11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 16: Ecosystem Assessment and Monitoring of Coral Reefs - New Technologies and Approaches
16-5
Development and Application of Variable Fluorescence Techniques and
Instrumentation for Monitoring and Assessing Coral Reefs
Maxim GORBUNOV* 1 , Dan TCHERNOV 2 , Liti HARAMATY 3 , Yael HELMAN 3 ,
Frank NATALE 3 , Sophia JOHNSON 3 , Paul FALKOWSKI 3
1 Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, 2 The
Interuniversity Institute of Eilat, The Hebrew University of Jerusalem, Eilat, Israel,
3 Rutgers University, New Brunswick, NJ
The development of advanced technologies for environmental monitoring of coral reef
ecosystems requires an understanding of how different environmental factors affect the
key elements of the ecosystems and the selection of specific monitoring protocols that are
most appropriate for the identification and quantification of particular stressors.
Documenting the environmental state of reef communities is critical to developing
remediation strategies that can both reduce anthropogenic insult and distinguish between
common natural factors and anthropogenic stressors. Bio-optical methods are
particularly useful for rapid and non-destructive assessment of the viability of coral reef
organisms. Here we present a methodology and instrumentation called Fluorescence
Induction and Relaxation (FIRe) System for assessment of photosynthetic and
physiological status of coral. We have designed and developed bench-top, diver-operated
and moorable instruments. The variable fluorescence technique relies on the relationship
between chlorophyll fluorescence yield and the efficiency of photosynthetic processes
and provides a comprehensive suite of photosynthetic and physiological parameters,
including the quantum yields of photochemistry in Photosystem II (PSII), the functional
absorption cross section of PSII, the rates of photosynthetic electron transport on the
acceptor side of PSII and between PSII and PSI, coefficients of photochemical and nonphotochemical
quenching. In combination with conventional biochemical and molecular
biological methods, the FIRe technique was employed to study the impact of common
natural stresses (episodes of elevated temperature and excess irradiance), as well as
selected anthropogenic factors (heavy metal contamination and pollution) on coral. The
analysis revealed that different stressors lead to specific damage to the coral symbioses
and are characterized by unique FIRe fluorescence signatures that can be can be used for
quantitative assessment of coral health and selective identification of the stressors.
16-6
Potential Application Of Pam Fluorometry in Reactive Coral Health Monitoring
Programs: A Pilot Study
Jeremy SOFONIA* 1
1 Marine and Coastal Science, Sinclair Knight Merz Pty. Ltd., Perth, Australia
Regulatory authorities in Australia increasingly require proponents of commercial
development to detect, and respond to, changes in water quality and coral heath prior to
the onset of mortality. The use of pulse-amplitude modulated (PAM) fluorometry as an
instrument to detect sub-lethal change within photosynthetic organisms is well
documented, however, the use of this tool on scleractinian corals in-situ is challenging as
ambient environmental conditions directly affect the measured result, monitoring is often
restricted to daylight hours and dark adaptation of individual colonies logistically
difficult. The use of PAM in reactive coral health monitoring programs is currently
limited as sampling is implemented on a set schedule, under a wide range of ambient
conditions, and often comprising large coral populations over a wide geographic area.
Here two photosynthetic corals, Turbinaria mesenterina and Porites lobata, are observed
in-situ across a natural range of light (0 – 320 µmol m-2 s-1) and temperature (18.9 –
30.0 °C). Three fluorescence parameters were estimated including effective quantum
yield of photosystem II (ΦpsII), slope of the initial linear range, alpha (α), of the
photosynthesis-irradiance (P-I) curve and the maximum relative electron transport rate
(rETRmax). Of these, obtaining ΦpsII was comparitively faster and better correlated to
changes in ambient light (PARamb). Mean ΦpsII was significantly higher in T.
mesenterina than P. lobata in both regimes, however, responses to PARamb were
virtually identical (T. mesenterina: y= -0.0011x + 0.668, R2= 0.59; P. lobata: y= -
0.0009x + 0.621, R2= 0.67) and temperature had no significant effect. The use of α and
rETRmax from so-called rapid light curves (RCL) were comparatively non-informative
and logistically restrictive. It is hypothesised that specific correlations between ΦpsII and
PARamb, if established prior to development, may be used as a benchmark to compare
the photosynthetic condition of coral symbiotes and potentially provide a rapid
assessment of sub-lethal change.
16-7
A Comparison Of Thermal History And fv/fm in Inner Lagoon And Outer Barrier Reef
montastrea Faveolata.
Karl CASTILLO* 1
1 Marine Science Program, University Of South Carolina, Columbia, SC
Pulse amplitude modulated (PAM) fluorometry has been suggested as a tool to complement
monitoring efforts for predicting environmental stress in corals. However, documented changes
in maximum quantum yields (Fv/Fm) of corals during non-bleaching periods have been limited.
Here, thermal exposures of inner lagoon and outer barrier reef Montastrea faveolata were
examined. The hypothesis that inferred differences in thermal histories would be reflected in
Fv/Fm values was tested. Ambient seawater temperatures adjacent to corals at 1, 3, 6, 9 and 15
m depth were measured every 10 min from October 2006 to June 2007 in the inner and outer
reefs of southern Belize. Maximum and mean diel seawater temperature and number days
above the local bleaching threshold of 29.8 °C were not significantly different between
locations and across each depth. However, minimum and standard error of the mean diel
seawater were significantly different between locations and across several depths. Since aspects
of seawater temperature varied across locations and depths, the photophysiology of these corals
was assessed to test for an association between physical and biotic factors. In June 2007, Fv/Fm
for M. faveolata were measured in situ across the same gradient and compared between both
locations. Fv/Fm correlated positively with depth in both locations, and was significantly higher
in the inner reefs. To test for a cause-and-effect relationship between temperature and
photophysiology, samples of M. faveolata were collected and exposed to controlled temperature
treatments. Exposure to elevated temperature caused Fv/Fm to be depressed to a greater extent in
corals from the outer compared to inner reef, but this effect was not constant at all depths.
These results suggest that thermal stress though important may not be the only factor
influencing the observed difference in Fv/Fm values for M. faveolata from the inner lagoon and
outer barrier reefs at this location.
16-8
Shifting Bleaching Thresholds: Acclimatization Or A Flawed Model?
Ray BERKELMANS* 1
1 Australian Institute of Marine Science, Townsville, Australia
Time-integrated bleaching thresholds are one of a suite of locally specific bleaching indices that
have been developed based on in situ measured temperature data. In recent years these have
been adopted as an early warning system on the Great Barrier Reef (GBR), augmented by
satellite-based early warning systems such as ‘HotSpots’ and ‘ReefTemp’. The original
bleaching thresholds were developed after the 1998 bleaching event, but how well have they
performed since then, especially in predicting the 2002 GBR bleaching event? This study
reviews the efficacy and accuracy of the time-integrated bleaching thresholds using statistical
and empirical techniques. The results show that time-integrated bleaching thresholds accurately
predicted bleaching (and non-bleaching) at most reefs in 2002. However, a number of reefs in
the central GBR exceeded bleaching thresholds in 2004 and 2005 without bleaching. These
anomalies are not explained by selective mortality or other meteorological factors, including
global radiation and UV. They are also not explained by pre-season acclimatization. Long-term
thermal acclimatization remains the most likely explanation. Mortality thresholds based on 50%
mortality of thermally sensitive and locally abundant coral taxa were derived for six reefs that
suffered high mortality during past bleaching events. An analysis of these curves in relation to
their bleaching thresholds indicates that at most of these sites thermally sensitive taxa die