Nutrients high productivity low o2 great lakes

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Unformatted text preview: c: low nutrients low productivity high O2 Eutrophic: high nutrients high productivity low O2 Great Lakes: largest group of freshwater lakes; 20% of world’s freshwater Lakes structure: parallels that of ocean, but on smaller scale Zones: Littoral (rooted plants; waterlillies) vs limnetic (phytoplankton) Epilimnion surface => bottom: epilimnion metalimnion hypolimnion Seasonal changes in lake dynamics mixing of water column = ecologically, most important water movement in lakes dependent on seasonal temperature changes + w ind Summer: thermal stratification (thermocline) prevents mixing Spring & Fall: wind-driven mixing Winter: ice prevents mixing Transitional communities Wetlands: land saturated at least part of the year - water either covers soil or is present at / near surface - water may flow through wetlands or stay in place - often nutrient-rich, highly productive Estuaries: saltwater “wetland” Marsh / Mangrove: Land - Ocean interface Wetlands 3 main types of freshwater wetlands: Swamps: have trees or shrubs (e.g., bald cypress) high productivity Marsh Swamp Marshes: no trees; tall grasses; high productivity Bogs/Fens: may or may not have trees; waterlogged soil, lots of peat; low productivity Fens: fed by groundwater & surface runoff Bogs: fed by precipitation Bog Fen Cedarburg Bog “string bog”: trees in elevated areas (ridges & islands) & sedges in lower, flatter, wetter areas southernmost string bog in North America diverse flora & fauna bladderwort sundew pitcher plant Importance of Wetlands Highly productive: water + nutrients + sunlight => ↑ plants = ↑ animals (i.e., breeding ground for migratory birds) Importance of Wetlands Ecological “services”: trap & filter water: - slow flooding by absorbing runoff (regulate river flow) - hold H2O, give time to percolate thru soil & replenish underground aquifers - silt settles, making water clearer - bacteria break down contaminants (e.g., denitrification) Estuaries: River - Ocean interface Marsh/Mangrove: Land - Ocean interface Fluctuating water cover, salinity & O2 (tides & variation in river flow) Important fish nurseries Salt marshes vs mangrove forests...
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This document was uploaded on 03/17/2014 for the course BIO SCI 310 at Wisconsin Milwaukee.

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