It's more complicated than that.

I can't find any good sources right now but here's some information[0] (with references to NASA and MIT). Here's one relevant bit:

> Along with sunlight, water and carbon dioxide, phytoplankton require a variety of other nutrients from the water including nitrogen, phosphorous and iron. The most important are nitrogen and phosphorous which are essential to survival and reproduction. Nitrogen is in short supply in some areas but in other areas, phosphorous is limited. Phytoplankton cannot continue to grow when one or the other has been used up.

[0]: https://sciencing.com/phytoplankton-eat-5065524.html

Yes, but the way they absorb those nutrients is by having dissolved ions pass through their cell membranes, just like land plants do it. That's not the kind of "eating" I'd associate with the consumption of plastic particles. Excess nitrogen and phosphorus from waste water are a problem, but mostly by causing too much growth at the expense of other organisms.

Are you saying that nanoparticles of plastic couldn't ever be small enough for "ingestion"?

I'm having trouble finding references to support my claim, other than phytoplankton attaching themselves to plastic particles, which are then consumed by zooplankton, or plastic particles blocking sunlight thereby preventing photosynthesis, but nothing about actual plastic "consumption".

Think about what plastic actually is on a molecular level: it's the exact same atoms that make up all of life. (Carbon, oxygen, hydrogen, nitrogen, rarely chlorine.)

So if anything the plastic might be beneficial, assuming that it's able to decompose it and absorb only those atoms it actually needs as nutrients.

That's kind of what the person you are replying to is saying: if the plant is absorbing it, it's obviously been decomposed into its constituents and is actually beneficial to it.

It doesn't work the same as it does for an animal that eats in the standard way you use the word eat.

Thanks for the clarification. I get now what you both are saying and I welcome the uplifting alternative viewpoint.

I was a bit confused (and at work) before but I was originally thinking of some species of dinoflagellates[0] who hunt/absorb/engulf prey (which I assumed to be larger than atoms), granted they are the exception. I could only find a study which noted higher concentrations of varying plankton/organisms (some dinofl.) near plastic[1] and partially related, on land some lifeforms were found to process PET bottles[2]. Life will hopefully find a way to process our trash before the ecosystem collapses ;)

[0]: http://oceandatacenter.ucsc.edu/PhytoGallery/dinos%20vs%20di...

[1]: https://www.sciencedirect.com/science/article/pii/S0025326X1...

[2]: https://phys.org/news/2016-03-newly-bacteria-plastic-bottles...

More generally: Leibig's Law of the Minimum.

https://en.wikipedia.org/wiki/Liebig's_law_of_the_minimum