Marine Studies I

Lesson Structure

There are 9 lessons in this course:

1. Marine Ecology Systems
   • Ecology; Marine Weather (including El Nino, Thermocline, Gulf streams, etc), Continental shelf, Nutrient cycle, Red tide, Plankton, Marine Plants (including Mangroves, Shallow & Deep water algae, etc)
2. Shallow Waters & Reefs
   • Coral Reefs, Rocky Shorelines, Estuaries, Introduction to marine arthropods
3. Shellfish & Crustaceans
   • Molluscs and Brachiopods. True Crabs, Hermit Crabs, Lobsters, Prawns etc
4. Squid, Octopus, and Other Primitive Animals
   • (Cephalopods and Clupeoids, etc)
5. Fish Part A
   • (Cartilaginous Fish) Sharks, Eels, Rays; Shark Lifecycle, How dangerous are sharks? Effect of sharks on tourism, etc.
6. Fish Part B
   • (Bony Fish) Fish Anatomy/structure (identifying external & internal parts); legalities (protection of wildlife), types of fish, etc
7. Marine Mammals
   • (Dolphins, Whales, etc) Types of marine mammals, protection and politics, position of these animals in the food chain, products derived from marine mammals & substitutes for those products.
8. Turtles, Sea Snakes and Seabirds
   • Types of turtles & sea snakes; toxicity of sea snakes; turtle protection, penguins and other sea birds (eg stints, knots, pelicans, swans, gulls, eagles, ibis, egrets, terns, shearwaters, gannets, albatross, prions, oyster-catchers and petrels).
9. Human Impact on Marine Environments & Fishing
   • Human impact on marine environments; commercial vs recreational fishing, significance of certain mesopelagic fish, techniques for managing stocks of fish & other marine life.

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

• Identify characteristics of various marine environments.
• Discuss the first basic groups of marine animal life.
• Identify characteristics of various marine environments.
• Describe the range of molluscs and crustaceans in the marine environment and their lifecycles.
• Describe the biology and ecological significance of Cephalopods and Clupeoids in the marine environment.
• Describe a range of cartilaginous fish (sharks, rays) and selected bony fish (eels) that inhabit the ocean.
• Describe selected species and the diversity of marine fish that exists in the world’s oceans.
• Describe a range of marine mammals
• Discuss the presence of marine mammals in the seas and oceans of the world.
• Describe a range of reptiles and birds that co-habitat with fish in the marine environment.
• Explain the impact of humans upon marine environments and of selected aspects of commercial fishing.

What is a Coral Reef?

Coral reefs are certainly one of our planet’s greatest natural attractions. They are frequently compared to tropical rain forests due to their abundance of species and ecological complexity. Coral reefs are limestone formations of organic origin. Coral reef development is optimum where sea temperatures are warmest (generally in the tropics and subtropics). Twenty degrees Celsius is considered the minimum temperature for sustained coral reef development. This is also associated with clean, clear water, and shallow depths.

Coral reefs first appeared more than 400 million years ago in the fossil record. However, the early species have been extinct for some time. Coral reefs today represent a developmental period of only 5000 tears or less. Sea levels do fluctuate over time and coral reef development is tied to these changing sea levels (i.e. during the ice ages).

Individual coral animals, most of which exists in colonies, are the primary building blocks of the reef. They lie just beneath the surface of the seawater along the tropical and subtropical shores or in shallow warm seas. The reefs are caused by a build up of marine organisms, both animals and plant. Their skeletal deposits of calcium carbonate (limestone) form the reefs that have occasionally become inhabitable islands.

Corals depend on microscopic unicellular plants (zooxanthellae) that live within their tissue to provide the bulk of their nutrition. This facilitates growth and production of the calcium carbonate skeleton that provides the reef’s structure.

The reef deposits include such organisms as the important reef builders: the hermatypic corals, found in tropical oceans, and belonging to the subclass Zoantharia of order Scleractinia (formerly Madreporaria). The latter are also known as stony corals in as much as the living tissue thinly covers a skeleton composed of calcium carbonate.

Coralline algae is a kind of hard, encrusting algae commonly found on reefs. The fronds are covered with calcareous deposits. These two groups between them contribute the greatest part of material on a coral reef. However, other types of animals and plants often contribute substantially. These include: molluscs, crustaceans, echinoderms, sponges, soft corals, forams (single-celled organisms), worms, and green algae.

These important reef-building organisms thrive from just under the surface of the sea to a depth of approximately forty metres. They thrive in tropical and subtropical temperature conditions, with normal salinity, freedom from silt, with an abundance of dissolved gases, and minute organisms for food. Coral growth can take place at a depth as far as sunlight penetrates. In clear water sunlight can penetrate to approximately 185 metres. However, in practice very little limestone is produced at depths of more than 120 metres.

The distribution of coral reefs is general throughout the tropical and subtropical seas, except those areas where cold water exists, for example, along the west coast of South America, and in places where silt inhibits growth.

The largest accumulation of coral reefs in the world is in the Coral Sea, part of the South Pacific, off the north coast of Australia. Some well-known reefs in the Coral Sea include the Great Barrier Reef and the reefs around Vanuatu. In the Pacific Ocean: The Hawaiian Islands, Fiji, Palau Islands and Micronesia.

Corals

Corals are small animals noted for the formation of a heavy skeleton of lime (calcium carbonate).

This skeleton persists long after the death of the animals and they help in the formation of reefs, atolls and islands. The term coral includes several types of coelenterates, for example, corals, jellyfish and sea anemones (all belonging to the phylum Cnidaria). The stony corals are the main builders of the coral reefs and they are found exclusively in tropical and subtropical waters. They inhabit two main regions:

• The Indo-Pacific region, especially the sea area to the north east of Australia, known as the Coral Sea

• The Caribbean Sea and related waters, including Florida, Bermuda and the Bahamas and the West Indies.

Live coral is made of polyps. Dead coral is a hard, stony substance made up of the skeletons of polyps. Some kinds of corals secrete an internal, hard skeleton structure composed of calcium carbonate. When they die, other corals build on top until a great reef is formed. Individual coral polyps have soft bodies topped by a ring of stinging tentacles for catching food. These polyps occupy the cuplike cavities in the dead coral. The polyps are fixed in the cups and they are connected to each other by a living membrane that covers the coral rock. The skeleton is secreted by the outer surface of the polyps. Most of the skeleton is formed beneath the base of the polyps. Therefore, the polyps are continually pushed outwards so that they always remain on the surface. The mass of coral continually increases if the polyps remain alive. The number of polyps also increases continually by the process known as asexual budding. The coral polyps also reproduce sexually. They produce minute eggs and sperm that settle in other places and start to grow new colonies. The release of these larvae is known as a mass spawning event. This where within a 24 hour period, all the corals from one species and often within a genus release their eggs and sperm at the same. Often many species do this at the same time. It is a spectacular event. At certain times of the year (generally only a few days per year) this event is documented and experienced by many scuba divers and reef enthusiasts. People have described it as being in a snowstorm in the ocean. It is a very important part of coral reef life.

WHERE CAN THIS COURSE LEAD YOU?

This course may lead you into any number of places.
Some graduates use this as a stepping stone to a business or career in something "marine" related. For others, it is a way to enhance a path they are already on; whether as an amateur or professional.

If you love the sea, this course will give you a foundation to build your knowledge and experience. You may continue studying formally or informally beyond this course, or you may not. We've seen all sorts of people do this course for all sorts of reasons; for example:

• Scuba divers who want a better understanding of the world in which they dive

• Ecotourism professionals -people who take guided tours on shorelines or into the sea

• Budding marine biologists

Armed with a better understanding and awareness of marine animals and environments, graduates can discover all sorts of opportunities which they may not have even considered before. Some may tell you that you need a degree to work in Marine Biology; but in reality, most who study marine biology at university don't end up working in this field. Conversely, many who do little more than a course like this may end up finding serious employment in something related to marine biology (eg. marine tourism, farming, environmental surveying, writing, etc).  We had one graduate who was given a job to research dolphins, because of their passion and the knowledge they ad developed. The fact that they lacked university training was of no importance to their employer. We've had others who have enhanced services offered through their dive businesses or ecotour services, through what they learned in this course.

Talk to one of our Marine Science tutors and discover more.