that's what I know too
the navy operated coastal batteries and had land personnel at the bases
this might be the reason why mountain troops were used for amphibious operations in Norway and Crete
as far as I know, the army was trained in France for Seelöwe, the supposed invasion of Britain, the Navy only operating the landing craft
as I read, all three arms were very jelous for competences, this going so far that initially the army did not have AA units above battery level, the AA divisional batallions being under Luftwaffe competence
The later Navy field units were indeed from surplus Navy personnel
I am not even sure if the Navy even operated the boatplanes as would be natural for coordination
just read that the CO and NCO cadres of the seebataillon were from the army, so maybe they were not regarded as navy
most of the service was on land anyway, they were not integral with sea units
soldiers aboard were "Marinestabswache" up to 1884
here you can see mounted seebataillon in china
http://en.wikipedia.org/wiki/File:Bundesarchiv_Bild_134-B2401,_Tsingtau,_Die_%22alten%22_Ostasiaten.jpg