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 1/3 rd 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)