Biol 302 Nutrient Cycling1 COMMUNITY AND ECOSYSTEM BIOLOGY Biology 302

Biol 302 Nutrient Cycling2 NUTRIENT CYCLING READINGS for this lecture series: KREBS cpt 27. Ecosystem Metabolism III: Nutrient Cycles KREBS cpt 28.Ecosystem Health: Human Impacts; Pp

Biol 302 Nutrient Cycling3 NUTRIENT CYCLING We are not dealing with: Energy – eventually gets “lost” We are dealing with: Nutrients – these cycle

Biol 302 Nutrient Cycling4 Aldo Leopold “A Sand County Almanac” “The Journey of Atom X”

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7 Thanks for buying my text book

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10 1. Biochemical cycles: Redistribution within an individual organism This really is r- and K-selection from first term 2. Biogeochemical cycles: Exchange within an ecosystem N, P - rapid exchange Ca - long if stored in long-lived tree tissue 3. Geochemical cycles: Exchange of chemicals between ecosystems Nutrients and dust CO 2, SO 2, NO x

Biol 302 Nutrient Cycling11 1. Biochemical cycles: Redistribution within an individual organism This really is r- and K-selection from first term 2. Biogeochemical cycles: Exchange within an ecosystem N, P - rapid exchange Ca - long if stored in long-lived tree tissue 3. Geochemical cycles: Exchange of chemicals between ecosystems Nutrients and dust CO 2, SO 2, NO x

Biol 302 Nutrient Cycling12 1. Biochemical cycles: Redistribution within an individual organism This really is r- and K-selection from first term 2. Biogeochemical cycles: Exchange within an ecosystem N, P - rapid exchange Ca - long if stored in long-lived tree tissue 3. Geochemical cycles: Exchange of chemicals between ecosystems Nutrients and dust CO 2, SO 2, NO x

Biol 302 Nutrient Cycling13 Krebs Fig ; p573 SULPHUR CYCLE

Biol 302 Nutrient Cycling14 Krebs Fig ; p579 NITROGEN CYCLE

Biol 302 Nutrient Cycling15 Krebs Fig. 28.7; p590 WATER CYCLE

Biol 302 Nutrient Cycling16 Krebs Fig. 27.8; p591 CARBON CYCLE

Biol 302 Nutrient Cycling17 These figures have: All sorts of rates of transfer We can compare between systems

Biol 302 Nutrient Cycling18 These figures have: All sorts of rates of transfer We can compare between systems More interesting: What influences the rates? What are the impacts of altering the rates?

Biol 302 Nutrient Cycling19 1. Biochemical cycle 2. Biogeochemical cycles: Exchange within an ecosystem 3. Geochemical cycles:

Biol 302 Nutrient Cycling20 BIOGEOCHEMICAL CYCLES: A few major points (general principles): 1.Nutrient cycling is never perfect i.e. always losses from system input and output Precipitation Runoff & stream flow Particle fallout from atmosphere Wind loss Weathering of substrate Leaching Fertilizer & pollution Harvesting

Biol 302 Nutrient Cycling21 3. Relatively 'tight' cycling is the norm 2. Inputs and outputs are small in comparison to amounts held in biomass and recycled 4.Disturbances (e.g. deforestation) often uncouples cycling 5.Gradient from poles to tropics

Biol 302 Nutrient Cycling22 Annual Nitrogen budget for the undisturbed Hubbard Brook Experimental Forest. Values are Kg, or Kg/ha/yr

Biol 302 Nutrient Cycling23 3. Relatively 'tight' cycling is the norm 2. Inputs and outputs are small in comparison to amounts held in biomass and recycled 4.Disturbances (e.g. deforestation) often uncouples cycling 5.Gradient from poles to tropics

Biol 302 Nutrient Cycling24 Krebs Fig. 27.7; p567 Stream water nitrate concentrations from Hubbard Brook watersheds, NH

Biol 302 Nutrient Cycling25 Concentrations of ions in streamwater from experimentally deforested, and control, catchments at Hubbard Brook.

Biol 302 Nutrient Cycling26 Disturbances (e.g. deforestation) often uncouples cycling, and a consequent:  loss of nutrients (Krebs p567 (Fig 27.7))  x13 normal loss in Hubbard Brook (become Atom X's)  reduction in leaf area  40% more runoff (would have transpired)  more leaching  more erosion, and soil loss  decouples within-system cycling of decomposition and plant uptake processes  all the activities (and products) of spring decomposition get washed away

Biol 302 Nutrient Cycling27 3. Relatively 'tight' cycling is the norm 2. Inputs and outputs are small in comparison to amounts held in biomass and recycled 4.Disturbances (e.g. deforestation) often uncouples cycling 5.Gradient from poles to tropics

Biol 302 Nutrient Cycling28 5. Patterns from: POLARTROPICS DecompositionSlowRapid Proportion nutrients in living biomass Low (mostly (OM) High CyclingSlowRapid

Biol 302 Nutrient Cycling29 Relative proportion of Nitrogen in organic matter components ROOTS

Biol 302 Nutrient Cycling30 Relative proportion of Nitrogen in organic matter components SHOOTS

Biol 302 Nutrient Cycling31 DECOMPOSITION IF SLOW: Nutrients removed from circulation for long periods Productivity reduced Excessive accumulations have impact on soil IF TOO FAST: Nutrient depletion Poor chemistry and physics of soil such as soil fertility, soil moisture and resistance to erosion

Biol 302 Nutrient Cycling32 RATE OF DECOMPOSITION humid tropical forests about weeks temperate hardwood forests years temperate / boreal forests yr Arctic/Alpine / dryland forests >40 years generally, rate of decomposition increases with increase amount of litterfall Residence time … the time required for the complete breakdown of one year’s litter fall

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Biol 302 Nutrient Cycling37 Decomposition Rates influenced by: temperature moisture pH, O 2 quality of litter soil type (influences bugs) soil animals type of fauna / flora rapid if bacterial slow if fungal

Biol 302 Nutrient Cycling38 Decomposition Rates influenced by: temperature moisture pH, O 2 quality of litter soil type (influences bugs) soil animals type of fauna / flora rapid if bacterial slow if fungal

Biol 302 Nutrient Cycling39 Plant species % weight loss in 1 year C/N ratio # bacterial colonies # fungal colonies Bact / Fungi ratio Mulberry9025 Redbud7026 White Oak5534 Loblolly pine 4043 Relationship between rate of litter decomposition and the balance between bacteria and fungi

Biol 302 Nutrient Cycling40 Decomposition Rates influenced by: temperature moisture pH, O 2 quality of litter soil type (influences bugs) soil animals type of fauna / flora rapid if bacterial slow if fungal

Biol 302 Nutrient Cycling41 (J) J A S O N D J F M A % leaf litter remaining 0.5 mm mesh bags 7.0 mm mesh bags

Biol 302 Nutrient Cycling42 Decomposition Rates influenced by: temperature moisture pH, O 2 quality of litter soil type (influences bugs) soil animals type of fauna / flora rapid if bacterial slow if fungal

Biol 302 Nutrient Cycling43 Plant species % weight loss in 1 year C/N ratio # bacterial colonies # fungal colonies Bact / Fungi ratio Mulberry Redbud White Oak Loblolly pine Relationship between rate of litter decomposition and the balance between bacteria and fungi

Biol 302 Nutrient Cycling44 WHAT DETERMINES THE TYPE OF, AND ABUNDANCE OF, MICROFLORA / FAUNA IN THE FIRST PLACE?  activities of soil fauna e.g. earthworms  species of plant producing the litter  chemical composition of the litter  C/N ratio - high gives poor decomposition  microbes need N to use C  N often complexed with nasties (tannin)  o ptimum is 25:1  Douglas fir wood548:1  Douglas fir needles58:1  alfalfa hay18:1  pH of litter and therefore of the forest floor  more acid promotes fungi, less bacteria  moisture and temperature

Biol 302 Nutrient Cycling45 1. Biochemical cycle 2. Biogeochemical cycles 3. Geochemical cycles: exchange between ecosystems examples: carbon and sulphur

Biol 302 Nutrient Cycling46 CARBON CYCLING (Krebs p ) CO 2 is in the atmosphere at 0.03%  99% locked up in coal, oil, limestone, chalk etc. Human activity produces about 5-10% of natural emissions  mostly due to fossil fuels  before industrial revolution 280ppm  currently about 355ppm  projected to be 700ppm by 2100 (unless rather profound change to human activities)

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Biol 302 Nutrient Cycling48  US Energy Information Admin forecast that world emissions will increase by 54% above 1990 levels by 2015, or x2 CO 2 in about 40 years (2030)  Canada produces only 2% of global greenhouse emissions (but with 0.5% of world’s population)  From 1960–1990, Canadian emissions increased by 250%  These GCM (General Circulation Models) predict x2 CO 2 = increase 1.3 to 4.5C

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Biol 302 Nutrient Cycling50 Next Fig.

Biol 302 Nutrient Cycling51 Krebs Fig. 28.9; p592 Concentration of CO 2 emissions in Hawaii

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Biol 302 Nutrient Cycling55 1. Lead to +3C at equator, and +5-8C at poles  a 0.6C increase in world temperatures since 1900  2 nd warmest year historically was 1997; warmest was 1998  ice shelf is melting faster than predicted in Antarctica  retreat of glaciers worldwide  N-ward movement of permafrost in the Mackenzie River Basin

Biol 302 Nutrient Cycling56 Krebs Fig. 28;14; p597 The Greenhouse Effect of CO 2 and other trace gases

Biol 302 Nutrient Cycling57 An estimate of temperature variations over last years, obtained by comparing O 2 isotope ratios in fossils taken from ocean cores in the Caribbean. Dashed line is the ratio from years ago. CLIMATE HAS ALWAYS CHANGED!

Biol 302 Nutrient Cycling58 Next Fig. Average temperature

Biol 302 Nutrient Cycling59 Average temperature Next Fig.

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Biol 302 Nutrient Cycling61 Estimated mean global surface temperatures, 1860 – 1990, relative to

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Biol 302 Nutrient Cycling cm sea level  already rising along the Gulf states  Louisiana losing approx. 40 ha of coastal wetland per day!  15 of the world’s largest cities (London, New Orleans, Cairo, NY, LA)  300m people will be displaced  Fiji, Tahiti, Bangladesh (disappear in the next 100 years)

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Biol 302 Nutrient Cycling % dry matter production  agriculture zones  population zones  most of prairies and Gt. Plains become desert  reserves and parks (1 C can shift miles)

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Biol 302 Nutrient Cycling71 4.Plant and animal responses (Krebs pp ) INDIVIDUAL PLANT RESPONSES (p593) i. increased plant growth x2 CO 2 leads to 40% increase growth in some trees ii. increased water use efficiency iii. Increased reproductive output (fruit, seed etc.) IV. influence migration rates

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Biol 302 Nutrient Cycling73 4.Plant and animal responses PLANT COMMUNITY RESPONSES (p594) i. Increased evaporation in the arctic tundra lose much fish habitat, and migratory birds ii. Release of enormous C-reserves from boreal forests iii. Other effects may be quite minimal

Biol 302 Nutrient Cycling74 Rate Temperature Photosynthesis Respiration Boreal forests 2. Temperate forests 3. Tropical forests

Biol 302 Nutrient Cycling75 Rate Temperature Photosynthesis Respiration Boreal forests 2. Temperate forests 3. Tropical forests 1 – 2.8% increased death rate during El Nino events

Biol 302 Nutrient Cycling76 4.Plant and animal responses INDIVIDUAL ANIMAL RESPONSES i.Migration vertically becomes a problem leads to local extinction

Biol 302 Nutrient Cycling77 TWO PROBLEMS:  rate of change is unprecedented and may be too fast for adaptation  major impact will come from extreme events  heat waves and floods  prob. that a heat wave of >5 days at >35C in Washington D.C. will rise from 17% to 47% with an increase of 3C  prob. of drought in mid-West will increase – 1988, 1993, 1994  more rainfall in India (good), but more flooding in Bangladesh  longer hurricane season  Boreal forest are vast store houses of carbon  fires give off carbon  earlier and drier summers give 50% more fires  20% of excess CO 2 in atmosphere is from forest burning  Amazon fires >1 km 2

Biol 302 Nutrient Cycling78 WEIRD WEATHER (MacLean's, Jan 1999) 1996  Floods in the Saguenay region  10 dead, 2000 displaced from homes  Vancouver's snowfall of the century 1997  Devastating floods in Manitoba; Red River  people displaced from homes

Biol 302 Nutrient Cycling  Ice storm in Quebec and Eastern Ontario (storm of the century)  China’s floods - Yangtze River burst its banks  The hottest year on record, worldwide (after '97, 94, 89)  A 200,000 ha fire in Florida - worst ever  Heat wave in the southern US:  Temperatures over 38 O C for over 2 weeks  Killed over 100 people  Heat wave in India killed 2500  and spawned raging bushfires in Australia  Hurricane Mitch  most devastating hurricane in 200 years  killed an estimated  In US Midwest - spate of tornadoes killed 129

Biol 302 Nutrient Cycling  The Ontario snow storm  In the state of Maine a record low of - 48 O C

Biol 302 Nutrient Cycling81 CENTER FOR CLIMATE MODELING (Environment Canada, Victoria)  violent winter storms will increase from 1 every 20 years to 1 every 10 years  in Canada’s north, extreme daily max. temperatures will peak at 10 O C above present  Record rain and snow storms will deliver 10% more ppt.  and become more frequent  “Vancouver’s famous drizzle ” will become “frequent torrential downpours”  “Blizzards in the east will last longer and dump more snow”  more avalanches  more spring flooding “Toronto’s Storm of ‘99, like Montreal’s Ice Storm of the Century and Winnipeg’s Great Flood, could well turn out to be a mere overture to the far greater wrath of the weather to come”

Biol 302 Nutrient Cycling82 U.S. NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION:  Number of heat waves  3 days has increased 88% between 1949 and 1995  Extreme snow and rainstorms increased 20% since 1900

Biol 302 Nutrient Cycling83 1. CLIMATIC "REALITIES"  The greenhouse effect - real on a planetary scale  Temperature - CO 2 correlations - real in earth's history  Atmospheric build-up of radiatively active gases - real within human observation

Biol 302 Nutrient Cycling84 U.S. Scientists' report doesn’t support the Kyoto treaty (Wall St. Journal November 2001) Last week the U.S. National Academy of Sciences released a report on climate change, prepared in response to a request from the White House, that was depicted in the press as an implicit endorsement of the Kyoto Protocol. CNN's Michelle Mitchell was typical of the coverage when she declared that the report represented “a unanimous decision that global warming is real, is getting worse, and is due to man. There is no wriggle room.”

Biol 302 Nutrient Cycling85 As one of 11 scientist who prepared the report, I can state that this is simply untrue. The full report makes clear that there is no consensus, unanimous or otherwise, about long-term climate trends and what causes them. But - and I cannot stress this enough - we are not in a position to confidently attribute past climate change to carbon dioxide or to forecast what the climate will be in the future.

Biol 302 Nutrient Cycling86 One reason for this uncertainty is that, as the report states, the climate is always changing; change is the norm. Two centuries ago, much of the Northern Hemisphere was emerging from a little ice age. A millennium ago, during the Middle Ages, the same region was in a warm period. Thirty years ago, we were concerned with global cooling. Richard S. Lindzen Professor of Meteorology MIT Member of National Acad. Sciences panel on climate change.

Biol 302 Nutrient Cycling87 2. WHAT CAN THE MODELS TELL US?  GCM's tend to agree on the big picture  1.3 to 4.5C for x2 of CO 2  BUT resolution is poor  they disagree at regional and local levels  they grossly oversimplify clouds and oceans  So, there is much uncertainty and ample room for doubt and scepticism

Biol 302 Nutrient Cycling88 3. THE CLIMATIC FUTURE  some sort of climate change is inevitable  increased frequency of extreme events and greater variability are probable  general warming is probably, but not certain  convincing observation are present  credible models years away

Biol 302 Nutrient Cycling89 SULFUR CYCLE (Krebs p ) Considerable exchange between oceans and atmosphere  mostly in the form of SO 2 and H 2 S Humans produce 160% of natural production  SO 2 emitted by plants, seawater, volcanoes  combustion of fossil fuels and organic matter  H 2 S anaerobic decomposition  H 2 S is oxidized to SO 2  SO 2 combines with atomic O and molecular O 2, and ozone O 3 to produce SO 3  SO 2 + H 2 O = H 2 SO 3 (sulphurous acid)  SO 3 + H 2 O = H 2 SO 4 (sulphuric acid)  NO x + H 2 O = HNO 3 (nitric acid)  NO x can destroy ozone

Biol 302 Nutrient Cycling90 Krebs Fig ; p575 Emissions of SO 2, NO x, and volatile organic compounds (e.g.. Methane) in USA.

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Biol 302 Nutrient Cycling92 ACID RAIN: Horrible topic - much ambiguity  by definition, rain with pH<5.6  'normal' rain is slightly acidic (carbonic acid)  pH 2.7 is common in Pennsylvania; a storm in West Virginia had 1.5 pH

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Biol 302 Nutrient Cycling95 Normal range of pecip.

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Biol 302 Nutrient Cycling97 Acidity of precipitation over Canada and US in 1982; changed little in past 2 decades

Biol 302 Nutrient Cycling98 In 1979 acid rain was described by the Federal Environment Minster (Canada) as “the most serious and pressing environmental problem Canada has ever faced.” Early evidence - absence of lichens on trees  on buildings (Parliament House in Ottawa, Taj Mahal, Capitol Bldg., Acropolis)  more insidious - effects on rivers, lakes and forests  some lakes in the Adirondacks  drop of 2pH units in 30 years i.e. x100!  180 lakes are fishless

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Biol 302 Nutrient Cycling100  estimated that 150,000 lakes of 700,000 in eastern Canada have been damaged  about 14,000 are believed to be acidified (i.e. losing normal life)  140 Ontario lakes are fishless  Nova Scotia, salmon disappearing from streams  In the Czech Republic nearly 60% of the forests d damaged or destroyed  In US, some high elevation spruce forests (Shenandoah and Gt. Smoky Mt) have been affected.

Biol 302 Nutrient Cycling101 Krebs Fig ; p577 Effects of acidification on eastern Canadian Lakes

Biol 302 Nutrient Cycling102 Catch of (percentage of average for ) Atlantic salmon in Nova Scotia streams pH >5 pH < 5

Biol 302 Nutrient Cycling103 PANTHER LAKE SAGAMORE LAKE WOODS LAKE One Rain – Three lakes in the Adirondaks

Biol 302 Nutrient Cycling Mean for Adirondak Lakes s

Biol 302 Nutrient Cycling Small mouth bass Lake trout Brook trout Yellow perch Salamander Mayfly Whirligig Water boatman Mean for Adirondak Lakes s

Biol 302 Nutrient Cycling106 Forests in Czech Republic, killed by acid rain

Biol 302 Nutrient Cycling107 but…  damages cuticle (Black Forest)  interferes with guard cells  disturbs metabolism and poisoning of cells  accelerates foliar leaching  alteration of N-fixation and mycorrhizal fungi  increased susceptibility to other stresses but …  organic forest floor is well buffered  but accelerates leaching of Ca (the buffer)  leads to mobilization of Al  toxic to fine roots  leads to a reduction in growth or die back (Black Forest)

Biol 302 Nutrient Cycling108 ALSO READ p12 of web hand out: ALSO READ p12 of web hand out: effects of acid deposition effects of acid deposition effects of ozone depletion effects of ozone depletion