Seafloor Ecology
Habitats and Food Chains
Insert image of animals under the sea
The marine environment
• Around 71% of the Earth’s surface is covered by oceans
• Oceans form one of the largest habitats on earth and many parts
have only recently begun to be explored
• Studying the seafloor is important to our understanding of how
animals live and survive in the marine environment.
Habitats
A habitat is an area where a group of animals live. There are many
different habitats around earth. Some animals don’t always stay in the
same habitat, but move depending on factors such as the season.
Image different habitats, desert, cold
mountains, rivers & trees, marine
Marine Habitats
Like anywhere else the marine environment contains many different
types of habitat. Due to the size and depth of some marine habitats little
is known about them and very few have been explored.
Open Ocean
The open ocean is anywhere in the ocean not near the coast or
seafloor. While this is a large part of Earth’s surface it is low in nutrients
and animals in this habitat often travel long distances.
Animals which live in the open ocean around the UK include: seagulls,
sharks, squid, seals, basking sharks and salmon.
Rocky seafloor
The rocky seafloor is part of the seabed. Animals here live permanently
directly above, on or under the seabed. Many of the animals have
adapted to the habitat by clinging onto the rocks or using the material
as homes.
Animals that live in the rocky seafloor around the UK include: ross
worms, amphipods, starfish, octopus and gobies.
Sandy Seafloor
The sandy seafloor is the part of the seabed which is mostly made up
of sand sediments. Though it doesn’t look like much would live here
there a wide number of animals that call the sandy seafloor home.
Animals which live in the sandy seafloor around the UK include:
catworms, shrimps and polychaetes.
Food
• As well as a home all living things need food for energy
• For many animals this energy comes from other animals
• We can classify animals by how they get their energy
Herbivores eat only
plant material
Omnivores eat both plants
and animals for energy
Carnivores eat only meat or
the flesh of other animals
Below are three marine animals, can you guess which is an
omnivore, which is a herbivore and which is a carnivore?
Seals are carnivores – they feed mostly on squid, octopus
and fish.
Zooplankton are herbivores – they feed on phytoplankton.
Sea urchins are omnivores – feeding on barnacles, algae
and seaweed.
Trophic Pyramid
Feeding relationships can be classified on an trophic (or ecological)
pyramid. Trophic means feeding, therefore each level on the
pyramid shows a different system of feeding. Animals fit into the
pyramid according to how they get their energy..
Producers
Producers make their own food. In the oceans they convert energy from
the sun into food through photosynthesis. Examples of producers
include seaweeds and phytoplankton.
Consumers
Consumers do not make their own food, instead they consume other
living things. Consumers can be herbivores, omnivores or carnivores.
There are three levels of consumers; 1st, 2nd & 3rd.
Decomposers
Decomposers do not fit into one level of the pyramid as they are
everywhere. These are the bacteria that feed the life cycle by breaking
down waste or dead organisms.
Food chains
• Food chains are
simple diagrams
showing what
animals eat.
• The animal next up
the chain eats the
one below and so
on.
•This shows the flow of
energy from the bottom
to the top.
•Food chains are more
specific versions of
ecological pyramids.
Food webs
• Food webs are far more complicated than food chains.
• Food webs show the relationships between producers, consumers
and decomposers in a habitat.
• A food web that links all animals and plants in an environment would
be very confusing and hard to understand.
Food webs
• To simplify food webs specific animals are used to represent a
whole group.
• By studying food webs scientists can learn about relationships
between animals in the marine environment.
• Food webs help scientists understand how fishing, pollution and
other marine industries affect the oceans and the animals living
there.
Environmental Impact
• Food webs help us understand the complex relationships in the
marine environment.
• When something happens in the environment it can impact on other
things.
• Using the previous food web imagine what would happen if there
was an oil spill which covered all the mammals and birds.
• What if all there was a massive increase in phytoplankton – such as
when there is an algal bloom?
• The relationships in a food web mean that when something happens
to one organism it will have an effect on many of the other
organisms it is linked to in a food chain.
RECs
• Scientists are continually studying the seafloor to find out more
information about it.
• Recently UK scientists have been involved in the Regional
Environmental Characterisation surveys or RECs for short.
• These studies looked at the archaeology, geology and ecology of
the seafloor around the UK.
• Here we are going to focus on the results of the ecological studies.
• But first, what is ecology?
Marine Ecology
• A huge number of scientists were involved in creating the four RECs.
One important group were the marine ecologists.
• Marine = related to the sea or saltwater environment
• Ecology = the study of living things and how they interact with each
other and their environment
• Marine ecologists study living things in the ocean, or marine
environment, and how they behave and interact with their environment.
Habitat
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Ecologists can investigate habitats
using many methods. Two
methods of exploring the seafloor
are explained here.
When dealing with a very small
area of seabed which is not very
deep divers can be sent down.
Once on the seafloor divers are
able to take pictures and pick up
samples.
Another method is to use cameras
and Remote Operate Vehicles to
take photographs and video of the
animals and their habitats.
Animals
• To collect animals the scientists
use Beam trawls and Hamon
grabs.
• Beam trawls involve towing large
nets across the seafloor. The net
is held open by a large metal
beam.
• These nets pick up creatures
which live on and near the
seafloor.
• Hamon grabs work by lowering
large claws onto the seafloor from
a boat. The claws then close
collecting organisms and seafloor.
• Hamon grabs are useful for
studying habitats also as they pick
up seafloor samples.
Food Chain
• During the RECs, scientists
focused on measuring and
recording animals which lived
on and in the seafloor.
• They know that any changes to
these organisms will ripple up
the food chain causing
problems for many other
animals.
Human Impact
• Now that you have seen how animals in the food web interact you
can imagine what would happen when humans impact on the
environment.
• The REC studies provide a benchmark of how healthy the seabed
is, future studies can measure any changes.
• It is important that we keep investigating the seafloor to help us use
it sustainably in the future.
Discussion Questions
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Why are food chains and webs important to understand?
What is the most important level in an trophic pyramid?
What would happen to top consumers if there was no sun?
Why do we need to use the sea sustainably?
How do we know if we are using the sea sustainably?
What type of consumer are you?
What affect do you think climate change will have on the oceans?