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Comment by A_D_E_P_T | Hacker News Reader

The scientific paper underlying the article is here: https://www.nature.com/articles/s41559-024-02448-y

There's a different article, and to my mind a more readable one, here: https://www.sciencedaily.com/releases/2024/07/240715135713.h...

> "Lakes and reservoirs have experienced oxygen losses of 5.5% and 18.6% respectively since 1980. The oceans have experienced oxygen losses of around 2% since 1960 and, although that number is smaller, it represents a more geographically and volumetrically extensive mass. Marine ecosystems have also experienced substantial variability in oxygen depletion. For example, the midwaters off of Central California have lost 40% of their oxygen in the last few decades."

If that holds true worldwide, and not just at a selection of measuring sites, it's a rapid and very concerning shift. It'll be interesting to see if their measurements are corroborated.

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Skimming the conclusion of the paper it seems that, unless there are overlooked measurement errors the effect is robust. The immediate question this suggests to me is this: are there any naturally occurring multi-year (or multi-decade) oxygen concentration cycles in the ocean analogous to already-known salinity cycles?

This was where I immediately started thinking. Is this something that cyclical? The article is long on effect and very short on causes.

"Reducing greenhouse gas emissions, nutrient runoff and organic carbon inputs (for example, raw sewage loading) would slow or potentially reverse deoxygenation," they write.

And what exactly is "raw sewage loading" they talk about as a way to reverse this? I did some quick googling and couldn't find anything about what exactly it is.

“raw sewage loading” is, I believe, an example of an organic carbon input that should be reduced.

In other words, stop letting raw sewage out into rivers. We’ve been working on that for decades.

I wonder if "raw sewage loading" includes traditional septic systems where there's just a leach field for ... raw sewage...

There are certainly technologies these days that allow you to filter the effluent to make it less harmful to the environment.

https://www.nutter.com/trending-newsroom-publications-massde...

a leach field aproximates wetland, and with some revisioning, can be made to emulate wetland, and will often facilitate succession to actual wetland.

I read that as a clarification of organic carbon inputs that could be reduced. I don't know the specific phrase "raw sewage loading," but in context I assume its something to do with sewage waste being released into rivers and oceans.

This article seems to be based on quite a technical paper but my reading is hot water holds less oxygen so global warming is a factor. Also excess organic matter from farming is causing oxygen loss as it decomposes to CO2 and a few other processes.

It's literally what it sounds like: dumping untreated sewage into waterways and oceans.

A big problem in all of these is adding nitrogen and phosphorus to the water, which facilitates algae growth, which consumes a lot of the available oxygen:

https://oceanservice.noaa.gov/education/tutorial_pollution/0...

Urine and feces are great sources of nutrients - good if you extract them, sterilize, and use responsibly on land, not good if you dump directly into water.

there is a natural phenomenon known as wetland. these things reclaim, and redistributex raw materials that are like rocket fuel for microbes. these wetlands are inconvienient for [growth] as they take up a lot of area, andget in the way of housing developments, parking lots, and sewage treatment plants.

the solution is attempted dilution,thus:

>>It's literally what it sounds like: dumping untreated sewage into waterways and oceans.<<

Data point: IIRC the Great Lakes were getting choked on algae until they banned phosphates in detergents. And of course there is always fertilizer runoff.

Reducing carbon inputs would slow or reverse this. Increasing sewage runoff would make the problem worse.

Raw sewage contamination is a huge problem:

https://environmentamerica.org/center/resources/safe-for-swi...

Don't go swimming too soon after it rains if you want to be safe from E. coli. Overdevelopment, underfunded utilities, and factory farms put runoff at a level that's barely tolerable when it's dry, and when there's excess surface water, they overflow in unsanitary ways that result in nutrient blooms and oxygen depletion.

Thanks! I've switched the URL above to your second link (instead of the absurdly baity https://www.sciencealert.com/earths-water-is-rapidly-losing-...).

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