| introduction | Oceanography covers all we know about the sea, its formation, geology, mineralogy, extraction, fisheries, biology and much more. For this web site we have made a conscious selection. If you are in a hurry, read this first. (located on this page) (3 pages) | |
| oceans | The world's oceans cover more than 70% of the Earth's surface. At places they are as deep as the tallest mountains. Read more about their size, surface distribution, origin, evolution, features, crust, tectonic plate movement and more. (14 pages) | |
| ocean properties | The salt water has important properties for life in the seas, properties that influence the circulation of the ocean water. Read more about its temperature, seasons, density and productivity. (8 pages) | |
| waves | Waves are caused by the wind blowing over the ocean's surface. They promote the exchange of gases between the ocean and the atmosphere and bring water movement to coastal habitats. They are responsible for the shape of our coasts and the formation of dunes and beaches. In this chapter you'll learn how waves work and how they relate to wind. (7 pages) | |
| Tsunamis and mega tsunamis are special waves, and so are seiches, bores and internal waves. Special attention is paid to the kind of damage waves cause to the land and the underwater seascape. (7 pages) | ||
| tides | The tides are caused by the rotation of the Earth in the presence of the gravitational pull of moon and sun. Often interpreted as a water 'bulge' travelling around the globe, being balanced by an equal bulge on the other side, recent discoveries have made this simplified concept much more interesting. (5 pages) | |
| circulation
and currents |
Waves and tides cause currents that see-saw to and fro but the large ocean basins have currents that flow mainly in one direction. Such currents cause upwellings of nutrients from the deep, influence the weather and bring about cyclical changes in coastal seas. (16 pages) | |
| dunes & beaches | Our beaches and dunes are made of sand, transported from the sea and deposited by wind. The process is simple, yet often misunderstood. (9 pages) Also read why beaches are disappearing (36 pages) and mining the sea sand (40 pages). | |
| storms | Extreme events such as storms, hurricanes and tsunamis have major effects on people living by the sea. They turn a peaceful ocean into a devouring monster. They make a difference to dunes and beaches and the underwater environment. (6 pages) | |
| special NZ | Why is New Zealand so special? Our geographical location on the planet, our history and economy make New Zealand a special place, with special problems that need special solutions. (10 pages) | |
| Engineers may think that there is a lot of sand in beaches, dunes, sand banks and on the continental shelves. But can it be mined sustainably? Sand is not as common as one may think. (19 pages) | ||
| Sea water is salty and contains many more elements, most importantly all elements necessary for life. It also contains gases and is thought to be an important sink for carbon dioxide. (10 pages) | ||
| As carbon dioxide levels are rising in air, it is feared that the oceans will become more acidic, with disastrous consequences for marine life. What is the story? What do the facts show? Is this another scare scam? (large, detailed and important) | ||
| The world's climates are changing, thought to be related to global warming. The world appears to be warming because of human emissions, is the consensus, but many scientists disagree. This large chapter views all issues from a wide perspective, to foster understanding. Learn about climate step by step. (140 pages) | ||
| Important tables | Table of the important elements for life, in
the universe, planet, plants, animals.
Periodic table of elements, with explanation, importance for life and more. Introduction to the structure of atoms, basic chemistry and radioactivity. Detailed composition of seawater: a concentration for all the elements known, salinity, gases and pH.. Geologic Time Table: the history of life and the planet, with earth maps and pictures. Beaufort scale: Wind strength and sea condition. Sailing conditions. Univ. of Virginia storm classification: relative occurrence and damage by wave height. Saffir-Simpson hurricane scale: hurricane strength classified by the damage caused. |
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| further reading | Books and references (on this page)
Valuable Internet links (on this page) Note that his section has been mirrored by POEMS, Practical Ocean Energy Management Systems (www.poemsinc.org) in the USA. They promote research into generating power from the oceans. Visit their link page for more info on oceanography and ocean energy. |
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| what's new? | A log of recent changes to this section (on this page) |
| Introduction
Oceanography covers all we know about the sea, its formation, geology, mineralogy, extraction, fisheries, biology and much more. Knowledge about our oceans was first acquired by those who used it and plied its waters. Although they provided for food, the oceans were largely seen as a strategic obstacle, hindering the trading of goods and the migrating of people. It is only recently that the oceans have been studied scientifically. Ironically, a large motivation came from the navies of seafaring countries. The oceans are truly difficult to lay bare to scientific scrutiny. They are so large, rough and deep. Consequently, there remains much to be discovered, but already the amount we know is too much to be included in this web site. |
The oceans are not just big buckets of water but a large and complex system of geological, physical, chemical and biological factors that have a decisive influence on the course of the terrestrial world, and thus also our lives. The oceans are perhaps the only habitat, large enough that we will not be able to change sufficiently to destroy its functioning, although we seem intent on doing so, and on the land we almost certainly will. The oceans may thus hold the key to our salvation. We have included in this large section everything you need to know to be an effective conservationist, understanding the big picture, life on this planet, marine life and the problems caused by humanity.
The first chapter looks at the beginning of Earth and ocean and how they evolved together. The movements of tectonic plates has shaped the continents and distributed their inhabiting species. Climate has changed dramatically, yet becoming more stable overall.
The second chapter looks at ocean properties like temperature, salinity and productivity. These are important for understanding ocean currents and fishing. The next chapter looks at waves and examines how they work. Waves shape the coasts and can damage organisms in the sea. Tsunamis are very slow waves that can travel vast distances, where they can cause massive coastal damage. Internal waves are mysterious water movements inside a body of water and invisible from above. The next chapter deals with another wave, the tide. It is an often misunderstood phenomenon.
The currents chapter looks at the atmosphere first and how sunlight passes through to warm the surface. On its way, various atmospheric gases filter the sunlight and also Earth's outgoing radiation. More about this will be discussed in the chapter on global warming. Solar radiation varies with latitude, but particularly with depth in the ocean. Heat is distributed from the warm tropics to the cold poles by means of air and water circulation. A major influence on the movement of air and water is the Coriolis force, explained in detail. The chapter ends with deep water currents.
Where the sea meets the land, often dunes and beaches are formed. In the chapter about these, it is explained how beaches and dunes form and how they interact with wind and waves. Examples of beaches are shown.
The chapter about why dunes and beaches are disappearing, is my own work, in which I challenge scientists and society to look at the problem in a different way. I've discovered a large gap in coastal science, where hard data about the most important factors affecting beaches and dune systems, is simply not available. It is a must-read for everyone working with, living by, or just enjoying sandy beaches.
Storms, particularly cyclones (hurricanes) have a major influence on our coasts and thus the beaches. This chapter shows why.
The chapter about why New Zealand is such a special country, was placed here because it links in with many of the factors discussed in oceanography. It shows how NZ's geographic location and tectonic past has made it unique in the world. Discovered by humans only recently, it is more sensitive to human actions than earlier discovered countries are. NZ's agricultural economy exploits the renewable solar energy but brings unique problems. It is knowledge that every Kiwi should learn at school.
I have deliberately left out the water, carbon and nutrient cycles because
these will be dealt with in the section about plankton. The El Nino climate
oscillation will be discussed in the section on global warming. The oceanography
of tideways (estuaries) will be treated in the section on habitats.
Several interesting tables have been put together with information
gleaned from many sources. The periodic table of elements introduces the
reader to the chemical elements on this planet and the structure of atoms.
The reader is introduced to basic chemistry and radioactive decay.
The table of the abundance of elements shows their journey through
the composition of the universe, our solar system, fresh and salt water
and eventually of plants and animals. Deficiency syndromes are also shown.
For suggestions and comments, please e-mail
me.
Floor Anthoni
| Further
reading
References in blue are available from the Seafriends Library Bird, E C F: Coasts - an introduction to systematic
geomorphology. 1976. Austr Nat Univ. Press. GEOLOGY.
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| Internet links:
NOAA (National Oceanic and Atmospheric Administration) educational section about severe weather phenomena. National Hurricane Centre: Hurricane tracking and warning. |
