When you stroll through dusk on a Lake Ohrid beach creating memories to treasure for the rest of your life, you may not realize that the lake has her own way of remembering things too, that she may never forget you just as you will never forget her.
Perhaps that sounds fantastical or overly romantic, but it’s actually just another way of describing how the lake stores information layer by layer in its sediments. If, like researchers from the recent SCOPSCO study, you know how to ask the right questions, these sediments can reveal environmental secrets from hundreds of thousands of years ago and even teach us about the way species evolved.
So what has Lake Ohrid whispered to researchers so far? Among other things, it has told the story of regional forests for the past 500,000 years, which is impressive recall. Critically, this story appears to show a continuous regional presence of most tree species, even during ice ages, suggesting that it is a sanctuary during climatic extremes.
Another intriguing narrative is that of humankind. Because the Ohrid region is known to be one of the oldest settlements in Europe, clues hidden in sediments are fascinating insights into how people have lived since prehistoric times. The earliest potential marker even suggests that people may have been supported on Lake Ohrid’s shores for up to 8,500 years!
There is, of course, a dark side to this. Large-scale deforestation with likely human cause is also evident in sediment records, which show a sudden spike in impact from people beginning about one century ago and accelerating to the present. These now include heavy metals like iron, copper and lead.
We hope and believe that Lake Ohrid will be recalling much more positive memories of humans from the 21st century onward. Whatever happens, you can be sure she will never forget…