Ocean Zones and Marine Habitats

• An ecosystem is the total environment, including biotic factors (living organisms) and abiotic factors (non-living physical and chemical aspects)

Abiotic Factors

• Temperature• Salinity• Pressure• Nutrients• Dissolved gases• Currents

• Light• Suspended

sediments• Substrate• River inflow• Tides• waves

Abiotic Continued

• Temperature can control– distribution – degree of activity– Reproduction of an organism

• Salinity can control– Distribution of organisms– Forces them to migrate when salinity changes

Ocean Zones by Depth

• Sublittoral zone is the depth where light is sufficient for photosynthesis

• Bathyal zone is the region of the seafloor from the shelf edge to the start of the abyssal zone, includes the continental slope and oceanic ridges and rises

Zones con’d

• Bathyal zones may be sites of coral reefs, which are communities of simple organisms called polyps

• A polyp secretes limestone, and after it dies, another polyp grows on the remains, secreting limestone, and so on

• Coral reefs supports 1/3rd of the world’s fish species

Zones con’d

• Abyssal zone: deepest part of the seafloor; there is no light

• The deep ocean• Contains unusual

species• Coelacanth is a “living

fossil”

Ocean Zones by Light Penetration

• Photic zone: layer of the ocean that is penetrated by sunlight;

• Dysphotic zone: illumination is too weak for photosynthesis

• Aphotic zone: receives no light from the surface because the water above absorbs it all

Boundaries of different ocean zones

Lifestyles - Plankton

• Plankton: float in the water and have no ability to propel themselves against a current

• They can be divided into phytoplankton (plants) and zooplankton (animals)

Lifestyles - Nekton

• Nekton: active swimmers and include marine fish, reptiles, mammals, birds, and others

Lifestyles - Benthos

• Benthos: organisms which live on the bottom (eipflora or epifauna) within the bottom sediments (infauna)

• Some organisms can cross from one lifestyle to another during their life – ie. Starts off pelagic and ends up benthic

Freshwater Ecology

• Inland fresh waters represent less than 1% of the world’s water

• Includes lakes, ponds, streams, rivers, wetlands, and estuaries (where freshwater meets salt water)

• Types of animals and plants will vary due to the size, depth, velocity, and temperature of the water

• Animals include beaver and otters, and fish

Freshwater Ecology

Marine Ecology

• More than 70% of the earth is covered by oceans

• Majority of life exists above the depth of 22m

• Most of it is sustained by plankton, which thrive on recycled nutrients, released by bacteria

Marine Ecology

• Includes tidal zone, shallow water, and deep ocean

• Animals and plants along the shore must adapt to the changes of the tides, and adapt to different types of shorelines (sandy versus rocky)