Icebergs that break off Antarctica and drift away might
turn out to be hotspots of life in the cold southern
ocean. Climate warming has led to an increase in the
number of icebergs breaking away from the Antarctica in
recent years. The ___1___
ice gradually releases particles into the ocean,
providing a pool of nutrients that feed plankton and
krill, which are tiny shrimplike creatures. Because of
this, drifting icebergs have become oases in Antarctic's
ocean, helping to promote life. By encouraging life
surrounding them, the icebergs also may have ___2___
impact on reducing the excess carbon in the atmosphere.
This at least somewhat counters the greenhouse warming
that helped make icebergs break free from Antarctica in
the first place.
It has been known that icebergs deposit material from
land into the ocean as they melt. Lack of iron is known
to ___3___
biological activity in the southern ocean. If icebergs
are transporting iron-rich minerals to offshore marine
settings, it is therefore logical that the icebergs ___4___
helping the base of the food chain, which then can have
positive effects all the way up the food chain.
The important consequence of this is that
free-floating icebergs can serve to increase biological
productivity, while serving as a ___5___
for carbon dioxide drawback and sequestration of
particulate carbon as it sinks into the deep sea. |