Density Plot from Scientific Research

Statistical distribution of long-term change rates in 395 data-rich sites with dissolved oxygen and water temperature data for at least 25 years. Rates of change for water temperature (e) were quantified using Theil–Sen slopes from the R package openair; the ‘deseason’ option was used to account for potentially important seasonal influences. DO sat was estimated using the ‘calc_DO_sat’ function from the stream Metabolizer R package 157. Positive and negative rates indicate increasing and decreasing trends, respectively. Only about 50% of the sites showed increasing water temperature (e) and decreasing dissolved oxygen (d), lower than the reported >70% in the United States and Central Europe rivers 97 and predominantly decreasing dissolved oxygen in the global survey 32. These contrasting results highlight the complexity of climate change on water quality and data scarcity challenges in water quality.

DOI