Lichens and Pollution - an Introduction

Lichens and Pollution …

Is our air clean?

Activities follow the information on the OPAL air survey web pages - http://www.opalexplorenature.org/

Compiled by Jacqui Middleton, 2010.

WHAT IS A LICHEN?o Lichens are made up of two different

organisms living together: A fungus and an alga

.

o The fungus provides the body in which the alga can live protected from light and drought.

o The alga makes the food for the fungus.

Many lichens do not like air pollution

There are many types of air pollution:o Smoke from chimneyso Car fumeso Dust and fertiliser from fieldso Fumes from factories and power stations

All of these types of air pollution contain NITROGEN – many lichens do not like too much NITROGEN.

What do our air-monitor lichens look like?

• Leafy lichens

• Bushy lichens

Evernia - Green top & White underside Usnea – like a

wirey beardHypogymnia – a puffy lichen with no hairs

Parmelia family – brown, yellow-green and grey-green leafy lichens – have short hairs on their underside

Xanthoria – orange leafy lichens

Physcia – with longish hairs on the edges

Our air-monitor

lichens will tell us how

clean our air is.

• We are going to find the 4 best lichen trees in the school grounds.

• Each group will choose one tree and measure its girth using a tape measure (or a piece of string and a ruler).

Looking for our lichens - 1

Looking for our lichens - 2• We are going to look for the

different lichens on the trunk of a tree up to our heads .

• We are also going to say how much of each type of lichen is on the tree and will tell our group leader.

• 0 = no lichens• 1 = enough lichens to cover a

quarter of a sheet of A4• 2 = enough lichens to cover

half a sheet of A4• 3 = enough lichens to cover a

whole sheet or moreA4 sheet of paper

1 2 3

1 2 3

•We are going to look for lichens on twigs

•We are going to look for algae (dark green or orange powder)

•Your group leader will make a note of what you see on your group’s record sheet.

Looking for our lichens - 3

What do the results mean?• Places with clean air have

more pollution sensitive bushy lichens (e.g. Usnea and Evernia)

• Places that have a lot of nitrogen will have a lot of the orange leafy lichens (Xanthoria)

• Places that have quite clean air will have lots of the green and brown leafy lichens (Parmelias)

• If both are growing together then the air might be changing

After we come back in …

• The oldest children will set up air pollution tubes to put outside.

• Everyone else will make drawings and/or write about what we did to put up on our display or into our Wildlife Club display book.

• Please stay with your groups today.

For more information and downloads concerning these activities go to the OPAL air survey web pages - http://www.opalexplorenature.org/