At roughly 4%, calcium (Ca) is the 5th most common element in the earth’s crust. Some regions, however, suffer from a calcium decline problem, both because crustal calcium is unevenly distributed on the earth’s surface, and because it has been depleted by human activities in some regions that didn’t have much Ca in the first place.
Muskoka is one of those regions.
We didn’t have much calcium in our soil historically, because our soil was “built” by the weathering of granitic rocks – a slow process that produces very little calcium – and then much of the soil we had was pushed south by glaciers only a few millennia ago.
Acid rain compounded the problem, leaching much of the Ca in the soil away. Muskoka soils lost roughly half a tonne  of Ca per ha  to acid rain, leaving so little Ca in the soils that the growth (and carbon capture) of Muskoka forests is now commonly limited by calcium supply, and Ca input to lakes has been reduced. These factors have led to a calcium decline problem in Muskoka. Ca is currently limiting the growth of trees, especially sugar maple, in Muskoka forests, and Ca levels have fallen to levels at or below 1.5 mg/L in many Muskoka lakes, levels that are too low for calcium-rich animals such as crayfish and Daphnia to survive, let alone thrive. It is this Ca decline problem that scientists have called “ecological osteoporosis”, by analogy to the syndrome in humans caused by long-term intake of too little Ca.
- one metric tonne (1000 kg) is equal to 2,204 pounds
- one hectare (ha) is equal to 2.47 acres