Lesson 5
Content Section -The Uses of Algae.
Both macroalgae and microalgae occur naturally and can be used in many different ways
so it would be such a waste to throw it away.
Food
Medicine
Biofuel
The Uses of Algae
Beauty Products
Pollution Control
Fertilizer
BioMara gratefully acknowledges the following funders:
A project supported by the
European Union’s INTERREG
IVA Programme managed by the
Special EU Programmes Body.
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Food - Red MacroalgaePalmaria palmata (Dulse/ Dilisk),
Porphyra (Nori),
Saccharina latissima (Sugar Kelp).
come from Chondrus crispus
(Carrageenen Moss).
Alginate and Agar/ Carrageenen are found
inside the cells of macroalgae.
In brown macroalgae called Laminaria
digitata and Ascophyllum nodosum
there is a substance called “alginate”. This
is produced within the cell walls of the
macroalgae. Alginate absorbs water and can
be used as a thickener for soups.
Agar and Carrageenen are similar products.
Macroalgae can be used for food not just
by marine life but also by humans.
Red macroalgae called Palmaria palmata
(Dulse/ Dilisk) is mainly used in food. It
must be washed and processed. It can then
be used as snack foods or as an ingredient
in a dish. It contains vitamins A, B, C, D, K
and E and Omega -3 which can be found in
fish that protect against heart disease.
Agar
Jelly
Brown algae called
Saccharina latissima (Sugar Kelp) is
dried and used as an ingredient in cooked
dishes.
Porphyra (Nori) is another red macroalgae used as an ingredient in sushi.
Food thickeners – Brown macroalgae –
Alginate come from Laminaria
digitata (Oarweed) and Ascophyllum
nodosum (Knotted wrack).
Red macroalgae - Agar or Carrageenen
They are thickening products that come
from certain red macroalgae.
They are found in the cell wall of some red
macroalgae such as Chondrus crispus
(Carrageenen Moss). They are used in
jellies or desserts or chemical products.
Agar can also be used in a science
laboratory to make “Agar” to help grow
micro-organisms.
Like macroalgae, certain species of microalgae can be mixed into ingredients.
Microalgae can also be used as food colour
if their pigments are extracted from them.
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Medical uses – Brown macroalgae Laminaria digitata (Sugar Kelp),
Red macroalgae – Phymatolithon calcareum (Maerl).
Macroalgae can also be used to treat medical problems.
Brown macroalgae have been used for colds. Brown macroalgae have many vitamins such
as A,B,C, E and K. Macroalgae contains a mineral called “Iodine” which can be made into
tablets. Brown macroalgae such as Laminaria digitata contains a substance called
“alginate” and this can be used in medicine for making bandages.
Maerl is a red macroalgae that is processed and used for its nutrients. Maerl contains
calcium and magnesium. It is sucked up by a pipe from the bottom of the sea.
Maerl can also be used as a nutritional supplement for people who need extra calcium.
Fertilizer - Brown macroalgae – Laminaria digitata (Oarweed),
Saccharina latissima (Sugar Kelp), Fucus vesiculosus (Bladder wrack) and
Ascophyllum nodosum (Knotted wrack). Red macroalgae - Phymatolithon calcareum
Maerl.
Brown macroalgae species are used as fertilizer. They are processed and can be dried
and used as a powder or in a liquid. There is a naturally occuring substance in macroalgae
that make plants grow especially the roots and stems.
Macroalgae is a conditioner for the soil as it has the important minerals needed for the
growth of healthy soil. Macroalgae contains nitrogen, phosphorus, potassium and other
minerals that are needed for plants to grow.
Nitrogen helps grass to appear green while potassium and phosphorus helps fruit, flowers
and roots. The letters N-P-K stand for Nitrogen – Phosphorus – Potassium
Maerl can be washed, dried and processed and used as an animal feed. Processed Maerl
is used by farmers as fertilizer on their fields.
Beauty Products - Brown seaweeds
Fucus vesiculosus (Bladder wrack), Fucus
serratus (Serrated wrack) and Ascophyllum
nodosum (Knotted wrack)
The brown macroalgae above are used to make
beauty products such as shampoos, creams, soaps
and toothpaste. The nutrients are taken out of
macroalgae and put into the products.
Fucus vesiculosus (bladder wrack) is used in seaweed baths where the macroalgae is
collected from the shore and used for bathing. The macroalgae provides nutrients and
minerals for the skin.
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Pollution Control
Algae is used in wastewater treatment plants. Algae is used to treat polluted water by
using the extra nutrients in the polluted water as food.
Pollution occurs when extra nutrients from factories or the environment enters the
water. These nutrients are nitrates, phosphorus, carbon, potassium and ammonium.
Special water treatment plants use algae to clean the water by inserting the algae into
polluted water. Macroalgae species maybe used such as Ulva. The algae absorb the extra
nutrients to grow and the algae releases oxygen into the environment. They act as a “biofilter”, this is like a sieve to filter out the nutrients from the polluted water and release
clean water.
The advantage of algae being used in this process is that it can also be used as a
fertilizer on land or as feed for animals. This is ideal as the algae now contains extra
nutrients from polluted water.
Biofuel
Algae can also be used to produce fuel, this will be discussed in chapter 6. Certain types
of macroalgae can be used for biofuel production. Microalgae can also be used to
produce biofuel.
The advantage of using algae is that it is an available source. It grows naturally and is
inexpensive. It is kind to the environment; when it is used as a biofuel it does not put any
extra carbon into the atmosphere. It is a natural fertilizer and it does not contain any
chemicals. It can remove pollution from water. It can be used as food and food
ingredients. It is rich in vitamins, minerals and can also be used as medicine. It can also
be used as animal feed.
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Activity Section – Lesson 5 – The Uses of Algae.
Brief summary
Aim: The aim of this lesson is to illustrate the uses of algae.
Food – Macroalgae can be used as food for humans. They are processed and used as a
food ingredients or packaged as a food. They are rich in vitamins and minerals. Red
macroalgae called Palmaria palmata (Dulse/Dilisk) can be used as a snack food. Nori
is the common name of the species Porphyra which is a common ingredient used to make
Sushi. Chondrus crispus (Carrageen moss) can also be eaten. Saccharina latissima
(Sugar Kelp) from brown macroalgae can also be used as a food ingredient. Macroalgae
contains a substance that can be used as food thickners. In the red macroalgae
Chondrus crispus, agar is produced inside the cell walls of the algae. Agar can be
used in jellies and desserts. In brown macroalgae the species Laminaria digitata
(Oarweed) contains alginate. This is produced inside the macroalgae and is used in soups
to help thicken them. Macroalgae also contains nutrients. Maerl contains calcium and can
be used as an ingredient in calcium supplements or animal feed. Colouring from microalgae are extracted and used as natural food colouring.
Medical uses – Brown and Red macroalgae are used for medical purposes. Brown
macroalgae are used to make bandages by using the alginate contained within the
macroalgae. It also contains vitamins and iodine which can be extracted and put into
tablets. Red macroalgae, such as Maerl, contain calcium which are used as calcuim
supplements.
Fertilizer – Brown macroalgae can be processed and used as fertilizer. Laminaria
digitata, Ascophyllum nodosum and Fucus vesiculosus can be used as dry or
liquid fertilizer. Minerals such as nitrogen, potassium and phosphorus are present within
the macroalgae. These are important for healthy soil.
Beauty Products - Brown macroalgae can be used in beauty products. Species such as
Fucus vesiculosus, Fucus serratus and Ascophyllum nodosum are used in
shampoos, creams and soaps. Nutrients are taken out of the macroalgae and put into
these products. Brown macroalgae are also used in seaweed baths.
Pollution Control - Algae may be used to treat polluted water. Water is polluted because
there are extra nutrients in the water but algae likes the nutrients so they can remove
them from the water. In a water treatment plant algae is put into the water and the
algae uses these extra nutrients which help clean the water.
Biofuel – Both macroalgae and microalgae can be use to produce fuel for cars. This type
of fuel is kind to the environment as it does not produce any extra carbon dioxide.
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Learning Outcomes:
►► Identify the uses of algae.
►► Identify the type and colour of algae used in food, fertilizer, beauty products,
pollution control, medicine and biofuel.
►► List the advantages of using algae.
Introduction:
Recall from Lesson 1 that there are different colours of macroalgae and the difference
between macroalgae and microalgae.
Explain briefly that there are different uses of algae and they can be used in food,
biofuel, fertilizer, beauty products, pollution control and medicine.
Show photographs of the different types of macroalgae and microalgae.
The teacher can use an image of macroaglae to show which type of macroalgae is involved
in different uses.
The cards labelled “The Uses of Algae” 15a -15f which are located after page 102 may be
cut by the teacher and individually displayed to explain the overall concept of the lesson.
Activities:
Activity 1 - How to Compost Seaweed.
Activity 2 - To make Sushi using Nori Sheets.
Activity 3 - Unscramble the words to find some uses of macroalgae.
Activity 4 – Find the Foods containing algae substances.
Questions.
Final Activity:
►► Teacher revises the main learning points.
►► Class will discuss different ways in which algae can be used in everyday life.
►► Try to encourage pupils to remember the colour/name/picture of algae (from lesson 1).
►► Draw a mind-map on the board or paper and include the uses of algae, different
types and the colours of algae in the mind map. The class can do this together or
individually.
►► Ask class how algae benefits the environment.
Vocabulary: fertilizer, agar and alginate.
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Curriculum Links
Scotland
Curriculum for Excellence
Level 1
Literacy and English
Listening and talking
Finding and using information
Health and Wellbeing
Food and health
Food and the Consumer
Sciences
Topical science
Social studies
People, place and environment
Literacy and English
Listening and talking
Finding and using information
As I listen or watch, I can identify and discuss the purpose, key
words and main ideas of the text, and use this information for a
specific purpose. LIT 1-04a
When preparing and cooking a variety of foods, I am becoming
aware of the journeys which foods make from source to consumer, their seasonality, their local availability and their
sustainability. HWB 1-35a
I have contributed to discussions of current scientific news
items to help develop my awareness of science. SCN 1-20a
I can consider ways of looking after my school and can care for
their environment. SOC 1-08a
As I listen or watch, I can identify and discuss the purpose,
main ideas and supporting detail contained within the text, and
use this information for different purposes. LIT 2-04a
Level 2
Health and Wellbeing
Food and health
Food and the Consumer
Sciences
Topical science
Social studies
People, place and environment
When preparing and cooking a variety of foods, I am
becoming aware of the journeys which foods make from source
to consumer, their seasonality, their local availability and their
sustainability. HWB 2-35a
Through research and discussion I have an appreciation of the
contribution that individuals are making to scientific discovery
and invention and the impact this has made on society.
SCN 2-20a
I can discuss the environmental impact of human activity and
suggest ways in which we can live in a more environmentally
responsible way. SOC 2-08a
Skills: Observe, investigate and comprehend.
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Ireland
National Council for Curriculum Assessment (NCCA)
First Class, Second Class
English
Reading,
Continue to build a sight vocabulary of common words from
Receptiveness to language
personal experience.
Social Environmental and
Scientific Education
(SESE)
Science
Environmental awareness and
Begin to recognise that people, animals and plants depend on one
care,
another.
Caring for my locality
Geography
Human environments,
Living in the local community
Social, Personal and Health
Education (SPHE)
Myself and wider world,
Developing citizenships
Become aware of the work of people in other areas who supply
food and other products to us.
Begin to appreciate how people depend on each other in many
aspects of life.
Third Class, Fourth Class, Fifth Class
English
Developing cognitive abilities
through oral language
Discuss issues that directly affect his/her life.
Social Environmental and
Scientific Education (SESE)
Science
Environmental awareness and
care, Environmental awareness
Social, Personal and Health
Education (SPHE)
Myself and wider world,
Developing citizenships
Come to appreciate the need to conserve resources.
Appreciate and respect the environment and learn that the
community is responsible for caring for the environment.
Skills: Observe, identify and comprehend.
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Northern Ireland
Council for Curriculum Examination and Assessment (CCEA)
Key Stage 1
Language and Literacy
Talking and listening
Participate in talking and listening in every area of learning.
Reading
Use a range of comprehension skills, both oral and written, to
interpret and discuss texts.
Writing
Spell correctly a range of familiar, important and regularly
occurring words.
The World Around Us
Interdependence
Interdependence of people and the environment.
Place
Positive and negative effects of people on places.
Change over Time
Positive change and how we have a responsibility to make an active contribution.
Key Stage 2
Language and Literacy
Talking and listening
Read aloud, inflecting appropriately, to express thoughts and feeling and emphasise the meaning of what they have read.
Reading
Use a range of cross-checking strategies to read unfamiliar
words in texts.
Writing
Use a variety of skills to spell words correctly.
The World Around Us
Interdependence
How living things rely on each other within the natural world.
Place
Positive and negative effects of the natural and human events
upon place over time.
Skills: Create, observe and comprehend.
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Activity 1 -
Name
How to Compost Macroalgae (This may not be applicable to all schools – depending on your
location).
Macroalgae contains a lot of nutrients. Macroalgae makes a great soil conditioner as it
contains many nutrients. Macroalgae decompose quicker than grass as it contains a lot
of water.
Materials:
An old bin/ container with no bottom
Grass cuttings, leaves, old flowers
A long garden fork to turn the compost
Water – wash macroalgae to remove salt
Macroalgae
Health and Safety: This activity should be carried out with the supervision of the
teacher. The teacher can get the pupils to help.
Method:
1. Collect grass cuttings after grass has been cut. Also you can collect dying flowers
and leaves and other biodegradable items.
2. Go to the beach and collect macroalgae that is on the shore which is already dying
and decomposing. Bring it back to the class in a plastic bag.
3. When you return to the school take it out of the bag. Using water try to remove
as much salt as possible from the macroalgae (on both sides).
4. Cut the macroalgae up as it will decompose quicker.
5. Get a container/bin. Ensure that it is dry and clean.
6. Have the washed macroalgae ready and the grass cutting/leaves/dying flowers etc.
7. First put a layer of grass cuttings and other biodegradable items in the container. Then cut the macroalgae and put a layer of the macroalgae into the container. Put three times as much grass cuttings and other biodiogredabale items as macroalgae
into the container. Macroalgae decomposes quicker than leaves/grass cuttings/
dead flowers.
8. Stir the contents every couple of days to introduce air.
9. You can add worms and other decomposers to the compost as this will help with the
decaying process.
11. Leave the compost for 3-4 weeks.
Questions
Why do you think macroalgae make a good ingredient for a compost?
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Activity 2 -
Name
To make Sushi using Nori Seaweed Sheets.
This is a demonstration only to be carried out by the teacher.
Materials/ Ingredients:
To make sushi rice
1 and a half cups of uncooked rice
2 cups of water
2 tablespoons of Sugar
1 tablespoon of Salt
One third of a cup of Rice Vinegar
Health and Safety: Ensure sharp objects are kept away from pupils. Ensure pupils do
not suffer from any allergies in the ingredients that you use.
(Teacher can make sushi rice in advance of class)
Rolling mat (you could use sheets of plastic cling film instead of a rolling mat)
Nori Sheets – dried seaweed sheets from the supermaket
Fish/Seafood filing – eg. canned tuna or smoked salmon
Vegetable filing – eg. raw peppers and raw carrots
Bowls
Sharp Knife
Method:
(Follow the pictures)
To make sushi rice
1. Rinse the one and a half cups of uncooked rice first.
Add 2 cups of water and bring to the boil.
2. Reduce the heat and simmer for 20 minutes.
3. When the rice is finished cooking let rice stand for 10 minutes.
4. Mix 2 tablespoons of Sugar, 1 tablespoon of Salt and Rice Vinegar
5. Allow to cool.
(This step may be prepared in advanced)
6. Prepare the vegetable fillings. Cut into large thin strips.
7. Prepare the fish filling.
8. Place one Nori sheet on the rolling mat. You may use plastic cling film if you don’t have
a rolling mat.
Ensure the bright side of the Nori sheet is facing towards the rolling mat/cling film.
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9. Take two handfuls of rice and place them on the nori
sheets. Spread the rice evenly over the nori sheet leaving a
few centimeters uncovered.
10. Put the other ingredients (Fish and Vegetable filling)
over the rice a few centimeters from the bottom of the
sheet. Be careful not to put too many ingredients as you may overfill.
11. Carefully roll up the sushi roll.
12. Wet the top edge of the Nori sheet (uncovered with
rice) so that it sticks.
13. Carefully slice the sushi rolls using a knife into little
pieces.
Questions:
What is the name of the macroalgae used in sushi?
What other macroalgae can you eat?
Can you name any other uses of algae?
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Activity 3
Name
Unscramble these words to find some important ingredients and uses of macroalgae.
Box A contains the scrambled words. Unscramble the words. Then draw a line and match
the correctly spelt words in Box A to Box B.
A
B
1. gaailnte
Agar
2. gecaarrecn
Alginate
3. lrreeiizft
Fertilizer
4. tomocps
Carrageen
5. gaar
Compost
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Activity 4 –
Name
Find the foods that contain algae substances.
Look at the labels of the food ingredients from the following foods.
See which foods contain carrageenan, agar or alginate.
Carrageenan may also be known as E407
Agar may also be known as E406
Alginate may also be known as E405
Cake mix
Chocolate mix
Ice cream
Toothpaste
Frozen desserts
Jelly
At home try to find foods using the food labels which contain macroalgae or the E number
shown above.
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Questions
1. Name some uses of algae?
2. In what way can algae be used to protect the environment?
3. What is alginate?
4. Name 3 types of food products that you can get from macroalgae?
5. Why is macroalgae a good nutritional product?
6. Why are macroalgae ideal for composting?
7. What is the name of the macroalgae that can be used for animal feed, fertilizers and
calcium products?
8. What is the name of the macroalgae used in sushi?
9. What is the name of the macroalgae that is used to make jelly?
10. What type and colour of algae does the substance alginate come from?
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Answers:
Activity 1 -Why do you think macroalgae make a good ingredient for a
compost?
Answer: It is natural, recyclable and it has a substance that helps roots
and stems grow.
Activity 2 -What is the name of the macroalgae used in sushi?
Porphya (Nori).
What other macroalgae can you eat?
Palmaria palmata (Dulse), Chondrus crispus (Carrageen Moss) and
Saccharina lastissima (Sugar Kelp).
Can you name any other uses of algae?
Fertilizer, medical uses, beauty products and pollution control.
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Activity 4 – Find the Foods that contain algae substances
Look at the labels of the food ingredients from the following Foods.
See which foods contain carrageenan, agar or alginate.
Carrageenan may also be known as E407
Agar may also be known as E406
Alginate may also be known as E405
Chocolate milk
Carrageenan
Ice cream
Carrageenan
Toothpaste
Carrageenan
Frozen desserts
Alginate
Pet Food Carrageenan
Jelly
Carrageenan
E400-599 includes vegetable gums so there are natural ingredients
in the food.
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Answers:
1. Name some uses of algae?
Answer: Food, fertilizer, beauty products, medical uses, biofuels and pollution control.
2. In what way can algae be used to protect the environment?
Answer: Using macroalgae as a natural compost so there is no chemical fertilizer. Algae
can be used in the production of biofuels as it does not cause as much pollution as other
fuels. Macroalgae can also be used in the treatment of polluted water.
3. What is alginate?
Answer: It is a substance produced by certain types of brown macroalgae within their
cell walls. It can be used in the food industry to help foods become thick.
4. Name 3 types of food products that are made using macroalgae?
Answer: Jellies, sushi, dried dulse/dilisk, calcium tablets.
5. Why is macroalgae a good nutritional product?
Answer: They contain vitamins such as A, B, C, D, E and K, nutrients and essential fatty
acids called Omega 3.
6. Why are macroalgae ideal for composting?
Answer: They contain nitrogen, phosphorus and potassium which are essential for growth.
Macroalgae decomposes quicker than other plants.
7. What is the name of the macroalgae that can be used for animal feed, fertilizers and
calcium products?
Answer: Phymatolithon calcaruem (Maerl).
8. What is the name of the macroalgae used in Sushi?
Answer: Porphyra (Nori).
9. What is the name of the macroalgae that is used to make jelly?
Answer: Chondrus crispus (Carrageenen moss).
10. What type and colour of algae does the substance alginate come from?
Answer: Brown macroalgae, Laminaria digitata (Oarweed) and Ascophyllum
nodosum ( Knotted wrack).
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(image 15)
Food
Medicine
Biofuel
The Uses of Algae
Beauty Products
Pollution
Control
Fertilizer
The Uses of Algae
(card 15a)
Beauty Products
(card 15b)
Fertilizer
(card 15c)
Food
(card 15d)
Biofuel
(card 15e)
Medicine
(card 15f)
Pollution Control