360 likes | 617 Views
MARINE ENVIRONMENTS. Life Zone. Definition: a region that contains characteristic organisms that interact with one another and with their environment. Coastal Life Zones. Intertidal Zone Located between high tide and low tide
E N D
Life Zone • Definition: a region that contains characteristic organisms that interact with one another and with their environment.
Coastal Life Zones • Intertidal Zone • Located between high tide and low tide • High tide marked by strandline- long line of seaweed and debris left on beach during each high tide. • Alternating dry and wet periods of time • Beach hoppers, worms, crustaceans (small crabs)
Coastal Life Zones • Supratidal Zone • Above intertidal zone up to dunes – beach area • Gets fine mist/spray from ocean waves • Mostly grasses, shrubs, trees
Coastal Life Zones • Subtidal Zone • Below high tide line • Remains underwater • Heavy wave impact and underwater turbulence of sandy area
Coastal Life ZonesSubtidal Zone • Organisms have structures that help them cling to hard surfaces so they will not be swept away. Examples: • Mussels secrete tough fibers (like threads) • Barnacles cement themselves with glue that they produce
Marine Life Zones The ocean is divided into 3 marine life zones • Pelagic Zone • Largest life zone • Covers the entire ocean above sea bottom • from the intertidal zone out into the deep ocean • Includes the Neritic zone (less than 200 m deep) and the Oceanic zone (more than 200 m deep)
Marine Life Zones • Neritic Zone • Beyond intertidal zone • Lies above continental shelf • Most of the world’s commercial fishing takes place here
Marine Life ZonesNeritic Zone • Productivity based on nutrients that come from runoff of rivers and land • Much of neritic zone has sunlit depths so plants and algae can carry on photosynthesis
Marine Life Zones • Oceanic Zone • Extends beyond continental shelf • Upper part receive light, lower part dark • Photic zone-(also called the euphotic zone) area of approx. 100 meters in depth that receives light. (max. depth of 200 m) • 99% of sunlight absorbed in photic zone
Marine Life ZonesOceanic Zone • Aphotic zone –zone with no light • Fewer communities of organisms • Deep-sea organisms are specially adapted to live in deep aphotic zone • Adaptation: any characteristic of an organism that enables it to live successfully in its environment.
Marine Life ZonesOceanic Zone • Examples:Anglerfish- has a huge mouth and long sharp teeth to help it catch prey in the darkness. Also has a lure over its mouth that glows in the dark to attract prey. • Other deep-sea fishes have mouths that point downward or upward to catch falling scraps of food.
Marine Life Zones • Benthic Zone • Anywhere at the bottom of the ocean from shallow intertidal zone to deep ocean basin also called the abyssal zone • Organisms that inhabit the benthic zone are called benthos
Plankton • Depend on currents for movement. • Jellyfish, any small organism like, copepods, krill
Nekton – swimming organisms- can move about freely by swimming within the “water column”. • Fish, shark
Estuaries • Estuary – formed at the mouth of a river where fresh water and salt water mix • Brackish water – mixture of fresh and salt water • Most productive environments along coast • Many organisms lay their eggs there • Nutrient-rich environment
Salt Marshes • Along Atlantic, Pacific, and Gulf coasts • Grasses grow in shallow water forming salt marsh communities (wetlands) • Contains cordgrass that contains lots of nutrients • animals do not eat it until after it dies • Bacteria decays it and it becomes detritus • Nutrients from detritus released into the estuary’s waters
Salt Marshes • Nutrients are: • Phosphates used for energy • Nitrates used for growth • Taken up by plankton • Plankton • Become food source for filter feeders, like mussels
Salt Marshes • Fiddler crabs and hermit crabs feed on bits of organic matter left behind by outgoing tides • Salt water marshes are “nurseries” for many species of ocean fish and crabs • Ex. Flounders that feed on killifish
Mud Flats • Dark, muddy sand with no marsh grasses • Very little aeration because of slight wave impact • Organic debris accumulates in the sand
Mud Flats • Mud flat is a “graveyard” • Bacteria decompose wastes and turn sand into dark mud • Gives off a foul odor, like rotting eggs. • Smell caused by Hydrogen sulfide (H2S) • product of decay and • Accumulation of sediments deficient in oxygen
Mud Flat • Decomposers, like decay bacteria covert wastes into useful nutrients • Tidal action transports the nutrients to other parts of estuary and out to sea • Nutrients from estuary are a major food source for oceanic plankton.
Mud Flat • Inhabitats are • Mud snails-”garbage eaters”, get rid of wastes • Soft shell clams “steamers” • Razor clams • other mollusks that dig through the sand and aerate it and to escape predators
Mangroves • Mangrove swamps • In tropical regions, like Florida • Mangrove trees • Like a natural wildlife sanctuary • Barnacles, oysters, snails, land crabs, fiddler crabs, conch, pelicans, osprey, raccoons