Just when you want to throw yourself out of your office window from the heat, and preferably right into the nearest swimming hole, the swimming hole in question is closed because of algae blooms. Stockholm city has closed one major beach, Lövstabadet, and even warned people from coming into direct contact with the ground around it (!).
EU, in cooperation with Stockholm County Administrative Board (länsstyrelsen), is tracking algae blooms, hoping to find them before they hit the beaches and hit all the people that are hitting the beaches ().
An algae bloom (algblomning) is that green, soupy mess that looks like huge vats of stringy pea soup were just poured into the water right where you want to go swimming. Don’t swim in it. The stuff is seriously bad for you, and for the environment. Algae blooms are entirely natural and can happen even without human interference. But they are worse, and more frequent, when fertilizers full of nitrogen and phosphorus wash away from farmland and into water.
Nitrogen and phosphorus are not just the greatest thing for growing crops, the also grow algae. All these sunny days, plus water, plus carbon dioxide plus the extra fertilizer? It’s one big bonanza for algae, and also for all the itsy bitsy bacteria in there. The bacteria start to hog all the oxygen that is naturally dissolved in the water, leaving less and less oxygen, and eventually none, for the fish and other air-needing organisms. So yes, fish death. Lake death. Baltic Sea death. It’s all bad. The soupy green stuff is often also toxic as all get out to us humans as well. These particular algae blooms in English are generally called HABs, or harmful algae blooms (so original!) and are the home of a particularly unpleasant strain of bacteria called cyanobacteria. Don’t even think about swimming in it, even if you’re really really cool, or really really hot. This goes for your pets too.
Shout out to Wikipedia ( https://en.wikipedia.org/wiki/Algal_bloom ), for the concise explanation of algae blooms.