underwater
algae
aquatic environment
aquatic invertebrate
aquatic life
aquatic plants
biodiversity
carbon dioxide
creature
decomposer
ecology
ecosystem
environment
fallen leaves
food chain
freshwater
freshwater ecology
freshwater snail
habitat
invertebrate
mollusk
nature
oxygen
photosynthesis
plant
pond
river
scavenger
shell
snail
spiral
stream
underwater habitat
underwater world
water conservation
water flow
water quality
water surface
wetland
wetland ecology