OCEANIC LIFE ZONES

Overview of the Ocean Life Zones

Horizontal Zones

Littoral Zone Neritic Zone Oceanic or PELAGIC

Zone

Vertical Zones

Sunlit Zone Twilight Zone Bathyal Zone Abyssal Zone

Horizontal life zones

Littoral Zone – The shallow water area between high and low tides.

Neritic Zone – The area of the continental margin between the low tide line and the edge of the continental shelf.

Oceanic Zone – The deep ocean beyond the continental margin.

Horizontal Zones Diagram

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.

V Z

E OR NT EI SCAL

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.

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.

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.

plankton or nekton?

Benthos

Questions: Complete and pass in.

1. List 5 examples of nekton, 5 examples of benthos and 3 examples of plankton.

2. List the marine communities you learned about in the last two classes and name the horizontal and/or vertical life zones to which they belong.

3. Turn a looseleaf page sideways and make a sketch of the horizontal and vertical life zones. Make it as much to scale as you can. Label each zone.

Producers

Producers – Organisms that capture energy (usually from sunlight) and fix this energy into their tissues.

Eelgrass

Planktonic Algae Many algae are microscopic

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.

Phytoplankton

bloom in the

Bering sea

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.

Zooplankton

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 differet shapes and sizes.

When they die they sink to the bottom to help form the ocean floor.

Dinoflagellates Dinoflagellates are bioluminescent. They have spinning flagella. Blooms produce toxins that kill finfish and

shellfish. (be careful !!!)

Dinoflagellate blooms

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___

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…

Consumers Consumers – Organisms that capture their

energy by eating other organisms.