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Long-term trends in productivity across Intermountain West lakes provide no evidence of widespread eutrophication
  • Samuel James Sillen,
  • Matthew Richard Voss Ross,
  • Sarah Collins
Samuel James Sillen
University of Wyoming

Corresponding Author:ssillen@uwyo.edu

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Matthew Richard Voss Ross
Colorado State University
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Sarah Collins
University of Wyoming
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Eutrophication represents a major threat to freshwater systems and climate change is expected to drive further increases in freshwater primary productivity. However, long-term in-situ data is available for very few lakes and makes identifying trends and drivers of eutrophication challenging. Using remote sensing data, we conducted a retrospective analysis of long-term trends in trophic status across the Intermountain West, a region with understudied water quality trends and limited long-term datasets. We found that most lakes (55%) were not exhibiting shifts in trophic status from 1984-2019. Our results also show that increases in eutrophication were rare (3% of lakes) during this period, and that lakes exhibiting negative trends in trophic status were more common (17% of lakes). Lakes that were not trending occupied a wide range of lake and landscape characteristics, whereas lakes that were becoming less eutrophic tended to be in more heavily developed catchments. Our results highlight that while there are well-established narratives that climate change can lead to more eutrophication of lakes, this is not broadly observed in our dataset, with more lakes becoming more oligotrophic than lakes becoming eutrophic.
05 Apr 2023Submitted to ESS Open Archive
11 Apr 2023Published in ESS Open Archive