ocean zones and marine habitats. an ecosystem is the total environment, including biotic factors...
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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)