# pH and dissolved oxygen levels in rivers **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 20, 2023, 8:45pm UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343 "2023-05-20T20:45:02Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [May 20, 2023, 8:45pm UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/1 "2023-05-20T20:45:02Z")
I have been doing some prospecting for gold this year and have been using the USGS site to check water depth and turbidity (clarity). Here is their page for the Vermilion River water height. We had some rain last night and you can see the water went up a few inches. It will drop back down in the next day or so like I would expect. Now scroll down a bit and you can select other parameters like pH, dissolved oxygen, turbidity, etc. Select pH and then dissolved oxygen. Hmm, they both go up and down sinusoidally every day. I wonder why? I see water temperature goes up and down also. maybe the dissolved O2 just follows. But if you select a 30 day span they don’t match the water temperature so closely. > **[Vermilion River Near Vermilion OH](https://waterdata.usgs.gov/monitoring-location/04199500/#parameterCode=00065&period=P7D)** > > Monitoring location 04199500 is associated with a Stream in Lorain County, Ohio. Current conditions of Discharge, Dissolved oxygen, Gage height, and more are available. Water data back to 1950 are available online. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [May 20, 2023, 9:35pm UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/2 "2023-05-20T21:35:11Z")
> [@mixdenny](#): > > Select pH and then dissolved oxygen. Hmm, they both go up and down sinusoidally every day. I wonder why? I would guess that this is related to photosynthesis - carbon dioxide causing acidity. ETA: I tried to look at the site to see if pH rises during the day, which would be consistent with photosynthesis consuming carbon dioxide and releasing oxygen, but you can’t tell the time of day from the axis. ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [May 21, 2023, 6:57am UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/3 "2023-05-21T06:57:19Z")
> [@Riemann](#): > > I would guess that this is related to photosynthesis - carbon dioxide causing acidity. True. But increasing photosynthesis = increasing acidity = falling pH. Another factor relating pH and temperature is the disassociation constant of the minerals carried by the flow say CaCO3 (insoluble) + CO2 + H2O \<-----\> Ca++ + 2HCO3- CaCO3 is less soluble in hot water than in cold water ie precipitation Conversely, an increase in water flow will favour disassociation. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [May 21, 2023, 10:51am UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/4 "2023-05-21T10:51:47Z")
> [@penultima\_thule](#): > > But increasing photosynthesis = increasing acidity = falling pH. Removal of CO2 increases pH. That’s not too say there isn’t other chemistry going on. ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [May 21, 2023, 3:42pm UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/5 "2023-05-21T15:42:55Z")
I should mention this is a very clear stream with fairly fast moving water. I don’t see anything growing in it to utilize photosynthesis. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [May 21, 2023, 4:46pm UTC](https://boards.straightdope.com/t/ph-and-dissolved-oxygen-levels-in-rivers/984343/6 "2023-05-21T16:46:47Z")
There will be more photosynthesis in clear water than turbid water. There are algae everywhere, growing on any underwater surface, not only when they are obviously visible in blooms or mats. And surely some vegetation, rooted aquatic plants.