Page 15 - AW SEPOCT 2019

WORLD NEWS

Calcium levels in freshwater

lakes declining

new global study has revealed that calcium levels are few decades to reduce sulphate deposition associated
A declining towards levels that can be critically low for with acid rain, lakes are now subject to less calcium
the reproduction and survival of many aquatic organisms. leaching from surrounding terrestrial areas. Paradoxically,
The study of how calcium concentrations are changing therefore, successful actions taken to address the harmful
in freshwater lakes around the world has revealed that in impacts of acid rain may have led a decline towards low
widespread areas in Europe and eastern North America. levels of calcium for many aquatic organisms,’’ said Gesa
It shows that the decline of calcium may have significant Weyhenmeyer, Professor at the Department of Ecology
impacts on freshwater organisms that depend on calcium and Genetics/Limnology, at Uppsala University in Sweden
deposition, including integral parts of the food web, such and lead researcher on the study.
as freshwater mussels and zooplankton. The study drew on 440,599 water samples from 43,184
In widespread diminishing anthropogenic effects on inland water sites from 57 countries and analyzed decadal
calcium in freshwaters, published recently in Scientific trends in over 200 water bodies since the 1980s. It was a
Reports, researchers discovered that some lakes are global study conducted by multiple researchers across
approaching levels of calcium that endanger organisms Europe and North America. IISD Experimental Lakes
that rely on that calcium for structure and growth. Area—the world’s freshwater laboratory— in northwestern
The study also attributes some of its results to freshwater Ontario, Canada, contributed expertise and data from
lakes’ ongoing recovery from the impacts of acid rain. its unparalleled long-term monitoring dataset of over 50
“Given governmental and industry action in the last years. AW

Asian Water SEPTEMBER/OCTOBER 2019 13