You could keep both projects and just add an umbrella project that would provide a page where all of the observations from both of the smaller projects were available.
Thank you - that would work for viewing the data together. What I ultimately want, however, is to have all new contributions to the traditional projects be to a single project, not multiple (i.e., its not a merging of viewable data, but of actual data into a new traditional project where all future contributions would go).
Maybe there’s some way to merge data, but I don’t know of it. Users have to agree to permissions on the data they contribute when they join projects, so that might prevent automated data mergers. My best suggestion is start a new project, maybe see if you can change permissions on the old ones to keep new people from joining or adding data, and perhaps use an umbrella project to display old and new data. I guess you could also use a similar approach, but just designate one of your current projects as the one you now want people to use, and try to phase out the other by restricting new users or data, if possible.