TREASURES OF
THE ANDAMAN SEA

1. WHAT'S IN A NAME? How Scientific Naming and Classification Works
2. ISLAND TOPOGRAPHY
3. THE IMPORTANCE OF ISLANDS
4. CLIMATIC CYCLES - Weather in the Long Run
5. SOME GENERAL CONCEPTS AND APPLICATIONS
6. THE TROPHIC PYRAMID or, Who Did You Have For Breakfast?
7. CORALS AND CORAL REEFS
8. MANGROVES
9. SEA GRASS MEADOWS .
10. INVERTEBRATES OF THE REEF (and a Few From The Mangroves)
11. SEA PLANTS
12. BIOLUMINESCENCE: The Lights in the Sea
13. VERTEBRATE REPRODUCTION
14. FISHES IN GENERAL
15. SHARKS AND RAYS - The Cartilagenous Fish
16. THE BONY FISHES
17. MARINE MAMMALS OF THAILAND
18. MARINE REPTILES OF THAILAND

INTRODUCTION:

When I first began diving and snorkeling in Thailand and Southeast Asia, there were few written guides to animals and plants seen underwater, and most of those books focused on organisms for saltwater aquariums. Slowly, marine biologists and educators began to gather existing scientific information and organize it in ways that are accessible to and understandable by non-scientists.

Marine biology is a new science in many ways. The development of sophisticated SCUBA gear within the last 20 years has opened the underwater world to more than casual visits. Yet, it is clear that the amount of information that we have about the creatures of the sea, even those in the shallowest waters close to land, is only a beginning. It is comparable to the amount of knowledge we had about life on dry land in 1700.

Until 30 years ago, most people believed that the resources of the sea were unending, that no amount of plunder could destroy its bounty. We have begun to realize that life in the seas is not limitless, that only our ignorance is without bounds. We have watched fishing catches collapse and areas of the oceans that used to be highly productive become barren. As our consciousness has risen, as the need and the ability to study various marine environments has progressed, we have begun to understand the interdependence of different ecosystems. With this increase in understanding has come a certain excitement about our learning and a desire to pass it on to friends, guests, and all those who enjoy the sea.

Coral reefs present a clearly defined ecosystem. An ecosystem is a community, or series of communities, and the surrounding chemical and physical environment. It includes all of the plants and animals that live within it. The study of the complex spectrum of interrelationships among all of those organisms and their environments, and among groups of organisms, is the focus of ecology. Our study, and the main focus of this course, will be on the ecology of coral reefs, in part because they can be easily visited by divers and snorkelers, and in part because they form a key element among coastal marine ecosystems.

However, we will also include material about two other ecosystems which form an interdependent triangle of relationships with coral reefs. These are mangrove forests and sea grass meadows. While these ecosystems are found throughout the tropics and even, to a limited extent, in temperate regions, this course will concentrate on these ecosystems as they present themselves in the tropics of Southeast Asia and, in particular, Thailand and the seas nearby.

The principles discussed here are applicable to these ecosystems wherever they may be found; only the exemplary animals and plants will be different - and, in fact, many will be the same. Similarly, the methods used to understand and explain the relationships within these environments are applicable to any ecosystem, and they can be used to understand how relationships are organized and dynamically interact on a global scale, for, when all is said and done, our Earth is a single, great ecosystem.

This syllabus is an effort to provide a truly scientific course, with most of the scientific terminology translated into ordinary language. It is also moderately complete, but not exhaustive. Nearly all of the major groups of invertebrates are covered, and the same is true for fish families. Tiny plants or animals and those in deep water that are unlikely to be seen, are not included.

CONTRIBUTORS, CONTRIBUTIONS AND ACKNOWLEDGEMENTS:

This course and its syllabus is a work in progress. Marine biology is not static; we find out more about life in the seas every day. You can see that there are many areas of study that are unclear, even more areas in which there is too little known for them to even be unclear.

You are invited to send to me, by e-mail or other writing, your observations, anecdotes, and any reported scientific discoveries which you happen upon. Your contributions may be incorporated in the text. All of them are appreciated, whether we print them, use them as examples, take guests to see what you saw or simply read them with pleasure. One of the benefits of being our own computerized publisher is the ability to amend any of the text with relative ease. Everyone who makes a contribution, whether or not it is used, will be mentioned as a contributor in future acknowledgements.

However, the nature and extent of the contribution will not be mentioned. None of the materials we use will be given specific credit in the text, either. It is too complicated to try to footnote each fact, observation and anecdote. We hope that you will contribute and that this syllabus will grow to be more informative, more complete and a greater stimulus to the exploration, understanding and wise administration of our environment.

CORALS AND CORAL REEFS:

Coral reefs are the result of a remarkable symbiotic relationship between a small animal, the coral polyp, and an even tinier plant, a single-celled alga. (plural: algae) Zooxanthellae are these algae, tiny sea weeds. They are classified among the dinoflagellates because they are free swimming during parts of their lives, using a pair of whip-like flagella to propel themselves through the water. The algae burrow into the tissue of the coral in great numbers, losing their flagella in the process. They fill every nook and cranny among the cells of the coral polyp. They, together with filamentous algae, provide the colors of living coral reefs, mainly yellow, brown, green or pink. Zooxanthella, the singular of zooxanthellae, means "living in an animal," and "golden". The filamentous algae, which form long strands, are usually red or green. A single coral polyp may contain 100,000 zooxanthellae, giving it a brown, yellow or green color; the other colors - reds, purples and blues - are usually the result of the filamentous algae. Coral skeletons, frequently white, may also be red, black or blue. All corals that contain zooxanthellae are called hermatypic corals. This includes all of the reef-building corals. The precise way that coral and zooxanthellae interact physiologically is still subject to debate, but their mutual dependence has been recognized for decades. The zooxanthellae contain chlorophyll which they use to manufacture food from sunlight. Chlorophyll, the machinery, is contained in a chloroplast, a bubble-like container. The closeness to the surface, the clarity of the water, and the nearness to the Equator, working together, determine the amount of sunlight available to the algae to manufacture food. The deeper the water above the coral, the fewer kinds of light that will penetrate. For example, red light dissipates at about 8-9 meters (25-28 ft) The more particles in the water from debris or silt, the less light of any wavelength that will be able to penetrate. Sunlight from directly overhead has the greatest penetrating power. It is likely that the number of hours of sunlight is the single most important factor. In an experiment on the Great Barrier Reef, some coral colonies were kept shaded by domes. These died within 2 to 6 months. These are the reasons why there are few reef building corals - those with zooxanthellae, living below 46 meters (150 ft) There just is not enough light there to do the work of providing energy and taking care of waste products for reef building to go on. In fact, most luxuriant coral growth is found in water less than 30 meters (100ft) deep. Soft corals, which do not use sunlight and do not build reefs, can live at much greater depths. Rather than secreting calcium carbonate, they secrete a softer skeleton, much like hardened skin or fingernail material.

Sea Plants:

Plants living in the sea include mangroves, sea grasses and seaweeds. Mangroves and sea grasses are flowering plants and produce fruits. Seaweeds are non-flowering plants. They belong to the groups of plants collectively called algae. Algae do not have true roots, the kind of stems found in flowering plants or leaves.

Seaweeds get energy from the sun, by photosynthesis, as all green plants do. They can live only as deep as light can penetrate. This depth varies, depending on angle of the sun (distance from the equator) and murkiness. Except for microscopic algae, or those that float, seaweed distribution is affected by light, temperature, salinity, bottom composition and water movement.

There are four kinds of algae, which can generally be recognized by their color:

Green algae have flourished in the seas for 3 billion years. Most of them are bottom dwellers, but some live on other seaweeds, as orchids do on trees. They gave rise to all of the green plants, and all of the flowers we know today. They are grass-green in color, and frequently look like small flowering plants (without the flowers.) They use solar energy to make food which they store as starch, an important food for grazing marine animals. One of the most unusual is Valonia ventircosa, a giant, single celled alga that produces dark green, or gray-green, grape-like clusters of balls 1-3 cm (0.3-1 in) in diameter.

Blue-green algae are found on intertidal reef flats and muddy surfaces. Of the 5 kinds found on the Thai coast, 4 are exposed at low tide. Only one, Lynbya, forms large, entangled masses of hair-like filaments that grow on dead corals, as well as reef flats and in tide pools. It ranges in color from green to dark brown or black in color.

Brown algae are among the largest and most complex algae. They are mainly found in temperate waters. A few kinds such as Sargassum are found here, and can be abundant. They are typified by the giant kelp.

Red algae are most abundant in tropical seas, most live on the sea floor; some live on other seaweeds. They appear orange, red, or even purple.

Sea grasses are flowering plants that live in the sea. They are not seaweeds, nor are they true grasses. They can easily be distinguished from seaweed by their creeping, root-like stems, called rhizomes, similar to crabgrass, from which true roots attach to the mud or sand. They have erect stems and true leaves.

They are mostly found in estuaries, bays and shallow lagoons. They are the backbone of the coral reef/mangrove/sea grass meadow marine community. They are the main food of dugongs and turtles. Many small seaweeds grow on them, supplying the food for tiny animals and young fish

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