Lichtgedanken 03

S C HW E R P U N K T 71 03 | LICHT GEDANKEN It is early September and in Thuringia the weather is mild. Mauro Alivernini stands with a colleague in a pedalo in the middle of the artificial lake at Ho- henfelden, some 20 kilometres south of the Thuringian capital Erfurt. The boat wobbles as, helped by Thomas Biehl, the athletic young man pulls a two- metre-long plastic cylinder, with metal weights attached, out of the water and into the boat. Water, brown from the churned-up mud, runs down the sides of the cylinder, soaking Alivernini’s feet. He looks satisfied: the sediment sample from the lake bottom promises to provide sufficient research material. The sampling session was a success. Four days later, Alivernini, Master’s student Thomas Biehl and Ghanaian scientist Lailah Akita are on a plane to Ghana. Their destination is Accra: the country’s capital and economic hub, and one of the most polluted places on Earth. On board are the scientists’ sam- pling and measuring devices. Aliverni- ni and his colleagues want to test a new environmental monitoring method in the West-African country. Ghana is a dumping ground for Europe’s electro- nic waste. On huge rubbish dumps in Accra, computers, photocopiers, fax ma- chines and television sets from the wes- tern world are disposed of. Workers ex- tract valuable metals from the devices simply by burning the plastic housing in the open air, without any protection for the soil, water or the workers them- selves. Rainwater washes away heavy metals and other harmful substances, which find their way into the lagoons on the city’s edge, and from there they are carried out to sea. »These are extre- me examples of environmental damage, which is being caused here and is sprea- ding at an alarming rate,« says Mauro Alivernini. Ecological standards are virtually non-existent and few people in Ghana are environmentally aware. The environmental destruction is par- ticularly severe along the coast, where the bulk of the population lives. Sustainable coastal management With their research, the scientists want to create the conditions for sustain- able coastal management in Ghana, and to this end they have been doing ground-breaking work. Over a three- week period from 9 to 27 September, they took sediment samples from va- rious bodies of water, first in Accra and its heavily contaminated surroundings, followed by the lagoons and mangro- ve forests in the less polluted western coastal area of the country. They analy- sed the first samples in Ghana, and also brought around 10 kilos of sieved and dried sediment back to Jena, in order to examine it in detail. Back in their own laboratory, Aliver- nini and his colleagues are studying ostracods and foraminifera : microscopi- cally small creatures that live in bodies of water around the world. Just a few millimetres in size, »they are normal- ly completely uninteresting for people. After all, they don’t transmit any di- seases and you can’t eat them«, jokes Alivernini. However, the tiny creatures are of enormous value for him and for other geologists: they accumulate in se- diments and provide information about the state of the water in which they live. Foraminifera are single-cell organisms— amoeba—which are usually enclosed in a calcareous shell. They occur prin- cipally in the sea. Ostracods are equally tiny crustaceans that live in all types of bodies of water. »These organisms react very sensitively to changing environ- mental conditions,« explains Aliverni- ni. Temperature fluctuations, changes in the salt content of the water or in- fluxes of contaminants quickly lead to morphological alterations to the creatu- res’ tiny calcareous shells. For this rea- son, the creatures’ appearance and the species composition enable researchers to assess environmental conditions such as water quality, and even to draw conclusions regarding climate change over the long term. »In some countries, ostracods and foraminifera are already used routinely for environmental mo- Photo left: Natural paradise on the west coast of Ghana. Photo right: Geoscientist Mauro Alivernini, accompa- nied by a Ghanaian fisher- man, sails through a mangro- ve forest close to shore, near the Amanzule River.