Conjecture part of the scientific process? It can be, but only when on solid scientific ground first.
Popperist thinking has really hurt science due to his/its rejection of inductivism. Francis Bacon had the right approach.
This thread's article is very brief, with few details, one of which was a finding that Earth's oxygen levels were only .1% prior to the Cambrian Explosion.
The article suggests that the "explosion" was delayed until oxygen levels rose significantly.
Why would oxygen levels suddenly rise?
The article suggests that the splitting apart of Gondwanaland changed ocean currents and brought more nutrients to the surface, feeding algae, re-oxygenating the atmosphere.
The article doesn't mention, but one can easily suppose that the recent melting of "snowball Earth" also contributed to increased plant growth and more oxygen.
Bottom line: one or two reports of new scientific facts which suggest important implications regarding the Cambrian Explosion of new life forms.
Yes, it's speculation, or hypothesis at best, but I'd say entirely appropriate, especially for a mass media news report.