water soldiers aquatic plant in shallow freshwater river, poor visibility due to dissolved organic particles, algae

algae aloides aquatic autumn background balance biotope brook challenge climate coldwater concept contrast current detritis detritus dirty dissolved due ecology ecosystem elodea environment essential europe exploration explore flora flow freshwater ground hornwort human impact lake leaf litter moderate nature organic particle particles plant poor ray river sand season shallow soldiers still stratiotes stream submerged substrate sun sunlight temperate threat ukraine underwater unusual vinnytsia visibility vulnerable water wild wilderness wonder