Identifying which factors lead to coral bleaching resistance is a priority given the global decline of coral reefs with ocean warming. During the second year of back-to-back bleaching events in the Florida Keys in 2014 and 2015, we characterized key environmental and biological factors associated with bleaching resilience in the threatened reef-building coral Orbicella faveolata. Ten reefs (five inshore, five offshore, 179 corals total) were sampled during bleaching (September 2015) and recovery (May 2016). Corals were genotyped with 2bRAD and profiled for algal symbiont abundance and type. O. faveolata at the inshore sites, despite higher temperatures, demonstrated significantly higher bleaching resistance and better recovery compared to offshore. The thermotolerant Durusdinium trenchii (formerly Symbiondinium trenchii) was the dominant endosymbiont type region-wide during initial (78.0% of corals sampled) and final (77.2%) sampling; >90% of the nonbleached corals were dominated by D. trenchii. 2bRAD host genotyping found no genetic structure among reefs, but inshore sites showed a high level of clonality. While none of the measured environmental parameters were correlated with bleaching, 71% of variation in bleaching resistance and 73% of variation in the proportion of D. trenchii was attributable to differences between genets, highlighting the leading role of genetics in shaping natural bleaching patterns. Notably, D. trenchii was rarely dominant in O. faveolata from the Florida Keys in previous studies, even during bleaching. The region-wide high abundance of D. trenchii was likely driven by repeated bleaching associated with the two warmest years on record for the Florida Keys (2014 and 2015). On inshore reefs in the Upper Florida Keys, O. faveolata was most abundant, had the highest bleaching resistance, and contained the most corals dominated by D. trenchii, illustrating a causal link between heat tolerance and ecosystem resilience with global change.
Coral reefs are exceptionally biodiverse and human dependence on their ecosystem services is high. Reefs experience significant direct and indirect anthropogenic pressures, and provide a sensitive indicator of coastal ocean health, climate change, and ocean acidification, with associated implications for society. Monitoring coral reef status and trends is essential to better inform science, management and policy, but the projected collapse of reef systems within a few decades makes the provision of accurate and actionable monitoring data urgent. The Global Coral Reef Monitoring Network has been the foundation for global reporting on coral reefs for two decades, and is entering into a new phase with improved operational and data standards incorporating the Essential Ocean Variables (EOVs) (www.goosocean.org/eov) and Framework for Ocean Observing developed by the Global Ocean Observing System. Three EOVs provide a robust description of reef health: hard coral cover and composition, macro-algal canopy cover, and fish diversity and abundance. A data quality model based on comprehensive metadata has been designed to facilitate maximum global coverage of coral reef data, and tangible steps to track capacity building. Improved monitoring of events such as mass bleaching and disease outbreaks, citizen science, and socio-economic monitoring have the potential to greatly improve the relevance of monitoring to managers and stakeholders, and to address the complex and multi- dimensional interactions between reefs and people. A new generation of autonomous vehicles (underwater, surface, and aerial) and satellites are set to revolutionize and vastly expand our understanding of coral reefs. Promising approaches include Structure from Motion image processing, and acoustic techniques. Across all systems, curation of data in linked and open online databases, with an open data culture to maximize benefits from data integration, and empowering users to take action, are priorities. Action in the next decade will be essential to mitigate the impacts on coral reefs from warming temperatures, through local management and informing national and international obligations, particularly in the context of the Sustainable Development Goals, climate action, and the role of coral reefs as a global indicator. Mobilizing data to help drive the needed behavior change is a top priority for coral reef observing systems.
Ocean acidification (OA) will result in lower calcification rates for numerous marine taxa, including many species of corals which create important reef habitat. Seawater carbonate chemistry fluctuates over cycles ranging from days to seasons, often driven by biological processes such as respiration and photosynthesis. The magnitude of diel fluctuations varies spatially and may become more pronounced in the future due to OA. Due to technical constraints, OA experiments that incorporate diel variability into treatments are few in number. As a result, the degree to which coral reef organisms are influenced by ambient daily carbonate chemistry variability is poorly understood. Here we describe an experiment conducted in a novel seawater system which can independently manipulate carbonate chemistry in 16 separate aquaria, in real time, allowing precise control of the mean and magnitude of pH oscillations while minimizing pseudoreplication. Five genotypes of the threatened Caribbean coral Acropora cervicornis were subjected to a total of five pH treatments, 7.80 ± 0.20, 7.80 ± 0.10, and 7.80 ± 0.00, as well as 8.05 ± 0.10 and 8.05 ± 0.00. Those corals exposed to variable contemporary conditions (8.05 ± 0.10) calcified faster than those in current and future static treatment levels, which did not significantly differ from each other. Variable contemporary pH also resulted in faster growth rates than highly variable future conditions (7.80 ± 0.20), but were not significantly different than future conditions with the same ±0.10 diel pH oscillation. These findings support the importance of incorporating diel variability into OA experiments and suggest that more variable natural ecosystems may yield higher calcification rates for corals.
The NOAA Coral Reef Early Warning System (CREWS) network is a growing number of oceanographic and meteorological monitoring stations situated at coral reef areas of critical concern. The near real-time data from these stations are archived at NOAA and form the basis of daily ecological forecasts for coral bleaching, hydrodynamic events, and other marine environmental events of interest to environmental managers, researchers, and the public. The network began over 15 years ago with NOAA funding as a station in the Bahamas, and grew to include stations in Puerto Rico, St. Croix, Saipan, and with other sources of funding, Jamaica and Little Cayman. However, storms and other realities resulted in the destruction or removal of all of those stations, excluding Little Cayman, which continues operating today as a new buoy design. A new collaboration between NOAA and the Caribbean Community Climate Change Center has resulted in the expansion of the network to include two stations each in Belize, Tobago, and the Dominican Republic, plus one in Barbados. Each of these sites has required collaborations among each country's environmental managers and agencies before agreement as to where to place the stations and as to who would be conducting maintenance. The second phase will include four to six new stations among these likely candidates: Antigua & Barbuda, Aruba, Bonaire, Cuba, Dominica, Grenada, Grenadines, Montserrat, San Andres, St. Kitts & Nevis, and St. Lucia & St. Vincent.
An acoustic Doppler current profiler was installed on the south side of the Port Everglades Inlet to measure the velocity of the water flow at levels starting near the surface and reaching down to near the channel bottom. The system was built using a commercial, horizontal-looking ADCP deployed in a hybrid manner to measure the vertical velocity structure. This system was calibrated so that its velocity measurements could estimate the mean channel velocity at specific depth layers by repeatedly transecting a vessel-mounted, down-looking ADCP across the channel at the location of the fixed system. The channel cross-sectional area at the location of the fixed system was measured, and a pressure sensor on the fixed system allowed the cross section of the channel to be estimated at the time of each velocity measurement. From the area and mean channel velocity measurements, an estimate of the volume transport per unit of time (Q) in a surface and deep layer was made. By integrating the Q measurements over a tidal phase, measurements of total volume transport per tidal phase in the surface and bottom layers were made. These volume estimates will be used to estimate the total seaward flux of certain substances measured by the Florida International University group during the study. Using an independent data set, the dispersion of materials advected seaward from the inlet into the coastal ocean was estimated.
Abstract: Over the last ten years several wireless architectures have been developed for transmitting meteorological and oceanographic data (in real-time or near real-time) from coral reef ecosystems in Florida, the Caribbean, Saipan, and Australia. These architectures facilitate establishing trends in environmental parameters and aid in ecosystem modeling and ecological forecasting. Here, existing architectures, as well as those currently in development, are described, incorporating use of Geostationary Operational Environmental Satellites, radio transceivers, wireless digital cellular modems, mobile wireless hotspots, and Android phones. Each architecture is reviewed for advantages and disadvantages, along with some examples of deployments. These summaries provide reef managers and scientists with a suite of options for monitoring, allowing the selection of the most appropriate architecture for the particular needs and capacities of each coral reef location.
Abstract: Assessment of coral reef ecosystems implies the acquisition of precision data and observations appropriate for answering questions about the response of multiple organisms to physical and other environmental stimuli. At the National Oceanic and Atmospheric Administrations Atlantic Oceanographic and Meteorological Laboratory, we model marine organismal response to the environment in terms of a Stimulus/Response Index (S/RI). S/RI is computed using an approach called heuristic programming, from parameters bounded in subjective terms, which are defined numerically by comparing historical data with expert opinion, so as to match research and our understanding of the process in question. The modeled organismal response is called an ecological forecast, or ecoforecast, and relative possibility and intensity of the response is reflected in a rising S/RI. We have had success to date in modeling coral bleaching response to high sea temperatures plus high irradiance and other parameters. The approach requires, a) highly robust instrumentation (in situ, satellite, or other) deployed for long periods and producing high quality data in near real-time, b) a basic understanding of the process, behavior and/or physiology being modeled, and, c) a knowledge of approximate threshold levels for single or synergistically acting environmental parameters that elicit the phenomenon in question.
Abstract: The Integrated Coral Observing Network (ICON) program has constructed and installed a series of Coral Reef Early Warning System (CREWS) stations which provide a wealth of high-quality meteorological and oceanographic data in near real-time. CREWS stations date back to 2001 with the deployment of an early buoy-type design in the Bahamas. Beginning in 2002, the program shifted to a pylon-type design which was reengineered in 2005, resulting in the modern CREWS stations found in the Bahamas, Puerto Rico, the U.S. Virgin Islands and Jamaica. The CREWS instrumentation architecture described herein has evolved over time into a robust package that, combined with a regimen of regular instrument cleaning and recalibration, has yielded a continuous, long-term, high-quality dataset from these harsh marine environments.
Abstract: Zooxanthellae fluorescence was measured in situ, remotely, and in near real-time with a pulse amplitude modulated (PAM) fluorometer for a colony of Siderastrea siderea and Agaricia tenuifolia at Lee Stocking Island, Bahamas during the Caribbean-wide 2005 bleaching event. These colonies displayed evidence of photosystem II (PS II) inactivation coincident with thermal stress and seasonally high doses of solar radiation. Hurricane-associated declines in temperature and light appear to have facilitated the recovery of maximum quantum yield of PS II within these two colonies, although both corals responded differently to individual storms. PAM fluorometry, coupled with long-term measurement of in situ light and temperature, provides much more detail of coral photobiology on a seasonal time scale and during possible bleaching conditions than sporadic, subjective, and qualitative observations. S. siderea displayed evidence of PS II inactivation over a month prior to the issuing of a satellite-based, sea surface temperature (SST) bleaching alert by the National Oceanic and Atmospheric Administration (NOAA). In fact, recovery had already begun in S. siderea when the bleaching alert was issued. Fluorescence data for A. tenuifolia were difficult to interpret because the shaded parts of a colony were monitored and thus did not perfectly coincide with thermal stress and seasonally high doses of solar radiation as in S. siderea. These results further emphasize the limitations of solely monitoring SST (satellite or in situ) as a bleaching indicator without considering the physiological status of coral-zooxanthellae symbioses.
Abstract: The National Oceanic and Atmospheric Administration (NOAA) has committed to integrating ocean data from a variety of sources into an Integrated Ocean Observing System, and to work towards operational ecological forecasting as part of its Ecosystem Approach to Management. Consistent with this, NOAA's Coral Reef Conservation Program has committed to integrating coral data from a variety of sources for the specific benefit of coral reef researchers and Marine Protected Area (MPA) managers; and NOAA's Atlantic Oceanographic and Meteorological Laboratory, together with its NOAA and University of Miami partners, are contributing to this goal through their Integrated Coral Observing Network (ICON) project. ICON provides Web-based software to integrate satellite, monitoring station (in situ), and radar data sources in near real-time; and utilizes an inference engine (artificial intelligence software) to provide ecological forecasts using some or all of these data. The capabilities of ICON software are currently being focused upon one area in particular, Molasses Reef in the Florida Keys National Marine Sanctuary, to provide proof-of-concept, and to provide a "discovery prototype" for consideration by the MPA managers assembled at the GCFI conference. Feedback to ICON developers from MPA managers--based upon their own specific management requirements and priorities, and knowledge of the prototype capabilities--is essential to set priorities and enable additional ICON software engineering specifically tailored to MPA managers' needs. Featured in the prototype are several levels of user access: layperson, researcher, site maintainer, MPA manager, and software developer colleague. Depending upon user access, information products can include recent and historical single-source and integrated data output, custom graphics output, and ecological forecasts for coral bleaching, coral spawning, upwelling, pollution impacts and larval drift.
The National Oceanic and Atmospheric Administration's (NOAA) Integrated Coral Observing Network (ICON) has been operational since 2000 and works closely with most U.S. Government and many international environmental partners involved in coral reef research. The ICON program has pioneered the use of artificial intelligence techniques to assess near real-time data streams from environment sensor networks such as the SEAKEYS Network (Florida Keys), the Australia Institute of Marine Science Weather Network, NOAA's Coral Reef Ecosystem Division network in the Pacific, and its own Integrated Coral Observing Network (ICON) of stations in the Caribbean. Besides its innovative approach to coral monitoring station deployments, the ICON program recently pioneered techniques for the near real-time integration of satellite, in situ, and radar data sources for purposes of ecological forecasting of such events as coral bleaching, coral spawning, upwelling, and other marine behavioral or physical oceanographic events. The ICON program has also ushered in the use of Pulse-Amplitude-Modulating fluorometry to measure near real-time physiological recording of response to environmental stress during coral bleaching, thus providing even better ecological forecasting capabilities through artificial intelligence and data integrative techniques. Herewith, we describe these techniques, along with a report on new coral calcification instrumentation augmenting the ICON Network sensor array.