THE OCEAN DEEP

Whales are marine mammals of order Cetacea which are neither dolphins – members, in other words, of the families Delphinidae or Platanistoidae – nor porpoises. They include the blue whale, the largest living animal. Orcas, colloquially referred to as "killer whales", and pilot whales have whale in their name but for the purpose of classification they are actually dolphins. For centuries whales have been hunted for meat and as a source of valuable raw materials. By the middle of the 20th century, large-scale industrial whaling had left many species seriously endangered. All cetaceans, including whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulate animals). Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippopotamuses. In fact, whales are the closest living relatives of hippos; they evolved from a common ancestor at around 54 million years ago.[1][2] Whales entered the water roughly 50 million years ago.[3] Cetaceans are divided into two suborders:
• The baleen whales are characterized by baleen, a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. They are the largest suborder of whale.
• The toothed whales have teeth and prey on fish, squid, or both. An outstanding ability of this group is to sense their surrounding environment through echolocation.
Whales are large, magnificent, intelligent, aquatic mammals. They breathe air through blowhole(s) into lungs (unlike fish who breathe using gills). Whales have sleek, streamlined bodies that move easily through the water. They are the only mammals, other than manatees (seacows), that live their entire lives in the water, and the only mammals that have adapted to life in the open oceans. Like all mammals:
• Whales breathe air into lungs,
• Whales have hair (although they have a lot less than land mammals, and have almost none as adults),
• Whales are warm-blooded (they maintain a high body temperature),
• Whales have mammary glands with which they nourish their young,
• Whales have a four-chambered heart.
The biggest whale is the blue whale, which grows to be about 94 feet (29 m) long - the height of a 9-story building. These enormous animals eat about 4 tons of tiny krill each day, obtained by filter feeding through baleen. Adult blue whales have no predators except man. The smallest whale is the dwarf sperm whale which as an adult is only 8.5 feet (2.6 m) long.

A Fringing reef is a kind of coral reef, that is located in the tropics generally immediately near the shoreline. This type of coral reef is the most common type of reef that is found. This type of reef grows the best on some kind of hard surface, so it preferentially grows on areas with rocky bottoms. They may also grow on softer bottoms as well if there are some hard areas. Fringing reefs grow as a thin strip along the shore at a rate of about 2 to 7mm per year. It is Darwin’s belief that fringing reefs are the first kind of reefs to form around a landmass in a long-term reef growth process. Sometimes it is hard to tell the difference between fringing reefs and another type of reef called a barrier reef. One of the ways that these two types of reefs are separated is based on the depth of the lagoon in the back reef which is the area near to shore. If the water in the lagoon is less than 10m deep it is a fringing reef. Another major difference is that barrier reefs tend to be farther away from shore than fringing reefs and have a larger lagoon. There are two main components that make up a fringing reef, the reef flat and the reef slope. Reef Flat : The reef flat is the flat, broadest area of the reef. This area is found in fairly shallow water, and is at some points in time uncovered during low tide. This area of the reef is only slightly sloped towards the open ocean. Due to this part of the reef being found adjacent or nearly adjacent to land it maintains the most damage from freshwater runoff and sediments. Based on this there is few living corals found here, though there are some. Located on this flat area are often such things as seagrasses, seaweeds soft corals.Reef Slope (Fore reef) : The reef slope is found at the outer edge of the fringing reef, closest to the open ocean. This area of the reef is often quite steep and may even be a straight vertical drop to the bottom of the ocean. There is much more abundant coral growth found on this slope as well as a greater number of different species than are found on the reef flat. This is mostly because there is not much affect felt in this part of the reef from freshwater runoff and sediments, unlike the flat which is nearer to the shore. This area of the reef also benefits and has much more growth due to waves which carry nutrients to this area and take away sediments that could harm the corals. The upper portion of this slope is called the reef crest. In this area the corals grow the best since it is closest to the surface and gets the most sunlight. The base of the slope which receives the least sunlight has the least growth out of the whole slope.

Coral reefs are aragonite structures produced by living organisms. In most reefs the predominant organisms are colonial cnidarians that secrete an exoskeleton of calcium carbonate. The accumulation of this skeletal material, broken and piled up by wave action and bioeroders, produces massive calcareous formations that make ideal habitats for living corals and a great variety of other animal and plant life. Coral reefs are estimated to cover 284,300 square kilometres, with the Indo-Pacific region (including the Red Sea, Indian Ocean, Southeast Asia and the Pacific) accounting for 91.9% of the total. Southeast Asia accounts for 32.3% of that figure, while the Pacific including Australia accounts for 40.8%. Atlantic and Caribbean coral reefs only account for 7.6% of the world total. Coral reefs are either restricted or absent from the west coast of the Americas, as well as the west coast of Africa. This is due primarily to upwelling and strong cold coastal currents that reduce water temperatures in these areas. Corals are also restricted from off the coastline of South Asia from Pakistan to Bangladesh. They are also restricted along the coast around north-eastern South America and Bangladesh due to the release of vast quantities of freshwater from the Amazon and Ganges Rivers respectively. Although corals are found in temperate and tropical waters, shallow-water reefs are formed only in a zone extending at most from 30°N to 30°S of the equator. This zone is very important to whales because many types of plankton live there. Tropical corals do not grow at depths of over 50 m (165 ft). Temperature has less of an effect on the distribution of tropical coral, but it is generally accepted that they do not exist in waters below 18 °C, and that the optimum temperature is 26-27 °C for most coral reefs. The reefs in the Persian gulf however have coral adapted to changing temperatures of 13 °C in winter and 38 °C in summer, thus having significantly colder and hotter ambient environments respectively than most coral reefs. Also, deep water coral is more exceptional still as it can exist at greater depths and colder temperatures. Although deep water corals also form reefs, very little is known about them.