Transcript The Diversity of Ocean Life

The Diversity of Ocean
Life
Chapter 15, Section 2
Classification of Marine Organisms
 Marine
organisms can be classified
according to where they live and how they
move
 Plankton include all organisms—algae,
animals, and bacteria—that drift with
ocean currents
 Phytoplankton – the algae that undergo
photosynthesis
 Zooplankton – animal plankton
Plankton
Phytoplankton
Zooplankton
Classification of Marine Organisms
 Nekton
include all animals capable of
moving independently of the ocean
currents, by swimming or other means of
propulsion
 The term benthos describes organisms
living on or in the ocean bottom
Nekton
Benthos
Marine Life Zones
 The
distribution of marine organisms is
affected by the chemistry, physics, and
geology of the ocean
 Three factors are used to divide the ocean
into distinct marine life zones: the
availability of sunlight, the distance from
shore, and the water depth
Availability of Sun
Photic Zone – the upper part of the ocean into
which sunlight penetrates
 The clarity of seawater is affected by many
factors, including the amount of plankton,
suspended sediment, and decaying organic
particles
 The euphotic zone is the portion of the photic
zone near the surface where light is strong
enough for photosynthesis (usually no deeper
than 100 meters)
 Below the photic zone is the aphotic zone,
where there is no sunlight
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Marine Life Zones
Distance from Shore
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Intertidal Zone – the area where the land and ocean
meet and overlap
The intertidal zone is a narrow strip of land which is
alternately covered and uncovered between high and
low tides
Neritic Zone – covers the gently sloping continental
slope
The neritic zone is often shallow enough to put all of it
in the photic zone, and is so rich with life that it
supports 90% of the world’s commercial fisheries
Oceanic Zone – area beyond the continental shelf
Surface waters in the oceanic zone tend to not have
many nutrients as they sink down to the deep ocean
floor
Marine Life Zones
Water Depth
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Pelagic Zone – open ocean of any depth
Animals in the pelagic zone swim or float freely
Benthic Zone – includes any sea-bottom
surface regardless of its distance from shore
The benthic zone is mostly inhabited by benthos
organisms
Abyssal Zone – a subdivision of the benthic
zone; includes the deep-ocean floor, such as
abyssal plains
The abyssal zone is characterized by high water
pressure, consistently low temperature, no
sunlight, and sparse life
Marine Life Zones
Marine Life Zones
Marine Life Zones
Hydrothermal Vents
 Seawater
seeps into the ocean floor
through crack in the crust
 The water is super-heated and saturated
with minerals, and escapes back into the
ocean
 The minerals precipitate out, giving the
water the appearance of black smoke
(black smokers)
 At some vents water temperature of 100ºC
or higher support communities of organisms
found nowhere else in the world
Hydrothermal Vents
Assignment
 Read
Chapter 15, Section 2 (pg. 428-432)
 Do Section 15.2 Assessment #1-5 (pg.
432)