Transcript Marine Ecology Notes

Marine Ecology Notes
Importance of the
Ocean Environment
Area
 Saltwater
covers about 71% of
the earth’s surface
Life
 There
are 250,000 known species
of marine plants and animals, many
are food for other organisms, like
us.
Temperature
Solar heat is distributed by ocean currents &
as ocean water evaporates.
 The oceans are major players in the earth’s
climate & are a gigantic reservoir for carbon
dioxide; therefore they help regulate the
temp. of the troposphere.

Zones of the Marine
Environment
Two major zones that break
up into smaller zones –
coastal and the open sea
Coastal Zone
Varies greatly during high
and low tide
Intertidal or Beach
Zone
Broken up into five areas
Lower Shoreface
 The
deepest part of the beach;
farther into the water, before
the breaker bar that forms
waves
Upper Shoreface
 Shallow
zone where the waves
begin to form
Forebeach
 Contains
the swash zone –
place where the waves crash.
Backbeach
 Only
under water during high tide
Fore-Island Dunes
 Sand
dunes; doesn't flood often,
except during hurricanes, etc.
Constantly changing due to the wind
Estuary
Where fresh water and salt
water meet
Definition
 An
estuary is a coastal body of
water, partly surrounded by land,
with access to the open ocean and
a large supply of fresh water from
a river
Characteristics
Water Levels
 Water
levels rise and fall with the tides
Salinity
 Salinity
fluctuates with tidal cycles,
the time of year, & precipitation.
The organisms that live here must
be able to tolerate these conditions
Fertility of Estuaries
 Estuaries
are the most fertile
ecosystems in the world
 Greater productivity than either the
adjacent ocean or the fresh water
upriver
Reasons for High Fertility
Nutrients are transported from the land into
rivers that flow into the estuary
 Tidal action circulates nutrients and helps
remove wastes
 A high level of light due to shallow water
 Many plants provide an extensive
photosynthetic carpet

The Shoreline
Between High and
Low Tides
Characteristics
 Abundant
levels of light,
nutrients, and oxygen
Difficulties

Sandy beach – Life must deal with a shifting
environment that threatens to engulf them & no
protection against wave action. Most animals
bury into the sand. They move with the tides,
so they’re always underwater & don’t dry out.
Difficulties (Continued)

Rocky shore – high wave action at high tide;
drying out & temperature changes during low.
Animals have a way of sealing in moisture like
a shell & find a way to cling to the rocks so they
don’t get washed away with waves.
The Open Ocean
Pelagic
 The
open ocean environment;
divided into neritic (open ocean
from the shoreline to a depth of
200m) and oceanic provinces
(depths > 200m).
Euphotic Zone
 Lots
of light.
From 0 - 200
meters.
Photosynthesis
takes place
here.
Bathyal Zone
 The
dimly lit
part of ocean.
From 200 1500 meters.
Benthic
The ocean floor or bottom
Benthic Characteristics
The ocean floor consists of sediments
(mostly sand and mud)
 Many marine animals, like worms and
clams, burrow
 Bacteria are common & can go down 500
meters below ocean floor. The Benthic
environment extends from the shore to
the deep.

Sea Grass Beds
 Flowering
plants that have adapted to
complete submersion in salty water.
Location of sea grass
 Found
in shallow water to depths
of 10 meters where they can
photosynthesize. Sea grasses are
found in quiet, temperate, tropical,
and subtropical waters; not in polar
waters.
Examples
Eel, turtle, and manatee grass.
Ecological Importance
 Reduce
surface erosion, provide
food, & provide habitats for many
marine organisms.
 Animals that eat sea grass are
manatees, green turtles, parrotfish,
sturgeon fish, and sea urchins.
Abyssal Zone
 Completely
dark.
Extends to a depth
of 4000 to 6000
meters (2.5 to 3.7
miles). Water here
is very cold & has
little dissolved
oxygen.
Kelp

The largest of the brown algae, many reach
lengths of 60 meters (200 feet). Common in
cooler water & are found along rocky coasts.
Provide habitat for many animals like
tubeworms, sponges, clams, fish, & mammals.
Some animals eat the kelp.
Coral Reefs
Characteristics
 Built
from layers of calcium carbonate,
coral reefs are found in warm, shallow sea
water. The living portions must grow in
shallow waters where light hits. They are
the most diverse of all marine ecosystems.
Examples
Many coral reefs are made of red coralline
algae that photosynthesize.
 Others have zooxanthellae (symbiotic algae)
that live and photosynthesize in their tissues.
 Not all corals have zooxanthellae, but only
those with it build reefs.
 Coral animals also capture food at night with
stinging tentacles that paralyze zooplankton
and small animals that drift nearby.

Coral Reef Waters
 The
waters where coral reefs are
found are often poor in nutrients.
Yet, other factors are favorable
such as temperature, sunlight year
round, and zooxanthellae.
Growth
 Coral
reefs grow slowly; as one
dies, another organism grows
on it.
Types of Coral Reefs
Fringing Reef
 The
most common type of coral
reef. It is directly attached to
the shore of a volcanic island or
continent.
Fringing Reef Bora Bora NASA JPL Satellite: Space Shuttle Sensor: SIR-C/X-SAR
Atoll
A
circular reef that surrounds a
central lagoon of quiet water.
 An atoll forms on top of the cone of
a submerged volcanic island.
 More than 300 atolls are found in the
Pacific and Indian Oceans.
View of Midway Atoll from Space Shuttle
Atolls in The Maldives Landsat 7
Barrier Reef
A
lagoon of open water separates
the land from the barrier reef.
 The largest barrier reef is the Great
Barrier Reef off the coast of
Australia.
 The second largest is off the coast
of Belize.
Ecological Importance
of Coral Reefs
Provides a Habitat
 Provides
a habitat for a wide
variety of marine organisms.
Coastline Protection
 Protects
erosion.
coasts from shoreline
Benefits for Humans
 Provides
humans with seafood,
pharmaceuticals, and
recreational/tourism dollars
Coral Reef Risks
 Of
the 109 countries with large reefs,
90 are damaging them, and 27% of
the coral reefs are at high risk,
especially off the coast of
Southeastern Asia.
 In the western Atlantic, 30-50% of
all coral species are either rare or
endangered.
Coral Reef Risks Con’t
Silt washing from downstream has
smothered the reefs
 High salinity from fresh water diversion,
over-fishing, boat groundings, fishing
with dynamite or cyanide, hurricane
damage, disease, coral bleaching, land
reclamation, tourism, and the mining of
coral for building materials.

This bottle still shows a slightly burned
fuse from its use to blow up the coral.
©1997-2001 Jeffrey N. Jeffords
Protection of
 300
coral reefs in 65 countries are
protected as reserves or parks, and
another 600 have been
recommended for protection.
 The good news is coral reefs can
often recover from damage.
Pollution and
Human Impact
Massive Oil Slicks in Bahrain
African Proverb
 “Water
may flow in a thousand
channels, but it all returns to the
sea.”
 The oceans are the ultimate sink
for much of the waste matter we
produce.
Differences of Opinion
Oceans dilute, disperse, and degrade large
amounts of raw sewage, sewage sludge, oil,
and some types of industrial waste, especially
in deep-water areas.
 Marine life has proved to be more resilient
than some scientists expected, some suggest it
is safer to dump sludge & other hazardous
wastes into the deep ocean than to bury them
on land or burn them.

Differences of Opinion
Other scientists disagree, pointing
out that we know less about the
deep ocean than we do about
space. They say that dumping
waste in the ocean would delay
urgently needed pollution prevention
and promote further degradation of
this vital part of the earth’s lifesupport system.
Oil Spills
 When
a tanker accident happens, it gets lots
of publicity.
 But, more oil is released by normal operation
of offshore wells, washing tankers & from
pipeline or storage tank leaks.
 One estimate says that oil companies spill,
leak, or waste per year an amount of oil
equal to that shipped by 1000 huge Exxon
Valdez tankers.
Floating Oil
 Oil
coats the feathers of birds (especially
diving birds) and the fur of marine
animals, destroying the animals’ natural
insulation and buoyancy
 Many drown or die of exposure from loss
of body heat.
Other Information
Oil is broken down by bacteria over time;
slower in cold waters.
 Heavy oil components can smother bottomdwelling organisms such as crabs, oysters,
mussels, and clams, or make them unfit to eat.
 Oil spills have killed coral reefs. A recent study
showed that diesel oil becomes more toxic to
marine life with the passage of time.

Clean Up
Mechanical Methods
Floating booms contain the oil spill or keep it
from reaching sensitive areas
 Skimmer boats are used to vacuum up some of
the oil into collection barges
 Absorbent pads or large feather-filled pillows
are used to soak up oil on beaches or in waters
that are too shallow for skimmer boats

Chemical Methods
Coagulating agents cause floating oil to clump
together for easier pickup or sink to the
bottom, where it usually does less harm.
 Dispersing agents break up oil slicks. However,
these can also damage some types of
organisms.
 Fire can also burn off floating oil, but crude oil
is hard to ignite.
