Earth Systems and Resources – College Board C. Global water resources and use: Freshwater/saltwater Ocean circulation Agricultural (use) Industrial and domestic use Surface and groundwater issues Global problems Conservation

Aquatic Ecology – Terms Abyssal zone Aphotic zone Bathyl zone Benthos (benthic) Currents El Nino Estuary Euphotic Eutrophic Freshwater biome Inland wetlands Intertidal zone Limnetic Littoral

Runoff Thermocline Transition zone Turbidity Upwelling Watershed Marine biome Nekton Oligotrophic Photic zone Plankton Riparian zones

Properties of Water Hydrogen bonding - creates properties of water that enable life to exist High heat capacity High heat of vaporization Expands as it freezes Universal solvent Adhesive/cohesive

Properties of Water High heat capacity Changes temperature slowly Uneven heating/cooling creates winds, currents Moderates climate Cold places are warmer, warm places are cooler High heat of Vaporization – as water evaporates, it removes heat Evaporative cooling

Universal Solvent Water can dissolve a lot of compounds Nitrates, K, Ca, glucose making them available to cells It can easily become polluted by water-soluble wastes

Properties of Water Expands as it freezes Most dense at 4oC Ice forms at the surface Upwelling - cooler water rises to the surface, bringing nutrients into the photic zone Turnover

Thermal Stratification In summer, the surface water is warm - less dense (lighter) Thermocline - middle layer prevents the transfer of nutrients from the bottom and dissolved oxygen from the top Oxygen dissolves into water at the surface Poop and dead stuff floats to the bottom – nitrogen cycle

Fall Turnover Temperature begins to fall Surface layer becomes more dense Sinks to the bottom Nutrients circulate to the surface and oxygen to the bottom Upwelling Winter – layers are fairly even

Spring Turnover Ice melts; cold water warms up Sinks below the cooler (less dense) water Oxygen circulates down and nutrients (nitrates) circulate to top (photic)

Aquatic Life Zones Abiotic factors determine who lives where: Sunlight Salinity Turbidity Temperature Dissolved oxygen Two aquatic biomes – fresh and marine

Marine Biomes – 71 % of Earth Economic benefits: Food Oil, natural gas, minerals Transportation Recreation Ecological benefits: Moderates climate Habitat and nursery areas Absorbs CO2 (CaCO3) Reduces storm impact

Life Zones Plankton – float or weak swimmers Phytoplankton – algae; Diatoms (1o producer) Euphotic zone Zooplankton – 1o consumers Necton – good swimmers Benthos – (benthic) bottom dwellers (barnacles, oysters) Decomposers: breakdown organic compounds (mostly bacteria)

Coastal Biome High tide to continental shelf 90% of all marine life

Estuary Where the river meets the oceans Bays, inlets, sounds, salt marshes, mangrove swamps Highly productive (1o productivity) Nutrient-rich nurseries Filter toxins Prevent beach erosion

Coastal Zones Salt marsh - nursery for many fish Lots of 1o production Prevent beach erosion Filters toxins Intertidal zone – between high and low tides Coral reef - slow growing coral animals build reefs Mutualism with zooxanthellae algae Close to surface

Open Ocean Pelagic Euphotic zone Bathyal zone Abyssal

Stratification Abiotic factors vary with depth: Temperature Sunlight Dissolved oxygen Nutrient availability Euphotic zone - sunlight can penetrate

Lakes Littoral zone (near shore, shallow, with rooted plants) Limnetic zone (open, offshore area, euphotic) Profundal zone (deep, open water, aphotic) Benthic zone (bottom of lake)

Lake Nutrients Oligotrophic - ‘few feed’ Not many food chains Low nutrients

Lake Nutrients Eutrophic – lots of nutrients Shallow, murky; filled with sediment

Cultural Eutrophication Human activities add too much nutrient to lake

Freshwater Inland Wetlands Reduce flooding, erosion caused by storms Replenish streams Recharge groundwater Habitats Nursery, spawning grounds Filter toxins (salt marsh)

Peat Moss Bog A wet area that over time fills in (the last stage of succession is peat moss). Can be very deep. May be burned as fuel.

Water Cycle Runoff - water that does not sink into the ground or evaporate Watershed or drainage basin - the land that drains water into a lake or river

Surface Water Can be flowing (rivers/streams) or standing (lakes, ponds, wetlands) Source – precipitation Watershed – Ex. small streams  larger streams  rivers  sea

Rivers and Streams Deliver nutrients to sea Deposit silt that maintains deltas Purify water Renew and renourish wetlands Provide habitats for wildlife

Headwaters Cold, clear water; waterfalls and rapids High amounts of dissolved oxygen (DO) Oxygen diffuses into water at the surface Many headwaters form a stream/river

Downstream Characteristics Waters spread out, move more slowly, warmer temperatures, less DO Algae and cyanobacteria Littoral zone grows more emergent plants

Freshwater Groundwater - precipitation that penetrates (percolates) the ground and is stored underground (aquifer) Aquifers–porous rock w/ water flowing through Water Table – the level of earth’s land crust to which the aquifer is filled Renewability – the circulation rate of groundwater is slow (300 to 4,600 years).

Water Usage Irrigation Industry – coolant (power plant) Domestic and Municipal We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025 Irrigation = 70%; Industries = 20%; Cities and residences = 10% About 70% of the water is not returned to the sources

Restoration Build huge aqueduct, or find other sources of fresh water and protect it federally under endangered species act, etc.

Flooding Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding. Floodplains, which usually include highly productive wetlands, help provide natural flood and erosion control, maintain high water quality, and recharge groundwater. To minimize floods, rivers have been narrowed with levees and walls, and dammed to store water.

Oxygen released by vegetation Diverse ecological habitat Evapotranspiration Trees reduce soil erosion from heavy rain and wind Agricultural land Steady river flow Leaf litter improves soil fertility Figure 14.23 Natural capital degradation: hillside before and after deforestation. Once a hillside has been deforested for timber and fuelwood, livestock grazing, or unsustainable farming, water from precipitation rushes down the denuded slopes, erodes precious topsoil, and can increase flooding in local streams. Such deforestation can also increase landslides and mudflows. A 3,000-year-old Chinese proverb says, “To protect your rivers, protect your mountains.” Tree roots stabilize soil and aid water flow Vegetation releases water slowly and reduces flooding

Evapotranspiration decreases Roads destabilize hillsides After Deforestation Tree plantation Evapotranspiration decreases Roads destabilize hillsides Ranching accelerates soil erosion by water and wind Winds remove fragile topsoil Gullies and landslides Agricultural land is flooded and silted up Figure 14.23 Natural capital degradation: hillside before and after deforestation. Once a hillside has been deforested for timber and fuelwood, livestock grazing, or unsustainable farming, water from precipitation rushes down the denuded slopes, erodes precious topsoil, and can increase flooding in local streams. Such deforestation can also increase landslides and mudflows. A 3,000-year-old Chinese proverb says, “To protect your rivers, protect your mountains.” Heavy rain leaches nutrients from soil and erodes topsoil Rapid runoff causes flooding Silt from erosion blocks rivers and reservoirs and causes flooding downstream Fig. 14-23b, p. 330

Too Little Water Drought Desertification Lake levels drop, recreation use drops, fisheries drop, and salinization occurs Ex. Soviet Union (Aral Sea); the inland sea drained the river that fed into it.

Water was diverted (irrigation) from the Aral Sea and its two feeder rivers About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared. Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.

Salinization of Irrigated Soil Water is poured onto soil and evaporates. Over time, as this is repeated, nothing will grow there anymore.

Saltwater Intrusion

Miami encroaches on everglades Drained for water and increased development People vs. wildlife