Ocean Exploration By Rachael Nicholas NOTE: While watching, please click to advance to the next slides.

Climate The average temperature of oceans is about 3.8°C. However, different oceans in different parts of the world can have very different climates. For example, tropical oceans, which are near the equator, are always warm and clear on the surface. In contrast, the polar regions of the far north and south are so cold that icebergs drift in the sea. The sun’s heat warms only the surface of the water. Deep down, it is cold and dark.

Obstacles Breathing The most obvious problem is oxygen. However, buying more time underwater is easy: simply get an external source of air, such as an air tank. But using compressed air also has hazards. It is denser than normal air so a diver breathing it will inhale proportionately more molecules of nitrogen and oxygen. Pressure As a person travels deeper in the ocean, water pressure increases so much that at some depths a human would be crushed from the pressure. To prevent injuries and allow for exploration in deep waters, the ‘bathysphere’ was designed. Built with steel hulls, the bathysphere maintains normal air pressure, making it safe to explore the ocean depths.

Temperature Divers also need protection from the cold. A wet suit lets in some water and keeps the diver warm by using body heat to warm the water and create a layer of insulation. An inflatable suit includes an insular dry air suit that maintains a comfortable temperature by pumping air to the diver through cords connected to a surface ship. Ocean Temperature Map

Difficult Conditions Creatures that thrive in the deep sea must survive in extremely harsh conditions, such as hundreds of bars of pressure, small amounts of oxygen, very little food, no sunlight, and constant extreme cold. To cope with the pressure, many fish are rather small, usually not exceeding 25 cm in length. The lack of light requires creatures to have special adaptations to find food, avoid predators, and find mates. Most animals have very large eyes with retinas constructed only of cones, which increases sensitivity. Many creatures have also developed very strong sense of smell to detect the chemicals released by other creatures. There is also not enough light for photosynthesis to occur and not enough oxygen to support a fish. To survive, these creatures have much slower metabolisms and therefore can survive using little oxygen. They can also go months without food.

Past Exploration: HMS Challenger The H.M.S. Challenger embarked from Portsmouth, England on December 21, 1872 and changed the course of scientific history. The Challenger was a corvette class ship that traveled by sail but had auxiliary steam power, which helped to stabilize the vessel during sampling. 16 of the 18 guns on board were removed, and in their place were 144 miles of sounding rope, 12.5 miles of piano wire, thermometers, water bottles, and bottom samplers. It was a 4 year journey, during which the ship sailed around the world, sounded the ocean bottom to a depth of 26,850 feet, found many new species, and provided collections for biologists. C. Wyville Thomson led the expedition, which ended on May 24, By then, the Challenger had sailed around the globe and visited every continent, including Antarctica. The Challenger expedition produced 50 volumes, most of which described the organisms collected from both deep and shallow water.

The HMS Challenger

Drawings of tiny plankton made during the expedition Water Samplers Bottom Samplers

Ocean Technology Various missions in open waters depend on technology. Technology is important because it supports research and explorations under and on the ocean. Vessels Vessels are the most critical tool for scientists when it comes to exploring the ocean. They are very advanced mobile research stations and can transport scientists, mariners and equipment over the ocean. The ships also provide platforms from which explorers can deploy equipment, divers, and submersibles.

Diving When depths are not too great or conditions are not too dangerous, divers can descend into the water to explore the ocean realm. However, it is only through recent advances in technology that this type of exploration has been possible. Observation Tools Scientists rely on an array of tools to collect weather and ocean observations such as water temperatures and salinities, the shape of the seafloor, and the speed of currents.

Submersibles Submersibles descend to sea floor depths that are not safe for divers, allowing us to explore ocean depths, make detailed observations, and collect samples of unexplored places.

Improving Technology Canada has a special interest in ocean exploration because of its access to three oceans: the Atlantic, Pacific and Arctic. Canada has developed technology for exploring its oceans, including specialized diving suits and submersibles. Canadian firms have established themselves as world leaders in ocean technology. The ocean technology industry owns many small and medium-sized firms as well as research and development organizations. The government has also been working to encourage small and medium-sized business innovations and to position Canadian companies to create the next generation technologies.

Pollution There are 5 sources of marine pollution: 1.land-based pollution 2.pollution from vessels 3.continental shelf drilling 4.deep-seabed mining 5.ocean dumping Land-based pollution comes from factories, sewage, and anything else that people put in the ocean. This accounts for about 90%, while the other 10% are from causes 2-4. Industrial dumping of heavy waste metals, such as mercury and nickel, can also be dangerous. Although many organisms can take in high concentrations of waste metals and not be affected by them, if the organisms are in turn eaten by humans the results can be extremely dangerous. Some of the problems are related to the balance of the oxygen in the water. For example, if large amounts of waste were dumped in the water, the growth of phytoplankton may increase to a point that they decay, using up all the oxygen in the water and leaving none for the other aquatic plants and animals.

Ocean Pollution

Responsible Exploration A few ways you can help protect the ocean: 1.Whether you enjoy diving, surfing, or relaxing on the beach, always clean up after yourself. Try to explore and appreciate the ocean without interfering with wildlife or removing rocks and coral. 2.Certain products are harmful to fragile coral reefs and marine populations. Avoid purchasing items such as coral jewelry, tortoise-shell hair accessories and shark products. 3.Many institutes and organizations are fighting to protect ocean habitats and marine wildlife. Find a national organization and consider giving them financial support or volunteering. 4.Reduce the effects of climate change on the ocean by leaving your car at home when you can and being conscious of your energy use at home and work. 5.When shopping or dining out, help reduce the demand for overexploited species by choosing seafood that is both healthful and sustainable.