1. Oceans
From wave to wave…

2. Ocean: What is it? One continuous body of water
Many basins: North Atlantic, South Atlantic, North Pacific, South Pacific, Indian, and Arctic
Contain dissolved salts (mostly sodium chloride)—from millions of years of dissolving them from rocks on the land
Connected to land via rivers, bays, and estuaries
Ocean Zones: Ocean organized vertically according to the amount of three factors:
1. temperature
2. pressure
3. light

3. Estuary: What is it? An estuary is formed where rivers meet the sea.
An estuary is a semi-enclosed river mouth or bay where salty seawater is diluted by freshwater from rivers and creeks.
An estuary is made up of tidal marshes, tidal flats, and open water channels.
An estuary is flooded by the tides.
These descriptions of an estuary help us to understand the physical place and the forces that shape an estuary. We will learn more about these special environments and the rich diversity of life they support as we study estuaries in the classroom and the field.

4. Estuaries: Functions
Habitat—for many types of marine fish, mollusks, crustaceans, etc.
Buffer Zone—from the river to the ocean
Breeding ground and nursery—for fish larvae, small young sea creatures
Filter—to filter out pollutants and sediment washed down from rivers.

5. Open Ocean Zones

6. The Ocean Zones Intertidal (Between High and Low Tide)
Neritic (Low Tide to Continental Edge)
Benthic (Ocean Floor)
Pelagic (Open Ocean )
Epipelagic (Sunlight)
Mesopelagic (Twilight)
Bathypelagic (Midnight)
Abyssopelagic (The Abyss)
Hadalpelagic (The Trenches)

7. Pelagic Intertidal Abyssal Benthic
Earth is typically divided into “-spheres”: hydrosphere refers to water, lithosphere to the landforms (“litho” means rock), biosphere to the living world (“bios” means living), and the atmosphere (“atmos” means air).
Four zones of interest in the hydrosphere are intertidal, pelagic, abyssal, and benthic.
Benthic

8. Intertidal Zone
Located at the edge of the ocean, between the highest high-tide line and the lowest low-tide line.
During periods of low tide, it is possible to explore the ocean floor in the intertidal zone.
Most thoroughly studied, and best-known, ocean area.
Even within the intertidal areas, the cycle of exposure to air varies markedly—so much that four different habitat bands have been identified: 1) the spray zone, 2) the high-tide zone, 3) the mid-tide zone, 4) the low-tide zone

9. Intertidal Zones

10. Intertidal Zone Creatures
High Tide
Some organisms need a hard bottom to attach to. Our beaches are generally sandy, without hard substrate, but piers, docks, boat ramps, bulkheads, etc. do provide hard bottom. Many of these organisms are motile (can move around) rather than attached– crawlers, grazers, burrowers, swimmers.
Low Tide

11. Neritic Zone From low tide line to edge of continental shelf
More organisms known than any other zone
Major fishing grounds—contain nekton, or free swimming animals like fish, octopus, and marine mammals
Sunlight and nutrients
Two diverse habitats
Coral Reefs
Kelp forests

12. Coral Reefs Made of tiny organisms surrounded by hard shells.
Shallow tropical waters
Develop over long periods of time (mm/yr)

13. Ratfish and ray, octopus, anemone, sea star, sea urchin, group of shells and mole crab, crab, soft coral and flatworm (black with ruffly edges), group of shells and spider crab, spiny oyster.

14. Kelp Forest Cold neritic waters Rocky bottoms
Holdfast - rootlike attachments
Kelp = algae
Photosynthesis
Symbiotic relationship with sea otters
Urchins eat kelp
Otters eat urchins
Kelp habitat for otters

15. Benthic Zone
* Benthic: a term meaning bottom. The zone goes from the shore to the deepest part of the ocean.
Benthos-- kinds of organisms that live either in or on the ocean floor– plants, anemones, sponges, fish, skates and rays, octopus, mollusks, crabs, sea stars, corals and worms. Most are scavengers.
Life in the deepest parts of the ocean is fairly sparse except around hydrothermal vents, where it is quite concentrated.

16. Benthic Zone– from the shore to the depths

17. Conditions in the Open Ocean
Light only at top
Fewer nutrients
Fewer organisms known
Five zones
Epipelagic Zone (Sunlight Zone)
Mesopelagic Zone (Twilight Zone)
Bathypelagic Zone (Midnight Zone)
Abyssopelagic Zone (Deep Ocean)
Hadalpelagic Zone (The Trenches)

18. Epipelagic Zone
The surface layer of the ocean is known as the epipelagic zone and extends from the surface to 200 meters (656 feet). It is also known as the Sunlight Zone because this is where most of the visible light exists.
With the light comes heat, which is responsible for the wide range of temperatures that occur in this zone.
Plankton: small organisms in this zone:
Phytoplankton—free floating, photosynthetic organisms, like diatoms and algae
Zooplankton—propel themselves, microscopic crustaceans, copepods, fish larvae

19. Mesopelagic Zone
The Twilight Zone extends from 200 meters (656 feet) to 1000 meters (3281 feet).
The light that penetrates to this depth is extremely faint. It is in this zone that we begin to see the twinkling lights of bioluminescent creatures.
A great diversity of strange and bizarre fishes can be found here. Many are soft and gelatinous, from transparent squid, octopuses and jellyfish to large colonial animals called siphonophores.

20. Bathypelagic Zone
The Midnight Zone extends from 1000 meters (3281 feet) down to 4000 meters (13,124 feet).
Here the only visible light is that produced by the creatures themselves.
The water pressure at this depth is immense, reaching 5,850 pounds per square inch. In spite of the pressure, a surprisingly large number of creatures can be found here.
Sperm whales can dive down to this level in search of food. Most of the animals that live at these depths are black or red in color due to the lack of light.

21. Abyssopelagic Zone
The Abyss extends from 4000 meters (13,124 feet) to 6000 meters (19,686 feet). The name comes from a Greek word meaning "no bottom".
The water temperature is near freezing, and there is no light at all.
Very few creatures can be found at these crushing depths. Most of these are invertebrates such as basket stars and tiny squids. Three-quarters of the ocean floor lies within this zone.

22. Hadalpelagic Zone
This layer extends from 6000 meters (19,686 feet) to the bottom of the deepest parts of the ocean in The Trenches.
The temperature of the water is just above freezing, and the pressure is an incredible eight tons per square inch. That is approximately the weight of 48 Boeing 747 jets. Invertebrates such as starfish and tube worms can thrive at these depths.
In the deep ocean, there are special benthic communities around hydrothermal vents whose energy comes from chemical reactions rather than from the sun.

23. Ocean Currents
An Ocean Current is a large volume of water flowing in a certain direction.
Wind-driven currents are called surface currents.
Surface currents carry warm or cold water horizontally across the ocean’s surface

24. Rip Currents
A rip current is a narrow, powerful surface current which flows away from the shore.
It is caused by pressure building up from uneven buildup of water from waves.
They can flow very quickly and can be difficult to detect until you are in one.
They are VERY dangerous, avoid them when swimming.

25. Upwelling
Upwelling is the vertical movement of water toward the ocean’s surface.
Upwelling occurs when wind blows across the ocean’s surface and pushes water away from an area. Deeper colder water then rises to replace it.
Upwelling often occurs along coastlines.
Upwelling brings cold, nutrient-rich water from deep in the ocean to the ocean’s surface.

26. Density Currents
Density Currents are a type of vertical current that carries water from the surface to deeper parts of the ocean.
Density Currents are caused by changes in density rather than wind.
Density currents circulate thermal energy, nutrients and gases.

27. Great Ocean Conveyor Belt
The Great Ocean conveyor Belt is the name for a model of the large system of ocean currents that affects weather and climate by circulating thermal energy around Earth.
In this model, high salinity water cools and sinks in the North Atlantic, and deep water returns to the surface in the Indian and Pacific Oceans through upwelling

28. Oceans: Human Uses
Oceans responsible for most of the rain (evaporation /precipitation) and ~50% of oxygen production (plankton) on Earth.
Humans use the ocean for food (fish), medicine (plants /animals), minerals, and other resources.
Ocean is limited—overfishing, global climate change, and pollution can severely affect the ocean environment.