Hmmm well i have several possible ones:
Something Medical or in Biology
Botany or Conservation related.
Marine Biology / Reef Conservation and Coral Propagation
I have done things i several fields, I have worked for a year and a half in Stream rehab / Conservation in Northern California near the Klamath River.
I also have worked in plant nursery both retail and educational.
I have a bunch or Orchids booming right now behind me.
I have had 2 Reef Tanks with Hard coral and all kinds of reef cirtters.