top, Anda Greeney ’07 and Suzanne O’Connell, associate professor of earth
and environmental sciences, prepare to deploy a bathyphotometer, an
instrument that measures bioluminescence, into a bay in Vieques, an island
off Puerto Rico.
At right, Tim Ku,
assistant professor of earth and environmental sciences, shows students how
to drill a core sample in a bay they are studying.
Research Team Studies Bioluminescent Bays in Puerto Rico
Ten miles off the east coast of Puerto Rico, on
the island of Vieques, three mangrove-lined bays are illuminated with
unicellular marine life known as dinoflagellates. One of the bays has an
unusually high abundance of these microscopic creatures that produce their
own light through bioluminescence, a chemical reaction similar to the one
that makes fireflies glow.
But why do these colorful creatures thrive so well in these bays? That is
the question Suzanne O’Connell, associate professor of earth and
environmental sciences and Tim Ku, assistant professor of earth and
environmental sciences, want to answer.
As part of a grant-funded research study, O’Connell, Ku and Anna Martini of
Amherst College took 13 students from eight colleges, including Anda Greeney
’07, Andrea Pain ’08 and Ulyana Sorokopoud ’08, to the Puerto Rican island
for a two-week intensive study. The trip was succeeded by two weeks of lab
analyses at Wesleyan and Amherst.
“This ecosystem is so special and we’re curious to know why so many
dinoflagellates live here,” Ku says, browsing through digital photos of the
turquoise-water bays. “It’s most likely very fragile. We hope to learn what
could destroy them, and also, how to maintain a bay that supports this type
The study, supported by the Keck Geology Consortium (now funded by the
National Science Foundation), began June 17. The students and researchers
hauled along their necessary research equipment to the Caribbean, including
sediment core samplers, water quality monitors and centrifuges.
rented a house on the ocean, living on the top floor and using the main
floor as a laboratory. Ku and O’Connell taught classes on the front porch,
overlooking the water.
Every day, the group drove to the south-central side of Vieques, and studied
the Puerto Mosquito, Puerto Ferro and Bahia Topin bays, each less than a
mile apart from each other. The researchers studied the hydrodynamics of the
water, present-day and past sediment sources, nutrient and metal cycles, and
satellite imagery to see how the area has changed through anthropogenic
development and hurricane activity. Studies were conducted by wading,
snorkeling, kayaking or and boating in the bays, and core samples were taken
of the layered sediment. These samples will be the basis of the student
research throughout the year on campus.
Ku says the most bioluminescent bays in Vieques have a narrow opening to the
ocean to maintain the necessary balance of temperature and water flow and;
the surrounding mangroves may supply other key nutrients to feed the
dinoflagellates. In addition, a nearby salt flat may be crucial in providing
proper nutrients. On the neighboring island Jamaica, a bioluminescent bay no
longer glows at night when developers decided to build a hotel in the salt
flats to better see the bay.
“To conserve these fragile environments we need to understand how they
function and how they respond to environmental threats,” O’Connell says.
The bays are a unique find, world-wide. For more than 60 years, they’ve have
been untouched by developers. The U.S. Navy used sections of the island for
military exercises, blocking access to the bays. In 2003, the land was
transferred from the Navy to the U.S. Department of Fishing and Wildlife to
become a wildlife refuge. Although the lack of development kept the area
pristine, pollution from the Navy’s bombing residues is being studied and
activities and plans are underway to clean-up material left by the Navy.
it’s not only the toxic pollution that concerns the researchers. It's
actually light pollution encroaching on the bays. Light beaming from a full
moon alone is enough to hide the brilliant bioluminescence. There are
pressures from both individuals and the Puerto Rican government to develop
the hills above the bay and in the public beach area to the west.
Wesleyan students Greeney, Pain and Sorokopoud, who were funded in-part by
the Mellon and Hughes programs, will continue their research during the
academic year. They’ve returned home with core samples, which will be
examined in depth inside Wesleyan laboratories. O’Connell and Ku hope to
obtain additional grant funding in the future to continue studying the
O’Connell made her first trip to Vieques seven years ago and returns each
year, most recently to teach courses in the Graduate Liberal Studies
“Once I saw these bays, I fell in love with them, and I want to study them
and preserve them,” she says.
|By Olivia Bartlett, Wesleyan
Connection editor. Photos contributed by Tim Ku and Suzanne O'Connell.