Why is The Vieques Mosquito Bay so brightly Bioluminescent?
A Delicate Balancing Act:
create a bioluminescent bay you need a lagoon surrounded
by Red Mangroves (which occur in the tropics and semi
tropics only). The roots of the red mangroves release
tannins that are rich in Vitamin B12, one of the important
nutrients for these light emitting dinoflagellates. The
decomposing mangrove leaves release many other nutrients
which add to the nutrient rich environment.
Bay must also be relatively free of pollution, which generally
requires protected lands surrounding the bay. Special
zoning for all the land in the watershed of the biobay
is essential. The zoning must assure sufficient forest
cover to hold back the sediment whenever there is significant
Bay requires enough size and depth to enable the water
to stay relatively cool in the daytime, it does, however,
remain warmer than the ocean outside. It also requires
a restrictive channel to the ocean, with a relatively
small tidal exchange. This biobay has the channel to the
ocean at the windward end of the bay which may also serve
to restrict the outflow of the dinoflagellates to the
sea as the tide goes out, while allowing sufficient water
exchange to avoid overheating and stagnancy.
alterations to the size of the channel to the ocean (such
as shallower or deeper or wider) can destroy a biobay.
Pollution flowing into the bay from chemicals in groundwater
and flood waters can ruin a biobay. Sufficient fluorocarbons
from motorboats adversely affects the bioluminescent dinoflagellates,
as would waste from any boats anchored in the bay. People
swimming, who have sprayed themselves with DEET, adversely
affect the biobay.
seen from the bay and ambient light in the sky ( reflected
from clouds) greatly reduce the visibility of the bioluminescence
at night. It is a real treat to be in the biobay when
the electricity goes out on the island! It is also considerably
better to see the biobay when there is no moon visible
in the sky.
why is this particular biobay (perhaps) the brightest
in the world? Because all these factors are perfectly
balanced, creating ideal circumstances for a constant
'super bloom' of Pyrodinium bahamense dinoflagellates,
over 700,000 per gallon of water!
fragile is this ecosystem? Well, the factors being constant,
this bay recreates itself continuously (for now). A recent
rainfall, of over 30 inches, poured sediment into the
bay turning it into a giant mud puddle... and killed most
of the dinoflagellates. The sediment flushed out with
the tides over a few weeks period, the dinoflagellates
reproduced like crazy, and repopulated themselves, and
the bay became, just as bright all over again.
important factors need control to protect the bay:
Too much sediment is washing out of the hills above, due
to lack of forest ground cover. This sediment is building
up in the biobay and the bay is changing slowly. However,
should agricultural chemicals to be added to the sediment
it would dramatically destroy the dinoflagellates.
An increase in motorboats entering the bay, especially
any boats overnighting in the bay, adding fluorocarbons
and sewage containing human bacteria.
Increasing light pollution in the nearby hills.
legislature of Puerto Rico needs to look into the protection
needed for the biobays of Puerto Rico, or the Biobay needs
the protection of becoming a United Nations Biosphere
Reserve. In short the legislature of PR must pass specific
laws of protection to insure the continuation of a biobay
into the modern, developing world.
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