Wednesday 15 June 2016

The Garden Bioblitz and Some Colourful Chemistry

A few weeks ago it was the Garden Bioblitz weekend. It has been set up to get an idea of the amount of wildlife that lives in peoples gardens across the country. Its aim is to survey all the wildlife that is found in your garden over a 24 hour period. When my daughter heard about this she wanted to get involved as part of her 30 days wild challenge, excellent! On Saturday morning she went out and started surveying and photographing all she found. 

Getting involved with the Bioblitz
  
Most photos were taken by Jemima!

Our garden is quite small and mainly comprised of a concreted patio, however, it soon became clear to my daughter that there was quite a lot of wildlife present. The star of the show was the mint moth. A small but beautiful day flying moth that will lay eggs on mint leaves and when the caterpillars hatch out they will feed on the mint. They are not a pest as they are very small; you will always have loads of mint so it's not a problem.

Mint moth on Forget-me-not

Hoverfly

The moth has two generations the 1st being around May to June. These will hatch out of the cocoon that they have over wintered in. They mate, feed on pollen and lay their eggs. These eggs will hatch out, feed on the mint and produce a cocoon. This cocoon turns into the second generation adult. It is the caterpillars of the second generation that produce the cocoon that over winters and will produce the 1st generation of the following year.

Garden Snail

Green Alkanet

In our front garden we do have a few wild flowers and the most numerous is the Green Alkanet. This is a fascinating wild flower that we were very interested in for several reasons. Initially it was clear that it was great for invertebrates as there were several species of bee and fly feeding off the nectar and pollen. This is really important as it helps to increase the biodiversity of our small garden.

Aphid 

Green Alkanet - Flowers start purple then blue

However, what really impressed me was some of the chemistry that this common weed, Green Alkanet, has up its sleeve. One of the first things you notice is the spiky hairs that the plant has. These are actually made from silicon dioxide and calcium carbonate they are called cystoliths and are produced by special cells in the leaf called lithoysts. They evolved as a deterrent to herbivores. In fact they will cause a mild rash to humans.


Cystoliths on the Green Alkanet

14 Spot Ladybird


Another aspect of the alkantes chemistry is the roots are used to make red dyes. This is a practice that has taken place hundreds of years. The chemical has now been isolated and identified as alkannin. Interestingly, the dye is also an acid/alkaline indicator as it changes colour depending on its pH. They are red in acidic conditions and blue in alkali conditions. This ability to change colour depending on the pH is a fascinating and really important part of chemical analysis.

Scarlet Tiger Moth

Garden Spider

They are not the only plant that can be used to make an indicator. The most well known example is the red cabbages. In fact you can have a lot of fun with with red cabbages and its dead simple to do in your kitchen. All you need is some red cabbage and coffee filter papers. To provide the acid and alkali you can use lemon juice (acid) and bicarbonate solution (alkali).

All the equipment needed

The Colourful Chemistry 

Mix the red cabbage with some warm water to extract as much of the pigment as possible. You can use a pestle and mortar to help. Then soak the paper in the indicator, it should go purple. Allow it to dry and then paint on the lemon juice (it goes red/pink) or bicarbonate solution (it turns blue). The chemical responsible is called anthocyanin. This is an activity that you can do at any age. You do not need to be as young as my friends children, shown here,. The chemistry of indicators is quite beautiful and indeed quite technical.

Friends children getting involve with the indicators

The final master piece 

I think it is amazing the diversity that can be found in your garden, just turn over that stone, look underneath the leaves in the nooks and crannies of your garden. Who knows what you will find. As well it is amazing what the plant life of your garden can offer the world of science as well. Just looking is often just the start of a fascinating scientific adventure. 


Forget-me-not

Woodlouse - one of the 40 species found in uk 

Most of these photos were taken by Jemima, 12. 

No comments:

Post a Comment