ocean water
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Spring 2014 . Ocean Water . Properties of Ocean Water . Physical properties of ocean water Temperature Density Color Chemical Properties Determine its composition Enable the ocean to dissolve other substances . Properties of Ocean Water . Composition of Ocean Water - PowerPoint PPT PresentationTRANSCRIPT
OCEAN WATER Spring 2014
Properties of Ocean Water Physical properties of ocean water
TemperatureDensityColor
Chemical Properties Determine its compositionEnable the ocean to dissolve other
substances
Properties of Ocean Water Composition of Ocean Water
Salts enter the ocean from rivers and streams
Gases enter the ocean from rivers, streams, & directly from the atmosphere
Elements in Ocean Water ○ 95.6% pure water ○ 75 chemical elements
6 most abundant: chlorine, sodium, magnesium, sulfur, calcium, & potassium
Properties of Ocean Water Dissolved Gases
3 most common○ Nitrogen○ Oxygen○ Carbon dioxide
Higher temperature= less dissolved gases Lower temperature= more dissolved gases Exchange of gases between the
atmosphere & the ocean is a constant thing
Properties of Ocean Water Salinity
The number of grams of dissolved solid per volume of liquid ○ Called salinity most dissolved solids are salts
78% of the dissolved salt in the ocean is NaCl (sodium chloride)
Increased by both evaporation & freezing Salinity varies by depth Because the ocean is constantly mixing the
average salinity is similar all over the globe
Properties of Ocean Water Temperature
Surface Temperture○ Movement of water throughout the ocean
thoroughly mixes the warmed surface water Distributes heat downward (100m – 300m)Temperature of this zone is relatively constant
○ Temperature decreases with increasing latitude Poles have colder surface temp than the middle
latitudes - Ice pack- floating layer of sea ice that covers the
surface of the ocean in both the Arctic & Antarctic during parts of the year
Properties of Ocean Water Temperature
Thermocline○ Zone of rapid temperature change ○ Exists because water near the surface that is
heated by the sun is less dense than the colder deeper water
○ Changing temperature or shifting currents may alter the depth or cause it to disappear completely
Properties of Ocean Water Density
Mass of a substance per unit of volume 2 factors affect the density of ocean water:
○ SalinityThe large amount of dissolved solids in ocean water
makes it more dense than fresh water ○ Temperature
Water becomes more dense as it get colder ***Affects density more than salinity
Properties of Ocean Water Color of Ocean Water
Color is determined by the way it absorbs or reflects sunlight
Only blue wavelengths tend to be reflected ○ Only the upper regions show color; the lower
region is in total darkness
Life in the Ocean Most marine organisms depend on 2
factors for their survival:Essential nutrients available in ocean waterSunlight
Life in the Ocean Ocean Chemistry & Marine Life
Animals & plants living in the ocean help maintain the chemical balance of ocean water
Nearly all life is regulated by the life processes of plants
Elements nitrogen, phosphorus, & silicon are critical nutrients for the growth of plants
Life in the Ocean Ocean Chemistry & Marine Life cont…
Marine plants & animals absorb & store the substances they need for life.
All of the elements necessary to marine life are consumed by marine plants & animals near the surface but released at great depths through decay
Upwelling- occurs when wind blows steadily parallel to the shore along a coastline, surface ocean water is moved farther offshore causing deep water to then move up
Life in the Ocean Sunlight & Marine Life
All marine plants & animals require sunlight in addition to the nutrients from water○ Plant growth is limited to the upper 100m of water
Plankton- free floating microscopic marine plants & animals ○ 2 main types of plankton
Phytoplankton- plants & other photosynthetic organismsZooplankton- non-photosynthetic animals
Nekton- eat plankton, forms of ocean life that swim Benthos- organisms that live on the ocean floor
Life in the Ocean Ocean Environments
2 general environments ○ Benthic- bottom
Divided into 5 zones ○ Pelagic- water
Divided into 2 zones ○ **The amount of sunlight, temperature, &
water pressure determine the distribution of marine life within these zones
Life in the Ocean Ocean Environments
Benthic Environments○ Intertidal zone- lies between low tide and high
tide lines Crabs, clams, mussels, sea anemones, & seaweed
live here○ Sublittoral zone- shallow & completely
submerged; located on the continental shelf; contains the largest number of benthosSea stars, brittle stars, & sea lilies
Life in the Ocean Ocean Environments
Benthic Environments○ Bathyal zone- starts at the continental slope &
ends at a depth of 4000mOctopuses, sea stars, & brachiopods Very little plant life
○ Abyssal zone- 4000m to 6000m of depthSponges, worms, & sea cucumbers No light at all
○ Hadal zone- inside ocean trenches; deeper than 6000m Virtually unexplored; life is sparse
Life in the Ocean Ocean Environments
Pelagic Zones○ Neritic zone- above continental shelves
Abundant sunlight, moderate temperatures, low pressure
Ideal for marine life Much of the seafood & fish that we eat lives here
○ Oceanic zone- extends into the deep ocean & open ocean waters beyond the continental shelfDivided into 4 zones based on depth
- Epipelagic ,Mesoplagic, bathypelgaic, abyssopelagic Marine life decreases with increasing depth
Ocean Resources Fresh Water from the Ocean
2 ways in which the need for fresh water can be met:○ Fresh water now available can be conserved
to avoid waste○ Amount of available fresh water can be
increased Can be done by finding a way to convert ocean water
to fresh water for a reasonable cost
Ocean Resources Fresh Water from the Oceans
Desalination- the removal of fresh water from salt water ○ Distillation- heating ocean water to remove the salt
Problem: evaporating liquid water requires a large amount of expensive heat energy
○ FreezingThe first ice crystals that form are free of saltChunks of ice can be melted & used as fresh water
○ Use of membranes (reverse osmosis) Allow water under high pressure to pass through while
blocking the dissolved salts
Ocean Resources Minerals from the Ocean
Nodules ○ Valuable source of manganese which is used making some types of
steel ○ Also contain iron, copper, nickel, & cobalt ○ Problem: expensive & difficult to retrieve
Minerals ○ Salt○ Magnesium○ Bromine
Petroleum is the most valuable mineral found beneath the ocean floor ○ Most comes from the continental shelves○ Productive offshore wells are located in the Gulf of Mexico, the North
Sea, the Persian Gulf, & off the coasts of California, Alaska, & Australia
Ocean Resources Food from the Ocean
Protein rich fish is an important part of the human diet
Aquaculture- farming of the ocean ○ Developing & raising species of marine
animals & plants that yield large amounts of food
○ Successful in growing catfish, salmon, oysters, & shrimp
Ocean Resources Ocean-Water Pollution
Oceans have been historically used as dumping grounds○ Garbage, sewage, nuclear wastes
Productive coastal waters are in the most danger