abstract
algae
amphibian
amphibious
animal head
backdrop
background
beauty in nature
bog
color image
common frog
contamination
cover
damp
dampness
deep
design
dirt
duckweed
ecology
effluents
environmental conservation
fossil fuel
grass
grass area
green
image
lake
landscape
marsh
plants
pond
river
riverbank
scum
summer
surface
swamp
texture
toad
vertebrate
water
wet
wetlands