International Journal of Marine Science, 2016, Vol.6, No.21, 1-20
4
patch reef groups while Western Head and Cliff Green are singular patch reefs (see Lidz et al. (2007) for mapping
and description of these patch reefs). Offshore reefs included Sand Key, Rock Key, Eastern Sambo, Looe Key, and
Sombrero Key. Each of these offshore bank reefs is characterized by spur and groove formations preceded inshore
by patch reefs.
2.2 Coral Community Characteristics at Inshore and Offshore Reefs
Colony size and abundance of corals were assessed biannually from 2011 to 2013 using photo-transects
established at our inshore patch reef site (Birthday reef: 24.57917’ N, -81.49692’ W) and offshore bank reef site
(Acer 24 reef: 24.55268’ N, -81.43741’ W), both located at depths of 6.5 m (Figure 1). Assessments were
conducted by divers using self-contained underwater breathing apparatus (SCUBA) during winter (February) and
summer (August) seasons. Divers photographed the benthos at random non-overlapping points (n = 15) along 30
m transects (n = 3) with a Nikon D5100 (Nikon Inc., Melville, NY) camera affixed to a 0.5 x 0.5 m quadrapod
(Coyer et al., 1999). Lighting was supplied by a Fantasea NanoFlash strobe (Fantasea, Blaine, WA). Transects
were measured using surveyor tape and extended out from a central location (the reciprocal transplant location at
each reef) in three randomly assigned directions. Each direction was selected with a random number generator
sampling points between 0 and 360 in increments of 5. The photo-quadrat method has been shown to be the most
cost effective method to assess coral and sessile benthic communities without sacrificing accuracy (Leujak and
Ormond, 2007). Images were analyzed using Coral Point Count with Excel (CPCe) extensions (Kohler and Gill,
2006). Coral species richness, abundance, area, percent cover, as well as benthos composition including coral,
sponge, algae, sand, and rubble were determined. Further, all individual
Montastraea cavernosa
and
Porites
astreoides
colonies within 1 m of transect were analyzed for photosynthetic capacity using a Diving Pulse
Amplitude Flourometer (PAM: Walz). We were unable to assess field corals in a dark adapted state and therefore
obtained the effective quantum yield of photochemical energy conversion (ΔF/F
m
ˊ). The change in F (ΔF)
represents the change in fluorescence from the maximal fluorescent yield of the coral in an illuminated
environment (F
m
ˊ) following a saturating pulse from the instrument. The use of these two measurements has been
found to be highly correlate with quantum yield (Genty et al., 1989). The effective quantum yield was determined
at the apex of colonies with the fiber quantum sensor held within the Surface Holder, to maintain a distance of 10
mm between it and the colony tissue (Cervino et al., 2012).
2.3 Location-Dependent Colony Brightness, a Bleaching Characteristic
Following the identification of species characteristic of the inshore patch reef and offshore bank reef systems, a
reciprocal transplant was carried out between Birthday Reef and Acer 24 with two species of coral,
M. cavernosa
and
P. astreoides
. Coral fragments (n=10; 16 x 16 cm) of both species were collected from colonies at least 10 m
apart at each reef using a steel mallet and cold chisel. Permission for field work at Birthday Reef and Acer 24 was
granted by National Oceanic and Atmospheric Administration National Marine Sanctuaries (Permit #
FKNMS-2011-107). Fragments were transferred in large coolers filled with site-derived water to the Mote Marine
Laboratory Tropical Research Laboratory (MML), where they were immediately sectioned into two 8 x 8 cm
fragments with a tile saw lubricated and cooled with sterile artificial sea water (Instant Ocean) sprayed on the
blade with a wash bottle. Following sectioning, fragments were transferred to MML flow-through seawater
raceways. Raceways were shaded from direct sunlight to decrease stress. Following 2 days of recovery, fragments
were attached to pucks (1 part concrete: 3 parts aragonite sand) with a two-part epoxy (All Fix Epoxy;
Philadelphia, PA USA). After another 3 days of recovery, corals were transferred in large coolers filled with
seawater from the MML flow-through system, to each field site. To complete the reciprocal transplant, ½ of each
colony was returned to the site of collection as a control and the other ½ transplanted to the alternate site. Each
field site consisted of 6 concrete blocks affixed to the calcium carbonate substrate using a 1 part plaster: 2 parts
concrete mixture in a hexagonal shape. Each concrete block consisted of 6-7 randomly assigned coral fragments
of a single species. Fragments were attached to each block with All Fix Epoxy. Neighboring blocks harbored
different species. We observed growth/ skeletal accretion in all coral fragments during the study, indicating that
the sampling and transplant procedures employed did not greatly impact coral physiology.
