This Scientific American article looks into the question but I also had a conversation with a publisher at a convention on the subject that I would like to share.
The clerk described the core of science as being good literacy. To be fair, she was at a conference for ESL teachers so the literacy angle was a marketable one.
I felt, and feel, that science is about questions and thinking. I can see that clear thinking is required and clear thinking is aided by clear unambiguous writing which is aided by being literate but we are a few steps removed from the core. Perhaps we are now in the mantle.
Being a science professional certainly requires good literacy as one must understand what other science professionals have done and write clearly ones further contribution to the field.