Lecture13_EcosystemsA0

Lecture13_EcosystemsA0 - Last Time How do energy and matter...

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Unformatted text preview: Last Time How do energy and matter move through ecosystems? Objectives 1. Relate trophic structure of ecosystems to the movement of matter and energy in ecosystems. 2. Trace the cycling of matter and flow of energy through ecosystems. 3. Understand what factors limit primary production and the types of experiments used to identify them. • Comparing communities - Diversity (richness, evenness) - Food webs (trophic structure) - Control (top-down, bottom-up) • • Disturbance & succession Global diversity patterns Thursday, November 12, 2009 1 Thursday, November 12, 2009 2 Scale in Ecology Trophic Structure • • • Population = group of individuals of the same species living in the same place at the same time Community = assemblage of interacting populations Ecosystem = community of organisms and the abiotic factors influencing that community • Trophic Structure: The different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical (matter) cycling Energy Flows... Food Matter Cycles... Population Community Ecosystem Thursday, November 12, 2009 3 Thursday, November 12, 2009 4 How do organisms get “food”? Trophic Level Autotrophs - Primary producers Heterotrophs - Primary consumers - Secondary consumers - Tertiary consumers - Decomposers Examples: Plants, some bacteria, some algae Make their own food; self-sufficient Eat plants; herbivore Eat primary consumer; carnivore Eat primary & secondary consumers; carnivore Eat dead things; recycle nutrients back to soil (some bacteria, fungi) How do organisms get “food”? Trophic Level Autotrophs - Primary producers Heterotrophs - Primary consumers - Secondary consumers - Tertiary consumers - Decomposers Energy Sun Matter CO2 from atmosphere, water, some nutrients from soil primary producers primary consumers primary & secondary consumers dead things Thursday, November 12, 2009 5 Thursday, November 12, 2009 6 Energy Flows and Matter Cycles Photosynthesis CO2 + H2O → glucose (C6H12O6) + O2 Energy Flows and Matter Cycles Rabbit eats grass: • What happens to the matter? - Law of conservation of mass - Body, waste - Where is the energy after photosynthesis? -- chemical bonds Cellular Respiration Organic compounds (e.g. glucose) + O2 → CO2 + H2O - Where is the energy now? -- other chemical bonds (plant growth) • What happens to the energy? - Second law of thermodynamics - Metabolism, heat Thursday, November 12, 2009 7 Thursday, November 12, 2009 8 Energy Flows and Matter Cycles Tertiary consumers Microorganisms and other detritivores Anza-Borrego Desert Food Web • • Hawk With your neighbor: Compare your food webs. List producers, primary consumers, secondary consumers, decomposers What is the food web/model depicting? Hawk Coyote Rattlesnake Secondary consumers Detritus Primary consumers Primary producers Heat Key Chemical cycling Energy flow Sun Rattlesnake Mouse Plant Lizards Insects Mice Rabbit Fungi/Bacteria Thursday, November 12, 2009 9 Thursday, November 12, 2009 Plants 10 -(.)) -) %+7(% !#&+7),-:7% % 9(8($+%,4% 2%+7(% % Energy Flow !"#$%&'()4'$-(.)5%"+) Energy Flow • • • How is •!rophic structure t =7'+%.6%8.66.$:%.$%+7.6% 8,1(>D% depicted in this model? E,2%.6%*#+,-./&0*#1/*1#!& Why is •! 1(&.?+(1%.$%+7.6%8,1(>D% this model shaped as a pyramid? •! =73%.6%+7.6%8,1(>%67'&(1% How could we represent '6%'%&3)'8.1D% energy flowing through this system?•! E,2%?,->1%2(%)(&)(6($+% $'$-(.%F,2.$:%+7),-:7% +7.6%636+(8D% • How much energy enters a food web? 0.8% photosynthesis 45% respiration growth 34% dead material (decomposers) storage & roots eaten (herbivores) reflection, heat, absorbed Energy transfer is inefficient! Only ~10% of energy put into plant growth enters the grazing food web Plant material eaten by caterpillar Thursday, November 12, 2009 6"+)$=0&$'9)&:)$'$-(.)9-2':,$-) ;$9+$$')9-">8&0?%$@$%:<) 11 Thursday, November 12, 2009 Feces Cellular respiration 12 Growth (new biomass) Coral Reef Degradation CQ Energy Flow Energy Flow This graph represents fish biomass on the Line Islands. These islands vary in the amount of human impacts (pop. size, fishing, pollution) that they have. 1.5 11 37 809 Coral Reef Degrad • Trophic efficiency: % of production transferred from one trophic level to the next - Reflects energy lost from uneaten, waste, respiration, heat - Usually 5 to 20% Tertiary consumers 10 J Trophic level 100 J Dry weight (g/m2) Secondary consumers Tertiary consumers Secondary consumers Q: What is the shape of the biomass pyramid on Kingman Is.? A. Figure 2. General aspect of fore reef habitats (left column) and representative 0.5-m2 photos of the bottom (right column) at Kingman (A–B), Palmyra (C–D), Tabuaeran (E–F), and Kiritimati (G–H), showing the degradation from a reef dominated by top predators and corals (Kingman) to a reef dominated by small planktivorous fishes and algae. Photo credits: A by Zafer Kizilkaya, B–H by Jennifer Smith. doi:10.1371/journal.pone.0001548.g002 Low Human Impacts High Primary consumers Primary consumers 1,000 J Primary producers Primary producers Pyramid of biomass 10,000 J 1,000,000 J of sunlight B. Figure 3. Fish biomass (A) and abundance (B), and cover major benthic functional groups (C) across the northern L Islands. Note that human impacts increase from left to right in this subsequent figures. CCA = crustose coralline algae. doi:10.1371/journal.pone.0001548.g003 Pyramid of production (energy) Thursday, November 12, 2009 13 Matter Cycles: Radish Experiment 1.5g 1.5g 1.5g Light, No Water Light, Water Dark, Water • • One week later, all plant material was dried in an oven (no water left) Plant biomass was measured in grams dominant predators at Kingman were snappers, jacks and sha (median total length = 33 cm, maximum = 200 cm) versus sm groupers (principally Epinephelinae; median = 13 cm, m Figure 3. Fish biomass (A) and abundance (B), and cover of mum = 65 cm) at (C) across Sharks comprised 74% of the major benthic functional groups Kiritimati.the northern Line Figure 2. General aspect of fore reef habitats (left column) and evaluate the effects 2009 Islands. that human impacts increase g m22 at Kingman and representative 0.5-m2 photos of the human populations at Thursday, November 12,of increasingbottom (right column) at Kiritimati Note predator biomass (329 from left) to right in this and 1457% at Palm subsequent figures. CCA22 Kingman (A–B), Palmyra (C–D), the baselines of Palmyra and Kingman. and Tabuaeran relative to Tabuaeran (E–F), and Kiritimati ), whereas they were (97 g m = crustose coralline algae. virtually absent at Tabuaeran doi:10.1371/journal.pone.0001548.g003 (G–H), showing the degradation from a reef dominated by top Detailed description of the microbial community is reported in a Kiritimati. Thus, the typical fish biomass pyramid observed predators and corals (Kingman) to a reef dominated by small companion paper [31]. planktivorous fishes and algae. Photo credits: A by Zafer Kizilkaya, dominant predatorsreefs around the snappers, jacks and sharks including thos most at Kingman were world today [12,32,33], B–H by Jennifer Smith. (median totalTabuaeran cm, maximum = 200 inverted atsmall length = 33 and Kiritimati, is cm) versus Kingman and Palm doi:10.1371/journal.pone.0001548.g002 CQ groupers (principally biomass pyramids of = 13 cm, maxi- been documen Results Inverted Epinephelinae; median fishes have only mum = 65 cm) at Kiritimati. Sharks comprised 74% of the top elsewhere in the Northwestern Hawaiian Islands [23]. Therm Reef the effects evaluate Fishes of increasing human populations at Kiritimati predator biomass (329 g m22) at Kingman and 57% at Palmyra dynamic were virtually absent at require that Biomass relative to the baselines Palmyra varied greatly(97 g m22), whereas theyconstraints, however,Tabuaeran and inverted biom from and Tabuaeran and abundance of ofreef fishand Kingman. Detailed description of the microbial community is reporteddecreased from pyramids be supported by bottom-heavy pyramids of produc Kingman to Kiritimati (Fig. 2). Total fish biomass in a Kiritimati. Thus, the typical fish biomass pyramid observed at companion132 g m22 (1-way ANOVA on atoll effect, F most reefs around the world today [12,32,33], includingrates of predators are m [34,35]. This suggests that turnover those of 527 to paper [31]. 3,97 = 27.6, Tabuaeran and Kiritimati,of their prey,Kingman and Palmyra. lower than is inverted at and that trophic efficiency is high a p,0.0001; Fig. 3A) whereas total abundance increased from 4 to Results Inverted levels. Such of fishes have only been documented 12 fishes m22 (F3,97 = 69.2, p,0.0001; Fig. 3B). This contrasting biomass pyramids dramatic alterations of rates and pathways of trop elsewhere in the Northwestern Hawaiian Islands [23]. ThermoReef Fishes flow have been require little research effort pattern of fish biomassof and abundance greatly from shiftdynamic constraints, however,afforded that inverted biomass to date (see nota reflects a from Biomass and abundance reef fish varied [36]). dominance by a (Fig. 2). Total fish biomass at Kingman many supported inbottom-heavy pyramids of production Kingman to Kiritimatifew large top predatorsdecreased from to pyramids be exceptionby biomass (A) and abundance (B), and cove Figure TheFish turnover lower trophic level fish assemblages 3. that much smaller, (1-way ANOVA on atoll effect, F3,97 = 27.6, [34,35]. 527 to 132 g m22 lower trophic level consumers, especially plankti- This suggests structure of rates of predators are much major benthic functional groups (C) across Figure 2. GeneralatFig. 3A) of foretotal abundance increasedfrom 4 to andlowerto ofchanged across the gradient. Carnivores all the northern vores, Kiritimati. Species habitats (left column) p,0.0001;aspect whereas reefrichness increased from Kingman than their prey, and that trophic efficiency is high at (principally preda Islands. Note that human impacts increase from left to right in this representative 0.5-m2 3,97 = 69.2, of the bottom (right in fish abundance 12 fishes m22 (F photos tracking the increase contrasting atlevels. Such dramatic alterations of rates and pathways of trophic upon invertebrates) had lower biomass at Kingman and Palm Kiritimati, generally p,0.0001; Fig. 3B). This column) subsequent figures. CCA = effort to coralline algae. Kingman (A–B), Palmyra (C–D), Tabuaeran reflects and Kiritimatiflow have been afforded little researchcrustose date (F notable p,0.0001). Sm pattern of1,fish biomass and abundance (E–F), a shift from than at Tabuaeran and Kiritimati (see = 68.1, (Table Fig. 3B). doi:10.1371/journal.pone.0001548.g003 3,97 dominance degradation from a reef Kingman to many topexception at dominated by (G–H), showing theby a few large top predators85% of total fish biomass at in [36]). planktivores trophica level fish assemblages also only few centimeters in length were the m Top predators accounted for predators much smaller, lower trophic level a reef dominatedplanktiand corals (Kingman) to consumers, especially by small The structure of lower numerous fish at Kiritimati, but planktivo Kingman, and (Fig. 3A). The vores, at Kiritimati. decreased to 19% at Kiritimati Kizilkaya,changed across the predators all atolls, especially atsnappers, jacks and sh planktivorous fishes and Species richness increased A by Kingman to algae. Photo credits: from Zafer dominant gradient. Carnivores (principally predators at Kingman were upon invertebrates) had lower biomass at Kingman and Palmyra Kiritimati, generally tracking the increase in fish abundance B–H by Jennifer Smith. (median totalKiritimati = 33 = 68.1,maximumSmall cm) versus s length (F cm, p,0.0001). = 200 than at Tabuaeran and (Table 1, Fig. 3B). 3,97 doi:10.1371/journal.pone.0001548.g002 groupers (principally Epinephelinae;| Volume 3 = Issue 2 | e1 median | 13 cm, m PLoS ONE | www.plosone.org 4 February 2008 Radish Experiment • In Your Notebook: Predict the biomass of each treatment. Treatment Initial Biomass (g) Final Biomass (g) A. Light, No Water 1.5g B. Light, Water 1.5g Top predators accounted for 85% of total fish biomass at Kingman, and decreased to 19% at Kiritimati (Fig. 3A). The planktivores only a few centimeters in length were the most numerous fish = 65 atolls, especially at Kiritimati, but planktivores mum at all cm) at Kiritimati. Sharks comprised evaluate the effects of increasing human populations at Kiritimati and Tabuaeran PLoS ONE |to the baselines of Palmyra and Kingman. relative www.plosone.org 4 Detailed description of the microbial community is reported in a Dark, Water 1.5g companion paper [31]. C. Results Reef Fishes Thursday, November 12, 2009 15 Biomass and abundance of reef fish varied greatly from Kingman to Kiritimati (Fig. biomass?biomass decreased from 2). Total fish 527 to 132 g m22 (1-way ANOVA on atoll effect, F3,97 = 27.6, p,0.0001; Fig. 3A) whereas total abundance increased from 4 to Thursday, November 12, 2009 12 fishes m22 (F3,97 = 69.2, p,0.0001; Fig. 3B). This contrasting pattern of fish biomass and abundance reflects a shift from dominance by a few large top predators at Kingman to many • Which treatment do you 74% of the predator biomass (329 g m22) at Kingman and 57% at Palm 22 (97 g m ), whereas theyVolume 3 | Issue 2 |absent at Tabuaeran February 2008 | were virtually e1548 Kiritimati. Thus, the typical fish biomass pyramid observe most reefs around the world today [12,32,33], including tho Tabuaeran and Kiritimati, is inverted at Kingman and Palm Inverted biomass pyramids of fishes have only been docume elsewhere in the Northwestern Hawaiian Islands [23]. think will have the highest that inverted Ther dynamic constraints, however, require bio pyramids be supported by bottom-heavy pyramids of produc [34,35]. This suggests that turnover rates of predators are m lower than of their prey, and that trophic efficiency is high a 16 levels. Such dramatic alterations of rates and pathways of tro flow have been afforded little research effort to date (see no exception in [36]). Radish Experiment: Results Treatment Light, No Water Radish Experiment Final Biomass (g) 1.46g Why?? Light, Water 1.83g Dark, Water 1.17g 1.46 g 1.83 g 1.17 g Thursday, November 12, 2009 17 Thursday, November 12, 2009 18 CQ The majority of actual weight (biomass) gained by plants as they grow comes from: A. Organic substances in soil that are taken up by plant roots B. Minerals dissolved in water taken up by plant roots C. Carbon dioxide in the air that enters through leaves D. Energy from the sun that is captured by leaves E. Carbon from decomposed leaf litter in soil How do plants get atmospheric CO2? • Stomata are microscopic pores on the surface of leaves that allow exchange of air between the plant and the atmosphere. Thursday, November 12, 2009 19 Thursday, November 12, 2009 20 How do plants get atmospheric CO2? Most important reaction in the world!! In a plant, what happens to the glucose? photosynthesis CO2 + H2O → glucose (C6H12O6) + O2 reflection, heat, absorbed Calvin-BensonBassham Cycle CO2, H2O respiration growth (biosynthesis) ATP Legend: → Energy Transfer → Carbon Transfer New Organic Molecules (carbs, fats, lipids, nucleic acids) Thursday, November 12, 2009 21 Thursday, November 12, 2009 22 CQ Primary Production Primary Production • • Gross Primary Production (GPP): The amount of carbon fixed by photosynthesis • Which treatment has a positive NPP? A. Light, no water B. Light, water C. Dark, water - Measured as grams C/area/time Net Primary Production (NPP): The amount of photosynthate available to organisms as food - NPP = GPP - Respiration - Measured in grams - Measure using fancy equipment, weigh or count plants Thursday, November 12, 2009 23 Thursday, November 12, 2009 24 Net Primary Production Net Primary Production • Satellite measures of chlorophyll • Satellite measures of chlorophyll http://www.nasa.gov/centers/goddard/mpg/97462main_npp_20012002_sm.mpg Thursday, November 12, 2009 25 Thursday, November 12, 2009 26 Net Primary Production Net Primary Productivity • Why are oceans so unproductive? What environmental factors influence NPP? • CO2 + H2O Photosynthesis Possible Limiting Factors: CO2 H 2O light Temperature nutrients If light is limiting ocean productivity, we’d expect to see higher productivity at the equator than the poles C6H12O6 + O2 Respiration CO2, H2O Thursday, November 12, 2009 Biosynthesis ATP New Organic Molecules (carbs, fats, lipids, nucleic acids) 27 Thursday, November 12, 2009 28 Net Primary Productivity Net Primary Production • Could nutrients be limiting NPP in the ocean? How would you test this? • Oceans are primarily limited by nitrogen - Some areas of high productivity -- why? - Fertilizer run-off, upwelling Thursday, November 12, 2009 29 Thursday, November 12, 2009 30 Net Primary Productivity Net Primary Productivity Phytoplankton • Coast of South America has high productivity Temperature • What limits NPP in freshwater ecosystems? C + N added Top: C + N added - Upwelling: Nutrient-deep rich water circulates to the ocean surface (winds, currents) El Niño (1997) can be stopped, for example during El Niño (ENSO) events - Lake-sized experiments Bottom: C + N + P added - Sometimes this upwelling • Phosphorus often limits primary productivity in freshwater systems C + N + P added La Niña (1998) View from above Lake 226 divider curtain in August 1973. The bright green colour results from bluegreen algae (Cyanobacteria), which are growing on phosphorus added to the near side of the curtain. 32 By the mid-1970's, North American interest in eutrophication had waned. However, this "nutrient pollution" problem remains the number one water quality problem worldwide. Eutrophication research at the ELA has continued in Lake Thursday, November 12, 2009 31 Thursday, November 12, 2009 CQ Net Primary Productivity What is the limiting factor in this ecosystem? • What about in terrestrial systems? A. Nitrogen B. Phosphorus C. Nitrogen and Phosphorus - Actual evapotranspiration: Measure combining light, water, and temperature Possible Limiting Factors: CO2 X H2O ✓ light ✓ Temperature ✓ nutrients ? Thursday, November 12, 2009 33 Thursday, November 12, 2009 34 Mount Saint Helens Announcement Bring a calculator to discussion section next week (Nov 16-20) • • Assignment: How do volcanic eruptions affect energy and carbon cycling? Due in class 11/17 ! Thursday, November 12, 2009 35 Thursday, November 12, 2009 36 ...
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This note was uploaded on 12/02/2009 for the course BILD BILD 3 taught by Professor Woodruff during the Fall '08 term at UCSD.

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