The Marine Biome

The Marine Biome
Environmental Science
Chapter 11
The Oceanic Hydrosphere
• All of the water that exists between the
lithosphere (continents) can be thought of as
ONE BIG OCEAN
• Even despite having several names, all of the
worlds oceans are interconnected
• It is essentially one MASSIVE biome with many
ecosystems & habitats
• It consists of all of the worlds interconnected
saline (salt) water
The Open Ocean
• Another name for the “open ocean” is the
oceanic zone or The DEEP
– This is by far the largest zone in the ocean
– Makes up about 90% of the total ocean biome
• This is an extremely deep biome that ranges
from 200m deep along the coast, all the way
to 11,000m deep.
• Most of the oceanic zone receives little to no
sunlight
Ocean Producers
• Because the vast majority of area in the open
ocean has no access to the ocean floor, any
and all producers must be able to float or
swim
• The producers that do this, and make up the
primary level of the oceanic food web, are
microscopic organisms called phytoplankton
• These microscopic Protists and algae carry out
the same photosynthesis that terrestrial
plants do, converting carbon dioxide into
essential sugars and food for other organisms
Sometimes,
water
pollution can
cause so many
phytoplankton
to grow that
the colony is
actually
visible.
The photic zone
• In the open ocean, the top 200m of water
receives enough sunlight to support
photosynthetic organisms
– This area is called the photic zone
• This area has the largest amount of life and
diversity and a large amount of available
biomass
• This area of the ocean is also the largest
remover of carbon dioxide from the
atmosphere
Beyond the Photic Zone
• Any area below the photic zone (deeper than
200m) is called the aphotic (no light) zone.
• Because there is no sunlight available, there is
no potential for photosynthesis
• No photosynthesis means no producers,
which means very little biomass
• This makes life difficult and causes there to be
MUCH LESS diversity here
• Most organisms here must feed on pieces of
dead organic matter and waste that float
down form above called Detritus
Its all the same… Kind of…
• Because the oceans of the world are all
interconnected, often its is said that it has the
same characteristics throughout
• However, this is not totally true
– The ocean waters are all affected by temperature,
sunlight intensity, salinity, and dissolved minerals
– Because the sunlight intensity near the equator is the
strongest it causes the water to be warmer, and the
increased evaporation causes for higher salt and
dissolved mineral concentrations
– The poles receive substantially less sunlight for
evaporation, and are often receiving melted
freshwater from glaciers which make them less saline
Continental Shelf
• The continents do not just suddenly drop off into
deep ocean.
• Most continents are surrounded by a shallow
border that surrounds the land mass and slowly
slants deeper into the ocean
• This area is photic (receives a lot of sunlight) and
is considered to extend from the shoreline down
to about 200m deep.
• This area usually has a diverse biomass do to the
available sunlight and ability to photosynthesize
Neritic Zones
• Within the continental shelf is another
division called the neritic zone
• The neritic zone is the area that stretches
from the edge of the continental shelf and
runs to the edge of the “low tide mark”
• The low tide mark is the lowest point that the
tide recedes to during low tide
– This area is therefore always covered in water
Coral Reefs
• Continental shelf zones have a
spectacularly diverse and unique
ecosystem called a coral reef
• The reef system is composed of large
structures of living and once living
organisms
• These reef organisms form hard structures
out of calcium carbonate
– As these organisms die, their skeletons form
structure for other living organisms to inhabit
and grow on
Coral Reefs
• Most of the animals on a coral reef are either
filter feeders who remove carbon material
from the water for food
• Or they are animals that have a symbiotic
relationship with a bacteria called
zooxanthellae
– The zooxanthellae bacteria are able to carry out
photosynthesis to make sugars which it shares
with the coral organisms
zooxanthellae
Protecting the Coral
• Coral reefs are extremely fragile ecosystems
• When humans are careless with building
harbors, fishing, and coral harvesting they can
permanently damage
• Warming of ocean waters and water pollution
have caused entire reefs to die (often called
coral bleaching), destroying the entire
ecosystem
• These ecosystems are great indicators of
ecosystem health
Estuaries
• The area where freshwater meets saltwater is
called a estuary
• These usually occur at the mouths of rivers where
they dump into the ocean.
• Because of the mixing of fresh and salt water
these areas are usually brackish (less salty than
ocean water but more saline then fresh water)
• These unique ecosystems have brackish water
inhabitants that can not survive in salt or
freshwater
Intertidal Zones
• The ocean tides are the ocean waters reaction
to the gravitational pull of the moon.
• Twice a day the tides change in intertidal
zones
• This means that the organisms who live in
these zones must be able to survive being
submersed in water for a time and then
exposed to dry air
• Often times, these areas are surrounded by
wetlands
Salt Marshes
• Intertidal areas that are flat, muddy wetlands
that are often surrounded by estuaries, bays,
and lagoons
• The salty water is usually very affected by the
tides
• These areas area still used as massive filters to
clean water as it leaves the various
ecosystems
• These areas are great for resting and feeding
areas for migratory birds & are unique in their
niches
Mangrove Swamps
• A special type salt marsh that is dominated by a
special tree called a mangrove tree or shrub
– These are found only in warmer, coastal climates
• The waters in a mangrove swamp are usually low
in oxygen, so in order to get the needed oxygen,
Mangrove roots grow up out of the water
• These roots catch sediment which forms dirt
clusters and allows other plants to grow
• These ecosystems are unique and have very
specialized niches and organisms
Specialized = Endangered
• Many of these oceanic ecosystems that we have
recently discussed are extremely unique and have
niches that exist nowhere else
• This causes specialized niches which in turn cause
specialized pressures
• For this reason, these ecosystems have small
numbers of VERY specialized organisms that can
live nowhere else
• Any changes to these ecosystems usually have
major ramifications and for this reason, most of
the organisms found here are threatened or
endangered