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Coral Reef Ecosystems. Our classical view of any ecosystem. Seen as systems which transform energy and process organic matter. Detritivores. Secondary consumers. Primary consumers. Detritus. Primary producers. Seen as systems which transform energy and process organic matter.
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Our classical view of any ecosystem • Seen as systems which transform energy and process organic matter Detritivores Secondary consumers Primary consumers Detritus Primary producers
Seen as systems which transform energy and process organic matter = pathway for material (or carbon) Secondary consumers Detritivores Detritus Primary consumers Primary producers
Seen as systems which transform energy and process organic matter = pathway for energy = pathway for material (or carbon) Heat Heat Secondary consumers Detritivores Heat Heat Heat Detritus Primary consumers Heat Heat Heat Primary producers
Measuring Ecosystem Dynamics Net water flow C, N, P, O Lagrangian Control Volume
Measuring Ecosystem Dynamics Time 1 Time 2 Eularian control volume
Useful measures of ecosystem ‘metabolism’ Pg = gross primary productivity (gC/m2/day) P/R = community respiration ratio E = excess production (gC/m2/day)
Fore reef Reef crest Back reef Water column Ocean Outer reef slope Lagoon Pg .2-.8 ? 2-7 2-7 2.6-27 .9-12.9 .01-2 E .01-.65 ? -1-5.1 .3-1.5 -8.7-7.3 -.5-3.4 -1.3-1.4 P/R .9-1.38 ? .5-5.5 1-4 .7-3.2 .7-1.4 .1-1.4
Fore reef Reef crest Back reef Water column Ocean Outer reef slope Lagoon Pg .2-.8 ? 2-7 2-7 2.6-27 .9-12.9 .01-2 E .01-.65 ? -1-5.1 .3-1.5 -8.7-7.3 -.5-3.4 -1.3-1.4 P/R .9-1.38 ? .5-5.5 1-4 .7-3.2 .7-1.4 .1-1.4 Algal turfs Seagrass Macroalgae Macroalgae Corals Microalgae 0 2 4 6 8 10 0 2 4 6 8 10
How do coral reefs differ from this model? 1. Fluxes– nutrient and otherwise 2. Scales 3. Fate of the carbon 4. The “unknowns”
Cycles – nutrient and otherwise The level of any nutrient depends partly on the flux between pools Water movement -depends on the type of reef Level of recycling Barrier reef
Cycles – nutrient and otherwise The level of any nutrient depends partly on the flux between pools Water movement -depends on the type of reef Level of recycling Barrier reef Fringing reef
Cycles – nutrient and otherwise The level of any nutrient depends partly on the flux between pools Water movement -depends on the type of reef Level of recycling Barrier reef Fringing reef Atoll
Cycles – nutrient and otherwise Barrier reef Fringing reef Atoll Degree of system closure + (factors increasing) Water residence time, Nutrient recycling, Internal fluxes, Infilling - (factors decreasing) Exports, External connectedness, Boundary fluxes, N limitation
Scales • nutrient level • inputs from ocean • -species composition • -heterotroph/autotroph • composition
Scales • nutrient level • inputs from ocean • -species composition • -heterotroph/autotroph • composition
Fate of the carbon Secondary consumers Detritivores Detritus Primary consumers Primary producers CaCO3
The Unknowns Detritus Dissolved organics Microbial community
The Unknowns Water (& nutrient flux) within a reef
The Unknowns Water (& nutrient flux) within a reef ?