SOSJ friend and colleague Chris Perkins sent us photographs of St Aubin’s bay showing what we believe is because of the phenomenon known as eutrophication. This is how it looked on Wednesday evening:

Foam in St. Aubins Bay, (picture Chris Perkins)
Foam in St Aubin’s Bay (Picture Chris Perkins)

Recent enquires from our Facebook members about possible health issues bathing in the newly refurbished Victoria pool were taken on board by SOSJ and earlier this week we wrote to the Regulator who assured us that weekly testing of the seawater in the bay (one of several bays tested) consistently passed for E.coli and other bacteria. The link you can check these tests is here: We have now sent him new pictures and he has promised to look into it.

Eutrophication (or more precisely hypertrophication) is the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system. We are all familiar with the green sea lettuce that covers the bay in periods of hot weather, sluggish water movement and high levels of nitrates. This is probably another similar effect.

Sea Lettuce pictured by Lee Fernandes in St. Aubin's Bay on 23 July, 2014
Sea Lettuce pictured by Lee Fernandes in St Aubin’s Bay on 23 July, 2014

The tests for bacteria are officially OK. We don’t think that nitrate levels are published in the same way and are perhaps not seen as an issue. We assume therefore that the Environment department rely on natural dispersion and dilution of the partially treated sewage that is pumped into the bay from Bellozanne through the very short outfall. We have all seen the flocks of seagulls converge on the area when that happens.

Whether you think it is advisable to swim in water that contains human sewage (however diluted) that we are assured tests negative for E.Coli but must test highly for nitrates and perhaps other substances, is a personal choice. We know from testing by undergraduates and post graduates who visit the island in the summer, that further round the south east coast the levels of E.Coli are often much higher and occur lower down the beach.

Norovirus has also been found and that is a ‘human only’ virus so cannot be caused by birds or normal run off from the land. This is a particular worry for our shellfish farmers who have to bring in and filter oysters in clean water for 48 hours when there is a high level of bacteria recorded.

Problems in St Aubin’s Bay? July 2014
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