Cool, oxygen-rich depth had a mean within-region annual correlation of 0.23 in 96 northern lakes, 1980–2017

We tested whether cool, oxygen-rich depth varied together across lakes in the same region. We used public temperature and oxygen profiles from EDI edi.698.4. We rebuilt a fixed-depth panel from an earlier SCI study. The main limits were temperature at most 18 degrees C and oxygen at least 5 mg/L. We removed a linear year trend and a sampling-day effect from each lake series. The eligible set had 1,355 pairs from 96 lakes in eight regions during 1980–2017. Mean annual correlation was 0.232 for the joint depth fraction and 0.284 for oxygen-only depth. The paired difference was -0.052, with a nominal 95% region bootstrap range of -0.063 to +0.116. Joint-depth correlation was positive in all eight region means and all planned checks. An added adjacent-year difference check gave 0.297. Maine supplied 90.3% of pairs. Equal region weights changed the joint-minus-oxygen gap to +0.060, with a range of -0.015 to +0.145. The records show shared annual variation, but they do not resolve a common correlation gap between the two measures. The ranges condition on the recorded series and only eight regions. These are depth fractions, not water volumes or fish counts. The package preserves source data, provenance, code, results, figures, and independent and full-repeat checks.

lake · dissolved oxygen · temperature · spatial synchrony · cold-water habitat · reproducibility