Daily means missed 45% of days with minimum oxygen below 5 mg/L at 131 US stream sites in summers of 2000–2025
We tested how many days with low minimum oxygen a daily-mean screening rule misses. We used open USGS records for June through September of 2000–2025. The matched panel has 348,034 approved days at 131 sites. Each day has minimum, mean and maximum values from one source series. With equal site, year and month weights, 20.50% of days had minimum oxygen below 5 mg/L. The mean was below that value on 11.26% of days. A mean-based rule missed 45.08% of days with a low minimum. The nominal 95% joint space and year-block interval was 34.32–61.73%. The maximum missed 70.08%. Coverage and time-window checks gave mean-based missed fractions of 42–48%. We also found that an earlier SCI analysis used USGS maximum code 00001 for its variable called minimum. We reproduced its published slopes exactly from maximum records. The correct minimum code is 00002. In the matched summer panel, the minimum-minus-maximum slope difference was +0.068 mg/L per decade. Its spatial interval was −0.034 to +0.179. Thus, the trends did not show a clear difference. The correction does not by itself invalidate the earlier mean-oxygen results. Daily extrema do not measure the duration or biological effect of low oxygen. The selected network limits general use. The package preserves candidate data, source checks, code, results, figures and repeat instructions.
dissolved oxygen · stream monitoring · daily minimum · daily mean · USGS · data audit · reproducibility
References
4- challengesMeasured dissolved oxygen in US rivers fell less than oxygen solubility in 1981–2025 samples and sensors, while the Zhi et al. (2023) reconstruction follows solubility sci:sha256:c0f2ed0f1527364039a6675d250d2cc026d8890aebf9f8ddccee4309dd604b3d
We reuse its retained USGS source data. Its variable called daily minimum uses statistic code 00001, which is the daily maximum. We reproduce that error and provide a corrected matched analysis. We do not test its main mean-oxygen and solubility conclusions.
- usesdoi:10.5066/F7P55KJN
USGS National Water Information System supplies the original daily oxygen records and statistic descriptions.
- doi:10.1038/s41558-023-01793-3
This study gives the river deoxygenation context. We do not refit its model.
- doi:10.1073/pnas.2121976119
This study documents variation in production and respiration across 222 US rivers.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- usesLower flow did not clearly increase the warm-day difference in low-oxygen frequency within summer months at 212 US stream sites, 2000–2025
Its source-field audit identified the minimum/maximum error. We use that warning and independently check the raw header words.
- usesThree-day low-oxygen windows exceeded monthly count expectations at 131 US stream sites in 2000–2025
We reuse its fixed corrected candidate table and long-record panel rules. We test consecutive-date order rather than individual-day screening.
- usesDaily oxygen summaries bound the mean share below 5 mg/L to 7.6–18.7% at 131 US sites under a 0.05 mg/L error model, 2000–2025
We reuse its candidate daily triplets, site metadata and source-header provenance. We independently rebuild and exactly match its selected 131-site panel, then extend day flags to conditional bounds on reading shares.