Oceans

Objective 8.E.1.2 Summarize evidence that Earth's oceans are a reservoir of nutrients, minerals, dissolved gases, and life forms: estuaries, marine ecosystems, upwelling, and behavior of gases in the marine environment, and deep ocean technology and understandings gained.

The Oceans Oceans are the largest bodies of water on Earth. Oceans account for 97% of all water on Earth. We have 5 Oceans total: Atlantic Pacific Indian Arctic Southern

The 5 Oceans

Ocean Zones

Intertidal Zone The intertidal zone, sometimes referred to as the “seashore”, is the area that is above water at low tide and under water at high tide. This area can include many different types of habitats, with many types of animals, such as crabs, starfish, sea urchins, and numerous species of coral.  Organisms living in the intertidal zone have adapted to an environment of harsh extremes the temperature range can be anything from very hot with full sun to near freezing in colder climates.

Intertidal Zone Low Tide – The intertidal zone becomes dry from low water levels. High Tide – The intertidal zone becomes submerged with water.

Neritic Zone The neritic zone is the relatively shallow part of the ocean between the low tide mark and the continental shelf. The neritic zone receives plenty of sunlight with a relatively stable temperature, making it suitable for aquatic plant life. The consistent temperatures and low pressure allow for marine life as small as plankton all the way to large fish, to thrive.

Oceanic Zone It is the region of open sea beyond the edge of the continental shelf where the water measures 200 meters deep, or deeper. The oceanic zone has a wide array of undersea terrain, including crevices that are often deeper than Mount Everest is tall, as well as deep-sea volcanoes and ocean basins. While it is often difficult for life to sustain itself in this type of environment, some species do thrive in the oceanic zone. Lets Name The Zones!

Oceanic Zone Oceanographers divide the oceanic zone into zones according to how far down sunlight penetrates. Photic Zone: 0-200m Epipelagic (Sunlight) Aphotic Zone: 200-4,000m Mesopelagic (Twilight) & Bathypelagic (Midnight) Abyssal Zone: ≥ 4,000m Abyssopelagic (The Abyss) & Hadalpelagic (The Trenches)

The Sunlight Zone The Twilight Zone The Midnight Zone The Abyssal Zone

Ocean Exploration

If we’ve never really explored the deepest parts of the ocean, how do we know what the seafloor looks like?

Divers Deep sea divers were the very first methods of exploring the ocean. Ocean divers go all the way back to the 1800’s

Sonar Sonar = SOund Navigation And Ranging A system that sends sound pings to measure the distance between objects in water Before sonar technology existed, early American surveyors used ropes and lead weights to survey our nation’s waterways.

Submersibles Satellites, sonar, and divers only scratch the surface of the oceans. Submersibles alone enable us to explore the abyssal depths. Submersible are capable of meeting the many challenges that the deep sea imposes upon explorers. Main types of submersibles: Submarines ROV (remotely operated vehicle) Underwater Habitat

ROV

Under Water Habitats

What are some of the benefits of these new technologies?

Parts of the Sea Floor

Parts of the Sea Floor Beneath the world's oceans lie rugged mountains, active volcanoes, vast plateaus and almost bottomless trenches. Oceanographers know these features exist because much effort has been spent on mapping the ocean bottom.

Mariana Trench The Mariana Trench is the deepest point on Earth. It is located in the western Pacific Ocean, to the east of the Mariana Islands In 2012 James Cameron became the first person to successfully complete a solo dive to the bottom of the Mariana trench.

Hydrothermal Vents Like hot springs and geysers on land, hydrothermal vents form in volcanically active areas—often on mid-ocean ridges, where Earth’s tectonic plates are spreading apart and where magma wells up to the surface or close beneath the seafloor. Seawater in hydrothermal vents may reach temperatures of over 340°C (700°F). Hot seawater in hydrothermal vents does not boil because of the extreme pressure at the depths where the vents are formed.

Hydrothermal Vents

Hydrothermal Vents Vents support complex ecosystems of exotic organisms that have developed unique adaptations to high temperatures and environmental conditions we would consider toxic. Learning about these organisms can teach us about the evolution of life on Earth and the possibility of life elsewhere

Chemosynthetic Organisms Most life on Earth is dependent upon photosynthesis, however, at hydrothermal vents in the deep ocean a unique ecosystem has evolved in the absence of sunlight, and its source of energy is completely different: chemosynthesis. Chemosynthesis is the process by which certain microbes create energy by mediating chemical reactions. So the animals that live around hydrothermal vents create their energy from the chemicals coming out of the seafloor in the vent fluids.

Ocean Water

Salinity Is a measure of the amount of dissolved salt in the ocean The oceans salinity has stayed the same for the past 1.5 billion years

Salts Ocean water is a solution. Sodium Chloride is the main solute For every 100 grams of water there are 3.5 grams of salt

Mass of Salt Recovered (grams) Percentage of Total Salts Sodium chloride 2.72 77.71 Magnesium chloride 0.38 10.86 Magnesium sulfate 0.17 4.86 Calcium sulfate 0.13 3.71 Potassium sulfate 0.08 2.29 Calcium carbonate 0.01 0.29 Magnesium bromide Total Salt 3.5 100%

Salt Water Density Salt water is more dense than fresh water Ex. The dead sea Is so dense people float on it Salt water has a higher mass and therefore a higher density.

Temperature Warm water is less dense than cold water so it stays on the surface The deeper you go, the colder and more dense the water is.

Elements in the Ocean There is oxygen, CO2, and other gases in the ocean…just like our atmosphere! All 92 naturally occurring elements can be found in the ocean water or floor.