Fig. 5
From: Dissolved organic compounds in geothermal fluids used for energy production: a review
a Mean concentrations of DOC, formate, acetate, propionate (\(\hbox {mg}\,\hbox {C}\,\hbox {L}^{-1}\)) and the temperature for each reported site of the North German Basin. The sites on the x-axis are arranged primarily after reservoir age (youngest to oldest from left to right) and secondarily after the well depth (shallowest to deepest from left to right) within the grouped rectangles. b Mean concentrations compared between production (dark fill) and injection (clear fill) well. Missing data represent either data below detection limit or not reported data