Introduction to ocean

• An ocean is a body of saline water that composes a large part of a earth's hydrosphere. They are, in descending order of area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans.

• The word "sea" is often used interchangeably with "ocean", but a sea is a body of saline water (possibly a division of the World Ocean) in a more inland location.

(source:en.wikipedia.org)

Introduction to ocean• Approximately 71% of the planet's surface

(~3.6x108 km2) is covered by saline water that is customarily divided into several principal oceans and smaller seas.

• The total volume is approximately 1.3 billion cubic kilometres, with an average depth of 3,790 metres

• It is the habitat of 230,000 known species, however much of the ocean's depths remain unexplored and it is estimated that over two million marine species may exist.

洋與海Major oceans and seas

geologyvirgin.blogspot.com

南中國海加勒比海地中海

墨西哥灣阿拉伯海鄂霍次克海日本海哈德遜灣

東海安達曼海黑海紅海

物理性質• The total mass of the hydrosphere is about 1,400,000,000,000,000,000

metric tons or 1.4×1021 kg, which is about 0.023 percent of the Earth's total mass. Less than 3 percent is freshwater; the rest is saltwater, mostly in the ocean.

• The area of the World Ocean is 361 million square kilometres (139 million square miles), and its volume is approximately 1.3 billion cubic Kilometres.

• Its average depth is 3,790 metres and its maximum depth is 10,923 metres. Nearly half of the world's marine waters are over 3,000 metres deep. The vast expanses of deep ocean (anything below 200 metres ) cover about 66% of the Earth's surface. This does not include seas not connected to the World Ocean, such as the Caspian Sea.

• The bluish color of water is a composite of several contributing agents. Prominent contributors include dissolved organic matter and chlorophyll.

(source: en.wikipedia.org

The Caspian Sea (裡海 ; 位於前蘇聯與伊朗之間的內海 )

• The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. it has no outflows and is bounded to the northwest by Russia, to the west by Azerbaijan, to the south by Iran, to the southeast by Turkmenistan, and to the northeast by Kazakhstan.

• The ancient inhabitants of its littoral perceived the Caspian Sea as an ocean, probably because of its saltiness and seeming boundlessness. It has a salinity of approximately 1.2%, about a third the salinity of most seawater.

(source: en.wikipedia.org)

Model of hydrogen bonds氫鍵 between molecules of water

wikidoc.org

Water—the universal solvent溶劑• Water is called the universal solvent because more

substances dissolve in water than in any other chemical. This has to do with the polarity of each water molecule. The hydrogen side of each water (H2O) molecule carries a slight positive electric charge, while the oxygen side carries a slight negative electric charge. This helps water dissociate ionic compounds into their positive and negative ions. The positive part of an ionic compound is attracted to the oxygen side of water while the negative portion of the compound is attracted to the hydrogen side of water

.

Surface tension表面張力• Surface tension is a contractive tendency of the

surface of a liquid that allows it to resist an external force.

• It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.

Surface tension表面張力• Surface tension has the dimension of force

per unit length, or of energy per unit area. The two are equivalent—but when referring to energy per unit of area, people use the term surface energy—which is a more general term in the sense that it applies also to solids and not just liquids.

Viscosity黏滯性• Viscosity is a measure of the resistance of a fluid which

is being deformed by either shear stress or tensile stress. In everyday terms (and for fluids only), viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity. Put simply, the less viscous the fluid is, the greater its ease of movement (fluidity).

• Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction.

En.wikipeida.org

炭循環

(Source: jochemnet.de)

Light penetration透光率

oceanexplorer.noaa.gov

Tropical marine biology file

Earth’s plate map 板塊圖

go.grolier.com

abernathyscience.com

Mid-ocean ridges

pubs.usgs.gov

• Ocean basins mapped with satellite altimetry. Seafloor features larger than 10 km are detected by resulting gravitational distortion of sea surface.

http://www.ngdc.noaa.gov/mgg/bathymetry/predicted/explore.HTML

Topographic map of the world and ocean floors

seajester.eq8r.net

World map showing tropical, temperate, and polar zones

source:gma.org

Wind waves風波• When waves propagate they

transport energy not water molecules. However the water is moving in a circular motion (Figure) whilst it acts as a medium through which kinetic energy flows. In more simple terms the water molecules behave similar to a turbine rotating, passing kinetic energy along their surface.

people.bath.ac.uk

Particle movement顆粒移動 in the wave

• As wave pass over the surface of the water, the particles of water do not move forwarfd with the waves. Instead, they gyrate in little circles or loops. Underwater, the particles more in even smaller loops. At a depth below about ½ the wavelength, they are quite still.

: Cousteau, 2006 :76; Ocean

Waves entering shallow water碎浪形成

seafriends.org.nz

地球風帶

• The main wind belts of the Earth and their prevailing direction of motion (arrows)

eolynchronicles.blogspot.com

Coriolis effect科氏力

en.wikipedia.org

艾克曼螺旋

www3.geosc.psu.edu

Ocean current file洋流

Major ocean currents of the world

physicalgeography.net

Deep Ocean Currents (Global Conveyor Belt)深海流 (全球輸送帶 )

science.howstuffworks.com

• Internal waves are usually caused by the lower layer being forced against a shallow obstacle, like a ridge, by tidal action. The ridge causes a disturbance, which creates a wave in the water layer, similar to the way that the wind can cause waves on the water’s surface. Unlike normal surface waves, however, internal waves can stretch tens of kilometers in length and move throughout the ocean for several hours.

earthobservatory.nasa.gov/IOTD/view.php?id=3586

• Internal waves alter sea surface currents, changing the overall “sea surface roughness.” Where these currents converge, the sea surface is more turbulent, and therefore brighter. Where the currents diverge, the surface is smoother and darker, creating zones called “slicks.” In this true-color Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) image acquired on April 8, 2003, the slicks created by internal waves appear as dark bands in the center of the image.

Internal wave內波• Internal waves are gravity waves that oscillate

within, rather than on the surface of a fluid medium. They are one of many types of wave motion in stratified fluids.(source:en.wikipedia.org)

iseis.cuhk.edu.hk

The Sulu Sea, like all major bodies of water, is composed of layers of water with differing densities. The topmost layer is the least dense, with each successively deeper layer being denser. Internal waves move along underwater at the boundary between layers of different densities

earthobservatory.nasa.gov/IOTD/view.php?id=3586

The Phosphorus Cycle磷循環

bhavanajagat.com

Importance of Phosphates

• It is the main constituent of energy rich compounds like ADP (Adenosine diphosphate), ATP (Adenosine triphosphate), GTP (Guanine tri phosphate) etc.

• Its a major constituent of cell membrane, nucleic acid, cellular energy transfer systems.

• Essential for metabolic reactions releasing energy.• Required for encoding of the information in genes

(as it is the component of nucleotides and nucleic acids).

Carbon cycle炭循環

Source: jochemnet.de

The Marine Carbonate System

Nitrogen cycle氮循環• Four processes participate in the cycling of

nitrogen through the biosphere: nitrogen fixation, decay, nitrification, denitrification

• Microorganisms play major roles in all four of these

Source: users.rcn.com

Nitrification固氮作用

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Denitrification

• The three processes above remove nitrogen from the atmosphere and pass it through ecosystems.

• Denitrification reduces nitrates to nitrogen gas, thus replenishing the atmosphere.

• Once again, bacteria are the agents. They live deep in soil and in aquatic sediments where conditions are anaerobic. They use nitrates as an alternative to oxygen for the final electron acceptor in their respiration.

• users.rcn.com

While the simplest organic compounds consist of carbon and hydrogen, many organic compounds also include one or more of the following elements:

phosphorussulfuroxygennitrogen