balance

biotope

brook

ceratophyllum

close

coldwater

current

danger

dark

demosponge

detritus

eater

ecosystem

environment

europe

filter

freshwater

gravel

habitat

healthy

human

impact

lacustris

lake

litter

lush

lutea

motion

movement

muddy

murky

nature

nuphar

organic

particle

plant

pollution

porifera

scenery

season

spongilla

spongillidae

stream

substrate

summer

sunny

temperate

turbid

ukraine

underwater

vegetation

vulnerable

water