11 Does microplastic density in the water change from June to November?

Yes. There appear to be lower concentrations in surface water during July and August. In summer, warmer water floats and cooler water sinks, forming layers that reduce circulation in the water column. In the spring and fall, when the temperature is the same at all depths, Ontario lakes experience “lake turnover”: the seasonal mixing of the water column. The entire lake can turnover, allowing nutrients, oxygen, and microplastics to mix.