A breathing exercise Controls on primary production on land Controls on primary production in waters Secondary production

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1 Outline A breathing exercise Controls on primary production on land Controls on primary production in waters Secondary production

2 What do you suppose is happening here?

3 What do you suppose is happening here?

4 The earth breathes just like we do

5 Summary of the components of productivity

6 Summary of the components of productivity

7 Summary of the components of productivity

8 what controls rates of primary production?

9 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3

10 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3 For a plant this means making tradeoffs

11 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3 For a plant this means making tradeoffs Examples:

12 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3 For a plant this means making tradeoffs Examples: Would I rather retain the water I have or maximize the amount of CO2 I can access?

13 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3 For a plant this means making tradeoffs Examples: Would I rather retain the water I have or maximize the amount of CO2 I can access? Would I rather put lots of roots below ground to get nutrients and water or maximize leaf area so I can have higher photosynthetic rates?

14 what controls rates of primary production? The ultimate goal of all non-human life is to reproduce First principle #3 For a plant this means making tradeoffs Examples: Would I rather retain the water I have or maximize the amount of CO2 I can access? Would I rather put lots of roots below ground to get nutrients and water or maximize leaf area so I can have higher photosynthetic rates? The specific physics and chemistry of the environment determine these tradeoffs

15 what controls rates of primary production?

16 what controls rates of primary production on land: water rates of evapotranspiration (ie availability of water) NPP greatest in warm and wet environments

17 what controls rates of primary production on land: water Amount of precipitation... (ie availability of water) Why does this matter for a plant?

18 what controls rates of primary production on land: water Why can t plants grow as well when there is no water? Short term response: close stoma

19 what controls rates of primary production on land: water medium-term response: reduce leaf area (reduces surface area for water loss) tropical dry forest, NM

20 what controls rates of primary production on land: water Long-term response (adaptation): reduce light absorption (smaller leaves, inclined leaves) change photosynthetic machinery: C4, CAM photosynthesis

21 what controls rates of primary production on land: water

22 what controls rates of primary production on land: light

23 what controls rates of primary production on land: light Photo-oxidation: Radical oxygen species produced under high light stress (inhibits plant growth)

24 what controls rates of primary production on land: light What would these leaves look like? These? These?

25 what controls rates of primary production on land: light

26 what controls rates of primary production on land: nutrients Liebig s law of the minimum! Zn Se C Mo Plants will only grow to Fe Cr Ca Na Co the extent allowed by the least abundant resource not the sum of all resources. V Mg Cu N Ni P S K Mn

27 what controls rates of primary production on land: nutrients nutrients play a role in NPP usually N sometimes P occasionally both

28 what controls rates of primary production on land: nutrients Element % of plant Limiting? C,H,O 90-98% Sort of N 1-4% Yes P % Yes K 1% Rarely S 0.2% Very rarely Mg 0.2% No Ca 0.8% No

29 what controls rates of primary production on land: nutrients The balance of nutrients required to support maximum growth is similar for most plants WHY?

30 what controls rates of primary production on land: nutrients The balance of nutrients required to support maximum growth is similar for most plants WHY?

31 what controls rates of primary production on land: nutrients Alfred Redfield

32 what controls rates of primary production on land: nutrients Alfred Redfield R/V Atlantis

33 what controls rates of primary production on land: nutrients Alfred Redfield R/V Atlantis

34 what controls rates of primary production on land: nutrients Alfred Redfield 106:16:1 R/V Atlantis

35 what controls rates of primary production on land: nutrients Alfred Redfield R/V Atlantis 106:16:1 C:N:P

36 what controls rates of primary production on land: nutrients Alfred Redfield REDFIELD RATIO: THE COOLEST NUMBERS IN THE WORLD!!!!!!!!!!!!!! R/V Atlantis 106:16:1 C:N:P

37 what controls rates of primary production on land: nutrients

38 what controls rates of primary production on land: nutrients Redfield ratio: 16 N : 1 P (Molar Ratio) A couple of rules to remember: 1: Any nutrient present at less than the optimal balance is likely to limit growth 2: plants invest preferentially to find the nutrient that most strongly limits growth

39 Lets do a thought exercise 1. If you wanted to determine what was limiting growth how could you do it besides adding different nutrients and seeing which grows best?

40 Lets do a thought exercise 1. If you wanted to determine what was limiting growth how could you do it besides adding different nutrients and seeing which grows best? If N:P ratio = 24? If N:P = 16? If N:P = 7?

41 what controls rates of primary production in the sea? Many of the same things that control it on land... light and nutrients!

42 what controls rates of primary production in the sea? Areas of upwelling bring deep, nutrient rich water to the surface to support primary production

43 what controls rates of primary production in the sea? Upwelling mixes high nutrient deep water in to surface waters

44 what controls rates of primary production in the sea? Due to upwelling the western edge of the oceans are most productive. Why are the centers of the ocean not very productive?

45 What causes spatial variation in climate? higher lower vertical movement horizontal movement

46 What causes spatial variation in climate? higher lower vertical movement horizontal movement Cold, dense liquids (air or water) fall, and hot, less dense liquids rise First principle #7

47 what controls rates of primary production in the sea? Hot liquids rise...cold liquids sink... In the case of the middle of the ocean this is called: THERMAL STRATIFICATION

48 what controls rates of primary production in the sea? We know nutrients matter from experiments too. Both in the ocean...

49 what controls rates of primary production in the sea?...and in lakes

50 what controls rates of primary production in the sea? Fish and squid production (g/ m sq/ year) Iverson (1990, in Jennings et al.) Phytoplankton production (g C/m sq/ yr) In both the oceans and on land, primary production matters because secondary production matters.

51 Primary production matters because it supports secondary production!

52 Primary production matters because it supports secondary production!

53 Primary production matters because it supports secondary production!

54 Primary production matters because it supports secondary production! Not all producers are created equally The amount of NPP that ends up being eaten is the exploitation efficiency

55 Components of secondary production Respiration, maintenance Gross primary production (GPP) Net primary production (NPP) Ingestion by herbivores Exploitation efficiency = Ingestion/NPP

56 Components of secondary production Plant Defenses trichomes (epidermal outgrowths) mechanical - disrupt herbivory exude noxious substances: makes plant unpalatable flower bud of capsicum trichomes on Cannibis contain noxious cannabinoids (aka THC)

57 Components of secondary production Tough indigestible tissue bark waxy/tough leaves lignified cell walls silica in cell walls Plant Defenses

58 Components of secondary production phenolics Plant Secondary Compounds tannins in high concentration in leaves of angiosperms and gymnosperms; reduce digestibility of plant tissue lignins provide structural strength and a barrier to herbivores alkaloids nitrogenous compounds with a bitter taste that can be toxic cocaine, caffeine, nicotine terpenes (mostly conifers) multiple units of the hydrocarbon isoprene (C 3 H 8 ) latex sap of Euphorbiaceae (spurge familiy) oil compounds in Lamiaceae (mint family) glucosinolates (bitter taste found in brussels sprouts, cabbage, etc) deter mammals and non-adapted insects found in Brassicaceae (mustard family)

59 Components of secondary production phytoplankton don t have these defenses... Question to ponder: why is the earth green and the ocean blue?

60 Components of secondary production Amount of energy actually absorbed from food is assimilated energy Assimilation efficiency proportion of ingested energy actually absorbed by the body seeds 80% young vegetation 60-70% grazing/browsing 30-40% wood 15% animals 60-90%

61 Components of secondary production Respiration, maintenance Gross primary production (GPP) Net primary production (NPP) Ingestion by herbivores Assimilation efficiency = Assimilation/Ingestion Indigestible Assimilation

62 Components of secondary production Growth and reproduction in heterotrophs adds biomass Net growth efficiency (also called Net production efficiency) = (biomass production)/(assimilated energy) the proportion of energy not used for maintenance and not lost as heat birds: 1% small mammals: 6% cold-blooded animals: 75%!

63 Components of secondary production Respiration, maintenance Gross primary production (GPP) Net primary production (NPP) Ingestion by herbivores Net Production Efficiency = Growth/Assimilation Respiration, maintenance Indigestible Assimilation Growth

64 Components of secondary production Respiration, maintenance Gross primary production (GPP) Net primary production (NPP) Decomposition Ingestion by herbivores Ingestion by predators Respiration, maintenance Growth Indigestible Assimilation

65 Synthesis of secondary production