ÜDS-Fen 2012-1 Soru=50

It is clearly stated in the passage that the communication of large baleen whales ----.

Noise drives many species of marine animals to change
their behaviour markedly – their calling, feeding and
migration patterns – sometimes onto a beach and
ending their lives. Fish like cod and haddock in the
Barents Sea have been found to escape from the area
when oil-prospecting air guns start firing, drastically
reducing fish catches for days. Large baleen whales
communicate over vast distances in the same
frequencies that ship propellers and engines generate.
On most days, the area over which whales in coastal
waters can hear one another shrinks to only 10 to 20
per cent of its natural extent. Christopher W. Clark
studies endangered northern right whales, whose
habitat includes busy shipping lanes for the port of
Boston. “Shipping noise is always there,” Clark says. “It
doesn’t have to be fatal to be problematic over time.
The whales’ social network is constantly being ripped
and reformed.” Unable to communicate, individual
whales have trouble finding each other and spend more
time on their own. The problem is getting steadily worse
for another reason. As we are making more noise, we
are also making the ocean better at transmitting it.
Seawater is absorbing less sound as carbon dioxide
from fossil-fuel burning seeps into the ocean and
acidifies it.