Press release

Calcium levels in freshwater lakes declining in Europe and North America with negative impacts on some species, new study

A new global study of how calcium concentrations are changing in freshwater lakes around the world has revealed that in widespread areas in Europe and eastern North America, calcium levels are declining towards levels that can be critically low for the reproduction and survival of many aquatic organisms.
August 5, 2019

WINNIPEG, August 6, 2019—A new global study of how calcium concentrations are changing in freshwater lakes around the world has revealed that in widespread areas in Europe and eastern North America, calcium levels are declining towards levels that can be critically low for the reproduction and survival of many aquatic organisms.

The decline of calcium may have significant impacts on freshwater organisms that depend on calcium deposition, including integral parts of the food web, such as freshwater mussels and zooplankton.

In Widespread diminishing anthropogenic effects on calcium in freshwaters, published recently in Nature, researchers discovered that the global median calcium concentration was 4.0 mg L-1, with 20.7% of the water samples showing calcium concentrations ≤ 1.5 mg L-1.

≤ 1.5 mg L-1 is a threshold considered critical for the survival of many organisms that require calcium for their survival, therefore, some lakes are approaching levels of calcium that endanger organisms that rely on that calcium for structure and growth.

The study also attributes some of its results to freshwater lakes’ ongoing recovery from the impacts of acid rain.

“Given governmental and industry action in the last few decades to reduce sulphate deposition associated with acid rain, lakes are now subject to less calcium leaching from surrounding terrestrial areas,” said Gesa Weyhenmeyer, Professor at the Department of Ecology and Genetics/Limnology, at Uppsala University in Sweden and lead researcher on the study.

“Paradoxically, therefore, successful actions taken to address the harmful impacts of acid rain may have led a decline towards critically low levels of calcium for many aquatic organisms.”

The study drew on 440,599 water samples from 43,184 inland water sites from 57 countries and analyzed decadal trends in over 200 water bodies since the 1980s. It was a global study conducted by multiple researchers across Europe and North America.

IISD Experimental Lakes Area—the world's freshwater laboratory—contributed a significant amount of expertise and data from its unparalleled long-term monitoring dataset of over 50 years.

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For more information, and to arrange an interview with the researchers, please contact:

Sumeep Bath,

Communications Manager.

IISD Experimental Lakes Area,

[email protected] or 1-204-958-7700 ext. 740

About IISD

The International Institute for Sustainable Development (IISD) is an award-winning independent think tank working to accelerate solutions for a stable climate, sustainable resource management, and fair economies. Our work inspires better decisions and sparks meaningful action to help people and the planet thrive. We shine a light on what can be achieved when governments, businesses, non-profits, and communities come together. IISD’s staff of more than 120 people, plus over 150 associates and consultants, come from across the globe and from many disciplines. With offices in Winnipeg, Geneva, Ottawa, and Toronto, our work affects lives in nearly 100 countries.

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Water
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Resources