The Tragedy of the Green Tide

This sounds like the title of a good book, but it is in fact a tragic story of mans continuing desire for progress and prosperity without consideration for the effect on the environment.

 

When we arrived in Brittany in 2002 we were continually amazed at the beauty of the Breton landscape and in particular the coastline; which in our area of the Pink Granite Coast is stunning. One of the most impressive coastal areas is the Bay of St Michel en Grève, which has one of the longest continuous beaches in Brittany. In July each year it is used for harness horse racing, due mainly to the long flat beach which is available when the tide exits the bay.

 

Over the past seven years this stunning coastal tourist destination has changed into an enormous green bed of slime, emitting a pungent odour as soon as the sun starts to warm the seas. In the spring, with rising temperatures and excess nitrogen (nitrate) arriving on the coast, the algae  begin to reproduce. It is an environmental nightmare which has descended on the peaceful bay and its residents, who for their part have been trying to stimulate the authorities into action against those thought to be responsible.

 

In truth the problem is not an easy one to resolve and there is a difference of opinion as to how best to tackle the problem. Scientists have been undertaking an increased number of studies into the growth of algae as it is acknowledged as a major polluter of the coasts of developed countries around the world. They all agree that one of the principle causes of the rapid increase in growth has been the increased use of fertilisers by the farming community accounting for nearly 90% of the nitrates released into the sea.

 

One of the scientific studies carried out on the bay of St Brieuc, which is also affected badly by the green tide, suggests that the pollution within the sediment layer of the bay is so bad it will take at least 150 years to release the phosphorous contained within. This of course is on the basis that the discharges of nitrates are stopped now.

 

St Michel en Grève has a number of water courses that discharge into the bay from the surrounding countryside and pollutants can be entering the streams many kilometres from the bay. One can understand that tracing the source of pollution must be a nightmare for authorities. In reality the majority of the nitrates enter the water courses by leaching through the soil rather than any one water outlet.

 

The more tidal movement the greater the formation of algae as this action causes each piece to divide and thereby multiply. This is why the algae is prevalent in bays and inlets with large tidal movement.

 

For their part the local authorities are trying to raise the profile on the regional and national agenda, for it is here that legislation is required to stop the further use of nitrates. There are even legal moves to force the government into action, but in the meantime all the local authority can do is try and deal with the physical results of the pollution. To this end at the beginning of   spring out come the tractors with their scrapers gathering up the algae into huge piles which are then loaded into waggon's for removal.

The complete irony of the situation is the removal of the algae by local farmers who use it as fertiliser on their fields; I think you would describe this as a win, win situation for the farming community.

 

It would be completely remise of me if I did not mention that the poor domestic sewage disposal in some rural properties also has a part to play in the pollution of the coast. One would hope that the stricter controls now in place will start to reduce the pollution from this source.

 

It is with some sense of relief that I can confirm that at the moment the green tide only affects a limited number of bays and inlets which present the correct conditions for algae growth. The pink granite coast still has some of the best beaches in Brittany which thankfully continue to attract tourists in increasing numbers.

 

In the meantime the residents of effected areas make the most of their beautiful beaches before the warmer temperatures stimulate the algae for another season of green tides.

 

 

Comments

[lavenderbongo]

Good pics - where did you take them?