bury
your head
deep 1 in the river bed 2
deep 1 in the river bed 2
1 oxygen diffuses slowly through water and takes time
to move from the surface to deeper areas
to move from the surface to deeper areas
2 contaminated sediments can accumulate
at the bottom of the river
at the bottom of the river
where flow is slow
& sedentary 3
& sedentary 3
3 sediments on the river bed where water
movement is limited are usually oxygen poor
movement is limited are usually oxygen poor
undulate
your body
stir waters
breathing is moving 4
moving is breathing 5
moving is breathing 5
4 those living in low oxygen environments often
use movement to bring oxygenated water into contact with their bodies
5 they absorb oxygen from the water across the skin
or from air bubbles held against the body
breathe
breathe in
breathe in 6
through your skin
breathe in 7
breathe in 6
6 some freshwaters can go from oxygen rich to virtually
no oxygen over the course of 24 hours
no oxygen over the course of 24 hours
through your skin
breathe in 7
7
heat and the decay of excessive plant and algal growth
deplete oxygen and can be considered pollution
deplete oxygen and can be considered pollution