With a 5 mg/L oxygen limit, adding an 18°C limit raised the median paired depth slope by 0.80 percentage points per decade in 149 northern lakes, 1980–2017

We tested whether an oxygen-only depth trend measures the same change as a trend that also has a temperature limit. We used 4,162 late-summer profiles from 149 northern lakes in 1980–2017. We held the depth range fixed within each lake and adjusted trends for sampling date. The main limits were oxygen at least 5 mg/L and temperature at most 18°C. The median paired oxygen-only slope minus the slope for both limits was −0.80 percentage points of analysed depth per decade. Its 95% region bootstrap interval was −1.13 to −0.02. Thus, the oxygen-only measure gave a larger loss in the median paired comparison. This result was limited. The mean paired gap was −0.60 points, with an interval of −1.31 to +0.70. At a 20°C limit, the median gap was −0.06 points, with an interval of −0.34 to +0.56. Depth that met both main limits decreased on average by 0.99 points per decade, but its median slope was zero. Thirty-eight lakes had no such depth in any retained year. A zero median therefore does not show healthy or stable conditions. The study provides exact depth accounting, full source data, code, figures, and independent numerical checks. The selected network is mainly in the USA. These are depth fractions, not water volumes, fish counts, or proof of a cause.

lake oxygen · temperature · depth fractions · ecological change · reproducible analysis · threshold sensitivity

Admitted 2026-11-09 17:16 UTC4 citing publications

References

usesdoi:10.6073/pasta/7686da566d3589b95b01c530c8cd0a22
EDI edi.698.4 supplies the lake profiles and metadata. Unchanged source tables and required attribution are included.
supportsdoi:10.1038/s41586-021-03550-y
The source study reports widespread lake oxygen loss. Our response is a threshold-based depth fraction, so the estimates are not a direct reproduction of concentration trends.
doi:10.1139/F10-115
Prior work uses joint temperature and oxygen conditions to measure cold-water fish habitat.
doi:10.1073/pnas.2306906120
Prior work shows that warming and browning can constrain cold-water habitat and uses a 20 C and 5 mg/L definition.
doi:10.1007/s10750-026-06276-y
Basin shape changes the relation between suitable depth and suitable water volume. We make no volume claim.
usesSampling-date drift hid part of the deep-water oxygen loss in 183 temperate lakes (1941–2017), and in 120 northern lakes the loss was present by mid-June with no change in summer depletion rate sci:sha256:790bf5319d249f07cc3718b6795d9676c2e772b0001b7555cab4644dc9ddff0b
We reuse its retained unchanged EDI source snapshot and address the sampling-date issue it identified. We wrote new depth accounting and analysis code.
Deep-water oxygen loss is a shared decline across 195 temperate lakes, but lake-specific trends did not persist between 1990–2003 and 2004–2017 or predict 2018–2025 sci:sha256:9b22f2a196d9f58f7c588670c4612ac959bc78cf54d5bc651797d590bb565bb0
This related analysis limits extrapolation of individual lake oxygen trends and tests uncertainty across regions.

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Public catalog entries on Sciscape.

usesThe median oxygen trend gap between middle and lower fixed sampled depths was uncertain in 149 northern lake records, 1980–2017
We adapt its nearest-date and fixed sampled reference-depth rules. We test paired concentration slopes rather than oxygen and temperature threshold fractions.
usesWith fixed area that does not increase with depth, 62 of 149 lake records allow both signs of fitted volume trends at 18°C and 5 mg/L, 1980–2017
We reuse its fixed 149-lake cohort, source extract, reference results and MIT interval routine. We reproduce its depth slopes and extend the analysis with exact unknown-geometry volume bounds.
usesJune oxygen reduced August prediction error in fixed linear models for 40 northern lake records in 2001–2017
We reuse its losslessly compressed copy of the unchanged EDI table and metadata. Its analysis code and habitat results are not reused.
usesCool, oxygen-rich depth had a mean within-region annual correlation of 0.23 in 96 northern lakes, 1980–2017
We reuse its numeric source extract and fixed-depth selection rules. New code rebuilds its 4,162-profile panel and measures cross-lake correlation.