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The EUREC M.Sc. In Renewable Energy
The Specialisation Modulus in Ocean Energy
Ocean Energy Resources 1
Ocean Habitat (III)
11-03-2014
Teresa Simas ([email protected])
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Outline
1. Descriptors of ocean habitat species
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Life cycle (seasonality and inter-annual variation)
Food needs and trophic levels
Intra and inter-specific relationships
2. Ocean habitat communities
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Plankton (phytoplankton and zooplankton)
Benthic communities
Fish communities
Marine mammals
Seabirds
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1. Descriptors of ocean habitat species
Species life cycles
Life cycle definition
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An organism developmental stages from its primary stage to the primary stage in its
offspring
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Life cycles range in complexity from
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Extremely simple – e.g. unicellular bacteria (starts with fission forming the parent
and ends when the parent asexually splits into two daughter cells)
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Increasingly complex – as with multi-cellular animals that begin with sexual
reproduction and morph through successive developmental stages where their
bodies undergo extreme changes (e.g. larvae, juvenile, reproductive adult)
The marine life cycle
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Many reproductive strategies in the ocean: fission, budding, eggs hatching externally,
eggs hatching internally, live births, some marine animals are born in freshwater, some
are born on land, etc.
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Research on marine life cycles helps documenting how marine organisms cope with
abiotic factors in the marine environment (e.g. ocean currents, tides, light, temperature,
habitat)
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The simplicity of the organism does not always correspond with the simplicity of the life
cycle.
Sexual reproduction: is a process that creates a new organism by combining the genetic material of two organisms
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Assexual reproduction: is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only
1. Descriptors of ocean habitat species
Marine species life cycle – Examples
Simple life cycle: do not undergo major morphological changes through their
development.
• Bladderwrack algae (Fucus vesiculosus)
• Brown algae that develops in the
intertidal area
• Occurs in temperate and cold waters of
the Atlantic and pacific oceans
Reproductive receptacles
form on the plants in
autumn
The sperm find the eggs
near the ocean floor;
these are fertilized and a
new male or female plant
starts to grow
Females can
produce more
than one
million eggs
Eggs form on the female
while sperm forms on the
male
The reproductive organs
are fully mature the
following summer; eggs
and sperm are released
in great quantities
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1. Descriptors of ocean habitat species
Marine species life cycle – Examples
Complex life cycle: the larval or juvenile stages are longer, the developmental stages are
more complicated, and the appearance of the organism throughout the developmental
stages changes dramatically
The jellyfish
• The Jellyfish experience an
alternation of generations
in which one generation
(the medusa) reproduces
sexually and the next
generation (the polyp)
reproduces asexually.
• The medusa form is the
dominant and most
recognized form of the
jellyfish.
Adult jellyfish, with its bellshaped body and long tentacles
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1. Descriptors of ocean habitat species
Species life cycles
The importance of habitat in the life cycle (examples)
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Some species select different habitats for different stages of life such as
breeding, nesting, juvenile development and maturity
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Other species are highly mobile and often migratory; therefore they may
rely on a number of different habitats throughout their developmental
stages
Examples of groups of marine species
that migrate during their life cycles
- Invertebrates
- Fish
- Seabirds
Scoty shearwater
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1. Descriptors of ocean habitat species
Species life cycles
The importance of habitat in species’s life cycle - Examples
South Atlantic peneaid shrimp (Penaeus spp)
Utilizes marine habitats in deeper ocean waters as its spawning ground and estuarine
waters in tidal wetlands for its nursing grounds
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1. Descriptors of ocean habitat species
Species life cycles
The importance of habitat in the life cycle - Examples
Salmons
• Spawn in freshwater rivers
• Migrate to the open ocean during the
juvenile development stage where nutrients
are abundant
• The salmon from Scottish rivers head north
to colder sub arctic waters where there are
rich feeding grounds.
• After spending from one to four years at
sea the salmon swim back to Scotland to the
river in which they were born
Sexual and assexual reproduction
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1. Descriptors of ocean habitat species
Trophic levels and food
chain
Definitions
The trophic level of an organism
is the position it occupies
in a food chain
A food chain represents a
succession of organisms
that eat another organism
and are, in turn, eaten
themselves
The number of steps an organism
is from the start of the
chain is a measure of its
trophic level
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1. Descriptors of ocean habitat species
Trophic levels and food chain
Trophic levels – definitions
Level 1: Primary producers or autotrophs –
make their own food
Heterotrophs
Level 2: Primary consumers – Herbivores
Level 3: Secondary consumers – Carnivores
which eat herbivores
Level 4: Tertiary consumers – Carnivores
which eat other carnivores
Level 5: Apex predators – which have no
predators and are at the top of the
food chain
Decomposers: broke down plant and
animal dead matter; examples of
decomposers are bacteria and fungi
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1. Descriptors of ocean habitat species
Trophic chain and food web
Definitions
The path along the chain can form
either a one-way flow, or a
food "web"
The feeding relationships in an
ecosystem consist of many
food chains interconnected
into a network called a food
web
Ecological communities with higher
biodiversity form more
complex trophic paths or food
web
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1. Descriptors of ocean habitat species
Trophic levels and food needs – energy transfer
In each trophic level energy is absorbed from the lower
trophic level
The amount of energy that is transferred from one
feeding level to the next is called the ecological efficiency
Consumers at each level convert on average only about
10% of the chemical energy in their food to their own
organic tissue. For this reason, food chains rarely extend
for more than 5 or 6 levels.
For example, the energy gained by animals that eat
phytoplankton is less than the amount of energy initially
available.
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1. Descriptors of ocean habitat species
Intra and inter-specific relationships
Definition
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Intra-specific relationships: between organisms of the same species
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Inter-specific relationships: between organisms of different species
Types of intra-specific relationships
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Competition: for space, food resources and mates
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Predation: trophic relations (trophic chain)
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Symbiosis: describes a close relationship between to organisms from different species. It
is sometimes, but not always, beneficial to both parties.
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Mutualism (1 1): both species will benefit from the relationship
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Commensalism (1 0): one organisms benefits greatly from the symbiosis. The other
is not helped but is not harmed or damaged from the relationship (one-sided
symbiotic relationship).
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Parasitism (1 -1): one organism benefits from the relationship but at the expense
of the other. The organism may live inside the other’s body or on its surface. In
some of these parasitic relationships the host dies and in others, it is important
that the host remain alive.
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1. Descriptors of ocean habitat species
Intra and inter-specific relationships – Examples of competition
Competition for space – mussels and barnacles
Competition for mates and space – Interspecific
competition for mates and habitat selection in five
species of crustacea
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1. Descriptors of ocean habitat species
Intra and inter-specific relationships – Types of symbiosis
Mutualism – manta ray and remoras; the remora
uses its host for protection, transportation, and
scraps from the larger predator’s meals. The remora
can also exist in mutualism with its host by cleaning
its skin of bacteria and parasites.
Commensalism – Barnacles and whales; the
barnacle reaps great rewards by attaching itself to
a whale because of its filter-feeding nature. It
stands to gain an abundant food source by
attaching itself to a whale for the duration of its
existence.
Parasitism – Marine fish diseases caused by
parasites.
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2. Ocean habitat communities
Several communities occupying different habitats
Plankton
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Is composed of the phytoplankton (“the plants of the sea”) and zooplankton which
are typically the tiny animals found near the surface in aquatic environments
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Are usually weak swimmers and thus just drift along with the currents
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Phytoplankton and zooplankton are key components of marine ecosystems forming
the base of most marine food webs
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It's possible that zooplankton migrate to lower depths during the day so they are
less visible to predators; at night, zooplankton can sneak up to the surface and
snack on phytoplankton relatively safely
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2. Ocean habitat communities
Several communities occupying different habitats
Benthic communities
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Organisms which live on, in, or near the seabed, also known as the benthic zone; from
tidal pools along the foreshore, out to the continental shelf, and then down to the
abyssal depths
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Food sources: algae and organic runoff from land
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Abiotic factors influencing benthos: water depth, temperature and salinity, and type of
local substrate (silt, sand, rock)
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The benthos communities include in coastal waters and other places where light
reaches the bottom, photosynthetic diatoms (microscopic) and algae; filter feeders (e.g.
sponges and bivalves) dominating hard and sandy bottoms; deposit feeders, such as
polychaetes, populate softer bottoms; fish, sea stars, snails, cephalopods, and
crustaceans are important predators; benthic organisms, such as sea stars, oysters,
clams, sea cucumbers, brittle stars and sea anemones, play an important role as a food
source for fish and humans.
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2. Ocean habitat communities
Several communities occupying different habitats
Fish communities
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Fish: any of a large group of cold-blooded, finned aquatic vertebrates that are scaled
and respire by passing water over gills
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About 20 thousand species of fish live in the ocean
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Modern fish are divided into three classes:
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AGNATHA, primitive jawless fish; e.g. lampreys and hagfish
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CHONDRICHTHYES, the jawed fish with cartilaginous skeletons; e.g. sharks, rays, rat-fishes
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OSTEICHTHYES, fish with bony skeletons. lungfish, trout, bass, salmon, perch, parrot fish
Fish reproduction: 3 modes on the method they care for their eggs:
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Ovopartity – Lay undeveloped eggs, external fertilization (90% of bony fish), internal
fertilization (some sharks and rays)
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Ovoviviparity – Internal development- without direct maternal nourishment – Advanced at
birth (most sharks + rays) – Larval birth (some scorpeaniforms-rockfish)
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Viviparity – Internal development – direct nourishment from mother – Fully advanced at birth
(some sharks, surf perches)
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2. Ocean habitat communities
Several communities occupying different habitats
Fish communities
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Hermaphroditism: Some fish individuals are both males and females, either
simultaneously or sequentially (individuals may change sex at some time in their life).
About 21 families of fish are hermaphrodites
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Fish schooling: advantages of hang out with other fish
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Anti-predator effect: by hanging out with other fish, each individual fish may gain an advantage
in not being eaten by other fish.
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Spawning aggregation: Many fish species form schools only when it comes time to mate. Eggs
and sperm are released in mass quantities and this advantages over a solitary egg. The egg
predators will eat as many eggs as they can, but some eggs will inevitably survive.
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Enhanced foraging: A school of fish may have better abilities to acquire food. With many more
eyes to detect food, many more meals may be found; but there would also be many more
mouths to feed; however working as a team, the school may be able to take larger food items.
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Migration: The migration abilities of fish in schools may possibly be enhanced due to better
navigation, etc.
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Hydrodynamic efficiency: Due to the complex hydrodynamic properties of water, a fish may gain
a swimming advantage by being in a school.
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2. Ocean habitat communities
Several communities occupying different habitats
Fish communities
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Fish migrations: many types of fish migrate on a regular basis, on time scales ranging from
daily to annually or longer, and over distances ranging from a few metres to thousands of
kilometers. Fish usually migrate because of diet or reproductive needs, although in some
cases the reason for migration remains unknown
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More information on fish biology e.g. “A Quick Course in Ichthyology” available from
http://www.marinebiology.org/fish.htm#FISH Definition
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2. Ocean habitat communities
Several communities occupying different habitats
Marine mammals
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Marine mammals evolved from their land dwelling ancestors over time by developing
adaptations to life in the water
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Are often very social animals and known to help each other when one member of the
group is injured
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Cetaceans (whales and dolphins) often hunt together, often with one leading the pod
to act as a scout when entering unfamiliar territory
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Many marine mammals also participate in yearly migrations, either in groups or
individually; some embark on extremely long migrations, moving from tropical
breeding grounds in winter to feeding areas in colder waters during the summer
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They use echolocation for navigation and for foraging (or hunting) in various
environments; echolocating animals emit calls out to the environment and listen to
the echoes of those calls that return from various objects near them; they use these
echoes to locate and identify the objects
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2. Ocean habitat communities
Several communities occupying different habitats
Seabirds
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Seabirds live longer, breed later and have fewer young than other birds do, but
they invest a great deal of time in their young
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Most species nest in colonies (size vary from a few dozen birds to millions)
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Many species are famous for undertaking long annual migrations, crossing the
equator or circumnavigating the Earth in some cases
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Food needs: from the ocean's surface and below it (sometimes feed on each
other)
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Seabirds can be highly pelagic, coastal, or in some cases spend a part of the
year away from the sea entirely.
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Many species are currently threatened by human activities, and conservation
efforts are under way
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