Publications

Export 21 results:
Sort by: Author Title Type [ Year  (Asc)]
2004
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.

2009
Diaz-Pulido, G, McCook LJ, Dove S, Berkelmans R, Roff G, Kline DI, Weeks S, Evans RD, Williamson DH, Hoegh-Guldberg O.  2009.  Doom and boom on a resilient reef: climate change, agal overgrowth and coral recovery. Plos One. 4   10.1371/journal.pone.0005239   AbstractWebsite

Background: Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance. Methodology/Principal Findings: In 2006, mass bleaching of corals on inshore reefs of the Great Barrier Reef caused high coral mortality. Here we show that this coral mortality was followed by an unprecedented bloom of a single species of unpalatable seaweed (Lobophora variegata), colonizing dead coral skeletons, but that corals on these reefs recovered dramatically, in less than a year. Unexpectedly, this rapid reversal did not involve reestablishment of corals by recruitment of coral larvae, as often assumed, but depended on several ecological mechanisms previously underestimated. Conclusions/Significance: These mechanisms of ecological recovery included rapid regeneration rates of remnant coral tissue, very high competitive ability of the corals allowing them to out-compete the seaweed, a natural seasonal decline in the particular species of dominant seaweed, and an effective marine protected area system. Our study provides a key example of the doom and boom of a highly resilient reef, and new insights into the variability and mechanisms of reef resilience under rapid climate change.

2010
Calamia, MA, Kline DI, Kago S, Donovan K, Dulunaqio S, Tabaleka T, Mitchell BG.  2010.  Marine-based community conserved areas in Fiji: an example of indigenous governance and partnership. Indigenous peoples and conservation: from rights to resource management. ( Walker Painemilla K, Rylands AB, Woofter A, Hughers C, Eds.).:95-114., Arlington, VA.: Conservation International Abstract
n/a
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.

Eakin, CM, Morgan JA, Heron SF, Smith TB, Liu G, Alvarez-Filip L, Baca B, Bartels E, Bastidas C, Bouchon C, Brandt M, Bruckner AW, Bunkley-Williams L, Cameron A, Causey BD, Chiappone M, Christensen TRL, Crabbe MJC, Day O, de la Guardia E, Diaz-Pulido G, DiResta D, Gil-Agudelo DL, Gilliam DS, Ginsburg RN, Gore S, Guzman HM, Hendee JC, Hernandez-Delgado EA, Husain E, Jeffrey CFG, Jones RJ, Jordan-Dahlgren E, Kaufman LS, Kline DI, Kramer PA, Lang JC, Lirman D, Mallela J, Manfrino C, Marechal JP, Marks K, Mihaly J, Miller WJ, Mueller EM, Muller EM, Toro CAO, Oxenford HA, Ponce-Taylor D, Quinn N, Ritchie KB, Rodriguez S, Ramirez AR, Romano S, Samhouri JF, Sanchez JA, Schmahl GP, Shank BV, Skirving WJ, Steiner SCC, Villamizar E, Walsh SM, Walter C, Weil E, Williams EH, Roberson KW, Yusuf Y.  2010.  Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005. Plos One. 5   10.1371/journal.pone.0013969   AbstractWebsite

Background: The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Methodology/Principal Findings: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Conclusions/Significance: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

2011
Bongaerts, P, Bridge TCL, Kline DI, Muir PR, Wallace CC, Hoegh-Guldberg O, Beaman RJ.  2011.  Mesophotic coral ecosystems on the walls of Coral Sea atolls. Coral Reefs. 30:335-335.   10.1007/s00338-011-0725-7   Website
2012
Kaniewska, P, Campbell PR, Kline DI, Rodriguez-Lanetty M, Miller DJ, Dove S, Hoegh-Guldberg O.  2012.  Major cellular and physiological impacts of ocean acidification on a reef building coral. Plos One. 7   10.1371/journal.pone.0034659   AbstractWebsite

As atmospheric levels of CO2 increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO2 conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification.

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.

2014
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.

Gattuso, JP, Kirkwood W, Barry JP, Cox E, Gazeau F, Hansson L, Hendriks I, Kline DI, Mahacek P, Martin S, McElhany P, Peltzer ET, Reeve J, Roberts D, Saderne V, Tait K, Widdicombe S, Brewer PG.  2014.  Free-ocean CO2 enrichment (FOCE) systems: present status and future developments. Biogeosciences. 11:4057-4075.   10.5194/bg-11-4057-2014   AbstractWebsite

Free-ocean CO2 enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through interspecific relationships and food webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is, however, extremely challenging. The main goal of this paper is to provide guidelines on the general design, engineering, and sensor options required to conduct FOCE experiments. Another goal is to introduce xFOCE, a community-led initiative to promote awareness, provide resources for in situ perturbation experiments, and build a user community. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

2015
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
n/a
Georgiou, L, Falter J, Trotter J, Kline DI, Holcomb M, Dove SG, Hoegh-Guldberg O, McCulloch M.  2015.  pH homeostasis during coral calcification in a Free Ocean CO2 Enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef. . Proceedings of the National Academy of Sciences . 112(43):13219-13224.   10.1073/pnas.1505586112  
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.

Beijbom, O, Edmunds PJ, Roelfsema C, Smith J, Kline DI, Neal BP, Dunlap MJ, Moriarty V, Fan TY, Tan CJ, Chan S, Treibitz T, Gamst A, Mitchell BG, Kriegman D.  2015.  Towards automated annotation of benthic survey images: Variability of human experts and operational modes of automation. Plos One. 10   10.1371/journal.pone.0130312   AbstractWebsite

Global climate change and other anthropogenic stressors have heightened the need to rapidly characterize ecological changes in marine benthic communities across large scales. Digital photography enables rapid collection of survey images to meet this need, but the subsequent image annotation is typically a time consuming, manual task. We investigated the feasibility of using automated point-annotation to expedite cover estimation of the 17 dominant benthic categories from survey-images captured at four Pacific coral reefs. Inter- and intra- annotator variability among six human experts was quantified and compared to semi- and fully- automated annotation methods, which are made available at coralnet.ucsd. edu. Our results indicate high expert agreement for identification of coral genera, but lower agreement for algal functional groups, in particular between turf algae and crustose coralline algae. This indicates the need for unequivocal definitions of algal groups, careful training of multiple annotators, and enhanced imaging technology. Semi-automated annotation, where 50% of the annotation decisions were performed automatically, yielded cover estimate errors comparable to those of the human experts. Furthermore, fully-automated annotation yielded rapid, unbiased cover estimates but with increased variance. These results show that automated annotation can increase spatial coverage and decrease time and financial outlay for image-based reef surveys.

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.

2016
Beijbom, O, Treibitz T, Kline DI, Eyal G, Khen A, Neal B, Loya Y, Mitchell GB, Kriegman D.  2016.  Improving automated annotation of benthic survey images using wide-band fluorescence. Scientific reports. 6:23166.: Nature Publishing Group Abstract
n/a
2017
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.

2018
Gormley, K, McLellan F, McCabe C, Hinton C, Ferris J, Kline DI, Scott BE.  2018.  Automated Image Analysis of Offshore Infrastructure Marine Biofouling. Journal of Marine Science and Engineering. 6(1):2.: Multidisciplinary Digital Publishing Institute Abstract
n/a
Du, N, Gholami P, Kline DI, Dupont CL, Dickson AG, Mendola D, Martz T, Allen AE, Mitchell GB.  2018.  Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures. PloS one. 13(6):e0199125.: Public Library of Science   10.1371/journal.pone.0199125   Abstract

n/a

Cyronak, T, Andersson AJ, Langdon C, Albright R, Bates NR, Caldeira K, Carlton R, Corredor JE, Dunbar RB, Enochs I, Erez J, Eyre BD, Gattuso JP, Gledhill D, Kayanne H, Kline DI, Koweek DA, Lantz C, Lazar B, Manzello D, McMahon A, Melendez M, Page HN, Santos IR, Schulz KG, Shaw E, Silverman J, Suzuki A, Teneva L, Watanabe A, Yamamoto S.  2018.  Taking the metabolic pulse of the world's coral reefs. Plos One. 13   10.1371/journal.pone.0190872   AbstractWebsite

Worldwide, coral reef ecosystems are experiencing increasing pressure from a variety of anthropogenic perturbations including ocean warming and acidification, increased sedimentation, eutrophication, and overfishing, which could shift reefs to a condition of net calcium carbonate (CaCO3) dissolution and erosion. Herein, we determine the net calcification potential and the relative balance of net organic carbon metabolism (net community production; NCP) and net inorganic carbon metabolism (net community calcification; NCC) within 23 coral reef locations across the globe. In light of these results, we consider the suitability of using these two metrics developed from total alkalinity (TA) and dissolved inorganic carbon (DIC) measurements collected on different spatiotemporal scales to monitor coral reef biogeochemistry under anthropogenic change. All reefs in this study were net calcifying for the majority of observations as inferred from alkalinity depletion relative to offshore, although occasional observations of net dissolution occurred at most locations. However, reefs with lower net calcification potential (i.e., lower TA depletion) could shift towards net dissolution sooner than reefs with a higher potential. The percent influence of organic carbon fluxes on total changes in dissolved inorganic carbon (DIC) (i.e., NCP compared to the sum of NCP and NCC) ranged from 32% to 88% and reflected inherent biogeochemical differences between reefs. Reefs with the largest relative percentage of NCP experienced the largest variability in seawater pH for a given change in DIC, which is directly related to the reefs ability to elevate or suppress local pH relative to the open ocean. This work highlights the value of measuring coral reef carbonate chemistry when evaluating their susceptibility to ongoing global environmental change and offers a baseline from which to guide future conservation efforts aimed at preserving these valuable ecosystems.

2019
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.