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Section 2
Large
Marine
Ecosystems
of the world
Objectives
 To understand relationships between organisms
within ecosystems
 To identify the connection between environment,
biodiversity and ecological niches
Review
 Binomial nomenclature created by Linneaus in the
mid-1700s
 Each species has a two part name
 1st – generic name (genus)
 2nd – specific name (species)
Terms to Know!
Term
Definition
Habitat
Place where organisms live
Ecological
Niche
The role of an organism within an ecosystem
Species
A group of similar organisms that can
interbreed and produce fertile offspring
Population
Organisms of the same species, living in the
same area
Example
Community All the different species living in a habitat at
the same time
Ecosystem
Living organisms and the chemical and
physical factors which influence them
With a partner, take 2-3 minutes and come up with marine examples of
the terms listed above!
The ecosystem is affected by…
Abiotic Factors
Biotic Factors
ECOSYSTEM
The ecosystem is affected by…
Abiotic
Factors
Biotic Factors
ECOSYSTEM
What identifies an ecosystem:
Biotic
Abiotic
 Living components of an
 Nonliving components of an
ecosystem
ecosystem
Greek meanings:
Bio = living
tic = of or pertaining to
A = not; without
List 5 examples of each!
Marine Ecosystem Example
 http://vimeo.com/28417462
 Rocky Shore – organisms living here, linked together
by flows of energy forming a food web, and their
environment
 Animals must be able to adapt to changing tides
Habitat Example
 Hydrothermal vent – provides habitat for species of
tube worms
Population Example
 Ghost crabs (Ocypode
saratan) living in the
sandy shores
 Mollusc community on a
rocky shore (all different
species of molluscs)
Species Examples
 Skipjack tuna
(Katsuwomus pelamis)
 Red mangrove trees
(Rhizophora mangle)
Ecological Niche Examples
 Ecological niche of great white shark = top predator
 Organisms which occupy similar niches will tend to
compete with each other for
 Resources


Food
Space in their habitat
Biodiversity
 Takes into account:
 # of different species present
 Range of habitats and ecosystems
 Examples:
CORAL REEFS
High biodiversity w/
many species present
SANDY SHORE
Low biodiversity w/ few
species present
Quadrat
 A square used in ecology and geography to isolate a
sample, usually about 1m2 or 0.25m2
 Used to investigate the diversity of organisms in a
suitable habitat (example: rocky shore or sandy shore)
Section 2 of Marine Ecosystems
Relationships between organisms
Symbiosis
 The relationship between 2 different organisms, where
BOTH derive some benefit from the relationship
 Examples



Corals and zooxanthellae
Cleaner fish and grouper
Chemosynthetic bacteria and tubeworms
Parasitism
 Relationship between organisms where 1 organisms
benefits at the expense of the other (the host)
 Parasites obtain nutrients from host
 Ectoparasites


Live on OUTSIDE of the host
Example: Fish lice
 Endoparasites


Live INSIDE host (digestive system, attached to gills, muscle
tissue)
Example: nematodes (roundworms)
living in fish
Trophic Levels
 “feeding levels” in a food chain or a
food web
 Producers 1st trophic level
 Primary consumers2nd trophic level
 Secondary consumers 3rd trophic level
More Terms…
Term
Definition
Producer
Organisms which synthesize organic substances from simple
organic compounds using light from the Sun
Consumer
An organism that obtains its energy by feeding on other
organisms
Primary
Consumer
Feed on plant material (AKA Herbivore)
Secondary
Consumer
Feed on herbivores ((AKA Carnivore)
Predator
An animal that catches, kills, and eats another animal
Predator-Prey Relationship
 Factors which affect # of predators in an ecosystem
 Availability of food


As the # of prey increases the # of predators increases
As the # of prey decrease the # of predators decrease
 http://vimeo.com/45154593
 What would a graph of this relationship look like?
 With a partner create a graph? Be prepared to explain your
graph!
Predator-Prey Graph
Chemosynthesis
 Symbiotic bacteria convert H2S into organic material:
H2S + CO2 + O2 + H20  CH2O + H2SO4
 Hydrogen sulphide is the primary energy source for
hot vents and cold seeps
What is a Shoal?
 Large numbers of fish of the SAME species and
approximately the SAME size.
 Referred to as a ‘school’ when the group of fish is
swimming together in a coordinated way.
Benefits of Shoaling
1. Hydrodynamic efficiency
Groups of fish save energy when swimming together
Benefits of Shoaling
2. Predator avoidance:
a) Confusion effect: It is difficult for predators to pick
out individual prey from groups
b) Many eyes effect as size of group increases, the task
of scanning for predators can be spread out
Benefits of Shoaling
3. Foraging Advantages : Time taken to find food is
decreased
4. Reproductive Advantages: Provides increased
access to potential mates
Types of shoalers
 Fish can be obligate or facultative shoalers:
 Obligate – spends all their time shoaling or schooling
and may become agitated when separated from the
group (examples: tuna, herring, anchovy)
 Facultative – shoal only some of the time, perhaps only
for reproductive purposes
(examples: Atlantic cod)
What is Succession?
 The gradual process of change that occurs in
community structure over a period of time
 Example
Succession
 As plant communities
change the animal
communities change.
Succession at Hydrothermal Vents
 One of the first animal species to inhabit the area
around a hydrothermal vent is the tube worm Tevnia.
 Tevnia is replaced by the larger and faster growing tube
worm Riftia.
Riftia tubeworms can
grow up to two meters
long. This adult
tubeworm that has been
removed from its white
tube.
Riftia
Tevnia
 Tevnia are usually white,
but this clump of worms is
stained brown from iron in
the vent fluids. The largest
worm in this clump (with
more white color) is a
different species - a Riftia
tubeworm.
What is a Whale Fall?
 When a whale dies, the carcass sinks to the sea
floor…this is known as a “whale fall”
 The video below shows the gradual change in the
community structure over time
Feast in the Deep
Boneworms on Dead Whales in Monterey Bay
Extreme & Unstable Environments
Tend to have LOW biodiversity!
Example 1: UNSTABLE Sand-easily
dries out and easily eroded by wind
and water currents

pressure,
Example 2: EXTREME hydrothermal vents-high
high temperature, high pressure
-harder to survive but specific species do
Hydrothermal Vents and Cold Seeps Support
Diverse Communities
The path of water associated with a hydrothermal vent.
 Seawater enters the fractured seabed near an active
spreading center and percolates downward, where it
comes into contact with rocks heated by a nearby
magma chamber.
 The warmed water expands and rises in a convection
current.
 As it rises, the hot water dissolves minerals from the
surrounding fresh basalt.
 When the water shoots from a weak spot in the
seabed, some of these minerals condense to form a
“chimney” up to 20 meters (66 feet) high and 1 meter
(3.3 feet) in diameter.
 As the vented water cools, metal sulfides precipitate
out and form a sedimentary layer down-current from
the vent.
 Bacteria in the sediment, in the surrounding water,
and within specialized organisms make use of the
hydrogen sulfide (H2S) in the water to bind carbon
into glucose by chemosynthesis.
 This chemosynthesis forms the base of the food
chains of vent organisms.
Bottom current
Precipitation
FeO(OH) MnO2
Chimney
Precipitation
CaSO4 FeS
Sedimentation
Seawater seepage
Basalt
H2S in water
Basalt
Precipitation
FeS, FeS2, CuFeS2
350ºC
(660ºF)
350ºC
Stepped Art
(660ºF)
Fig. 16-21, p. 453
Stable & Favorable Environments
Tend to have HIGH biodiversity!

Example: Coral Reefs
Specialized Niche
 Narrow range of food
Generalized Niche
 Exploit a wider range of food
requirements
 Live in specific habitat
sources
 Live in wider range of habitats
Example: Butterfly fish
 Territorial
 Live closely w/corals and
anenomes
Ex: Tuna
 Migratory
 Feed on many different species
of fish
Why do habitats with high
biodiversity tend to contain
narrow ecological niches?
 Each species has its OWN niche within the ecosystem
 What would happen if the niches overlapped?


INTERSPECIFIC COMPETITION and one species will die out!
Narrow niches reduce overlap and therefore reduce
competition