The document discusses various methods for preserving algae, including liquid preservation with formalin, Lugol's solution, and dried herbarium specimens. It emphasizes the importance of proper storage conditions to maintain algae viability and notes that fresh specimens are sometimes essential for accurate identification. Additionally, it outlines methods for preparing dried specimens and provides information on other preservatives used in algae preservation.

1. Preservation of algaePreservation of algae
=MANSI R. MORE
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2. Preservation of algae
 General method
 Liquid preservation
 Commercial Formalin
 Lugol’s solution
 Dried herbarium specimens
Preservation of algae
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3. Introduction
 Algae can be stored initially in a bucket, jar, bottle or
plastic bag, with some water from the collecting site.
 The container should be left open or only half filled with
liquid and wide shallow containers are better than narrow
deep jars.
 Note that glass is reportedly not satisfactory for some
Chrysophyta and other algae of acidic waters due to its
inherent alkalinity damaging cells.
 However, glass phials are commonly used to collect algae.
 If refrigerated or kept on ice soon after collecting most
algae can be kept alive for short periods (a day or two).
Algae can be stored initially in a bucket, jar, bottle or
plastic bag, with some water from the collecting site.
The container should be left open or only half filled with
liquid and wide shallow containers are better than narrow
Note that glass is reportedly not satisfactory for some
and other algae of acidic waters due to its
However, glass phials are commonly used to collect algae.
If refrigerated or kept on ice soon after collecting most
algae can be kept alive for short periods (a day or two).
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4.  If relatively sparse in sample, some algae can continue to
grow in an open dish stored in a cool place with reduced
light.
 For long term storage, specimens can be preserved in
liquid, dried, or made into a permanent microscope
mount.mount.
 Even with ideal preservation, examination of fresh
material is sometimes essential for an accurate
determination.
 Motile algae particularly must be examined while flagella
and other delicate structures remain intact.
If relatively sparse in sample, some algae can continue to
grow in an open dish stored in a cool place with reduced
For long term storage, specimens can be preserved in
liquid, dried, or made into a permanent microscope
Even with ideal preservation, examination of fresh
material is sometimes essential for an accurate
Motile algae particularly must be examined while flagella
and other delicate structures remain intact.
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5. Liquid preservation
 Commercial formalin (which is a solution of 40% formaldehyde),
diluted between 1/10 and 1/20 with the collecting solution, is the most
commonly used fixative.
 Note that formaldehyde is thought to be carcinogenic and all contact with
skin, eyes and air passages should be avoided.
 FAA (by volume, 40% formaldehyde 1: glacial acetic acid 1: 95% alcohol 8:
water 10) or 6-3-1 (by volume, water 6:90% alcohol 3: 40% formaldehyde 1)
solutions give better preservation results for some of more fragile algae,
whereas the standard alcohol and water mix will ruin the larger algae.
 Algae can be kept in diluted formalin for a number of years, but the solution
is usually replaced by 70% ethyl alcohol with 5% glycerine.
(which is a solution of 40% formaldehyde),
diluted between 1/10 and 1/20 with the collecting solution, is the most
Note that formaldehyde is thought to be carcinogenic and all contact with
FAA (by volume, 40% formaldehyde 1: glacial acetic acid 1: 95% alcohol 8:
1 (by volume, water 6:90% alcohol 3: 40% formaldehyde 1)
solutions give better preservation results for some of more fragile algae,
whereas the standard alcohol and water mix will ruin the larger algae.
Algae can be kept in diluted formalin for a number of years, but the solution
is usually replaced by 70% ethyl alcohol with 5% glycerine.
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6.  Lugol’s solution is commonly used for short term (e.g. a few months,
but possibly a year or more) storage of microalgae.
 Dissolve one gram of iodine crystals and two grams potassium iodine in 300 ml
of water.of water.
 Use three drops of this solution in a 100 ml sample (it should look like very
weak tea).
is commonly used for short term (e.g. a few months,
year or more) storage of microalgae.
Dissolve one gram of iodine crystals and two grams potassium iodine in 300 ml
Use three drops of this solution in a 100 ml sample (it should look like very
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7. Dried herbarium specimens
 Dried herbarium specimens can be prepared by ‘floating out’ similar
to aquatic flowering plants.
 Ideally, fresh specimens should be fixed prior to drying. Most algae
will adhere to absorbent herbarium paper.
 Smaller, more fragile specimens or tangled, matSmaller, more fragile specimens or tangled, mat
dried onto mica or cellophane.
 After ‘floating out’, most freshwater algae should not be pressed but
simply left to air in a warm dry room.
Dried herbarium specimens
Dried herbarium specimens can be prepared by ‘floating out’ similar
Ideally, fresh specimens should be fixed prior to drying. Most algae
Smaller, more fragile specimens or tangled, mat-forming algae maySmaller, more fragile specimens or tangled, mat-forming algae may
After ‘floating out’, most freshwater algae should not be pressed but
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8.  If pressed, they should be covered with a pieces of waxed paper,
plastic or muslin cloth so that the specimen does not stick to the
drying paper inn the press.
 To examine a dried herbarium specimen add a few drops of water to To examine a dried herbarium specimen add a few drops of water to
specimen.
 After a minute or so the specimen will swell and lift slightly from the
paper.
 Carefully remove a small portion of the specimen with forceps or a
razor-blade.
If pressed, they should be covered with a pieces of waxed paper,
plastic or muslin cloth so that the specimen does not stick to the
To examine a dried herbarium specimen add a few drops of water toTo examine a dried herbarium specimen add a few drops of water to
After a minute or so the specimen will swell and lift slightly from the
Carefully remove a small portion of the specimen with forceps or a
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9. Other preservatives
 NaNO3 : 25g
 CaCl2 2H2O: 2.5g
 K2HPO4 : 7.5g K2HPO4 : 7.5g
 KH2PO4 : 17.5g
 MgSO4, 7H2O : 7.5g
 NaCl : 2.5g
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10.  EDTA =
Dissolve 5 g of ethylene diamine tetra-acetic acid and 31 g potassium hydroxide
(KOH) in one litre of distilled water.
 Iron solution =
Dissolve 4.98 g of iron sulfate heptahydrate (FeSO4
water prepared by adding 1 ml of sulfuric acid in 999 ml of distilled water.
 Solution of boron Solution of boron =
Dissolve 11.42 g of boric acid (H3BO3) in one litre of distilled water.
 Microelements
acetic acid and 31 g potassium hydroxide
7H20) in one litre of acidified
water prepared by adding 1 ml of sulfuric acid in 999 ml of distilled water.
) in one litre of distilled water.
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11. References
 https://biocyclopedia.com/index/algae/algal_culturing/collection_storage_a
nd_preservation.php
 https://courses.botany.wisc.edu/botany_330/preservation.html
 https://www.sciencedirect.com/science/article/pii/014486099090022R https://www.sciencedirect.com/science/article/pii/014486099090022R
https://biocyclopedia.com/index/algae/algal_culturing/collection_storage_a
https://courses.botany.wisc.edu/botany_330/preservation.html
https://www.sciencedirect.com/science/article/pii/014486099090022Rhttps://www.sciencedirect.com/science/article/pii/014486099090022R
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12. THANK YOUTHANK YOUTHANK YOUTHANK YOU
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