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Kline, DI, Teneva L, Schneider K, Miard T, Chai A, Marker M, Headley K, Opdyke B, Nash M, Valetich M, Caves JK, Russell BD, Connell SD, Kirkwood BJ, Brewer P, Peltzer E, Silverman J, Caldeira K, Dunbar RB, Koseff JR, Monismith SG, Mitchell BG, Dove S, Hoegh-Guldberg O.  2012.  A short-term in situ CO2 enrichment experiment on Heron Island (GBR). Scientific Reports. 2   10.1038/srep00413   AbstractWebsite

Ocean acidification poses multiple challenges for coral reefs on molecular to ecological scales, yet previous experimental studies of the impact of projected CO2 concentrations have mostly been done in aquarium systems with corals removed from their natural ecosystem and placed under artificial light and seawater conditions. The Coral-Proto Free Ocean Carbon Enrichment System (CP-FOCE) uses a network of sensors to monitor conditions within each flume and maintain experimental pH as an offset from environmental pH using feedback control on the injection of low pH seawater. Carbonate chemistry conditions maintained in the -0.06 and -0.22 pH offset treatments were significantly different than environmental conditions. The results from this short-term experiment suggest that the CP-FOCE is an important new experimental system to study in situ impacts of ocean acidification on coral reef ecosystems.

Kline, DI, Bryant J, Kisflaudy E, Rohwer G, Nostropaur F, Grayson J, Knowlton N, Rohwer F.  2006.  The aquatic automated dosing and maintenance system (AADAMS). Limnology and Oceanography-Methods. 4:184-192. AbstractWebsite

The maintenance and dosing of aquatic organisms, such as corals and mollusks, are essential for ecotoxicology studies, yet it is difficult to maintain many of these sensitive organisms for an extended period. Consequently, many previous aquatic ecotoxicology experiments have been limited in their number of replicates and maintained in one or a few experimental aquaria, with only a limited number of stressors tested in each experiment. Here we describe a modular system that overcomes many of the difficulties of maintaining large numbers of sensitive aquatic organisms in separate containers, and allows testing of a large suite of stressors in each experiment. The AADAMS (aquatic automated dosing and maintenance system) allows testing of 40 independent stressors with 10 independent replicates per stressor (400 individuals total). The AADAMS provides surge and regular water changes simultaneously with accurate dosing via Venturi valves. In a series of experiments over a 1-year period, the AADAMS was used to test the effects of various factors affecting water quality on Caribbean coral reefs. Roofing tar and road asphalt were two of the most damaging pollutants tested, with LD50 values (lethal dose that killed 50% of the corals) of 0.013 g L-1 and 0.079 g L-1, respectively, thus suggesting that runoff from roads and near-shore construction could be contributing to reef decline. The AADAMS is an accurate, reliable system for highly replicated ecotoxicological studies of sensitive aquatic organisms, which are important indicators of ecosystem health.

Kline, DI, Teneva L, Hauri C, Schneider K, Miard T, Chai A, Marker M, Dunbar R, Caldeira K, Lazar B.  2015.  Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies. PloS one. 10(6):e0127648.: Public Library of Science Abstract
Kline, DI, Vollmer SV.  2011.  White Band Disease (type I) of Endangered Caribbean Acroporid Corals is Caused by Pathogenic Bacteria. Scientific Reports. 1   10.1038/srep00007   AbstractWebsite

Diseases affecting coral reefs have increased exponentially over the last three decades and contributed to their decline, particularly in the Caribbean. In most cases, the responsible pathogens have not been isolated, often due to the difficulty in isolating and culturing marine bacteria. White Band Disease (WBD) has caused unprecedented declines in the Caribbean acroporid corals, resulting in their listings as threatened on the US Threatened and Endangered Species List and critically endangered on the IUCN Red List. Yet, despite the importance of WBD, the probable pathogen(s) have not yet been determined. Here we present in situ transmission data from a series of filtrate and antibiotic treatments of disease tissue that indicate that WBD is contagious and caused by bacterial pathogen(s). Additionally our data suggest that Ampicillin could be considered as a treatment for WBD (type I).

Kline, DI, Kuntz NM, Breitbart M, Knowlton N, Rohwer F.  2006.  Role of elevated organic carbon levels and microbial activity in coral mortality. Marine Ecology-Progress Series. 314:119-125.   10.3354/meps314119   AbstractWebsite

Coral reefs are suffering a long-term global decline, yet the causes remain contentious. The role of poor water quality in this decline is particularly unclear, with most previous studies providing only weak correlations between elevated nutrient levels and coral mortality. Here we experimentally show that routinely measured components of water quality (nitrate, phosphate, ammonia) do not cause substantial coral mortality. In contrast, dissolved organic carbon (DOC), which is rarely measured on reefs, does. Elevated DOC levels also accelerate the growth rate of microbes living in the corals' surface mucopolysaccharide layer by an order of magnitude, suggesting that mortality occurs due to a disruption of the balance between the coral and its associated microbiota. We propose a model by which elevated DOC levels cause Caribbean reefs to shift further from coral to macroalgal dominance. Increasing DOC levels on coral reefs should be recognized as a threat and routinely monitored.

Kuntz, NM, Kline DI, Sandin SA, Rohwer F.  2005.  Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species. Marine Ecology-Progress Series. 294:173-180.   10.3354/meps294173   AbstractWebsite

Anthropogenic inputs, including organic carbon and nutrient loading, are increasingly changing the water quality on coral reefs. Herein we show that treating Montastraea annularis, Agaricia tenuifolia and Porites furcata with various organic carbon sources (starch, lactose, arabinose and mannose) results in different species-specific and carbon-specific pathologies and rates of mortality. The variation in the pathological characteristics caused by stressors showed that visual cues for determining coral health and disease may be misleading. The probability of mortality increased significantly over time with continual exposure to several of the stressors, suggesting that chronic stressors may be more harmful than acute stressors. In contrast to the organic carbon sources, high concentrations of nutrients (phosphate, ammonium and nitrate) did not directly kill corals. The variation in coral responses to anthropogenic stressors means that changes on disturbed coral reefs will depend on the type of and duration of exposure to the stressor, as well as on the species of coral.

Levitan, DR, Fukami H, Jara J, Kline D, McGovern TM, McGhee KE, Swanson CA, Knowlton N.  2004.  Mechanisms of reproductive isolation among sympatric broadcast-spawning corals of the Montastraea annularis species complex. Evolution. 58:308-323.   10.1554/02-700   AbstractWebsite

Many coral species spawn simultaneously and have compatible gametes, leading to controversy over the nature of species boundaries and the frequency with which hybridization occurs. Three western Atlantic corals, Montastraea annularis, M. faveolata, and M. franksi, typify this controversy; they all spawn sympatrically on the same evenings after the fall full moons. Here we show, in both Panama and the Bahamas for multiple years, how a variety of mechanisms may act in concert to reproductively isolate all three species. Field studies indicate that M. franksi spawns two hours earlier than the other two species, and the eggs released during this earlier period disperse an average of 500 m by the time the other species spawn. Field measures of fertilization indicate that peak fertilization occurs when spawning synchrony is high and that corals that spawn at the tails of the spawning distributions have greatly reduced fertilization success. Laboratory studies indicate that there is a gametic incompatibility between M. faveolata and the other two species. There are regional differences in the gametic compatibility of M. franksi and M. annularis. In Panama, the two species are completely compatible, whereas in the Bahamas, M. franksi sperm can fertilize M. annularis eggs but the reciprocal cross often fails. Gamete age influences patterns of fertilization, such that very young eggs seem resistant to fertilization and old sperm lose viability after two hours. In sum, the combination of temporal differences in spawning, sperm aging, gamete dispersal and dilution, and gametic incompatibility act in various combinations among the three species, making it unlikely that hybrid fertilization would occur.

Mass, T, Kline DI, Roopin M, Veal CJ, Cohen S, Iluz D, Levy O.  2010.  The spectral quality of light is a key driver of photosynthesis and photoadaptation in Stylophora pistillata colonies from different depths in the Red Sea. Journal of Experimental Biology. 213:4084-4091.   10.1242/jeb.039891   AbstractWebsite

Depth zonation on coral reefs is largely driven by the amount of downwelling, photosynthetically active radiation (PAR) that is absorbed by the symbiotic algae (zooxanthellae) of corals. The minimum light requirements of zooxanthellae are related to both the total intensity of downwelling PAR and the spectral quality of the light. Here we used Stylophora pistillata colonies collected from shallow (3 m) and deep (40 m) water; colonies were placed in a respirometer under both ambient PAR irradiance and a filter that only transmits blue light. We found that the colonies exhibited a clear difference in their photosynthetic rates when illuminated under PAR and filtered blue light, with higher photosynthetic performance when deep colonies were exposed to blue light compared with full-spectrum PAR for the same light intensity and duration. By contrast, colonies from shallow water showed the opposite trend, with higher photosynthetic performances under full-spectrum PAR than under filtered blue light. These findings are supported by the absorption spectra of corals, with deeper colonies absorbing higher energy wavelengths than the shallow colonies, with different spectral signatures. Our results indicate that S. pistillata colonies are chromatically adapted to their surrounding light environment, with photoacclimation probably occurring via an increase in photosynthetic pigments rather than algal density. The spectral properties of the downwelling light are clearly a crucial component of photoacclimation that should be considered in future transplantation and photoacclimation studies.

Nash, MC, Troitzsch U, Opdyke BN, Trafford JM, Russell BD, Kline DI.  2011.  First discovery of dolomite and magnesite in living coralline algae and its geobiological implications. Biogeosciences. 8:3331-3340.   10.5194/bg-8-3331-2011   AbstractWebsite

Dolomite is a magnesium-rich carbonate mineral abundant in fossil carbonate reef platforms but surprisingly rare in modern sedimentary environments, a conundrum known as the "Dolomite Problem". Marine sedimentary dolomite has been interpreted to form by an unconfirmed, post-depositional diagenetic process, despite minimal experimental success at replicating this. Here we show that dolomite, accompanied by magnesite, forms within living crustose coralline alga, Hydrolithon onkodes, a prolific global tropical reef species. Chemical micro-analysis of the coralline skeleton reveals that not only are the cell walls calcitised, but that cell spaces are typically filled with magnesite, rimmed by dolomite, or both. Mineralogy was confirmed by X-ray Diffraction. Thus there are at least three mineral phases present (magnesium calcite, dolomite and magnesite) rather than one or two (magnesium calcite and brucite) as previously thought. Our results are consistent with dolomite occurrences in coralline algae rich environments in fossil reefs of the last 60 million years. We reveal that the standard method of removing organic material prior to Xray Diffraction analysis can result in a decrease in the most obvious dolomite and magnesite diffraction patterns and this may explain why the abundant protodolomite and magnesite discovered in this study has not previously been recognized. This discovery of dolomite in living coralline algae extends the range of palaeo-environments for which biologically initiated dolomite can be considered a possible source of primary dolomite.

Nash, MC, Opdyke BN, Troitzsch U, Russell BD, Adey WH, Kato A, Diaz-Pulido G, Brent C, Gardner M, Prichard J, Kline DI.  2013.  Dolomite rich coral reef coralline algae resist dissolution in acidified conditions.. Nature Climate Change. 3:268-272.   10.1038/nclimate1760   Abstract

Coral reef ecosystems develop best in high-flow environments but their fragile frameworks are also vulnerable to high wave energy. Wave-resistant algal rims, predominantly made up of the crustose coralline algae (CCA) Porolithon onkodes and P. pachydermum1, 2, are therefore critical structural elements for the survival of many shallow coral reefs. Concerns are growing about the susceptibility of CCA to ocean acidification because CCA Mg-calcite skeletons are more susceptible to dissolution under low pH conditions than coral aragonite skeletons3. However, the recent discovery4 of dolomite (Mg0.5Ca0.5(CO3)), a stable carbonate5, in P. onkodes cells necessitates a reappraisal of the impacts of ocean acidification on these CCA. Here we show, using a dissolution experiment, that dried dolomite-rich CCA have 6–10 times lower rates of dissolution than predominantly Mg-calcite CCA in both high-CO2 (~ 700 ppm) and control (~ 380 ppm) environments, respectively. We reveal this stabilizing mechanism to be a combination of reduced porosity due to dolomite infilling and selective dissolution of other carbonate minerals. Physical break-up proceeds by dissolution of Mg-calcite walls until the dolomitized cell eventually drops out intact. Dolomite-rich CCA frameworks are common in shallow coral reefs globally and our results suggest that it is likely that they will continue to provide protection and stability for coral reef frameworks as CO2

Neal, BP, Khen A, Treibitz T, Beijbom O, O'Connor G, Coffroth MA, Knowlton N, Kriegman D, Mitchell BG, Kline DI.  2017.  Caribbean massive corals not recovering from repeated thermal stress events during 2005-2013. Ecology and Evolution. 7:1339-1353.   10.1002/ece3.2706   AbstractWebsite

Massive coral bleaching events associated with high sea surface temperatures are forecast to become more frequent and severe in the future due to climate change. Monitoring colony recovery from bleaching disturbances over multiyear time frames is important for improving predictions of future coral community changes. However, there are currently few multiyear studies describing long-term outcomes for coral colonies following acute bleaching events. We recorded colony pigmentation and size for bleached and unbleached groups of co-located conspecifics of three major reef-building scleractinian corals (Orbicella franksi, Siderastrea siderea, and Stephanocoenia michelini; n=198 total) in Bocas del Toro, Panama, during the major 2005 bleaching event and then monitored pigmentation status and changes live tissue colony size for 8years (2005-2013). Corals that were bleached in 2005 demonstrated markedly different response trajectories compared to unbleached colony groups, with extensive live tissue loss for bleached corals of all species following bleaching, with mean live tissue losses per colony 9 months postbleaching of 26.2% (+/- 5.4 SE) for O. franksi, 35.7% (+/- 4.7 SE) for S. michelini, and 11.2% (+/- 3.9 SE) for S. siderea. Two species, O. franksi and S. michelini, later recovered to net positive growth, which continued until a second thermal stress event in 2010. Following this event, all species again lost tissue, with previously unbleached colony species groups experiencing greater declines than conspecific sample groups, which were previously bleached, indicating a possible positive acclimative response. However, despite this beneficial effect for previously bleached corals, all groups experienced substantial net tissue loss between 2005 and 2013, indicating that many important Caribbean reef-building corals will likely suffer continued tissue loss and may be unable to maintain current benthic coverage when faced with future thermal stress forecast for the region, even with potential benefits from bleaching-related acclimation.

Neal, BP, Condit C, Liu G, dos Santos S, Kahru M, Mitchell BG, Kline DI.  2014.  When depth is no refuge: cumulative thermal stress increases with depth in Bocas del Toro, Panama. Coral Reefs. 33:193-205.   10.1007/s00338-013-1081-6   AbstractWebsite

Coral reefs are increasingly affected by high-temperature stress events and associated bleaching. Monitoring and predicting these events have largely utilized sea surface temperature data, due to the convenience of using large-scale remotely sensed satellite measurements. However, coral bleaching has been observed to vary in severity throughout the water column, and variations in coral thermal stress across depths have not yet been well investigated. In this study, in situ water temperature data from 1999 to 2011 from three depths were used to calculate thermal stress on a coral reef in Bahia Almirante, Bocas del Toro, Panama, which was compared to satellite surface temperature data and thermal stress calculations for the same area and time period from the National Oceanic and Atmospheric Administration Coral Reef Watch Satellite Bleaching Alert system. The results show similar total cumulative annual thermal stress for both the surface and depth-stratified data, but with a striking difference in the distribution of that stress among the depth strata during different high-temperature events, with the greatest thermal stress unusually recorded at the deepest measured depth during the most severe bleaching event in 2005. Temperature records indicate that a strong density-driven temperature inversion may have formed in this location in that year, contributing to the persistence and intensity of bleaching disturbance at depth. These results indicate that depth may not provide a stress refuge from high water temperature events in some situations, and in this case, the water properties at depth appear to have contributed to greater coral bleaching at depth compared to near-surface locations. This case study demonstrates the importance of incorporating depth-stratified temperature monitoring and small-scale oceanographic and hydrologic data for understanding and predicting local reef responses to elevated water temperature events.

Neal, BP, Lin TH, Winter RN, Treibitz T, Beijbom O, Kriegman D, Kline DI, Mitchell BG.  2015.  Methods and measurement variance for field estimations of coral colony planar area using underwater photographs and semi-automated image. Environmental Monitoring and Assessment. 187   10.1007/s10661-015-4690-4   AbstractWebsite

Size and growth rates for individual colonies are some of the most essential descriptive parameters for understanding coral communities, which are currently experiencing worldwide declines in health and extent. Accurately measuring coral colony size and changes over multiple years can reveal demographic, growth, or mortality patterns often not apparent from shortterm observations and can expose environmental stress responses that may take years to manifest. Describing community size structure can reveal population dynamics patterns, such as periods of failed recruitment or patterns of colony fission, which have implications for the future sustainability of these ecosystems. However, rapidly and non-invasively measuring coral colony sizes in situ remains a difficult task, as three-dimensional underwater digital reconstruction methods are currently not practical for large numbers of colonies. Twodimensional (2D) planar area measurements from projection of underwater photographs are a practical size proxy, although this method presents operational difficulties in obtaining well-controlled photographs in the highly rugose environment of the coral reef, and requires extensive time for image processing. Here, we present and test the measurement variance for a method of making rapid planar area estimates of small to medium-sized coral colonies using a lightweight monopod image-framing system and a custom semiautomated image segmentation analysis program. This method demonstrated a coefficient of variation of 2.26 % for repeated measurements in realistic ocean conditions, a level of error appropriate for rapid, inexpensive field studies of coral size structure, inferring change in colony size over time, or measuring bleaching or disease extent of large numbers of individual colonies.

Reyes-Nivia, C, Diaz-Pullido G, Kline D, Hoegh-Guldberg O, Dove S.  2013.  Ocean acidification and warming scenarios increase bioerosion of coral skeletons. Global Change Biology. 19:1919-1929.   10.1111/gcb.12158   Abstract

Biological mediation of carbonate dissolution represents a fundamental component of the destructive forces acting on coral reef ecosystems. Whereas ocean acidification can increase dissolution of carbonate substrates, the combined impact of ocean acidification and warming on the microbioerosion of coral skeletons remains unknown. Here, we exposed skeletons of the reef-building corals, Porites cylindrica and Isopora cuneata, to present-day (Control: 400 μatm – 24 °C) and future pCO2–temperature scenarios projected for the end of the century (Medium: +230 μatm – +2 °C; High: +610 μatm – +4 °C). Skeletons were also subjected to permanent darkness with initial sodium hypochlorite incubation, and natural light without sodium hypochlorite incubation to isolate the environmental effect of acidic seawater (i.e., Ωaragonite <1) from the biological effect of photosynthetic microborers. Our results indicated that skeletal dissolution is predominantly driven by photosynthetic microborers, as samples held in the dark did not decalcify. In contrast, dissolution of skeletons exposed to light increased under elevated pCO2–temperature scenarios, with P. cylindrica experiencing higher dissolution rates per month (89%) than I. cuneata (46%) in the high treatment relative to control. The effects of future pCO2–temperature scenarios on the structure of endolithic communities were only identified in P. cylindrica and were mostly associated with a higher abundance of the green algae Ostreobium spp. Enhanced skeletal dissolution was also associated with increased endolithic biomass and respiration under elevated pCO2–temperature scenarios. Our results suggest that future projections of ocean acidification and warming will lead to increased rates of microbioerosion. However, the magnitude of bioerosion responses may depend on the structural properties of coral skeletons, with a range of implications for reef carbonate losses under warmer and more acidic oceans.

Reymond, CE, Lloyd A, Kline DI, Dove SG, Pandolfi JM.  2013.  Decline in growth of foraminifer Marginopora rossi under eutrophication and ocean acidification scenarios. Global Change Biology. 19:291-302.   10.1111/gcb.12035   AbstractWebsite

The combination of global and local stressors is leading to a decline in coral reef health globally. In the case of eutrophication, increased concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) are largely attributed to local land use changes. From the global perspective, increased atmospheric CO2 levels are not only contributing to global warming but also ocean acidification (OA). Both eutrophication and OA have serious implications for calcium carbonate production and dissolution among calcifying organisms. In particular, benthic foraminifera precipitate the most soluble form of mineral calcium carbonate (high-Mg calcite), potentially making them more sensitive to dissolution. In this study, a manipulative orthogonal two-factor experiment was conducted to test the effects of dissolved inorganic nutrients and OA on the growth, respiration and photophysiology of the large photosymbiont-bearing benthic foraminifer, Marginopora rossi. This study found the growth rate of M. rossi was inhibited by the interaction of eutrophication and acidification. The relationship between M. rossi and its photosymbionts became destabilized due to the photosymbiont's release from nutrient limitation in the nitrate-enriched treatment, as shown by an increase in zooxanthellae cells per host surface area. Foraminifers from the OA treatments had an increased amount of Chl a per cell, suggesting a greater potential to harvest light energy, however, there was no net benefit to the foraminifer growth. Overall, this study demonstrates that the impacts of OA and eutrophication are dose dependent and interactive. This research indicates an OA threshold at pH 7.6, alone or in combination with eutrophication, will lead to a decline in M. rossi calcification. The decline in foraminifera calcification associated with pollution and OA will have broad ecological implications across their ubiquitous range and suggests that without mitigation it could have serious implications for the future of coral reefs.

Silverman, J, Kline DI, Johnson L, Rivlin T, Schneider K, Erez J, Lazar B, Caldeira K.  2012.  Carbon turnover rates in the One Tree Island reef: A 40-year perspective. Journal of Geophysical Research-Biogeosciences. 117   10.1029/2012jg001974   AbstractWebsite

During November-December 2009 community rates of gross photosynthesis (P-g), respiration (R) and net calcification (G(net)) were estimated from low-tide slack water measurements of dissolved oxygen, dissolved inorganic carbon and total alkalinity at the historical station DK13 One Tree Island reef, Great Barrier Reef, Australia. Compared to measurements made during the 1960s-1970s at DK13 in the same season, P-g increased from 833 to 914 mmol O-2 center dot m(-2).d(-1) and P-g:R increased from 1.14 to 1.30, indicating that the reef has become more autotrophic. In contrast, G(net) decreased from 133 mmol C.m(-2).d(-1) to 74 +/- 24 mmol C.m(-2).d(-1). This decrease stems primarily from the threefold increase in nighttime CaCO3 dissolution from -2.5 mmol.m(-2).h(-1) to -7.5 mmol.m(-2).h(-1). Comparison of the benthic community survey results from DK13 and its vicinity conducted during this study and in studies from the 1970s, 1980s and 1990s suggest that there have been no significant changes in the live coral coverage during the past 40 years. The reduced G(net) most likely reflects the almost threefold increase in dissolution rates, possibly resulting from increased bioerosion due to changes in the biota (e.g., sea cucumbers, boring organisms) and/or from greater chemical dissolution produced by changing abiotic conditions over the past 40 years associated with climate change, such as increased temperatures and ocean acidification. However, at this stage of research on One Tree Island the effects of these changes are not entirely understood.

Silverman, J, Schneider K, Kline DI, Rivlin T, Rivlin A, Hamylton S, Lazar B, Erez J, Caldeira K.  2014.  Community calcification in Lizard Island, Great Barrier Reef: A 33 year perspective. Geochimica Et Cosmochimica Acta. 144:72-81.   10.1016/j.gca.2014.09.011   AbstractWebsite

Measurements of community calcification (G(net)) were made during September 2008 and October 2009 on a reef flat in Lizard Island, Great Barrier Reef, Australia, 33 years after the first measurements were made there by the LIMER expedition in 1975. In 2008 and 2009 we measured G(net) = 61 +/- 12 and 54 +/- 13 mmol CaCO3 m(-2).day(-1), respectively. These rates are 27-49% lower than those measured during the same season in 1975-76. These rates agree well with those estimated from the measured temperature and degree of aragonite saturation using a reef calcification rate equation developed from observations in a Red Sea coral reef. Community structure surveys across the Lizard Island reef flat during our study using the same methods employed in 1978 showed that live coral coverage had not changed significantly (similar to 8%). However, it should be noted that the uncertainty in the live coral coverage estimates in this study and in 1978 were fairly large and inherent to this methodology. Using the reef calcification rate equation while assuming that seawater above the reef was at equilibrium with atmospheric PCO2 and given that live coral cover had not changed G(net) should have declined by 30 +/- 8% since the LIMER study as indeed observed. We note, however, that the error in estimated G(net) decrease relative to the 1970's could be much larger due to the uncertainties in the coral coverage measurements. Nonetheless, the similarity between the predicted and the measured decrease in G(net) suggests that ocean acidification may be the primary cause for the lower CaCO3 precipitation rate on the Lizard Island reef flat. (C) 2014 Elsevier Ltd. All rights reserved.

Stark, JS, Peltzer ET, Kline DI, Queiros AM, Cox TE, Headley K, Barry J, Gazeau F, Runcie JW, Widdicombe S, Milnes M, Roden NP, Black J, Whiteside S, Johnstone G, Ingels J, Shaw E, Bodrossy L, Gaitan-Espitia JD, Kirkwood W, Gattuso J.  2019.  Free Ocean CO2 Enrichment (FOCE) experiments: Scientific and technical recommendations for future in situ ocean acidification projects. Progress in Oceanography. 172:89-107.   10.1016/j.pocean.2019.01.006   AbstractWebsite

Free Ocean CO2 Enrichment (FOCE) experiments are a relatively recent development in ocean acidification research, designed to address the need for in situ, long-term, community level experiments. FOCE studies have been conducted across different marine benthic habitats and regions, from Antarctica to the tropics. Based on this previous research we have formed some core operating principles that will aid those embarking on future FOCE experiments. FOCE studies have potential to provide important insight into the effects of ocean acidification that can add to or refine conclusions drawn from laboratory or single species studies because they are conducted in situ on intact assemblages. Scaling up from sub-organismal and individual effects to also include indirect impacts on the ecosystem and ecosystem services, make FOCE experiments essential in filling in current knowledge gaps in our understanding of ocean acidification. While FOCE systems are complex, relatively costly, and somewhat difficult to operate, the challenges they pose are tractable and they have proven to be a useful approach in ocean acidification research. The aim of this paper is to draw from the experiences of past FOCE experiments and provide practical advice for designing, building and operating a FOCE experiment. Some of the most important recommendations include: field testing the system design; having a backup power supply; using replicate treatment enclosures; monitoring and maintaining the chemistry appropriately; allowing sufficient time to achieve near CO2 equilibrium conditions; and having a scientific focus with a core set of hypotheses. Future FOCE experiments could focus on longer durations, multiple factors, and testing more intact benthic marine communities and ecosystems. We hope this paper will encourage further FOCE deployments and experiments, as well as provide some guidelines to improve future FOCE studies and advance ocean acidification research.

Treibitz, T, Neal BP, Kline DI, Beijbom O, Roberts PLD, Mitchell BG, Kriegman D.  2015.  Wide field-of-view fluorescence imaging of coral reefs. Scientific Reports. 5   10.1038/srep07694   AbstractWebsite

Coral reefs globally are declining rapidly because of both local and global stressors. Improved monitoring tools are urgently needed to understand the changes that are occurring at appropriate temporal and spatial scales. Coral fluorescence imaging tools have the potential to improve both ecological and physiological assessments. Although fluorescence imaging is regularly used for laboratory studies of corals, it has not yet been used for large-scale in situ assessments. Current obstacles to effective underwater fluorescence surveying include limited field-of-view due to low camera sensitivity, the need for nighttime deployment because of ambient light contamination, and the need for custom multispectral narrow band imaging systems to separate the signal into meaningful fluorescence bands. Here we describe the Fluorescence Imaging System (FluorIS), based on a consumer camera modified for greatly increased sensitivity to chlorophyll-a fluorescence, and we show high spectral correlation between acquired images and in situ spectrometer measurements. This system greatly facilitates underwater wide field-of-view fluorophore surveying during both night and day, and potentially enables improvements in semi-automated segmentation of live corals in coral reef photographs and juvenile coral surveys.

Tresguerres, M, Barott K, Barron ME, Deheyn D, Kline D, Linsmayer LB.  2017.  Cell Biology of Reef-Building Corals: Ion Transport, Acid/Base Regulation, and Energy Metabolism. Acid-Base Balance and Nitrogen Excretion in Invertebrates. ( Weihrauch D, O'Donnell M, Eds.).:193-218.: Springer International Publishing   10.1007/978-3-319-39617-0_7   Abstract

Coral reefs are built by colonial cnidarians that establish a symbiotic relationship with dinoflagellate algae of the genus Symbiodinium. The processes of photosynthesis, calcification, and general metabolism require the transport of diverse ions across several cellular membranes and generate waste products that induce acid/base and oxidative stress. This chapter reviews the current knowledge on coral cell biology with a focus on ion transport and acid/base regulation while also discussing related aspects of coral energy metabolism.

Vollmer, SV, Kline DI.  2008.  Natural Disease Resistance in Threatened Staghorn Corals. Plos One. 3   10.1371/journal.pone.0003718   AbstractWebsite

Disease epidemics have caused extensive damage to tropical coral reefs and to the reef-building corals themselves, yet nothing is known about the abilities of the coral host to resist disease infection. Understanding the potential for natural disease resistance in corals is critically important, especially in the Caribbean where the two ecologically dominant shallow-water corals, Acropora cervicornis and A. palmata, have suffered an unprecedented mass die-off due to White Band Disease (WBD), and are now listed as threatened under the US Threatened Species Act and as critically endangered under the IUCN Red List criteria. Here we examine the potential for natural resistance to WBD in the staghorn coral Acropora cervicornis by combining microsatellite genotype information with in situ transmission assays and field monitoring of WBD on tagged genotypes. We show that six percent of staghorn coral genotypes (3 out of 49) are resistant to WBD. This natural resistance to WBD in staghorn corals represents the first evidence of host disease resistance in scleractinian corals and demonstrates that staghorn corals have an innate ability to resist WBD infection. These resistant staghorn coral genotypes may explain why pockets of Acropora have been able to survive the WBD epidemic. Understanding disease resistance in these corals may be the critical link to restoring populations of these once dominant corals throughout their range.

Wegley, L, Yu YN, Breitbart M, Casas V, Kline DI, Rohwer F.  2004.  Coral-associated archaea. Marine Ecology-Progress Series. 273:89-96.   10.3354/meps273089   AbstractWebsite

The coral holobiont includes the coral, zooxanthellae, fungi, endolithic algae, and >30 species of Bacteria. Using culture-independent techniques, we now show that Archaea are also abundant and widespread on corals. Sequence analyses of Archaea on 3 species of Caribbean corals revealed that coral-associated Archaea are novel, diverse, and include representatives from both the Crenarchaeota and Euryarchaeota. Unlike zooxanthellae and Bacteria, the Archaea do not appear to form species-specific associations with reef-building corals. Fluorescent in situ hybridizations with peptide nucleic acid (PNA) probes showed that Archaea were present at >10(7) cells cm(-2) on Porites astreoides, comprising nearly half of the prokaryotic community. This study and one by Kellogg (Mar Ecol Prog Ser 273:81-88) show that Archaea are abundant, diverse, and potentially important components of the coral holobiont.