Dataset for: Tracking freshwater browning and coastal water darkening from boreal forests to the Arctic Ocean

The forest cover of Northern Europe has been steadily expanding during the
last 120 years. More terrestrial vegetation and carbon fixation leads to
more export to surface waters. This may cause freshwater browning, as more
degraded plant-litter ends up as chromophoric (coloured) dissolved organic
matter. Although most freshwater ultimately drains to coastal waters, the
link between freshwater browning and coastal water darkening is poorly
understood. Here, we explore this relationship through a combination of
centennial records of forest and coastal water clarity, contemporary
optical measurements in lakes and coastal waters, as well as an ocean
drift model. We suggest a link between forest cover in Northern Europe and
coastal water clarity in the Baltic, Kattegat and Skagerrak Sea and show
how brown coloured freshwater from Northern European catchments can
dictate coastal water clarity across thousands of kilometres, from the
Baltic lakes to the Barents Sea.