u.s. virgin islands as a pdf

U.S. Virgin Islands Seeing
Site-specific decline
in Coral Communities
ABOVE LEFT: FIG.11 - Collection of marine surface sediment and porewater in Hawksnest Bay.
ABOVE RIGHT: FIG.13 - Trunk Bay, St. John, U.S Virgin Islands
BELOW: FIG.14 - Trunk Bay, St. John, U.S Virgin Islands. Photo courtesy of Rafe Boulon.
ABOVE: FIG.9 - Frank Bay, St. John, USVI. Large Acropora palmata colony photographed in October
2008 that was later discovered to be nearly demolished in June 2009. Skeleton for this species at this site is
extreme weak and brittle. None of the broken branches from this colony survived, resulting in a complete
failure of asexual fragmentation dispersal.
U.S. Virgin Islands
Coral communities along the coast of the U.S. Virgin Islands have exhibited site-specific
behavior in declines (Fig 1). Since 2005, we have been investigating these declines (Fig.
2). In order to determine if these specific coral communities are stressed and whether a
pollutant or environmental factor present at this site is a probable stressor, we surveyed
seven near-shore coral communities in St.
John, a site on St. James Island, and a site
on St. Thomas Island for environmental
pollutants and to determine the cellular
physiological condition of corals. Six of
the seven sites within St. John are Cruz
Bay, Caneel Bay, Hawksnest Bay, Trunk
Bay, Tektite Reef in Beehive Bay, and
Red Point (Fig. 3). Red Point was considered the reference site because of its
abundance and diversity of species, and
it was the furthest removed from downstream and down-current anthropogenic
activities. All of the sites showed distinct
cellular-stress marker patterns, indicating
that the physiological condition of each
population was different – that corals
at the different sites were responding to
different types of stressors. Populations
at Cruz, Hawksnest, Trunk, and Tektite
exhibited definitive physiological duress, as indicated by high levels of DNA
lesions and expression of stress proteins
(Fig. 4 & Fig. 5). Their physiological
profiles were consistent with corals that
would have difficulty reproducing sexually and asexually, as well as resisting infectious disease or healing from wounds.
As predicted, corals at these sites would
not regenerate from wounds for over
three years. Healthy corals inflicted with
a 1cm2 wound should be completely
healed in a year. Corals from Caneel,
Hawksnest, Cruz, Trunk and Tektite did
not regenerate any of their wounds within
three years (Fig. 6). Coral have also
experienced sexual reproductive pathologies at all of the USVI sites that we have
studied (Fig. 7 & Fig. 8). Furthermore,
the skeleton of Acropora palmata, usually
one of the hardest Caribbean coral skeletons, was weak and brittle at many of
the sites, making them extremely suscepABOVE: FIG.1a, 1b and 1c - Dying reefs
in the U.S. Virgin Islands
tible to storm and other forms of physical
damage (Fig. 9).
Hawksnest and Tektite were contaminated with polyaromatic hydrocarbons
(PAHs), while Cruz was contaminated
with semi-volatile organochlorines and
nitrogen-based biocides (See Downs et
al., 2011). At least for Hawksnest and
Tektite, some of the stress-marker patterns were consistent with an exposure
to an organo-pollutant. Fecal coliform
levels were high in Cruz and Trunk,
indicating fecal contamination and were
high enough that they were above action
levels for management intervention (Fig.
10). Further information concerning this
work can be found in:
Downs, C.A., Woodley, C.M., Fauth,
J.E., Knutson, S., Burtscher, M., May,
L., Avadanei, A., Higgins, J., Ostrander,
G.K. (2011). A survey of environmental
pollutants and cellular-stress biomarkers of Porites astreoides at six sites in St.
John, U.S. Virgin Islands. Ecotoxicology
20:1914-1931.
ABOVE: FIG.8 - A degenerate egg cell from an Acorpora palamata colony in the U.S. Virgin Islands.
BELOW: FIG.6 - Two lesions on a colony of
Porites astreoides from Trunk Bay, St. John, U.S. Virgin
Islands. These two lesions have not healed in three
years and are actually larger by about 25% when the
photograph was taken compared to the initial size of the
lesion.
In 2010, in collaboration with the U.S.
National Oceanic & Atmospheric Administration and with a student intern
from Sweet Briar College, we examined
the hypothesis that boat anti-foulant
paint associated with the mooring field
in Hawksnest Bay, St. John could be a
threat to corals and coral reefs within the
Bay. Sediment samples were collected
on land within the Hawksnest watershed,
as well as in the Bay (Fig. 11). Samples
were subject to contaminant chemistry analysis, as well as porewater toxicity assay using
cultured cells of laboratory grown Acropora cervicornis. Results from our study indicated
high levels of copper (component of cuprous oxide anti-foulant paint) and breakdown
products of tributyl tin within the mooring field, and progressively lower concentrations
of these compounds the further away from the mooring field (Fig. 12). Furthermore, data
from the porewater toxicity assay indicated highly toxic and lethal responses of culture
coral cells from porewater taken from within the mooring field, and lethality progressively
decreased the further away from the mooring field (Fig. 12).
We are currently examining the decline of corals in Trunk Bay (Fig. 13). Corals at Trunk
do not regenerate from wounds (Fig. 6), and there is very little recruitment of juvenile coral
to this area. Locals suggested to us that the massive density of visitors to this small beach
could be a contributing factor to coral morbidities and mortalities (Fig. 14).
ABOVE: FIG.4 - Canonical analysis of cellular diagnostic “biomarkers” and the six populations of Porites
astreoides on St. John, U.S. Virgin Islands.
BELOW: FIG.2 - Dr. John Fauth of the University of Central Florida collecting data.
ABOVE: FIG.3 - Six of the seven field sites in St. John, U.S. Virgin Islands
BELOW: FIG.7 - Histopathology of Acropora palmata from three different sites in the U.S. Virgin Islands.
All four samples were collected within seven days of each other. The GTMO reference is what healthy looking tissue should look like. The arrows point to healthy eggs (Ova) and reside adjacent to healthy spermaries.
Most corals that we examined in the U.S. Virgin Islands were sterile – they had no reproductive tissue. Other
coral in the U.S. Virgin Islands had Ova that were present, but non-viable.
ABOVE: FIG.5 - Levels of a DNA lesion in six populations of Porites astreoides on St. John, U.S. Virgin
Islands. High-levels of this type of DNA damage can result in an increase risk to genetic mutation, reduction
in reproductive viability and effort, and a decrease in coral resistance to infectious diseases.
BELOW: FIG.12 - Location of samples collected, and the concentrations of total copper and total tin from
those samples. Measurement of copper (Cu) and tin were proxies for concentration of cuprous oxide and
tributyl tin (TBT) species. MBT = the concentration on monobutyl tin, a breakdown product of TBT. Porewater toxicity % indicates the number of Acropora cervicornis coral cells that died after exposure to porewater from sediment collected at those locations.
ABOVE: FIG.10 - Top panel shows the relationship between tidal stage and bacterial counts recovered. Total
coliform (TC/100 ml) and Escherichia coli (E.coli/100 ml) were sampled at Cruz Bay to determine optimal
collection times. Bars show untransformed means (±SE), n = three water samples per site. Lower panel
shows Total coliform (TC/100 ml), fecal coliform (FC/100 ml), Escherichia coli (E.coli/100 ml) and (microscopic) bacterial direct counts (BDC 9 104/ml) for three different sampling sites (Cruz Bay, Caneel Bay and
Trunk Bay), Bars show untransformed means (±SE), n = two water samples per site.
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