Chapter 12 Flashcards
Fresh Water, Oceans, and Coasts
Fresh water
water that is relatively pure/free from salts (2.5% of Earth’s water)
Surface water
located atop Earth’s surface (like rivers/lakes)
Groundwater
water beneath the surface (in pores in soil/rock); water that does not evaporate, flows into waterways, or gets taken up by organisms
Aquifers
porous, spongelike formations of rock/sand
Water table
upper border of an aquifer
Recharge zone
area where water can infiltrate through the surface and reach the aquifer
Confined aquifers
aquifers trapped between impermeable clay
Unconfined aquifers
aquifers not trapped between impermeable clay
Runoff
water that falls from the sky/melts from snow/glaciers and flows over a land surface; converges in low-lying areas, forming streams, which merge into rivers and eventually reach a lake/ocean
Drainage basin/watershed
area of land drained by a river system and its tributaries
Floodplain
areas near a river’s course that are flooded periodically
Riparian forests
forests near riversides, in floodplains (which have especially fertile soil), which are especially rich in species
Littoral zone
shallow area along the edges of lakes and ponds where aquatic plants can grow (abundant in invertebrates)
Benthic zone
extends along the bottom of lakes and ponds
Limnetic zone
upper layer of lake/pond water that is shallow enough to receive sunlight and allow photosynthesis by phytoplankton
Profundal zone
area of lakes/ponds between benthic and limnetic zones that lacks photosynthesis and dissolved oxygen
Oligotrophic lakes/ponds
low in nutrients, high in oxygen
Eutrophic lake/pond
oligotrophic ponds/lakes transition to high-nutrient, low-oxygen conditions and nutrients are added
Wetlands
systems where soil is saturated with water, often containing standing shallow water
Freshwater marshes
wetlands where cattails and bulrushes grow above the water’s surface
Swamps
wetlands in forested areas that contain standing water
Bogs
ponds covered with thick floating mats of vegetation
Vernal ponds
seasonal wetlands that form from snowmelt in early spring and dry up in summer
How much of Earth do the five oceans cover?
71%
Currents
riverlike flows of water driven by differences in density, heating, cooling, gravity, and wind
Upwelling
pulls cold, deep, nutrient-rich water to the surface
Downwellings
converging surface currents transport warm surface water to deeper waters, providing an influx of dissolved oxygen and burying carbon dioxide from the atmosphere
Continental shelves
shelves that sit below shallow waters bordering continents which drop off and angle steeply downward toward the ocean basin
Shelf-slope break
where continental shelves drop off
Continental slope
where continental shelves angle steeply downward toward the deep ocean basin
Thermohaline circulation
worldwide current system in which warmer, low-salinity water moves along the surface and colder, saltier, denser water moves horizontally below the surface; moves warm water in the Gulf Stream to the Atlantic Ocean near Europe, where heat is released and cooler water sinks
North Atlantic Deep Water (NADW)
region of downwelling near Western Europe
El Niño-Southern Oscillation (ENSO)
systematic shift in atmospheric pressure, sea surface temperature, and ocean circulation in the tropical Pacific Ocean
El Niño conditions
triggered when air pressure decreases in the eastern Pacific and increases in the western Pacific, weakening equatorial winds, allowing warm water to flow eastward, and suppressing upwelling along the Pacific American coasts - can create storm activity in arid regions and drier conditions in Indonesia
La Niña events
cold water rises to the surface and extends westward, strengthening westward-blowing winds
Intertidal ecosystems
spread between uppermost reach of high tide and lowest limit of low tide
Tides
periodic rising and falling of the ocean’s height at a location due to the gravitational pull of the sun and moon
Estuaries
bodies of water where rivers flow into the ocean, mixing salt and freshwater; saltwater fluctuates due to tide and river flow changes; sheltered from heavy waves
Salt marshes
where tides wash over gently sloped sandy/silty substrates - provide biodiversity, filter pollutants, stabilize shorelines
Tidal creeks
currents that carry water from rising/falling tides in/out of salt marshes
Mangroves
salt-tolerant trees with roots that grow upward to gather oxygen and roots that grow down to support the tree
Kelp
large brown algae that grow toward the surface from the floor of continental shelves
Coral reef
mass of calcium carbonate composed of shells of corals, found along extensions of a shoreline, in a barrier island, or an atoll
Corals
tiny animals that make up coral reefs
Barrier island
coral reefs paralleling a shoreline
Atoll
island surrounded by a coral reef ring
Zooxanthellae
symbiotic relationships between coral and algae, which produce food through photosynthesis
Coral bleaching
when zooxanthellae lose color and die, depriving coral of nutrition, which happens when coral are stressed by increased water temperature and pollution
Photic zone
top layer of open ocean, where microscopic phytoplankton constitute the base of the food chain
Pelagic habitats
found between the ocean surface and floor
Benthic habitats
on the ocean floor
How is our freshwater use distributed?
70% agriculture, 20% industry, 10% residential
Consumptive use
irrigation removes water from aquifers and surface waters, but the water is not returned
Nonconsumptive use
does not remove or temporarily removes water from a source, like hydroelectric dams
Water mining
withdrawal of water faster than it can be replenished
Sinkholes
land surface subsides, causing buildings to lean/large areas of land to collapse, as aquifers lose water and cannot support overlying strata anymore
Flooding
snowmelt or heavy water swells the volume of a river so it spills out
Levees
built along the banks of main channels to protect against floods
Aqueducts/canals
artificial rivers that channel water from rivers/lakes to homes/farms
Dam
obstruction in a river/stream to block the flow
Reservoirs
artificial lakes created by dams to store water for human use (prevent floods, provide drinking water, facilitate irrigation, generate electricity)
Desalination/desalinization
removal of salt from sea water/other water
Distillation
desalination through heating and evaporating ocean water
Reverse osmosis
desalinating by filtering through membranes with tiny pores that trap salt
Rainwater harvesting
process of collecting rainwater with a rain barrel
Graywater
used water from showers/sinks, which can be used for watering in some places
Xeriscaping
landscaping using plants adapted to arid conditions
Water pollution
changes to chemical/physical/biological properties of water due to human activity
Point sources
discrete locations that release water pollution
Non-point sources
multiple inputs over large areas pollute a water source (farms, city streets, residential neighborhoods)
Nutrient pollution
from fertilizers/other sources, causes eutrophication and hypoxia in surface waters
Harmful algae blooms
population explosions of toxin-producing algae due to excessive nutrient concentrations
Red tide
harmful algae blooms that produce a red pigment that discolors the water
Wastewater
water affected by human activities (toilets, sinks, dishwashers, washing machines)
Sediments
eroded soils carried to rivers by runoff, transported long distances
Exxon Valdez
1989 oil spill disaster along the Alaskan coast
Deepwater Horizon
offshore oil platform exploded in 2010, spilling oil that washed ashore throughout the Gulf of Mexico region
Gyres
parts of the ocean where currents converge, where discarded fishing nets/lines, plastic bags/bottles, and trash accumulate
Great Pacific Garbage Patch
area in the southern Pacific where plastic outnumbers plankton 6:1
What happens to water from reservoirs/aquifers before it reaches the tap?
treated with chemicals to remove particles, filtered by sand/gravel/charcoal, disinfected with chlorine, tested for 90 contaminants based on EPA standards
Septic systems
separate solids and oils from water in rural eras, which then runs downhill through gravel-filled trenches where it can be decomposed
Primary treatment
physical removal of contaminants in settling tanks/clarifiers in urban treatment facilities
Secondary treatment
stir and aerate wastewater so bacteria can naturally decompose the wastes in it, in urban areas
Effluent
treated to kill bacteria and returned to rivers/lakes/the ocean
Biosolids
removed from water in treatment facilities and used as fertilizer
Purse seining
deploys large nets, suspended by buoys, around surface schools of fish
Driftnetting
use of long nets that span large expanses of water - targets species that traverse open water in schools
Longline fishing
setting out extremely long lines with hundreds/thousands of baited hooks spaced between their lengths
Trawling
dragging weighted cone-shaped nets through the pelagic zone
Bottom-trawling
drags weighted cone-shaped nets through the benthic zone; can destroy entire benthic ecosystems
Bycatch
accidental capture of animals during industrial fishing (up to 17% of commercially harvested fish are caught unintentionally)
Marine protected areas/MPAs
restrict some human activities but allow fishing/other extractive activities (about 3% of ocean waters)
Marine reserves
areas of ocean where fishing is prohibited
Ocean acidification
ocean becomes more acidic from absorbing carbon-dioxide, making it difficult for shell-forming organisms to use carbonate ions to make shells, which also begin to erode faster than they are made after the concentration hits a certain level
Zone of aeration
aquifer’s upper layer, which contains pore spaces partly filled with water
Zone of saturation
aquifer’s lower layer, completely filled with water
Tributary
smaller river flows into a larger one
River system
river and all its tributaries
