Aquatic Biomes Broad aquatic ecological associations can be
• Aquatic Biomes Broad aquatic ecological associations can be characterized by their physical environment, chemical environment, geological features, photosynthetic organisms, and heterotrophs
97% oceans 2% glaciers 1% lakes, rivers, streams Solar energy Transport over land Net movement of water vapor by wind Precipitation Evaporation over ocean from ocean Precipitation over land Evapotranspiration from land Runoff and groundwater Percolation through soil
30ºN Lakes Coral reefs Rivers Oceanic pelagic and benthic zones Estuaries Intertidal zones Tropic of Cancer Equator Tropic of Capricorn 30ºS fresh water or salt water (marine) Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere
Inland aquatics “Areas of marsh, fen, peatland, or water, whether natural or artificial, permanent or temporary, static or flowing, fresh, brackish, or salt, including areas of marine water, the depth of which at low tide does not exceed 6 meters” International Union for the Conservation of Nature ENSC 2400 will cover the intertidal in Marine Biomes lecture
Running water flows down • Standing water – LENTIC systems • Flowing water – LOTIC systems
Oligotrophic lakes Lakes Eutrophic Lakes
Fig. 52 -18 d Streams and Rivers Current Life Effect of damming A headwater stream in the Great Smoky Mountains The Mississippi River far from its headwaters
Fig. 52 -18 c Wetlands Okefenokee National Wetland Reserve in Georgia
Fig. 52 -18 f Estuaries An estuary in a low coastal plain of Georgia
Fig. 52 -16 a Littoral zone Limnetic zone Photic zone Benthic zone Pelagic zone Aphotic zone Rooted and floating aquatic plants live in the shallow and well-lighted littoral zone Limnetic zone is too deep
Stratification - Dimictic example, effects oxygen and nutrient levels in water 2º 4º 4ºC Summer Spring Winter 0º 4º 4º 4ºC 4º Thermocline Autumn 22º 20º 18º 8º 6º 5º 4ºC 4º 4º 4ºC 4º
Hydrology and wetland diversity • Climate (rainfall, temperature, seasonality) • Geomorphology (soils, geology, relief) Impact defined by the water budget where the volume of water depends on Precipitation Interception Surface flow Groundwater in and outflow Tidal flow
• General Water budgets • Marsh – Borders open water (rivers, estuaries), high energy, may be tidal, no OM buildup, plenty of dissolved O 2 • Swamp – Occur in depressions, low energy, OM buildup – peat formation, low O 2 • Bog- On level ground high rain, low evaporation, low energy, organic sediment, high water table Precipitation Interception Surface flow Groundwater in and outflow Tidal flow
Permanence and periodicity Hydroperiod: Frequency of inundation tidal marsh groundwater fed (constant) vernal pool seasonal rapid flooding from rain or meltwater
Hydrology factors and results High energy Low Energy • Streams, rivers, tidal marshes • High dissolved O 2 • High flushing • Open cycling • Erosion dominant • Not much organic matter • High primary productivity • Benthic invertebrates • Swamps and bogs and lakes • • Low dissolved O 2 Low flushing Closed nutrient cycling Sedimentation dominant Organic matter accumulates Variable Primary Productivity Benthic/planktonic inverts.
Human impacts • Water removal for human use – Wetlands drained, rivers dammed, groundwater depleted – Sustainable water usage requires considering the needs of the environment – Global warming effects on montaine snow
Environmental factors • Light, Temperature, Dissolved O 2, p. H, Salinity, Nutrients, Stratification
Light • Light penetration depth determines how deep photosynthesis can occur • Penetration of light into the water depends on color of the water and turbidity – Color – caused by dissolved substances from decaying organic matter – Turbidity – from suspended materials (clay, algae) • Depends on flow, erosion, rainfall rate
Human Impacts - Light • Clearing vegetation – increased sediment, less shading, quicker photodegradation of organic matter • Runoff from impermeable surfaces (roads) • Nutrients in sediments cause algal blooms, clog gills, increase turbidity for other aquatic vegetation
Temperature and Dissolved O 2 Temperature • Temperature more variable due to shallower depth • Changes seasonally or daily • Affects stratification, metabolism • Affects dissolved O 2 • Human impacts include: – Tree clearing reduces shading – Warm/cold water pollution release from power plants or dams Dissolved O 2 (DO) • Depends on energy of system, temp, photosynthesis, and stratification • Used during respiration and decomposition • Fish kills occur when DO is low – Secondary human impacts due to effects on other things like temperature
p. H (acidity), Salinity p. H Salinity • Decreases due to decomposition • Reduces wetland metabolism at extremes (peat or limestone bogs) • Human impacts include acid rain (Nox, SO 2) from power generation , acid sulfate soils in depleted waters. • Lowered p. H increases availability of heavy metals which then kills fish • Heavy metal waters can pollute groundwater • Salts – Fresh water, brackish, sea water, salt marsh, hypersaline • Changes in salt concentration affect osmoregulation of animals
p. H (acidity), Salinity p. H • Decreases due to decomposition • Reduces wetland metabolism at extremes (peat or limestone bogs) • Human impacts include acid rain (Nox, SO 2) from power generation , acid sulfate soils in depleted waters. • Lowered p. H increases availability of heavy metals which then kills fish • Heavy metal waters can pollute groundwater Salinity • Salts – Fresh water, brackish, sea water, salt marsh, hypersaline • Changes in salt concentration affect osmoregulation of animals • Human impacts: secondary salinity (removal of deeper rooted perennials with shallow rooted annuals, or through irrigation ) causes salts from the soil to rise and stay in surface soil. Then runoff adds salinity to waterways.
Fig. 55 -14 c N 2 in atmosphere Assimilation Nitrogen-fixing bacteria NO 3– Decomposers Ammonification NH 3 Nitrogen-fixing soil bacteria Nitrification NO 2– NH 4+ Nitrifying bacteria Denitrifying bacteria Nitrifying bacteria
Fig. 55 -14 d Precipitation Geologic uplift Weathering of rocks Runoff Consumption Decomposition Plankton Dissolved PO 43– Uptake Sedimentation Leaching Soil Plant uptake of PO 43–
Oligotrophic lakes Lakes Eutrophic Lakes
Eutrophication • When excess nitrogen and phosphorus is discharged from the watershed, massive algal blooms develop which result in the depletion of dissolved oxygen.
Pollution A Dead Zone 6, 000 -7, 000 sq miles develops
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