Wetter winter and warmer summer hit marine life
BBCRecord winter rainfall is flushing pollution and sediment into Devon and Cornwall's coastal waters, raising risks to marine life, shellfish and potentially human health as conditions warm.
In March, forecasters said parts of Cornwall and Devon had seen rainfall totals reach about 150% of the long-term average and, in February, the Met Office recorded Cornwall's wettest winter since records began.
If future winters are mild, wet and wind may have long-term impacts, not just on land, but also in our marine environment and coastal ecology and health.
The Plymouth Marine Laboratory has been using equipment including satellites and drones to monitor the waters, testing levels of viruses and bacteria, and looking at the numbers of different species of algae.
'Large sediment plumes'
Bio-optical oceanographer Dr Gavin Tilstone, of the Plymouth Marine Laboratory, said: "The first thing that we notice is a large freshwater plume and that can reach way offshore.
"The second thing is sediment... large sediment plumes will completely block the light, and therefore it has an effect on submerged vegetation; seagrass, for example, maybe even seaweed."
Tilstone said this could be taken advantage of by certain species which were harmful to humans, fish and shellfish.
Within this sediment are high levels of nutrients from farm run-off to sewage spills, which has an impact on algal growth. The more nutrients in the water, the more prolific the algal growth.
Algal blooms are prominent going into spring and some of them are toxic to all marine life.
The sediment and nutrients from the winter stays in coastal waters throughout the year and can also contain high levels of bacteria and virus material.
It often sinks to the seabed but can be stirred up by wave action and, as the water warms, the bacteria thrive and high levels of sediment could smother marine vegetation and reduce growth of all types.
Another thing the team looks for is bacteria.
Tilstone said: "We run samples for bacterial counts, viral counts, and then we can see the numbers of bacteria that are coming down the rivers and along the coast.
"We've sampled for E. coli, a bacteria that's harmful to humans, and, indeed after any heavy rainfall event, we can detect large counts of E. coli."
He said the impact on the environment going forward was dependent on how spring and summer progressed.
"It could be that we get persistent rainfall, in which case we could get larger, possibly noxious and harmful blooms occurring on the coast.
"Or it could be that we get very dry and hot summer conditions, which can also have a big impact on the coastal environment.
"The system is in a state of flux and it will continue to change."
Bruce Newport, area environment manager for bathing waters at the Environment Agency, said there was difference in the work the Plymouth Marine Laboratory and the Environment Agency.
He said: "Ours is very much more looking at sewerage indicators and, where we find those, we can then begin to work to understand where they've come from."
Newport said there was not methodology which would allow "real-time testing" to give information "moment by moment".
"Over the last 30 years, we've been collecting bathing water samples once a week through the summer and that long-term data set gives you the best idea of where is safest to swim."
'Much better place'
He added if people called the agency and gave information, it would respond to that but "many of our beaches have got very long records of being excellent bathing waters".
He said: "There are only a few of those beaches where you're likely to find issues, especially after heavy rain.
"It is disappointing to see sewage going into our rivers and into our bathing waters, but, if you look back in time, we're in such a much better place we are today than we were 10 or 15 years ago.
"The water is so much cleaner and now, with pretty well 98% of our bathing waters meeting brilliant standards, we're in a really great place right across Devon and Cornwall.
"I think the biggest challenge that we've got is, now we've got most of our bathing waters to a very clean state, it's actually now becoming more difficult to find out which of the pipes is causing the problem."