I have two distant relatives who immigrated to Iowa in the early to mid-1800s,settling somewhere near Davenport. They were brother and sister - ElisabethMargaretha Paulsen (b. 29 Oct 1847) and Hans Paulsen (b 11 Nov 1823; d. June 1890). According to my data, Hans married a Christine Kroger in the USA.
Both Hans and Elisabeth Margaretha were the children of Johann Paulsen (b.September 26, 1794 in Welmbuttel, d. January 21, 1867 in Albersdorf) and Johanna Catharina Margaretha Hayken (b. November 29, 1792 d. February 26, 1835 in Albersdorf).This was a first marriage.Johann later remarried and had a number of other children by Ida Louise Engeholm.
Elisabeth Margaretha married an Eduard Adolph Ahrens (b. 23 december 1829 in Hamburg) on 23 September 1847 in Albersdorf, Germany. It is not clear whether he also immigrated to the US though my data seems to indicate that he did. Ahrens was the son of a Doctor Andreas Heinrich Ahrens of Hamburg and Margaretha Henriette Deneken.
If any of the above rings any bells with someone, please let me know. Otherwise, good luck in your own quest.