Newsademic British English edition 260

12th November 2015 
N e w s a d e m ic .co m ™
 - British English edition 
page 
6
washes some o f the fertilizers into 
rivers, which drain into the sea. The 
fertilizers contain extra nutrients 
called phosphates. These make the 
algae grow much faster. The ever- 
expanding algae blooms can then 
create ‘dead zones’.
W hen the algae dies it sinks 
to the bottom. There, it uses dis­
solved oxygen in the seawater to 
decompose. The rotting algae take 
more oxygen from the water than 
is added naturally. M ost oxygen 
in the sea comes from the atmos­
phere. The process by which oxy­
gen moves from air into water is 
called diffusion. As there is so little 
oxygen in the water, organisms that 
live on the bottom cannot survive. 
M ost fish use gills to extract oxy­
gen from the water. If it contains 
little or no oxygen, fish either die 
or go elsewhere.
C om puter g e nerated underw ater view o f
the algae sea ha rve ste r (Fredrik Ausinsch)
The algae sea collector would 
work like a floating lawn mower. It 
can collect algae to a depth o f 1.5 
metres (five feet). The machine’s 
power comes from hydrogen fuel 
cells. It will also have two electric 
pumps. These pump the seawater 
and algae into a tank. There, the al­
gae blooms (or biomass) are sepa­
rated from the seawater. This water 
can then be used to push the device 
forward. The algae are dried with 
heat produced by the hydrogen 
fuel cells. The harvester could be 
remotely controlled from a nearby 
companion, or service, boat. When 
the machine is full, the collected
biomass can be emptied onto this 
boat. Biofuels mainly come from 
crops that have recently been har­
vested. The plant matter is used 
to make ethanol. This is usually 
mixed with petrol or diesel. More 
modern cars, trucks and buses can 
use biofuels. The sea harvester’s 
designer says that the algae bio­
mass can also be used for other 
things. Fertilizer and cosmetics are 
examples. The next step will be to 
build a prototype to check that the 
device works. □
T