'Jellification' of freshwater

You might have heard Andrew Tanentzap talking separately this morning (26 November) with BBC Radio 5, BBC World Service, BBC Wales, and BBC Cambridgeshire.  The interest is in a new paper published last week in the Proceedings of the Royal Society B, which he jointly led with two Canadian research groups.

The research has discovered a startling shift in the composition of freshwater towards jelly-clad invertebrates (shown in the side photo), which is being driven by falling lake water calcium concentrations.  The cause is historical acid pollution that displaced calcium from soils much more quickly than it was being replaced by natural weathering processes.  Despite curbing pollution, there is now much less calcium left in soils and being exported into lakes throughout North America and Northern Europe.  Less calcium means that the dominant grazing animals living in these lakes cannot get the nutrients that they need to survive and reproduce, leaving more algae uneaten and available for other organisms.  The study finds that jelly-clad invertebrates with 1/10 the calcium requirements of the dominant water flea organisms are now exploiting these increases in food availability.  As these jelly-clad animals can clog filtration devices (as should be obvious from the photo), they are posing hazards for the extraction of surface waters.