Surface accumulations of the toxic blue-green algae have already been seen off the coast of Gotland, warns the World Wide Fund for Nature, WWF.
“Unfortunately, we see that nitrogen emissions are increasing and it is due to emissions from our activities. It is what we all do and consume that drives the eutrophication,” says Mats Johansson, expert on water management and eutrophication at WWF, in a press release.
With the June heat, the algal bloom started outside Gotland, which is unusually early.
Algal blooms are normal and occur in all lakes and oceans. But it has become a problem as it has multiplied as large amounts of plant nutrients have been released by agriculture around the Baltic Sea, which has created an overflowing sea. Emissions from treatment plants, industry and individual sewers also contribute.
Outside Bohuslän, the algae are already causing the sea fire phenomenon. But it’s not just the emissions that are behind it. Climate change also contributes to the warming of the oceans and the algae thrive in the heat.
“The warming of the oceans affects and stresses them and makes it even more important to reduce eutrophication. We don’t yet know what the effects will be, but the rapid warming of both the world’s oceans and the Baltic Sea is very worrying and we know what needs to be done,” says Mats Johansson .
According to WWF, this involves measures such as precision fertilising, keeping agricultural land vegetated all year round so that nitrogen and phosphorus remain in the soil and improving the degree of sewage treatment.
Fact: Different types of algal blooms
Algal blooms have different colors and appearances depending on how big they are and what species they are. Blue-green algal blooms in the Baltic Sea often look like green-yellow soup or blue-green stringy mass. The toxicity varies between different species.
Fire is a phenomenon that occurs mainly in late summer or autumn and is most common on the west coast. In the evening, luminescent plankton can be seen as flashes of light in the water. During the day you see brick-red streaks in the water. When they gather in large enough groups, so-called mareld is created.
Source: SMHI and WWF