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Comment by tokyodude | Hacker News Reader

I am curious about the opposite. December 2017 I was staying on the New Port Beach peninsula in So Cal and the water was clearer then I think I've ever seen anywhere in the entire world. I grew up in the OC and have been to or by the beach 100s of times, I had never seen it so clear. Any idea why? Is it common? Was it fluke? Is it seasonal? Has something changed?

Picture: https://i.imgur.com/9WFTldz.jpg

You could walk half way down Balboa Pier and still clearly see the bottom of the ocean. I don't think I'd ever seen the bottom of the ocean through waves in any beach in So Cal ever. Never thought of it as dirty so much as just normal for sea water.

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Not easy to say without chemically analyzing the water. Oceanographers deal with this questions all the time

Roughly speaking, clear water means less life, less phytoplancton. The algae had gone. Is registered in lakes when water turns more acidic by contamination. They appear pristine, but is an ilusion. The ecosystem is very ill.

At sea this can normally indicate a different water mass by natural processes. Different salinity or temperature, a change on winds, barometric pressure, or sea currents can change this. Is totally normal.

And this could happen also when trowing signifiant amounts of something that kills microscopic life to the water (chlorine to pipelines for example).

It happens occasionally when there's very little tidal motion (slack tide), not a lot of small particulates from run off or recent rain, and most importantly not a lot of nutrients in the water - most murky water I run into in SoCal is from various species of plankton blooming, and the various zooplankton and copepods that follow in their wake.

It's really interesting when the visibility is radically different at different depths because of temperature and salinity gradients. Last time I dove it was crystal clear for 15 feet, then a floor of murky green with 2 foot viz, then the clarity opened up about 30 feet down.

I lived on the Balboa peninsula for a few years. Although it's rare, if the waves are very calm for a few days the water clears up a great deal.

Not arguing that they're aren't huge problems with the health of the ocean, but I have seen the water clear up that much a few times a year.

Warmer water supports less oxygen and life, so less stuff to see through. Not sure if that's the case here, but waters in the tropics are much more clear, but support much less life vs a kelp forest off CA.

Interesting. I've never seen Newport Beach look like that.

You’ll never see water like that after a rain. It takes at least 3 days before the run off clears out.

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