What the article tells us is what is relevant. Articles like this are notorious for giving the wrong impression about what the real science is.
The article says "Scientists have caught a once-in-a-billion-years evolutionary event in progress, as two lifeforms have merged into one organism that boasts abilities its peers would envy." in the first sentence and goes on to say, close to the end, "Altogether, the team says this indicates UCYN-A is a full organelle, which is given the name of nitroplast. It appears that this began to evolve around 100 million years ago, which sounds like an incredibly long time but is a blink of an eye compared to mitochondria and chloroplasts."
The question is, "What has been observed?"
There is nothing in the article about scientists seeing the 2 species merge.
The scientists say they have identified 2 species in the one, and that the functioning of the 2 species have been altered to reflect the 2 becoming one species, that divides and functions as one species instead of as 2 species in a symbiotic relationship.
Sheesh...
You said and i quote "Scientists have caught a once-in-a-billion-years evolutionary event in progress,"
Then you say
"There is nothing in the article about scientists seeing the 2 species merge."
I know you are desperate to disprove science but make up your mind before trying fruitlessly to dis it.