbers, they make up half the living biomass in some soils.  The weight of all the bacteria in one acre of soil can equal the weight of a cow or two.  Actinomycetes have cells like bacteria, but grow as long filaments like fungi. Like fungi, they help degrade tough materials, but unlike fungi, they prefer high pH (over 7.0).  A teaspoon of farm soil may contain tens of yards of fungi. The same amount of soil from a coniferous forest may hold tens of miles of fungi. Nematodes are amazingly diverse. Twenty thousand species have been described, but it is thought that 500,000 species may exist. Five thousand soil species have been described. Earthworms move from lower strata up to the surface and move organic matter from the soil surface to lower layers. Where earthworms are active, they can turn over the top 6 inches of soil in 10 to 20 years.

50. More Fun Facts About Soil Twenty thousand species of nematodes have been described, but it is thought that 500,000 species may exist. Every time you take a step in a mature forest, your foot is being supported on the backs of 16,000 invertebrates held up by an average total of 120,000 legs. There is an estimated one quadrillion individual ants on the planet; that’s approximately 150,000 ants for every one human being.  Where earthworms are active, they can turn over the entire top 6 inches of soil in 10 to 20 years. Pocket gopher mounds can cover as much as 25% of a grassland’s ground surface, depositing on average 20 tons of soil per acre per year. SOURCE: USDA-NRCS The tips of small plant roots move through the soil with a twisting screw-like motion.  Mature trees can have as many as 5 million active root tips. A single spade full of rich garden soil contains more species of organisms than can be found above ground in the entire Amazon rain forest. Although the soil surface appears solid, air moves freely in and out of it. The air in the upper 8 inches of a well-drained soil is completely renewed about every hour. The plants growing in a 2-acre wheat field can have more than 30,000 miles of roots, greater than the circumference of the Earth. The wonderful "earthy" smell of newly plowed ground is believed to result from chemicals produced by micro-organisms.  One of these chemicals, called geosmin, is produced by actinomycetes, organisms that have some properties of both bacteria and fungi. Soil can act as either a sink or a source of greenhouse gases.  An estimated 30 percent of the carbon dioxide, 70 percent of the methane, and 90 percent of the nitrous oxide released to the atmosphere each year pass through the soil. It takes about 4,000 to 6,000 pounds of crop residue per year to maintain the content of organic matter in a soil. Modern farming practices that minimize soil disturbance (plowing) and return plant residues to the soil, such as no-till farming and crop rotations, are slowly rebuilding the Nation's stock of soil organic matter. Of the carbon returned to the soil as plant residue, about 5 to 15 percent become tied up in the bodies of organisms and 60 to 75 percent is respired as carbon dioxide back to the atmosphere. Only 10 to 25 percent is converted to humus in the soil. “We know more about the movement of celestial bodies than about the soil underfoot.”---Leonardo Da Vinci, circa 1500's “Every time you take a step in a mature Oregon forest, your foot is being supported on the backs of 16,000 invertebrates held up by an average total of 120,000 legs.” –Dr. Andrew Moldenke, Oregon State University. Even in agricultural soils, more than a thousand arthropod legs support your every step. One cup of soil may hold as many bacteria as there are people on Earth. Bacteria and actinomycetes are exceedingly tiny. Yet, because of their tremendous numbers, they make up half the living biomass in some soils.  The weight of all the bacteria in one acre of soil can equal the weight of a cow or two.  Actinomycetes have cells like bacteria, but grow as long filaments like fungi. Like fungi, they help degrade tough materials, but unlike fungi, they prefer high pH (over 7.0).  A teaspoon of farm soil may contain tens of yards of fungi. The same amount of soil from a coniferous forest may hold tens of miles of fungi. Nematodes are amazingly diverse. Twenty thousand species have been described, but it is thought that 500,000 species may exist. Five thousand soil species have been described. Earthworms move from lower strata up to the surface and move organic matter from the soil surface to lower layers. Where earthworms are active, they can turn over the top 6 inches of soil in 10 to 20 years.