It is possible if the author is a member of one or more teams of researchers who share authorship on the same papers. The author with 150 publications may have contributed only a small part of each paper, e.g., a radiocarbon date. Formerly, scientists advised one another that if you coauthored a paper, every member of the team should be able to present the entire research; today, in a world where movies end with credits to hundreds of people, even small contributions are valued in scientific papers.

The number of publications can also rise if the authors choose to write their papers as "least publishable units," that is, short papers that each present only one aspect of a larger research project. For example, when an entomologist studies a family of insects, he can present this information as a single long paper, or as a series of short articles on single species. This practice has some advantages; for instance, the title is likely to accurately reflect the content of the paper; and each paper showcases only one new idea, so new ideas are not lost within the verbiage of long papers. But it also has disadvantages, such as scattering information across different journals, losing sight of the big picture, and, perhaps, losing status among other professionals who may find the shorter papers unimportant and the inflation of papers annoying. Most of us would rather read one interesting paper, however long, than ten trivial ones.

I think that the author worked on more than 150 publications since several years. But, the publication procedure started this year.

I think that it is great achievement as it is not common to reach to that number of publications in such period; considering his/her little or only a small part of contribution for each paper. The author must guide other researchers to repeat such manner.

My wishful thinking that every co-author would have serious and significant contribution to a paper. Maybe the author you met just happened to get all the great effort from the past few decades published in the same year by coincidence. But it really depends on the culture of teams, especially the very large ones that everyone in the team can publish ... and the boss/PI can be too busy and only have some kind of bottom line contribution, e.g. checking the spellings under the title... in this way, one could have a lot of publications very soon.