On Tuesday night (28 Oct 2014) three members of SOSJ attended a TTS presentation by invited speaker Dr Kieran Conlan on our sea lettuce (ulva) problem. Apart from the estimated tonnage lying stranded in the bay 9,000 tonnes, with between 10-30 tonnes arriving on each tide, there was nothing in the information that we heard that was new.
The sea lettuce takeaway
It is generally agreed that the sea lettuce is caused by a combination of factors: high sea temperatures early in the year, a period of warm settled weather in the summer months and the general sheltered nature of the shallow enclosed St. Aubin’s Bay. Add to that the steady feed into the bay from the sewage treatment works (STW) and the phosphate rich agricultural run off from the land, and the sea lettuce happens as if by magic.
TTS seem to want to focus on where it comes from as if the sea lettuce had a ‘mother plant ‘ somewhere and want to prove beyond doubt that by reducing the nitrate load the sea lettuce would diminish. Our team believe that the ulna cells are free floating in our local waters and when certain conditions come together the cells rapidly multiply and sea lettuce is formed.
The new SWT plant – no denitrification yet
The first stage of the new SWT plant will be a standard carbonaceous plant and will not include a denitrification plant. The denitrification system would be added to stage 2 (some years away), but only if TTS and Environment are satisfied that the nitrates really are causing the problem before committing public money. This could mean a delay of maybe 4 years! Yet the Minister for TTS at a meeting with SOSJ last month was keen at that time on including a denitrifier in the new plant. So why the change of emphasis?
Possible, exciting answer to the sea lettuce problem
SOSJ believe that without the extra nutrients, the sea lettuce would not flourish. Therefore there is no need for comprehensive research (that the French have already done in Brittany). The French have decided that they just have to deal with it and so should we.
There is an exciting natural method that will absorb excess nitrates from the area. If successful it would benefit everybody and cost the taxpayer nothing and need only departmental good will in working with organisations such as ours. We will bring you news of that when we can, but first it has to be run by the departments and the new Ministers of both TTS and Planning and Environment and this will take time, and the Ministers are not yet in place. More news as we have it.
(Pic courtesy of Jacqui Carrel)
© SOS J
So the French have this problem too.
The article mentions Brittany , but not where exactly, is it on ‘our ‘ side of the french coast?
If they have it, and in an area with a lower intensity agricultural system than ours, then it likely helps to rule out the nitrates as being the cause.
Would be interested to see what areas around the French coast do have this issue, and what the local land management and sewerage disposals systems are.
I was a science teacher for 20+ years and have a degree in Environmental Science; others who were there have similar levels of understanding and good local knowledge. The presentation was aimed at very lay people or young school children and not at the level we would have expected given the attendees’ collective knowledge.