It's that time of year again. If you
talk to most tour guides, they'll tell you that they've experienced it
and have likely known quite a few people who have also. Every spring,
cases of "Pica Pica" run rampant, and this season is no different. With a
name meaning "itchy itchy" this annual phenomenon makes its presence
known on the skin of divers and snorkelers with a rash similar to chicken
pox. While the resulting rash is completely harmless, it is nonetheless
uncomfortable and can last up to ten days. With the continued increase of
Pica Pica outbreaks over the past few years, scientific research has
helped identify the varying origins of this phenomenon and how it can
best be recognized and avoided.
The majority of Pica Pica cases were
originally thought to be the result of spherical thimble jellyfish blooms
that contain millions of unseen juvenile jellyfish. These creatures have
a medusa, which bear nematocysts, poisonous microscopic structures that
are activated by physical contact. While some cases of Pica Pica may
result from these blooms, current research claims that there is an
increase of cases resulting from cyanobacterial toxins in particular,
Trichodesmium in the water.
Dr. Gary Gaston, a Professor of Biology at the
University of Mississippi has spent a significant amount of time in
Belize, particularly around the South Water Caye area, and has witnessed
an increase of Trichodesmium over the years. This type of blue-green
algae blooms in a manner similar to that of jellyfish, resulting in a
scattering of what is known as "sea sawdust" on the ocean surface. This
algae has the ability to produce an array of potent toxins, all of which
can have an adverse affect on humans who come into contact with it.
Unlike the rash resulting from jellyfish blooms, this type of Pica Pica
does not respond to topical home remedies of ammonia or vinegar;
unfortunately, it responds to almost nothing at all for seven to ten
days.
Skin rashes are not the only problem that result from
Trichodesmium. Around the world, these algae blooms have also been linked
to liver and pulmonary damage, as well as gastrointestinal illnesses in
humans. Furthermore, because these blooms can occur in both marine and
freshwater environments, they can have a potentially adverse affect on
drinking water supplies and freshwater fisheries. There have also been
worldwide outbreaks that have poisoned farm animals, birds and
fish.
Interestingly, despite the negative effects of
Trichodesmium blooms, they may play an important role in slowing down
global warming. While it grows, Trichodesmium uses photosynthesis to
remove carbon dioxide (a damaging greenhouse gas) from the atmosphere.
Likewise, Trichodesmium has the ability to remove nitrogen from the
atmosphere and use it for nourishment. Thus, Trichodesmium plays a
critical role in keeping these gases in check and quite possibly delaying
the progression of global warming.
Clearly, further research about Trichodesmium algae
blooms is needed to learn more about its potentially positive and
negative effects. At the very least, we know enough now to possibly avoid
contact with the blooms (patches of "sawdust") and prevent this type of
Pica Pica from occurring.
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