Download Chapter 9 Marine Ecology

Marine Ecology
Ecology is the study of the interrelationships between the physical and
biological aspects of the environment. It
is the study of how organisms adapt to
their environment and in turn alter it.
Marine ecology is the branch of ecology
dealing with the interdependence of all
organisms living in the ocean, in shallow
coastal waters, and on the seashore. The
marine environment for all organisms consists
of non-living, abiotic factors and living, biotic
factors.
Ocean Habitats
There are two major marine provinces: the
benthonic (bottom) and the pelagic (water column).
• The benthonic environment is divided by depth
into the: Intertidal zone, Sublittoral zone, Bathyal
zone, Abyssal zone, and the Hadal zone
• The pelagic environment is divided into the
Neritic Zone and the Oceanic Zone
Ocean
Habitats
Ocean Habitats
The ocean can also be divided into zones based
upon depth of light penetration.
• The photic zone is the depth where light is
sufficient for photosynthesis.
• The dysphotic zone is where illumination is too
weak for photosynthesis.
• The aphotic zone receives no light from the
surface because it is all absorbed by the water
above.
Classification of Lifestyle
Marine organisms can also be classified by
lifestyle.
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Plankton are the organisms which float in the water and have no ability
to propel themselves against a current.
• They can be divided into phytoplankton (plants) and zooplankton
(animals).
Nekton are active swimmers and include marine fish, reptiles, mammals,
birds and others.
Benthos are the organisms which live on the bottom (epifauna) or within
the bottom sediments (infauna).
Some organisms cross from one lifestyle to another during their life,
being pelagic early in life and benthonic later.
Classification of Organisms
In 1735 Linnaeus developed the taxonomic
classification used in zoology.
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The categories are from largest to smallest: Kingdom, Phylum,
Class, Order, Family, Genus and Species.
The name of a species consists of the genus name combined with a
trivial name.
• The genus name begins with a capital.
Classification of Organisms
The five major kingdoms in the ocean are: Monera, Protista, Fungi,
Metaphyta and Metazoa.
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Monera are the bacteria and blue-green algae.
Protista are single-celled organisms with a nucleus.
Fungi are abundant in the intertidal zone and are important in
decomposition.
Metaphyta are the plants that grow attached to the sea floor.
Metazoa include all multicellular animals in the ocean.
Basic Ecology
Environmental factors in the marine environment
include: temperature, salinity, pressure, nutrients,
dissolved gases, currents, light, suspended
sediments, substrate (bottom material), river inflow,
tides and waves.
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Ecosystem is the total environment including the biota (all living
organisms) and non-living physical and chemical aspects.
Temperature can control distribution, degree of activity and
reproduction of an organism.
Salinity can control the distribution of organisms and force them to
migrate in response to changes in salinity.
Selective Adaptive Strategies
More than 90% of marine plants are algae and most are unicellular and
microscopic.
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To photosynthesize (produce organic material from inorganic matter
and sunlight) plants must remain within the photic zone.
Diatoms are single cells enclosed in a siliceous frustrule (shell) that
is shaped as a pillbox.
Dinoflagellates are single cells with two whip-like tails (flagella).
Land vs. Ocean Plants
Phytoplankton Maximize Surface Area
Diatoms
Selective Adaptive Strategies
Zooplankton include the copepods and foraminifera.
• Copepods are small herbivores (plant-eating
organisms) that filter diatoms from the water.
• Foraminifera are single-celled, microscopic
organisms which build shells of calcium
carbonate.
Zooplankton - Copepods
Selective Adaptive Strategies
Intertidal benthonic communities generally display
vertical zonation that parallels sea level.
• Zonation reflects the amount of time the area is
submerged and the ability of the organism to
survive the stress of exposure.
• Benthonic communities also vary in response to
substrate (bottom material).
Rocky intertidal - vertical zonation
Basic Ecology
• Hydrostatic pressure is the
pressures exerted by a column
of water surrounding an
organism.
Selective Adaptive Strategies
The morphology of fish has evolved to allow them to move through the
water easily.
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The fish’s body must overcome three types of drag
(resistance): Surface drag, Form drag, and Turbulent drag.
Speed is dependent upon body length, beat frequency, and
the aspect ratio of the caudal fin.
Aspect ratio is the ratio of the square of the caudal fin height
to caudal fin area:
AR = (Caudal Fin Height)2/Caudal Fin Area
There are three basic body forms, each adapted to a
different life style.
There is a strong correlation between predation success
and body form.