Common sense tells me it’s got to be 1) something really small that 2) lives in the ocean. Is one of the phytoplankton the heaviest species on the planet? My little girl thinks I’m a genius – don’t let me tell her the wrong thing!
I’d say probably bacteria. Most likely one of the pervasive cyanobacteria that were some of the earliest cellular lifeforms.
I don’t have a cite, but I once heard that the animal kingdom’s largest single-species (or would this be genus?) bioweight was made up by ants.
Among multi-cellular animals, it is probably Krill, a small shrimp-like sea creature that are the Nachos of the ocean:
Angry whale chasing another whale away: “Nacho krill! Nacho krill!”
Could bacteriophages have a shot? Some fresh water ecosystems contain up to a billion tailed phages per milliliter, and around one million per milliliter in coastal seawater – the global population of tailed phages alone is calculated to be 10^30. Together all the phages in the world would outweigh the world population of elephants by a thousand-fold or more.
My cite was here when I wrote a paper on bacteriophages 3 years ago, but the page has changed a little since so the numbers don’t seem to be there anymore.
Yes, but there might be ?millions of species of bacteriophage- we are looking at the heaviest individual species.
Perhaps a common phytoplankton species would have a good shot; and then there are megatonnes of extremophile organisms living deep in the rocks of the Earth; how diverse these species are I haven’t a clue, but they might be contenders as well.
A previous discussion on this topic is in this thread
I agree with eburacum45; considering the vast expanse of their environment underground, an arceobateria species has got to be a good contender.