A year of coral-saving science – 2020 Annual Report

This story is a highlight from our 2020 Annual Report.

CORAL RESTORATION: BREAKTHROUGHS & BABIES

In August 2020, years of Mote Marine Laboratory’s coral research and restoration coalesced into one special moment: Mote-restored mountainous star corals on the reef released what looked like a burst of pearls. Those “pearls” were something far more valuable—bundles of eggs and sperm ready to combine in the water and turn restored corals into reef-sustaining parents.

This was the first time anywhere that massive (mounding) corals were observed spawning after being restored. Spawning is part of sexual reproduction needed to produce the next generation of coral offspring. It was one of the most spectacular successes, but far from the only one this year, in Mote’s scientific restoration efforts focused on saving Florida’s Coral Reef from functional extinction.

Florida’s Coral Reef—an ecological and economic treasure estimated to be worth $8.5 billion—has lost all but 2% of its living coral cover in recent decades and is struggling to survive amid the growing pressures of disease, climate change, pollution and other serious challenges. The ongoing, widespread outbreak of stony coral tissue loss disease (SCTLD) is one of the most urgent and devastating threats to massive corals—including brain, maze, boulder, star, pillar and other slow-growing species—that form the very foundations of Florida’s Coral Reef.

Specifics on Mote’s spawning success:

• At least 10 colonies of Mote-restored mountainous star coral (Orbicella faveolata) released their gametes (sperm and eggs) on the reef in August 2020. Mote scientists originally planted these corals in 2015 at Cook Island in the Florida Keys, and since then, the corals have shown great resilience—surviving a global coral bleaching event in 2015, Category-4 Hurricane Irma in 2017, and the 2019 outbreak at this site of SCTLD, which kills over 90% of infected corals.
• Colonies of branching staghorn coral (Acropora cervicornis), outplanted by Mote in 2016, 2017 and 2018 at Eastern Dry Rocks off Key West, also reached sexual maturity on the reef this year. Survey results indicate that they also produced and released their gametes. Their success demonstrates that staghorn corals can reach the critical milestone of sexual maturity within as little as two years, an observation cited only once before. These corals survived Hurricane Irma and other stressors, and now they’re thriving.

Restoration worthy of celebration:

• This year Mote scientists restored their 100,000^th coral to Florida’s Coral Reef, a critical milestone in our restoration efforts since 2008, which span approximately 100 acres. This grand total includes 69,728 staghorn corals and 8,506 elkhorn corals—two branching species listed as threatened under the U.S. Endangered Species Act—and 25,590 massive or mounding corals. Since our earliest five years of restoration, Mote’s annual number of outplanted corals has grown by two orders of magnitude. Most important, Mote is using science to ensure that our restored corals have the best possible chances to survive and reproduce on the reef.

  Our unique, science-based strategy for coral restoration focuses on identifying, selectively breeding, growing and restoring genetically diverse, native coral genotypes (genetic varieties) with resilience to environmental stress. Mote currently maintains a collection of over 1,600 verified coral genotypes from 17 species, with plans to add about 3,600 more genotypes from three species to our collection over next two years.

  The hub of our coral science and restoration is Mote’s Elizabeth Moore International Center for Coral Reef Research & Restoration (IC2R3) on Summerland Key, Florida. There, Mote scientists:

  • Grow large numbers of multiple coral species in underwater and land-based nurseries.
  • Help slow-growing massive corals (such as the mountainous star corals that spawned this year) to grow 50 times faster through microfragmentation and fusion—breaking corals into tiny microfragments and later allowing the growing fragments to fuse and cover a dead coral skeleton on the reef.
  • Conduct managed breeding of corals (assisted sexual reproduction to add fresh genetics) in land-based systems along with asexual reproduction (fragmenting corals into genetically identical pieces).
  • Raise and study corals through every stage of life.
  • Scientifically test corals’ resilience to stress, including increased temperatures, ocean acidification and disease, to identify resilient genotypes. In addition, Mote scientists study why some corals are more resilient and whether that resilience comes with any tradeoffs or side effects.
  • Restore corals using science-based strategies, focusing on resilient and diverse coral genotypes.
  • Monitor restored corals longer and in more detail than other organizations—which allows Mote to document the corals’ long-term survival and sexual maturation.

    These efforts are proving successful. Mote-restored corals had an outstanding one-year survival rate of 86% on average as of 2020.

• Mote is a core partner in Mission: Iconic Reefs—an unprecedented team effort announced in December 2019, focused on restoring seven ecologically and culturally significant coral reefs within Florida Keys National Marine Sanctuary. Led by the National Oceanic and Atmospheric Administration (NOAA), Mission: Iconic Reefs represents one of the largest investments in coral restoration to date.
• Mote scientists are leading or partnering in more than 30 scientific efforts in support of resilient, efficient, lasting coral restoration.  Some examples:
  • Determining the cost and benefit associated with outplanting corals of different sizes from Mote’s land-based nursery
  • Assessing the survival of corals susceptible to stony coral tissue loss disease (SCTLD) after conducting regional restoration efforts—in  collaboration with FWC, University of Miami, Nova Southeastern University, Florida Atlantic University, Coral Restoration Foundation
  • Assessing the application of probiotics to protect against SCTLD (in collaboration with Smithsonian Research Institute)
  • Integrating 3D photogrammetry to assess ecosystem recovery of restoration sites
  • Assessing the physiology of corals grown using trees (branched structures made of PVC pipe) versus blocks under different climate change and ocean acidification scenarios
  • Researching mangroves as refugia for coral against acidification (in collaboration with Woods Hole Oceanographic Institution, UM)
  • Developing and optimizing assisted sexual reproduction protocols including methods for spawning, fertilization, settlement, and rearing of multiple coral species
  • Testing for trade-offs between fecundity (capacity for reproduction) and disease-resistance among staghorn broodstock
  • Tracking sexual reproduction (e.g., timing and synchronicity of spawning) of Mote-restored coral populations over time
  • Exploring the potential for using coral pheromones to regulate spawning timing
  • Using ex situ spawning systems to induce spawning in corals outside of their typical spawning times for various research objectives
  • Using parent-offspring staghorn samples to construct genetic maps (in collaboration with Penn State University)

Sex for survival:

• This year, Mote scientists expanded their efforts to help corals reproduce sexually—a natural process that is failing in many wild coral populations. During sexual reproduction, two corals of the same species release their gametes, which meet in the water, allowing their DNA to recombine—processes called spawning and fertilization. This results in the next generation of genetically diverse coral offspring that can replenish depleted adult populations and disperse to establish new reefs. Genetic diversity, powered by sex, is a safety net that promotes population resilience by providing a buffer against environmental change and the flexibility to adapt. When sexual reproduction breaks down, so does that safety net, just when corals need it most. Mote scientists collected gametes from the few remaining wild elkhorn coral (Acropora palmata) colonies at Looe Key in the Florida Keys and combined them in sexual reproduction efforts in the lab, producing “baby” elkhorn corals. Based on the parents’ genetics, these babies are estimated to include more than 400 genotypes, some of which will survive and have their genes sequenced to become part of Mote’s carefully documented, long-term collection. These  offspring will add fresh genetics to Mote’s coral restoration efforts—essential to aid this struggling species. Wild elkhorn populations have been declining at accelerating rates and failing to reproduce sexually on the reef.
• Mote scientists were exceedingly successful with staghorn coral sexual reproduction this year. In land-based systems at Mote’s IC2R3, Mote scientists strategically spawned 52 adult colonies representing 10 different stress-tested genotypes and conducted 33 different two-parent crosses as part of Mote’s managed-breeding scheme to investigate the compatibility of the parents and their ability to pass on disease resistance to offspring. After achieving high fertilization rates (96% on average), Mote scientists settled the resulting coral larvae (babies) to begin growing new coral colonies. Based on the parent corals’ genetics, the scientists estimate the offspring include more than 5,000 new, sexually-produced genotypes of staghorn coral—some of which will survive and join Mote’s carefully documented, long-term collection. These offspring will be used in genetic, epigenetic and microbiome research, resilience-based restoration. Success in the lab bodes well for coral restoration on the reef: The parent staghorn corals Mote spawned this summer had high synchrony—often releasing their gametes around the same time—which means outplanted corals with the same genetic makeup have better chances of successful reproduction after being restored to the reef. That’s particularly important because spawning synchrony is declining in wild corals of this and other species.
• Corals from Mote’s past sexual reproduction events are now thriving on the reef. This year, Mote scientists began restoring reefs with their new, sexually produced genotypes of native staghorn coral. These “sexual recruits,” planted on Looe Key within Florida’s Coral Reef—showed a whopping survival rate of 99.7% after one month and continued signs of success afterward. Other staghorn coral genotypes produced sexually by Mote were outplanted at two new restoration sites, also exceeding 99% survival after one month.
• Mote scientists also settled and began growing  new genotypes of mountainous star coral for research and restoration—yet using larvae provided through sexual reproduction efforts by our partners at Biscayne National Park.

Keeping up with our own success:

With plenty of new coral genotypes being produced at Mote’s IC2R3 campus, Mote scientists are seeking faster ways to screen them for resistance to stress—to help restoration efforts continue growing in scale. For example, Mote scientists can screen 20-30 coral genotypes per year for resilience to stressors, but in time, they hope to be able to screen hundreds to keep pace their own successful production of new coral genotypes. Research and partnership are key for the next steps. In the coming year, Mote will seek to develop new methods for screening corals to high temperatures and ocean acidification more quickly. New screening technology for heat tolerance is currently being developed by one of Mote’s research partners; when it’s available, Mote will begin a series of trials to test its efficacy.

We’re growing to help coral reefs keep going:

Year 2020 marked the 10-year anniversary of Mote’s underwater coral nursery at Looe Key, where corals of multiple species are raised for restoration and research. Most corals there were propagated asexually—a common practice of breaking parent corals into pieces that continue growing into new corals, which have the same genes as their parents. Now, Mote has added 35 new, sexually produced staghorn coral genotypes to our field nursery and restoration pipeline, providing a continued source of fresh genetics for restoration.

This year, Mote scientists established two spawning nurseries that will raise elkhorn corals to sexually mature size. These nurseries are projected to be used for land-based spawning and assisted sexual reproduction of this threatened species in 2021.

With an ever-deepening commitment to saving Earth’s coral reefs, Mote announced two exciting expansions of our coral science and restoration footprint (details in the “Looking Ahead” section here):

• This year, Mote was honored to establish a partnership with the famed Bud n’ Mary’s Marina to bring the first science-based coral nursery for restoration to Islamorada in the Upper Florida Keys
• When this annual report went to press, Mote had just completed construction of its new International Coral Gene Bank—a “Noah’s Ark” to protect living corals and their genetic diversity for future restoration and research. This state-of-the-art, secure, Category 5 hurricane-resistant facility is located inland at Mote Aquaculture Research Park in eastern Sarasota County, Florida, and is designed to store dozens of genotypes from at least 30 coral species in triplicate. Mote’s gene bank vision began with a focus on corals endemic to Florida and U.S. jurisdictions of the Caribbean, and it is expanding to include others from around the globe.

Mote’s coral research and restoration activities described above were permitted by NOAA’s Florida Keys National Marine Sanctuary (FKNMS-2018-088-A2 & FKNMS-2015-163-A3). Funding for this research is provided by the National Science Foundation (Award #: 1452538), NOAA Restoration Center (NA19NMF4630259), the State of Florida, a Mote Postdoctoral Fellowship award to Dr. Hanna Koch and philanthropic donations to Mote from several sources.

CORAL SCIENCE: WHERE BREAKTHROUGHS BEGIN

Mote scientists are problem solvers at the best of times—and especially during challenging times. This year, while communities scrambled to cope with COVID-19, Mote scientists were working with similar fervor to help coral reefs—the “rainforests of the sea”—fight their own battles against disease and other threats.

• Deciphering a dangerous disease:
  • In March 2020, Mote scientists and partners published the largest-scale, peer-reviewed epidemiological study to date on the unprecedented and deadly outbreak of stony coral tissue loss disease (SCTLD) across multiple years throughout Florida’s Coral Reef.

    The study “Spatial Epidemiology of the Stony-Coral-Tissue-Loss Disease in Florida” was published in Frontiers in Marine Science by researchers at Mote, Florida Fish and Wildlife Conservation Commission (FWC), Florida Institute of Technology and a former Mote intern now at University of Guam. The study was funded by the Florida Department of Environmental Protection (DEP).

    Scientists already knew that SCTLD has spread like wildfire through Florida’s Coral Reef since 2014 and reached several Caribbean sites recently, causing major mortality in multiple species of reef-building corals. The unknown pathogen(s) are suspected to be bacterial, waterborne and spread contagiously.

    This new, “big-picture” study made sobering new discoveries while helping validate results of other, smaller-scale projects to date. The study showed that SCTLD: can form hotspots of more than 140 kilometers (87 miles) at once; is more prevalent on deeper reefs with more diverse coral species; spreads at an unfortunately persistent pace regardless of changing temperature and nutrients; and—as suspected—appears to be spread contagiously by a novel pathogen or group of pathogens. The latter finding, while not unexpected, provides another great reason for divers to follow best practices to avoid spreading SCTLD.

    The study also raised intriguing possibilities. For example, it suggested that bottom-water currents and sediments could play bigger roles in the disease spread than previously realized. In addition, the study reported that a hotspot of what may have been SCTLD occurred off Palm Beach and Broward counties in 2014. However, the study found no cases recorded off of Virginia Key in Miami-Dade County, where the disease was previously reported as originating, suggesting further research into the location of origination of the outbreak is warranted.

  • In June, scientists announced the first discovery of similar “bacterial signatures” among corals sick with SCTLD and nearby water and sediments. Results hint at how this deadly disease might spread, and which bacteria are associated with it, on Florida’s Coral Reef.

    This study is only the second peer-reviewed publication focused on characterizing the community of bacteria (the bacterial “microbiome”) associated with these sick corals—a critical effort because the disease is believed to be caused by one or more bacterial pathogens.

    The new study was published in the peer-reviewed scientific journal Frontiers in Microbiology and authored by scientists from UM, NOAA, Mote, and FWC’s Fish and Wildlife Research Institute. The project was supported by a grant from the U.S. Environmental Protection Agency and by NOAA’s ‘Omics Initiative.

    The scientists found that two groups of bacteria, Rhodobacterales and Rhizobiales, were associated with the disease lesions on corals. That doesn’t necessarily mean they are the primary pathogens but suggests they may be important. They were also found in the sediment and water, with Rhodobacterales elevated in zones affected by the disease compared with zones yet to be affected.

  • Many other studies of SCTLD and other coral diseases have been advancing this year. Examples:
    • Developing methods for the treatment of coral diseases at Virgin Islands National Park, St. John and Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands
    • Collaborating with the Department of Environmental Protection, the University of Miami, and NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) to find a biomarker for resistance for SCTLD and use the information to identify and reproduce disease-resistant corals and create new resistant genotypes
    • Collaborating with Oregon State University to examine the effect of nutrients (including those contributed by human activity in polluted, nutrient-rich runoff) in water on coral disease susceptibility
    • Collaborating with FWC and NOAA AOML to characterize the microbiome of corals with SCTLD to determine if a specific microbial signature exists among species
    • Finalizing development of a long-term deployment “Coral Cam,” which will help scientists identify when and how coral mortality occurs— allowing scientists to pick the best genotypes to resist specific stressors
    • Exploring how butterflyfish use sensory cues to locate infected corals from long distances and target SCTLD-lesioned corals
    • Evaluating the epigenetic/microbiome-mediated mechanisms underlying the heritability of disease resistance in staghorn corals (in collaborations with Texas A&M University and University of Oregon, respectively)
• Corals get a break from heat-driven bleaching:

  When corals are stressed by increased water temperatures, they can bleach—lose the colorful algae that live in their tissues. These algae are necessary for the corals’ survival, and bleached corals eventually perish if conditions don’t improve.

  Fortunately, coral reefs in the Florida Keys experienced relatively mild bleaching in the past year, according to Mote scientists and community-science volunteers in Mote’s BleachWatch program, operated in partnership with NOAA’s Florida Keys National Marine Sanctuary.

  Mote received 292 BleachWatch reports from 20 different trained observers this year. Bleaching was mild overall but a few inshore sites showed more than 50% of corals bleached in August and September 2020.

  Mote scientists are grateful to all those who continued to report environmental changes in the Keys through BleachWatch and Mote’s other monitoring program, C-OCEAN (Community-Based Observations of Coastal Ecosystems and Assessment Network), even amid the challenges of the COVID-19 pandemic.