Black Sea Study Pack: A Resource for Teacher

This section is a classroom exercise that does not require any outside activities. It should appeal to science teachers in particular. The group exercise is designed to make the learning process more lively and entertaining for the students. The final exercise is deeply thought provoking and no prescribed outcomes are given. Eutrophication is an issue that requires wide cooperation and student and teachers requiring additional information are recommended to examine the material produced by the Black Sea Commission and the Black Sea Ecosystem Recovery Project (see reading list). Care has been taken in the presentation to avoid assigning blame to any state of sector. This is not for diplomatic purposes; this really is a shared problem – assigning blame is unhelpful.

For enterprising biology teachers an addition exercise to grow phytoplankton is included in this section.

Group exercise: Classroom quiz

This is an alternative approach to teaching this often proves effective for groups of all sizes. It is important to rehearse your answers (or to take your own written notes to the classroom). You should find the following notes helpful:

List one:	Comments
1. Human sewage	This is a major source of nutrients in some places (both nitrogen and phosphorus). Of course sewage also introduces bacteria that may cause sickness to humans using the marine environment for recreation.
2. Traffic exhaust	The release of nitrogen oxides from engines burning fossil fuels (oil, coal) results in increased nitrates in the atmosphere and in rainfall and contributes to eutrophication.
3. Bus factory	This is unlikely to have any serious contribution to eutrophication.
4. Washing detergent	Washing detergent in most Black Sea countries has high levels of phosphate and certainly contributes to eutrophication.
5. Animal farms	Animal waste from intensive ‘factory' farms is often discharge to rivers. For animal grazing in open fields, much nitrogen is emitted as ammonium from urine and faeces and this reaches rivers via rainfall.
6. Nuclear power station	This is one kind of pollution that cannot be caused by nuclear power stations!
7. Oil refinery	Surprisingly, oil refineries produce quite large amounts of nitrogen and phosphorus compounds in their waste. Efficient power station will treat the waste before disposal.
8. Potato farm	All farming introduces nitrogen and phosphorus to the environment. The amounts depend on the technique employed

List two	Comments
1. Wastewater treatment plant	A treatment plant can remove all traces of nitrogen and phosphorus but this is often very expensive to operate. Many of the sewage treatment plants around the Black Sae are designed to remove solid wastes and dangerous bacteria but do not efficiently remove nutrients.
2. Use of alternative substance	In the case of detergents, alternative products exist but are slightly more expensive than conventional ones.
3. Restoring a wetland	This can reduce the nutrient loads to rivers and the sea. It is not a substitute for other reduction techniques but certainly helps to remove nutrients from agriculture and sewage. The area of wetlands has to be quite large however and there are certainly not enough wetlands around the Black Sea to remove all the nutrients added by human activities.
4. Applying waste to fields	This helps to lower the impact of animal waste and reduce fertiliser requirements. Application of human sewage is not recommended however as some human pathogens may enter the food supply.
5. Improving agricultural practices	This one of the best ways of reducing nutrients from farming. Techniques used include leaving a belt of unfertilised pasture land around fertilised fields to capture excess nutrients or planting winter crops to avoid soil loss during rainy periods.

For the enterprising biology teacher:

You may wish to try this experiment:

Eutrophication in your own classroom

Materials

4 glass jars (the 2-3 litre ones used for pickling)
3 one litre flasks that can be used for heating
10 litres of Black Sea water (or pond water if you don't live near the sea)
1 cup of fresh soil from a fertile field or garden
a coffee filter or a piece of filter paper
some vitamin pills containing thiamine (B1), biotin and cyanocobalamine and iron (preferably as NaFeEDTA)
a few grams of fertiliser containing both nitrogen and phophorus

Engage

Ask students what they remember about the oxygen cycle-most early elementary students are familiar with photosynthesis as the oxygen/carbon dioxide exchange between plants and animals. There are no trees in the Black Sea . So, where's the oxygen coming from? Encourage speculation.

Explain/Explore

At the lowest end of the food web are phytoplankton, the "food" of tiny marine animals called zooplankton (some of which are fish larvae). Phytoplankton make their food through photosynthesis. Fuelled by the energy of sunlight, they convert carbon dioxide and water into simple, sugary food. During photosynthesis, they release oxygen as a waste product. They also incorporate carbon dioxide.

In order to grow, plants need light and ‘nutrients': nitrogen, phosphorus and tiny quantities of minerals (such as silica, iron and manganese) and vitamins. When they die, they release this material back into the water enabling another generation of plants to grow. We can make our own microcosm by using some grass (the terrestrial relative of phytoplankton) to provide the essential components for a phytoplankton culture. Then we can find out what happens when material from the land is washed into the sea….

Procedure

Make a culture medium:

Boil the soil in two cups of fresh water for ten minutes and then filter the mixture through the coffee filter or filter paper.
Dissolve about 1g of fertiliser in 100 ml of cooled boiled water
Dissolve one vitamin pill in a litre of cooled boiled water

Conduct the experiment:

Fill the jars with some water from the Black Sea (or a pond if you live a long way from the sea). Make sure it is as ‘clean' as possible by avoiding inclusion of sand or slime.
Add 10 ml of soil extract for each litre of water in the jars to all of the jars
Add 1 ml of the vitamin solution per litre of sea water in each of the jars
Add different amounts of fertiliser to each of the jars, 0, 0.5 ml, 1 ml, 5 ml.
Stand the jars close to a well-lit window in your classroom. Make sure they are not in a place where they get very hot. Stir the tanks gently once a day. The sea is never warmer than 30 degrees and phytoplankton grow best when it is 20 degrees or less.
Record the colour of the water - greener will indicate more growth. Photos may be taken to keep track of colour changes: make sure to write a date on a small piece of paper and stick it on the jars at the time of taking a photo, so that it appears on the picture for later reference.
After a few days, the water in the tanks should be looking a little green. Follow the colour for several days and record the difference between the jars.
Record findings in a brief lab report: how can you explain the differences?

Hints

Like all plants, the phytoplankton cultures take a little time to get started (scientists call this the ‘lag phase'). Don't be surprised if nothing happens for 2/3 days. Once they begin to grow however, growth is exponential and the greening should occur very quickly. When the phytoplankton run out of nutrients, they die (the ‘decay phase') and the water becomes clear again.