THE HYDROSPHERE PART 3
Groundwater About 1/3 of all freshwater on the planet is found underground. Part air part water unsaturated zone Water table Saturated zone: water fills all pores and cracks
Freshwater: Groundwater Aquifer Aquifer is an underground sand/gravel or rock layer that stores water and allows water to flow through it. Drinking water supply. Anyone who has a well gets water from an aquifer. About half of all Americans get most of their water from wells. aquifer aquifer
Global Groundwater Resources Major basins hold abundant, relatively easily extracted groundwater.
Groundwater Recharge Sun Belt The rate at which rain, snow and surface waters are able to replenish groundwater varies from one place to another, mostly due to geology and climate. The recharge rate determines how much of groundwater can be sustainably withdrawn for human use.
USA Freshwater Stress The highest rates of groundwater depletion are in California's Central Valley and Midwest. Water scarcity is one of the defining issues of the 21 st century
Saltwater (Saline Water) Saltwater is water that contains a certain amount of salts with dissolved salt concentration of more than 1%. Oceans and seas. Saltwater is also found in some lakes and ponds as well as underground.
Seas: large bodies of saline water connected with an ocean. Ancient literature often spoke of the Seven Seas how many seas are in the world? I counted 111! Atlantic Ocean (27!) Baltic Sea, Mediterranean Sea, Black Sea, Caribbean Sea, Argentine Sea, Bay of Biscay, Bay of Campeche, Bay of Fundy, Celtic Sea, Chesapeake Bay, Davis Strait, Denmark Strait, English Channel, Gulf of Guinea, Gulf of Maine, Gulf of Mexico, Gulf of St. Lawrence, Gulf of Venezuela, Irish Sea, Labrador Sea, Marmara Sea, North Sea, Norwegian Sea, Sargasso Sea, Sea of Azov, Sea of the Hebrides, Wadden Sea Southern Ocean (19!) Amundsen Sea, Bass Strait, Bellingshausen Sea, Cooperation Sea, Cosmonauts Sea, Davis Sea, D'Urville Sea, Drake Passage, Great Australian Bight, Gulf St Vincent, King Haakon VII Sea, Lazarev Sea, Mawson Sea, Riiser- Larsen Sea, Ross Sea, Scotia Sea, Somov Sea, Spencer Gulf, Weddell Sea
How many seas are in the world? Pacific Ocean (35!) Arafura Sea, Banda Sea, Bering Sea, Bismarck Sea, Bohai Sea, Bohol Sea (also known as the Mindanao Sea), Camotes Sea, Celebes Sea, Ceram Sea, Chilean Sea, Sea of Chiloé, Coral Sea, East China Sea, Flores Sea, Gulf of Alaska, Gulf of California (also known as the Sea of Cortéz), Gulf of Carpentaria, Gulf of Thailand, Halmahera Sea, Java Sea, Koro Sea, Molucca Sea, Philippine Sea, Salish Sea, Savu Sea, Sea of Japan, Sea of Okhotsk, Seto Inland Sea, Sibuyan Sea, Solomon Sea, South China Sea, Sulu Sea, Tasman Sea, Visayan Sea, Yellow Sea Indian Ocean (10!) Andaman Sea, Arabian Sea, Bay of Bengal, Gulf of Aden, Gulf of Oman, Laccadive Sea, Mozambique Channel, Persian Gulf, Red Sea, Timor Sea Arctic Ocean (15!) Amundsen Gulf, Baffin Bay, Barents Sea, Beaufort Sea, Chukchi Sea, East Siberian Sea, Greenland Sea, Hudson Bay, James Bay, Kara Sea, Kara Strait, Lincoln Sea, Prince Gustav Adolf Sea, Pechora Sea, White Sea Landlocked seas (large saltwater lakes actually) (5!) Aral Sea, Caspian Sea, Dead Sea, Great Salt Lake, Salton Sea
Quick Sea Facts 1. Largest sea: Philippine Sea, ~2 million sq mi. 2. Smallest sea: Marmara Sea (Turkey), at 4,380 sq mi. 3. Saltiest true (open) sea: Red Sea, ~4.0%, due to high evaporation, little precipitation, and few (and mostly seasonal) inflowing rivers. 4. Saltiest land-locked sea: Dead Sea, ~30%!. 5. Lowest salt content: Baltic Sea, only 1.0-1.5%, due to low evaporation and many inflowing rivers. 6. Warmest sea: the Persian Gulf contains the warmest sea water in the world reaching at 35 C; Red Sea is the second warmest. 7. Coldest seas are found near the poles. 8. The only sea without a land boundary: Sargasso Sea, home to free-floating seaweed called Sargassum and an amazing variety of marine species.
Waves on the Bodies of Water As the wind blows over an area of water, pressure and friction perturb the equilibrium of the water surface and transfer energy from the air to the water, forming waves. Ripples: produced by light wind; disappear quickly after wind has stopped. Seas: larger-scale, often irregular motions that form under sustained winds; tend to last much longer, even after the wind has died. Swells: waves propagating away from their area of origin; not affected by local wind. Waves in the oceans can travel thousands of miles before reaching land, and range in size from small ripples, to waves over 100 ft (30 m) high. Three different types of wind waves develop over time:
Waves at the Shore Wave motion is influenced by water depth and shape of the shoreline. Waves often break at the shore. Water molecules move in circles Wave action decreases with depth. Waves are slowed down; wave action adds up. Back of wave moves faster than the front. Wave breaks and retreats.
Tides Tides are the slow, periodic vertical rise and fall of the sea surface. Tide is a giant wave caused by gravitational pull of the Moon and Sun on the rotating Earth. The gravitational pull on liquids is much more noticeable than on solids (because liquids move more easily than solids). One low-tide/high-tide cycle takes about 12 hours and 25 minutes (the lunar day is equal to about 24.8 hours). Tidal range is the difference in water level between high-tide and low-tide. Tides produce oscillating currents known as tidal streams. While tidal changes in sea level are easier to observe where land and water meet, they exist everywhere - even in the middle of the ocean.
Gravitational Pull of the Moon and Sun The relationship between the masses of the Earth, Moon and Sun and their distances to each other play a critical role in affecting the Earth's tides. The Sun is 27 million times more massive than the Moon. It is also 390 times further away from the Earth than the Moon. As a result, the Sun s tide-generating force is about half that of the Moon. Tide-Generating Force Mass ~ (Distance) 3 The Moon is the dominant force affecting the Earth s tides.
Tidal Bulges gravitational attraction of the Moon centrifugal force due to Earth rotation two tidal bulges of water The Sun has a similar effect, however ~2 times smaller.
Types of Tides Diurnal Semi-diurnal : one tidal cycle per day (Gulf od Mexico) Semi-diurnal: two high waters and two low waters each day (Boston, MA) Mixed: two high and two low waters each day, all four with different heights (Los Angeles, CA). Mixed
Monthly Tidal Cycle (29½ days) About every 7 days, Earth alternates between: Spring Tide Alignment of Earth-Moon-Sun system (syzygy) Neap Tide Spring Tide large tidal range, highest high tide and lowest low tide Neap Tide moderate tidal range Earth-Moon-Sun system at right angles (quadrature)
Our Local Tides Exact times of high/low tide as well as tide level strongly depend on the coastal shape and near-shore bathymetry. Port Jefferson 3:11 AM Herod Point 2:44 AM
The Bay of Fundy, Canada: world s largest tidal range Tidal energy is focused by shape and shallowness of bay. Maximum spring tidal range in Minas Basin = 17 meters (56 feet). Alma harbor at High Tide and Low Tide