Ecosystem functioningNatural microcosms: eukaryote - microbe symbiosesPowerPoint PresentationSlide 4Slide 5Slide 6Slide 7Slide 8Slide 9DiversityNutrient and energy exchangeSlide 12Slide 13Slide 14Slide 15Slide 16Internal Ecosystem II: Cnidarian and DinoflagellateSlide 18Slide 19Slide 20Slide 21Stability and dynamicsBleachingSlide 24:)Ecosystem functioningThe relationship of diversity to various ecological processes at very, very small scalesNatural microcosms: eukaryote - microbe symbioses•A note about symbiosis•Are frequently “internal ecosystems”•Completely widespread•Very strong interactions–Not simple trophic level interactions –What does this imply about ecosystems that are dominated by these symbioses?arbuscular mycorrhizal fungi & grassesBob-tailed squid and VibrioLegumes and rhizobiaLeaf-cutter ant, fungal cultivar, and protective bacteriaWolbachia and insectsInternal Ecosystem I: The gastrointestinal tract & its microbesTake humans, for example:• Human body contains 1014 cells• 90% of those cells are microorganisms living within us• Colonization changes both temporally and spatially:• Gut flora are initially from mother • They change with environment and eating habitsDiversityVery high diversity: Human colon has at least 400 microbial speciesshort chain fatty acids, vitamins (plus protection against pathogens)anaerobic environment, nutrientsNutrient and energy exchangeHow stable/dynamic are population and community densities?•High diversity in ecosystems w/out variety of structural niches•Despite artificial environmental / biotic disturbance we see:–diversity and community density are maintained–relative population densities change drastically.Internal Ecosystem II: Cnidarian and Dinoflagellate•Symbiosis originated about 225 mya (Stat, 2006)•Occurs in many cnidarians, including:–Corals, anemones, jellyfish•Very low diversity within the host environmentTEMs of coral cells (Gates, 1992)Coral reefs are extremely productive.95% transfer of photosynthate.sugar1° MAA2° MAACHPsugarCO2CAO2free radicalsSODsNutrient and Energy ExchangeStability and dynamicshttp://www.coralcoe.org.au/news_stories/butterflyfish/images/bleachedreeffish.jpgBleaching• Loss of 70-90% of dinoflagellates (Fitt et al., 2000)• Anthropogenic causes lead to irreversible bleaching• Adaptive bleaching hypothesis suggests diversity => stabilityAdaptive bleaching hypothesis:)•Too many citations and sources–Please see me if you are interested in any of
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