Ecology Week 4 Class Notes
Ecology Week 4 Class Notes BIOL 3060
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This 6 page Class Notes was uploaded by Naomi Hampton on Wednesday September 21, 2016. The Class Notes belongs to BIOL 3060 at Auburn University taught by Dr. John Feminella in Fall 2016. Since its upload, it has received 5 views. For similar materials see Principles of Ecology in Ecology at Auburn University.
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Date Created: 09/21/16
BIOL 3060 9/6/16 Surface-Fresh Water <0.05% o Distribution Aquatic (61%) Lakes/reservoirs (60%) Streams (1%) Terrestrial (33%) Atmospheric (6%) Hydrologic Cycle-interactions of all sources of2H O o o When precipitation>infiltration, will have overland flow o Urbanization ↑, permeability ↓ o ↑ urbanization ↓ infiltration & interception o ↓permeability→↑overland flow ↑flooding ↑erosion ↑sedimentation & nutrient runoff ↑pollution ↓water quality Nutrient=energy source/fuel=element ~60 elements common in Biosphere; 30-40 in organism Sources of Nutrients: o Terrestrial system Inorganicchemical weathering rocks/soil Organicorganismsdecompositionsliberates nutrients o Aquatic Dissolved/precipitated in sediments Organic/inorganic o Atmosphere O, P,S, H, N Sources for organisms o Plants (autotrophs)-(local ambient environment) o Animals/microbes (heterotrophs) 18 essential nutrients/elements o Carbon o Hydrogen o Oxygen o K o Calcium o Mg o Nitrogen o Phosphorous o Sulfur o Fe o Mn o Boron o Iodine o Cu o Zn o Nickel o Mo o Cl Macronutrients o Need >1000mg/kg o C HOPKiNS Car Is an Mg Micronutrients o A Festive MoB Comes in Clapping Nicely Decomposition o Breakdown of organic matter o Food webs o Decomposition=nutrient cycling Simple cycle: living organismdeathdecomposers nd colonizebreakdownnutrient transformation/releaseuptake by 2 organismdeathetc. Energy passes through system only once whereas nutrients are continually recycled Carbon Cycle: Think P and R o Leaf litter decomposition o Stages of breakdown: Leaching (first 24hrs) Microbial conditioning (weeks) Fragmentation/skeletonization (months) 9/8/16 Quantifying Breakdown Rule o K=-ln(x/xt)0t o Natural experiment, no control group, just treatments o Time-series experiment o Why the difference? Differences in temp/moisture Role of Physical and Chemical actors in Breakdown o Soft leaves w/higher nitrogen content lost more mass o Tough leaves w/lower nitrogen content lost less mass o N content vs. Toughness (lignin) o Role of Leaf Lignin in Breakdown o Leaves with higher lignin content decompose at much slower rate o Common Pattern of Breakdown o “Exponential Decay” model o Each time x increases by 1, y decreases by half its previous value Role of Abiotic Factors in Forest Litter Breakdown o Which shows the better fit? Use of linear regression to test strength of a relationship R =1 means all points are on the line Regression or correlation does not imply causation K vs. K Decomposition Experimentrature Precipitation o Question: Do leaves containing more carbon compounds (lignin) degrade more slowly? Bigleaf magnolia vs. southern magnolia o Question: Does presence of macroinvertebrates accelerate leaf decomposition? Coarse vs. fine mesh bags Physiological Ecology o Essential nutrients o Sequestration: P:~1.5x more abundant in organism C:~367x N:~220x Limiting Factors o Factor governing success of organism (population) o Key points: Success limited by supply If limitednegative effect (impact) o Types of Limiting Factors: Condition: (eg. Temperature) Varies in space & time Can’t be lowered by organism Resource: (eg. Water, nutrients, space) Varies spatially & temporally Can be lowered by organism Limiting resources: o H O2(moisture) o O 2 o Light o Nutrients (some) Limiting Factor Desert Stream H2O (moisture) Resource Condition O Condition Resource 2 Light Condition Resource Nutrients Resource Resource o von Liebig limiting factorslaw of the minimumthe most limiting nutrientgoverns success PNK-most limiting in the environment