How to press algae

Specimens of algae can be preserved by pressing in the same way that leaves, flowers and other parts of land plants can be pressed. Professional herbarium presses do a great job, but a press can easily be assembled from common household materials. The main steps are as follows:

1. Place the specimen on a heavy sheet of paper (such as card stock) that won’t disintegrate when wet. Remove any dirt, small crustaceans and other marine life attached to the specimen. Lay it out as flat as possible. If you are pressing multiple specimens, make sure to add field notes to this sheet of paper so you can keep track of which notes belong to which specimen.

2. Cover this with a sheet of something that it will not stick to, such as wax paper, Handi Wipes-type cleaning towels, or rags made from smooth fabrics, such as cotton diapers or cotton-poly blend t-shirt material.

3. Sandwich the covered specimen between layers of newspaper or other absorbent paper.

4. If available, add a sheet of corrugated cardboard on the bottom and top of the pile. This will help keep everything flat.

5. Apply weight to the specimen, using heavy books, bricks, or an herbarium press.

6. After 24 hours, and each day until the specimen is dry, replace the wet newspaper with dry newspaper.

Algae pressings can be quite beautiful as well as useful scientifically. The key to artistic pressings is in the arrangement of the seaweed on the pressing paper. Many people place the specimen on the card stock and then float the specimen just a bit by placing the whole thing in a shallow tub of seawater. This allows the specimen, which will have collapsed a bit after being taken out of the ocean, to open up. You can then arrange the specimen further more with you fingers or gentle squirts of water from a turkey baster (or an eye dropper, depending on the size of your specimen). Once your specimen is arranged, gently lift the paper out of the pan, and tilt it to one side to let the water run off. Then press following the steps above.