1. The Open Ocean
AKA EPIPELAGIC

2. OPEN OCEAN / EPIPELAGIC ZONE
From surface to m ( ft)
Beyond shelf break
Similar to photic zone – layer from surface to the depth where light limits photosynthesis
Phytoplankton main primary producers (where nutrients are available)
Copepods most abundant zooplankton
Almost all nekton carnivorous predators

3. ABIOTIC FACTORS Light Limited nutrients
Organic particles sink before they can be released by bacteria, surface waters poor in nutrients, phytoplankton growth nutrient-limited
Nitrogen limiting nutrient in ocean
Iron limiting in Southern & equatorial Pacific oceans
At high latitudes winter overturn & mixing bring nutrient-rich deep water to surface

6. BIOTIC FACTORS Staying afloat Finding food and avoid being eaten
Cells & tissues denser than water
Shells & skeletons more dense
Finding food and avoid being eaten

7. ADAPTATIONS Staying afloat Increased water resistance to sink slower
More surface area, more drag, slower sinking
Increase buoyancy
Storing lipids, gas-filled floats/swim bladders

8. ADAPTATIONS Finding food and avoid being eaten
highly developed sense organs
Vision – well developed eyes
Lateral line – sense vibrations in the water
Hearing
Echolocation – built in SONAR in cetaceans
Coloration & camouflage
Countershading (dark top & light bottom)
Excellent swimmers
Streamlined
Well-developed & efficient muscles
High, narrow tails