1. OCEANIC LIFE ZONES

2. Ocean Zonation There are 2 main groups:
Pelagic – referring to water column
Benthic – referring to the sea floor
These groups are subdivided based on depth.

3. Overview of the Ocean Life Zones
Horizontal Zones
Littoral Zone
Bathyal Zone
Abyssal Zone
Vertical Zones
Sunlit Zone
Twilight Zone
Bathyal Zone
Abyssal Zone

4. Horizontal life zones
Littoral Zone – The shallow water area between high and low tides.
Bathyal Zone (Neritic) – The area of the continental margin between the low tide line and the edge of the continental shelf.
Abyssal Zone (Oceanic) – The deep ocean beyond the continental margin.

5. Horizontal Zones Diagram

6. Vertical Zones
Sunlit Zone – (epipelagic) Extends from the surface of the ocean to a depth of 200 meters.
Twilight Zone – (mesopelagic) the area of the ocean between 200 meters and 1,000 meters.
Bathyal Zone – (bathypelagic) extends from 1,000 meters to 4,000 meters.
Abyssal Zone – (abyssalpelagic) the area of the ocean that is deeper than 4,000 meters.

7. V Z E O R N T E I S C A L

8. Vertical Zones, Life and Light
Sunlight is the energy basis for nearly all marine ecosystems and is therefore critical for life.
The Sunlit Zone receives large amounts of sunlight. As a result many of the oceans organisms thrive here. This the area most of our seafood comes from.

9. Vertical Zones, Life and Light
Twilight Zone – an area of the ocean that receives some light but is darker than the sunlit zone. Some fish and other organisms live here.
Bathyal and Abyssal Zones are in complete darkness. Life forms in these zones contain tube worms, lantern fish, angler fish, as well as other forms of life.

11. Types of Oceanic life
Plankton – float near the ocean surface. There are two types: phytoplankton, plantlike and zooplankton, animal like. Plankton are moved at the mercy of ocean currents
Benthos – Organisms that live on the ocean floor.
Nekton – Organisms that can swim.

12. Plankton or Nekton?

13. Benthos

14. Producers
Producers – Organisms that capture energy from sunlight and fix this energy into their tissues.
Eelgrass

15. Planktonic Algae
Many algae are microscopic

16. Phytoplankton
Phytoplankton are the most abundant producers in the ocean and are said to be the basis for marine food webs.
Phytoplankton produce approximately 80% of the worlds oxygen.

17. Phytoplankton
bloom in the
Bearing sea

18. Diatoms
Single shelled yellow-green algae. Its two shells fit together like a lid over a box.
They can live alone or in colonies. They come in many different shapes and sizes.
When they die they sink to the bottom to help form the ocean floor.

19. Dinoflagellates Dinoflagellates are bioluminescent.
They have spinning flagella.
Blooms produce toxins that kill finfish and shellfish. (be careful !!!)

20. Dinoflagellate blooms

21. Consumers
Consumers – Organisms that capture their energy by eating other organisms.

22. Plankton continued…
Zooplankton eat phytoplankton and follow them through the water column.
Haloplankton- Zooplankton that spend their entire lives as zooplankton.
Meroplankton- Temporary plankton such as eggs and larvae.

23. Zooplankton

24. Ways plankton stay afloat
Spikes or other projections help distribute the weight over a larger surface area.
Some produce oil sacs which help float.
Some produce air filled sacs to help float.
WHY DO THEY NEED TO STAY NEAR THE SURFACE???
LIGHT

25. Seasonal Population Variations
Seasonal populations occur because of the complex nature and availability of nutrients and light, temperature and predators.
In Nova Scotia we have blooms in spring and fall.
Daily movements occur as some sink to deeper levels to avoid the midday sun. They move up in the morning and evening.
Zooplankton follow the phytoplankton…