My Ahrens and Ahrens nee Soker left (probably Jever) Oldenburg about 1869
but, possibly relevant to you, the oldest child Mary married Anton W Harms
in 1880 in Illinois. See my Oldenburg List note of 2002/11/4 for my (still
unanswered) question on Mary's family (some who knew her are still alive).
I haven't tracked her husband's line but I have some contacts with it.
Anton came with several brothers. Because of that I pay some attention to
Harms. I do remember seeing quite a few in Filby & Glaziers encyclopedia
Germans to America.
Good luck in your search
Bob Cooper