OCEAN FLOOR

Common Core/EssentialStandard #: 8.E.1Understand the hydrosphere and the impact of humans on local systems and the effects of the hydrosphere on humans. Clarifying Objective: 8.E.1.2 Summarize the evidence that Earth’s oceans are reservoirs of nutrients, dissolved gases, and life forms: Estuaries Marine ecosystems Upwelling Behavior of gases in the marine environment Deep ocean technology and understandings gainedInstructional

Ocean floor

Continental Shelf - DEPTH Relatively shallow –Water depth over the continental shelves averages about 60 meters but can be as deep as 130 meters (This is about 200 to 430 feet)

Continental Shelf -FEATURES similar to features we see on land, including hills, ridges, and canyons. Size of the shelf varies widely. There is almost no shelf off the coast of Florida due to erosion In some places, deep submarine canyons have their beginnings as they cut through the continental shelves mostly off the mouths of major rivers such as the Amazon, Mississippi, etc

DEFINE – SUBMARINE CANYONS Submarine canyons are deep, narrow, steep-sided valleys on the sea floor. They begin as shallow valleys on the continental shelf and deepen as they move further from land across the continental slope Submarine canyons are the main pathways by which sediments reach the deep sea

Continental Slope Depth From about 130 meters to a depth of about 2500 -3000 meters 3000 meters is about 1.86 miles

Features of Continental Slope Steady slope - steeper in the Pacific Ocean than in the Atlantic.   Slope can range from only about 4o to nearly vertical. Especially steep where mountains hug the coastline Deep valleys and gullies, including deep submarine canyons, are more noticeable. Many were carved by turbidity currents.

Continental Slope

DEFINE – TURBIDITY CURRENTS Turbidity currents begin when mud and sand on the continental shelf are loosened by earthquakes, collapsing slopes, etc. The turbid water then rushes downward like an avalanche, picking up sediment & increasing speed as it flows. Turbidity currents can change the physical shape of the sea floor by eroding large areas and creating underwater canyons

Turbidity current

Continental Rise DEPTH: 3000 to 4000 + meters (about 2 to 2.5 miles) FEATURES: Gently sloping thick deposits of sediment that have been delivered from the continental shelf. Generally, the rise is larger at the mouth of a large river Relatively smooth

Abyssal plain DEPTH Begins where temperatures drop below 4oc. This is around a depth of about 3000 meters and it continues to about 6000 meters below the surface (or about 3.7 miles)

AbySsal PLAIN FEATURES Covers almost a third of earth’s surface Consist of beds of volcanic rock topped with sediments that are up to thousands of feet thick Most is nearly featureless & very flat. Total darkness, nearly freezing, with intense pressure. Flat plain is broken by volcanic hills and mountains (some part of the abyssal plain) and the mid oceanic ridge (considered separate from the plain).

Mid Oceanic RIDGE The mountain ranges can have peaks as high as 12,000 feet (2,500 meters) above the plates where they formed Some even reach above the ocean's surface. Iceland, along the mid-Atlantic ridge, is an example of this.

MID OCEANIC RIDGE _FEATURES At mid-ocean ridges, two plates are pulling apart from each other. Liquid rock (magma) emerges to fill the cracks and piles up forming the mountain ranges. A valley lies between the mountain ridges where the two plates meet consists of 1000s of individual volcanoes which periodically erupt forming seamounts, guyots and islands the longest mountain ranges on earth. (nearly 60,000 kilometers (37,000 miles) The vast majority of volcanic activity on the planet occurs along the mid-ocean ridge .

DEFINE Seamounts are isolated volcanic mountains scattered across the ocean floor. Most common in the Pacific Ocean, seamounts generally rise more than 1,000 meters above the sea floor. They are often found in clusters or rows near plates or hot spots. If a seamount eventually breaks the water's surface, it becomes an island. Seamounts whose peaks have eroded and become a flat surfaces are called guyots

Trenches – the hadal zone DEPTH: Begin at around 6000 meters. The deepest known trench depth is in the challenger deep of the Mariana Trench – about 11,000 m (about 36,000 ft) below sea level.

Hadal Zone Consists mainly of long, narrow, steep-sided walls of the deep sea trenches. …. Trenches form where 2 tectonic plates collide with one another. At this collision point, one of the plates sinks below the other. Marked by enormous pressure and extreme cold…….except for the extremely hot hydrothermal vents

Define – Hydrothermal vents Hydrothermal vents occur at cracks along a rift or ridge in the deep ocean floor that spews out water heated to high temperatures by magma under the earth's crust. Like hot springs and geysers on land, hydrothermal vents form in volcanically active areas—often on mid-ocean ridges, The water from the can reach temperatures of 572 degrees f (300 degrees c).

VIDEO CLIPS

Good reviewGOING THE DEPTH http://www.harcourtschool.com/activity/science_up_clo se/518/deploy/interface.html http://www.untamedscience.com/biology/world-biomes/deep-sea-biome