Geoscience Reference
In-Depth Information
As carbon dioxide is dissolved in seawater, it forms carbonic acid. This process
is called ocean acidi
cation and is thought to have a major impact on the ability
of many marine organisms to build their shells and skeletal structures. Since the
beginning of the Industrial Revolution 250 years ago, seawater acidity has increased
by 30%. If present trends continue, by 2060 the acidity of the oceans will be greater
than anything experienced in the past 20million years. The major research focus
to date has been on the possible increased dissolution of skeletal material, as the
current rate of change is many times faster than anything experienced in the last
55million years and animals and plants may not be able to adapt to changing
conditions. Major changes in phytoplankton assemblages are likely to occur too.
Under increased carbon dioxide conditions, some species of phytoplankton will
grow more effectively, whereas others will be less successful owing to the
increased acidity. As phytoplankton underpin the entire ecosystem, major impacts
are possible but the current level of understanding is low, so no reliable predictions
are possible. Since much more carbon dioxide is dissolved in cold water compared
with the warm tropical regions, the impacts in the polar regions of ocean
acidi
cation are likely to be much more immediate and more signi
cant.
Increased acidi
cation improves the propagation of sound
-
it could increase
by as much as 70% by 2060. Thus whales and dolphins will
find it harder to navigate
and communicate as the ocean becomes noisier, natural noises will be louder
and there is an ever-increasing number of anthropogenic sources including drilling,
sonar and boat engines.
Antarctica is physically remote, inhospitable, unpredictable and potentially
dangerous, but as such captures the imagination of young and old alike, through the
heroic exploits of the early explorers, the amazingly beautiful landscapes, the near-
pristine environment and the characteristics of iconic species, such as penguins,
albatrosses, whales and seals. Antarctica is the world
'
is largest wilderness and as
a result has high aesthetic value in many cultures.
Tourism in Antarctica started in the 1950s, and the industry has grown
steadily over the intervening decades with numbers reaching about 33 000 in
2010
11 arriving by sea, or air. Most of the tour operators are members of the
International Association of Antarctica Tour Operators (IAATO), which has a strict,
but voluntary, code of conduct to minimise the impact on the environment and the
wildlife. Also currently most tourism is focussed on a very small number of sites.
Increasing travel of humans to Antarctica, both for science and tourism,
combined with climate change, enhance the possibility of new species being
introduced despite the climate being inhospitable. Perhaps the most challenging
area concerns viruses, bacteria, yeasts, fungi and micro-algae. Globally these
micro-organisms represent more than 90% of the species diversity, yet in Antarctica
there are few measurements and no
-
firm baselines from which to determine change,
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