Caribbean Compass Yachting Magazine January 2016

JANUARY 2016 CARIBBEAN COMPASS PAGE 10
Caribbean ECO-News
Shipboard Samples Provide Sargasso Updates
Massive quantities of Sargassum, a distinctive brown
seaweed, have flooded Caribbean shores in recent
years, setting off local concerns about economic
impacts on fishing and tourism. Trinidad & Tobago
has even declared these so-called “inundation events”
to be a natural disaster. But little is understood about
the ecological implications of these Sargassum invasions
or how they should be managed. New research
published by Sea Education Association, a leading
ocean education and research institution based in
Woods Hole, Massachusetts, provides first-hand observations
in support of these questions.
In the September 2015 issue of the journal
Oceanography, Drs. Jeffrey Schell, Amy Siuda and
Deb Goodwin, all SEA Semester oceanography faculty
members, report the results of shipboard sampling
during and after the latest Caribbean inundation event
in 2014 and 2015.
Major findings include:
• PREVIOUSLY RARE TYPE: According to most existing
resources, open-ocean forms of Sargassum consist
of two main species: S. fluitans and S. natans, distinguished
by their differing stems, blades and bladders.
Decades of SEA sampling had indicated that two
Sargassum forms within those species, S. natans I Parr
and S. fluitans Parr were the most common in the
North Atlantic, Caribbean Sea, and Gulf of Mexico.
However, in their latest fieldwork, SEA researchers
found that a third form — S. natans VIII Parr — dominated
the Western Tropical Atlantic, Eastern Caribbean,
The tall ship Corwith Cramer carried researchers from the Canary Islands to the Eastern Caribbean and then
up to the US East Coast to gather data on the unprecedented 2014-2015 sargassum inundation
and Antilles. This abundance was significant because
in the past this form rarely appeared in these areas.
• UNEXPECTED SOURCE: Based on the abundance
and forms of Sargassum found through their net
sampling, SEA researchers concluded that the
Sargasso Sea, a vast region of the North Atlantic
Ocean long known for hosting the biologically-important
seaweed, has no connection to the recent
Caribbean inundation events.
While S. natans VIII dominated the Caribbean samples,
a different type of seaweed, S. natans I, dominated
the South Sargasso Sea. These findings support
the theory proposed by other scientists that the
Sargassum washing ashore on Caribbean beaches is
coming from another location, such as a more southern
portion of the Atlantic known as the North
Equatorial Recirculation Region.
• UNPRECEDENTED AMOUNTS: SEA research found
that the average concentration of all Sargassum forms
combined was ten times greater in samples collected
during autumn 2014 than those analyzed during a
previous 2011-12 inundation event — and a whopping
300 times greater than that of any other autumn over
the last two decades of SEA research. Therefore, SEA
researchers concluded that the 2014-15 Caribbean
inundation event was truly unprecedented.
Data for this study was collected by SEA faculty,
crew, and SEA Semester undergraduate students on
board the institution’s 135-foot tall sailing ship, the
SSV Corwith Cramer, from November 2014 to May
2015. Cruises began in the Canary Islands, traversed
the Sargasso Sea and Western Tropical Atlantic to the
Lesser Antilles, and then sailed the Eastern Caribbean
before heading to New England.
SEA researchers have been studying Sargassum in
the field for about four decades in an effort to understand
more fully the ecosystems that rely upon this
floating seaweed. SEA’s datasets are extraordinary in
that they represent the only long-term quantitative
record of Sargassum abundance before and during
these Caribbean inundation events. The authors of
this study note: “pressing future questions include the
ecological impacts of inundation events on coral reefs,
sea turtles and fisheries. Continued Sargassum field
observations are essential to these efforts.”
In an effort to better understand critical aspects of
this phenomenon, the University of Southern
Mississippi research team is accepting reports from
cruisers in the Atlantic who come across large quantities
of Pelagic Sargassum. Data received will help
researchers identify the source and examine the movements
and causes of this extraordinary event. Data
can be submitted via the web or by e-mail.
Web: USM Website - use this form to report your
sightings: www.usm.edu/gcrl/sargassum/sargassum.
observation.form.php
E-mail: For yachts at sea who only have e-mail capability,
Joan Conover of the SCCA has volunteered to receive
feedback and post it to the Research website. E-mail
sargasso@sv-growltiger.com with the following findings:
• Lat/Long from GPS
• Date and Time
• Description (to include direction of surface currents,
approximate size, number of mats, observations
of marine life)
• Photo (if possible)
The Sargasso Sea Commission is also interested in
photographs of Sargasso weed as well as feedback on
large mat sightings from cruisers in the Sargasso Sea
area. Sightings from this area should be posted directly
to the USM website (as above).
Meanwhile, participants in Caribbean-bound rallies
last fall also helped collect information. Andrew Bishop,
Managing Director of World Cruising Club, organisers of
ARC Caribbean 1500, ARC+ and ARC, commented, “In
ARC 2014, cruisers reported seeing large clumps of
Sargasso weed on approach to the Cape Verdes.
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