I don’t know who came up with this — it’s been bouncing around science journals for 50 years:

hydromicrobiogeochemist: one who studies small underwater flora and their relationship to underlying rock strata by using chemical methods

microhydrobiogeochemist: one who studies flora in very small bodies of water and their relationship to underlying rock strata by using chemical methods

microbiohydrogeochemist: one who studies small flora and their relationship to underlying rock strata by using chemical methods and SCUBA equipment

biohydromicrogeochemist: a very small geochemist who studies the effect of plant life in hydrology

hydrobiomicrogeochemist: a very small geochemist who studies wet plants

biomicrohydrogeochemist: a very small, wet geochemist who likes lettuce