The paper was published in Nature and entitled “Widespread deoxygenation of temperate lakes” (see full citation below). Study co-author Kevin C. Rose, is a professor of biology at Rensselaer Polytechnic Institute, and an active member of GEO AquaWatch Working Group 3.

Rose and his co-authors found dissolved oxygen levels declined in 393 temperate lakes in the United States and Europe between 1941 and 2017 – a result of anthropogenic climate change altering the physical and chemical environment in lakes.  Oxygen values dropped in both surface and deep lake waters, but for different reasons.  Surface values mostly dropped due to less soluble oxygen in warmer surface waters, but enhanced phytoplankton production led to more surface dissolved oxygen in some of the most productive warming lakes.  Dissolved oxygen declined in deeper waters was associated with thermal stratification and reduced water clarity limiting primary production and enhancing respiration, but not altering gas solubility in the warming lakes.  Lake oxygen declines were ~3-9 times greater than oxygen declines observed in oceanic waters, threatening ecosystem services, and leading to increased fish kills, algal blooms and methane emissions.  Read more here.