Ocean

The open ocean is the most extensive region on earth.

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The open oceans are the areas away from the coastal boundaries and above the seabed ( oceanic crust). It encompasses the entire water column of the seas and the oceans and lies beyond the edge of the continental crust.

CHARACTERISTICS

• • • • 70% of the planet’s surface is covered by water Average depth of the ocean: 3000 meters Life in the oceans is distributed over 3 dimensions There is a very high diversity of marine environments

Arctic

OUR OCEANS

Pacific Indian

All “ONE OCEAN” are thanks to an important system of oceanic currents both at surface and in the depths.

interconnected

Primary Production (gC/m 2 /year) Notice how productive certain areas are, like the North Sea, a region intensly fished!

What limits life in the Oceans?

• • • • Temperature – Influences the quantity of O 2 water – Influence on ocean currents dissolved in the Salinity – Importance for marine animals’ capacity for osmoregulation (process by which we control the quantities of minerals in our cells).

– Along with Tº has an influence on water density Sunlight (necessary for photosynthesis) Nutrients (ditto)

Light

Euphotic layer Oligophotic layer Receives enough light for photosynthesis Dusk Zone Aphotic layer Total Darkness PROBLEM: PHOTOSYNTHESIS REQUIRES LIGHT + NUTRIENTS, BUT FOUND IN THE UPPER LAYER BOTTOM!

WHEREAS LIGHT IS NUTRIENT-RICH WATERS ARE NEAR THE SOLUTION: UPWELLINGS + STORMS (mix up the water column)

Vertical Distribution of Life

Plankton Pelagos Nekton Benthos

Benthos

Communities that live asociated with the ocean floors (from the coast to the deep trenches)

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Plankton

Plankton are basically any and all organisms (plant or animal) that live in the water and are pulled this way and that by the currents. Generally microscopic.

Phytoplancton (single-celled algae) PRODUCERS = responsible for primary production via photosynthesis.

cocolithophorids Phytoflagellates

Zooplankton The CONSUMERS You don’t want to know how many of these you can swallow in a bucket full of sea water…

Other crustaceans krill amphipod Many animals that live on the sea floor actually live in the water column as plankton when they’re young. As they grow older and bigger (and go through several metamorphosis) they migrate back down to the bottom.

Medusas

Nekton

• • Animals who live in the water column and are capable of travelling independantly from the currents Examples: Cefalopods (squid, cuttlefish…)

Fish

Marine Mammals and Reptiles

Human Impact

Humans have a lot of 'waste' that is often disposed of in the ocean trash, sewage, oil, chemicals, heat, and even 'noise' to name a few.

Human Impact

Over fishing Climate change Oil spills Noise pollution Habitat destruction Introduction of alien species Sewage and trash

1. Which are colombian oceans?

2. Have you even been in the ocean?

3. What do you like most of oceans?

4. What problem did you observ?

5. If you go to the beach, what advices will you give to people around to take care the ocean region? 6. Draw a Colombian map and color in blue the ocean region in our country , in green the tropical rain forest and in

yellow the deserts.