Water We Talking About? Is It Safe to Swim?

Happy Friday! We are 9finally) back with Water We Talking About – a series where kids send us freshwater-related questions and we track down real-life scientists to answer them. This week, brothers Will and Tom sent in a whole bunch of questions. But one, in particular, stood out because, as anyone living near a southern Wisconsin lake knows, it is algae season out there!

The Question:

Is the water safe to be in? Does blue green algae hurt fish and other wildlife? – Will, Age 13 and Tom, Age 9. Monona, WI

The Answer:

Krystyn Kibler.

Thanks for the questions guys! The answer to this particular two-part query is “usually” and “it depends.” But we’ll let Krystyn Kibler explain further. Krystyn is a graduate student here at the UW-Madison and she’s spending the whole summer sampling for blue green algae blooms along our lakes’ shorelines. Here’s what she had to say:

Hi Will and Tom! Blue-green algae, or you what us scientists call ‘cyanobacteria,’ is a natural microorganism that lives in the lakes around Madison. There is a large variety of different types of these tiny bacteria that exist throughout the year and not all of them are bad! For the most part, the lakes are safe to be in but, when there’s a sudden increase in ‘bad’ blue-green algae, they can form scums on the surface of the water and that’s when it can be dangerous to swim in and it can also be a danger to fish and other animals in the water like ducks. When this happens, it’s called a “bloom” and blue-green blooms of certain species can release toxins that are not safe to drink and can irritate your skin. So when you see a scum don’t swim in it or drink it (or let your dogs swim in it or drink it!) Always pay attention to any warning signs and stay safe on the lakes this summer!
Thanks, Krystyn, and good luck sampling this summer! We should add that you can always check for beach conditions on the Public Health Madison & Dane County website – but you should know that conditions can change quickly. Often, by the time officials have tested the water and run them in the lab, the winds may have shifted and the bloom is no longer lingering at the beach. Or a toxic algae bloom may start in the morning and make the water unsafe well before someone gets out to test it. This is where your common sense kicks in – if the water looks weird – with streaks of bluish-green particles floating on the surface, it’s probably best not to swim! In other words, if you see anything that looks like the picture below, just skip the beach for the day!
Photo: Samantha Oliver

Oh, and one last bit of breaking news – check out this cool new technology Dane County is using to try to remove bluegreen blooms once they hit!

If you’re a kid with a question of your own, ask us at hinterthuer@limnology.wisc.edu – @WiscLimnology on Twitter – or our Center for Limnology Facebook Page!