Flower Garden Banks Research Articles

Growth characterization of mesophotic rhodoliths in the northern Gulf of Mexico using radiocarbon dating

Boxwork rhodoliths are characterized by a multitaxonomic composition and excessive void spaces, and they are distributed from intertidal to mesophotic depths. Growth rates and patterns in rhodoliths from shallower depths and simpler morphologies have been assessed using incremental and geochemical analyses, but rhodoliths from mesophotic depths have been harder to access and require more studies. Boxwork rhodoliths have proved too structurally complex for age and growth rate assessment techniques such as stable oxygen isotopes profiling or elemental mapping. We therefore utilized sequential radiocarbon analysis for growth characterization of mesophotic boxwork rhodoliths. Rhodoliths were collected from the Flower Garden Banks National Marine Sanctuary in the northern Gulf of Mexico from one location at 48–72 m and another at 103 m. Specimens were extensively sampled for radiocarbon concentrations from predicted nucleation points and along growth axes. From depths of 48–72 m, nucleation ages ranged from 795 ± 20 to 3270 ± 25 14C yr B·P. From depths of 103 m, nucleation ages ranged from 8960 ± 110 to 13,050 ± 150 14C yr B.P., dating back to the end of the Pleistocene in some cases. Several rhodoliths contained evidence of growth hiatuses, with deeper samples displaying age reversals that complicated the apparent growth history. We define age reversals to be non-sequential ages within a sampling sequence, typically a singular age before the return to normal age sequence. The research presented here includes the oldest known living rhodoliths, with the oldest rhodoliths grown before and after Holocene sea-level stabilization. These results have implications for the use of rhodoliths as paleoenvironmental indicators, and provide better understanding of the range and volume of carbonate production in these habitats.

Mesoscale Eddies Influence Coral Reef Environments in the Northwest Gulf of Mexico

AbstractCoral reefs globally are experiencing more frequent and severe warming events due to anthropogenic driven climate change. Subtropical reefs experience more seasonal variability than lower latitude reefs making them typically more resilient to climate change. With relatively stable coral cover in comparison to other global coral reefs, Flower Garden Banks National Marine Sanctuary (FGBNMS) in the Gulf of Mexico is a series of 17 reefs and banks located on the continental shelf‐edge containing a variety of shallow (0–30 m) and mesophotic (30–150 m) coral reef habitats. Here, we use satellite data products to associate open ocean Argo float profiles with eddy features over FGBNMS to study the shelf‐edge reef environment spanning nearly two decades (2003–2022). Satellite data show that FGBNMS is frequently influenced (∼15 days/month) by mesoscale eddies. The upper water column variability (0–25 m) is most influenced by the seasonal mixed layer despite eddy interaction. Subsurface seasonal ranges of temperature and salinity are enhanced or suppressed depending on the influence of eddies in relation to the mixed layer depth. Within the mesophotic zone (0–150 m), the largest range of thermal variability between anticyclonic and cyclonic eddies is between 50 and 150 m upwards of 5°C. However, these observed dynamics will likely change as a result of eddy variability associated with projected warming and Loop Current weakening, leading to increased thermal stress in the future.

A quantitative assessment of the status of benthic communities on US Atlantic coral reefs using a novel standardized approach

As coral reefs decline globally, the need for an objective approach to quantify the status and trends of corals has become increasingly important. Empirical data on predisturbance conditions are rare, and integrating data from multiple and disparate survey designs and methods can be analytically challenging. Our goal was to conduct a holistic, data-driven evaluation of the status of corals and benthic communities in US Atlantic coral reef jurisdictions: Florida, Flower Garden Banks, Puerto Rico, and the US Virgin Islands. A quantitative approach based upon standardized data was used to compare the change in multiple indicators of coral condition (hard coral, macroalgae, and crustose coralline algae cover, coral density, and old mortality) from historic to current conditions in each geographic region. For each indicator, historic, reference baseline conditions from long-term monitoring data or literature data were first identified, reviewed, and classified on a categorical scale from Very Good to Critical by regional experts to account for condition changes that pre-dated current monitoring data. A reference-centering approach then allowed for categorization of statistical changes from historic to current conditions on the same scale to produce results that could be communicated to a broad audience. Our findings show continued declines for multiple indicators in all regions except Flower Garden Banks, illustrate particularly dire declines from regions that had been impacted by Stony Coral Tissue Loss Disease at the most recent monitoring included in this study, and demonstrate the increasingly critical need for effective coral reef conservation.

Intersection of coral molecular responses to a localized mortality event and ex situ deoxygenation.

In July 2016, East Bank of Flower Garden Banks (FGB) National Marine Sanctuary experienced a localized mortality event (LME) of multiple invertebrate species that ultimately led to reductions in coral cover. Abiotic data taken directly after the event suggested that acute deoxygenation contributed to the mortality. Despite the large impact of this event on the coral community, there was no direct evidence that this LME was driven by acute deoxygenation, and thus we explored whether gene expression responses of corals to the LME would indicate what abiotic factors may have contributed to the LME. Gene expression of affected and unaffected corals sampled during the mortality event revealed evidence of the physiological consequences of the LME on coral hosts and their algal symbionts from two congeneric species (Orbicella franksi and Orbicella faveolata). Affected colonies of both species differentially regulated genes involved in mitochondrial regulation and oxidative stress. To further test the hypothesis that deoxygenation led to the LME, we measured coral host and algal symbiont gene expression in response to ex situ experimental deoxygenation (control = 6.9 ± 0.08 mg L-1, anoxic = 0.083 ± 0.017 mg L-1) in healthy O. faveolata colonies from the FGB. However, this deoxygenation experiment revealed divergent gene expression patterns compared to the corals sampled during the LME and was more similar to a generalized coral environmental stress response. It is therefore likely that while the LME was connected to low oxygen, it was a series of interconnected stressors that elicited the unique gene expression responses observed here. These insitu and ex situ data highlight how field responses to stressors are unique from those in controlled laboratory conditions, and that the complexities of deoxygenation events in the field likely arise from interactions between multiple environmental factors simultaneously.

An annotated and illustrated identification guide to common mesophotic reef sponges (Porifera, Demospongiae, Hexactinellida, and Homoscleromorpha) inhabiting Flower Garden Banks National Marine Sanctuary and vicinities.

Sponges are recognized as a diverse and abundant component of mesophotic and deep-sea ecosystems worldwide. In Flower Garden Banks National Marine Sanctuary region within the northwestern Gulf of Mexico, sponges thrive among diverse biological and geological habitats between 16-200+ m deep (i.e., coral reefs and communities, algal nodules, and coralline algae reefs, mesophotic reefs, patch reefs, scarps, ridges, soft substrate, and rocky outcrops). A synoptic guide is presented, developed by studying common sponge species in the region, through direct sampling and in-situ photographic records. A total of 64 species is included: 60 are Demospongiae (14 orders), two are Hexactinellida (one order), and two are Homoscleromorpha (one order). Thirty-four taxa are identified to species and 13 were identified to have affinity with, but were not identical to, a known species. Fifteen taxa could only be identified to genus level, and the species remain as uncertain (incerta sedis), with the potential to represent new species or variants of known species. One specimen received only a family assignation. This study extends geographic or mesophotic occurrence data for eleven known species and includes several potentially new species. This work improves our knowledge of Gulf of Mexico sponge biodiversity and highlights the importance of the region for scientists and resource managers.

The Flower Garden Banks Siderastrea siderea coral as a candidate Global boundary Stratotype Section and Point for the Anthropocene series

The proposed Anthropocene Global Boundary Stratotype Section and Point (GSSP) candidate site of West Flower Garden Bank (27.8762°N, 93.8147°W) is an open ocean location in the Gulf of Mexico with a submerged coral reef and few direct human impacts. Corals contain highly accurate and precise (<±1 year) internal chronologies, similar to tree rings, and their exoskeletons are formed of aragonite and can be preserved in the rock record. Here we present results from a large Siderastrea siderea coral (core 05WFGB3; 1755–2005 CE) sampled with annual and monthly resolutions that show clear markers of global and regional human impacts. Atmospheric nuclear bomb testing by-products (14C, 239+240Pu) have clear increases in this coral starting in 1957 for 14C and the first increase in 1956 for 239+240Pu (potential bases for the Anthropocene GSSP). Coral δ13C declined especially after 1956 consistent with the Suess effect resulting from the burning of fossil fuels. Coral skeletal δ15N starts to increase in 1963 corresponding with the increase in agricultural fertilizers. Coral Hg concentrations (1933–1980) loosely track fluctuations in industrial pollution and coral Ba/Ca increases from 1965–1983 when offshore oil operations expand after 1947. Coral temperature proxies contain the 20th-century global warming trend whereas coral growth declines during this interval.

Coral disease outbreak at the remote Flower Garden Banks, Gulf of Mexico

East and West Flower Garden Bank (FGB) are part of Flower Garden Banks National Marine Sanctuary (FGBNMS) in the northwest Gulf of Mexico. This geographically-isolated reef system contains extensive coral communities with the highest coral cover (>50%) in the continental United States due, in part, to their remoteness and depth, and have historically exhibited low incidence of coral disease and bleaching despite ocean warming. Yet in late August 2022, disease-like lesions on seven coral species were reported during routine monitoring surveys on East and West FGB (2.1–2.6% prevalence). A series of rapid response cruises were conducted in September and October 2022 focused on 1) characterizing signs and epidemiological aspects of the disease across FGB and within long-term monitoring sites, 2) treating affected coral colonies with Base 2B plus amoxicillin, and 3) collecting baseline images through photostations and photomosaics. Marginal and/or multi-focal lesions and tissue loss were observed, often associated with substantial fish and invertebrate predation, affecting the dominant coral species Pseudodiploria strigosa (7–8% lesion prevalence), Colpophyllia natans (11–18%), and Orbicella spp. (1%). Characterizing this disease event during its early epidemic phase at East and West FGB provides a critical opportunity to observe how coral disease functions in a relatively healthy coral ecosystem versus on reefs chronically affected by various stressors (e.g., Caribbean reefs adjacent to urban centers). Insights into the etiology, spread, and impacts of the disease can ultimately inform efforts to mitigate its effects on coral communities.

Geological faulting a possible trigger for brine-induced reef mortality at East Flower Garden Bank, NW Gulf of Mexico

Localized mortality within reef crest depressions in Flower Garden Banks National Marine Sanctuary in 2016 may have resulted from inundation by brine that erupted when reef rock collapsed into a solution cavern in the salt dome below the bank. This mechanism offers an alternative explanation of mortality that has previously been attributed to hypoxia caused by either offshore movement of brackish, organically rich flood waters, upwelling, or both. Faults at the mortality site, discovered previously, and field observations of water conditions and mortality patterns during the event suggest that salt dissolution, undermining, and collapse may have driven a brine eruption. Elsewhere on the bank, anoxic, sulfurous brine flows have been found adjacent to areas of seafloor collapse, producing localized, brine-induced stress and mortality, but evidence of acute, lethal brine eruptions caused by active faulting would be novel for this system.

Fish community characterization of mid-shelf and shelf- edge mesophotic coral ecosystems in the expanded Flower Garden Banks National Marine Sanctuary

The mid to outer continental shelf in the northern Gulf of Mexico is composed of a patchy distribution of coral and rock reefs designated high priority for marine protection. To better understand the influence of deepwater habitat on fish community dynamics and conservation needs, we compared altiphotic-mesophotic transition (20– 40 m), upper mesophotic (40–60 m), and middle mesophotic (60–80 m) fish communities between mid-shelf (Sonnier Bank) and outer-shelf (McGrail Bank) banks from before their inclusion into the Flower Garden Banks National Marine Sanctuary. Surveys performed over two years with a remotely operated vehicle indicated that each bank and depth zone had distinct fish communities. Both banks were dominated by planktivores and piscivores, with an increase in depth specialists (e.g., deepwater anthiids and serranids) at the deeper zones surveyed, particularly in middle mesophotic depths at McGrail. An increased frequency of snappers, groupers, and amberjack was observed at Sonnier Bank, predominately in mesophotic depths, indicating the Sonnier Mesophotic Coral Ecosystem as either a hotspot or potential refuge for meso- and apex predators. This study fills a temporal gap in fish community dynamics of these two banks, serving to create a more continuous dataset available to assist in conservation assessments of the Flower Garden Banks National Marine Sanctuary.

Characterizing the Biological Community before and after Partial Removal of an Offshore Gas Platform in the Northwestern Gulf of Mexico.

High Island A-389-A (HI-A-389-A) is a gas platform situated in 125 m water within Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico, and provides habitat to a diverse array of benthic organisms and fish species. Platform production ceased in 2012, beginning the decommissioning process for structural removal. Rather than complete removal of the structure, the lower portion was left intact as an artificial reef and the upper 21 m was removed. The biological communities (benthic and fish) were characterized during diver and remotely operated vehicle surveys, both before and after removal of the upper structure. The platform's benthic community, primarily categorized as fouling organisms, was mainly composed of sponges, hydroids, macroalgae, bivalves, zoanthids, and stony corals. The dominant stony coral was orange cup coral (Tubastraea sp.), an exotic species, while native coral species were rare. Fish species were predominantly demersal planktivores. Analyses of the benthic and fish communities documented four distinct biological zones strongly associated with depth. Significant differences in the benthic community were observed after partial removal and varied with depth, including the loss of hydroids, increase in macroalgae cover, and sponge and coral community changes. Both demersal and pelagic fish communities exhibited significant differences by depth after removal but no significant changes were observed in federally managed species. Results reflect changes in benthic and fish communities after partial removal of the platform that is likely, in part, influenced by structure removal and temporal variations.

Improved biodiversity detection using a large-volume environmental DNA sampler with in situ filtration and implications for marine eDNA sampling strategies

Metabarcoding analysis of environmental DNA samples is a promising new tool for marine biodiversity and conservation. Typically, seawater samples are obtained using Niskin bottles and filtered to collect eDNA. However, standard sample volumes are small relative to the scale of the environment, conventional collection strategies are limited, and the filtration process is time consuming. To overcome these limitations, we developed a new large – volume eDNA sampler with in situ filtration, capable of taking up to 12 samples per deployment. We conducted three deployments of our sampler on the robotic vehicle Mesobot in the Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico and collected samples from 20 to 400 m depth. We compared the large volume (∼40–60 L) samples collected by Mesobot with small volume (∼2 L) samples collected using the conventional CTD rosette – mounted Niskin bottle approach. We sequenced the V9 region of 18S rRNA, which detects a broad range of invertebrate taxa, and found that while both methods detected biodiversity changes associated with depth, our large volume samples detected approximately 66% more taxa than the CTD small volume samples. We found that the fraction of the eDNA signal originating from metazoans relative to the total eDNA signal decreased with sampling depth, indicating that larger volume samples may be especially important for detecting metazoans in mesopelagic and deep ocean environments. We also noted substantial variability in biological replicates from both the large volume Mesobot and small volume CTD sample sets. Both of the sample sets also identified taxa that the other did not – although the number of unique taxa associated with the Mesobot samples was almost four times larger than those from the CTD samples. Large volume eDNA sampling with in situ filtration, particularly when coupled with robotic platforms, has great potential for marine biodiversity surveys, and we discuss practical methodological and sampling considerations for future applications.

Assessment of Rhodolith Diversity in the Northwestern Gulf of Mexico Including the Description of Sporolithon gracile sp. nov. (Sporolithales, Rhodophyta), and Three New Species of Roseolithon (Hapalidiales, Rhodophyta)

In the past, non-geniculate coralline algae in the northwestern Gulf of Mexico have been identified based primarily on comparative morpho-anatomy. Recent studies employing DNA sequencing techniques combined with morpho-anatomical studies using SEM have revealed a wealth of previously undocumented diversity of rhodolith-forming non-geniculate coralline algae in the Corallinales, Hapalidiales and Sporolithales from mesophotic hard bank communities at 45-90 meters depth. Although many advances in the last decade have been made in clarifying species names and describing new species of corallines from offshore Louisiana and Texas, total diversity estimates are still incomplete and many species remain to be described. Collections from offshore Louisiana at Parker Bank in the newly expanded Flower Garden Banks National Marine Sanctuary yielded thin, finely branched rhodoliths. DNA sequence analyses of plastid-encoded psbA and rbcL loci, and nuclear-encoded LSU rDNA of these rhodolith-forming specimens revealed that some belong to an unnamed species of Sporolithon (Sporolithales) that we herein newly describe. Additionally, comparative DNA sequence analyses of rhodolith collections from Ewing Bank and other hard banks offshore Louisiana were conducted to assess rhodolith diversity in these mesophotic communities. The results revealed new reports of taxa for the region, including new rhodolith-forming species of Roseolithon (Hapalidiales) to be described herein as well. Our new biodiversity findings will be compared with historical studies from the NW Gulf of Mexico.

Microbial Community Dynamics Provide Evidence for Hypoxia during a Coral Reef Mortality Event.

In July 2016, a severe coral reef invertebrate mortality event occurred approximately 200 km southeast of Galveston, Texas, at the East Flower Garden Bank, wherein ∼82% of corals in a 0.06-km2 area died. Based on surveys of dead corals and other invertebrates shortly after this mortality event, responders hypothesized that localized hypoxia was the most likely direct cause. However, no dissolved oxygen data were available to test this hypothesis, because oxygen is not continuously monitored within the Flower Garden Banks sanctuary. Here, we quantify microbial plankton community diversity based on four cruises over 2 years at the Flower Garden Banks, including a cruise just 5 to 8 days after the mortality event was first observed. In contrast with observations collected during nonmortality conditions, microbial plankton communities in the thermocline were differentially enriched with taxa known to be active and abundant in oxygen minimum zones or that have known adaptations to oxygen limitation shortly after the mortality event (e.g., SAR324, Thioglobaceae, Nitrosopelagicus, and Thermoplasmata MGII). Unexpectedly, these enrichments were not localized to the East Bank but were instead prevalent across the entire study area, suggesting there was a widespread depletion of dissolved oxygen concentrations in the thermocline around the time of the mortality event. Hydrographic analysis revealed the southern East Bank coral reef (where the localized mortality event occurred) was uniquely within the thermocline at this time. Our results demonstrate how temporal monitoring of microbial communities can be a useful tool to address questions related to past environmental events. IMPORTANCE In the northwestern Gulf of Mexico in July 2016, ∼82% of corals in a small area of the East Flower Garden Bank coral reef suddenly died without warning. Oxygen depletion is believed to have been the cause. However, there was considerable uncertainty, as no oxygen data were available from the time of the event. Microbes are sensitive to changes in oxygen and can be used as bioindicators of oxygen loss. In this study, we analyze microbial communities in water samples collected over several years at the Flower Garden Banks, including shortly after the mortality event. Our findings indicate that compared to normal conditions, oxygen depletion was widespread in the deep-water layer during the mortality event. Hydrographic analysis of water masses further revealed some of this low-oxygen water likely upwelled onto the coral reef.

A National Status Report on United States Coral Reefs Based on 2012–2018 Data From National Oceanic and Atmospheric Administration’s National Coral Reef Monitoring Program

National Oceanic and Atmospheric Administration’s Coral Reef Conservation Program supports the National Coral Reef Monitoring Program (NCRMP) in the United States Pacific, Atlantic, Caribbean, and Gulf of Mexico. NCRMP conducts standardized observations of biological, climatic, and socioeconomic indicators across American Samoa, Guam, the Main Hawaiian Islands, the Northwestern Hawaiian Islands, the Northern Mariana Islands, the Pacific Remote Islands, Florida, the Flower Garden Banks, Puerto Rico, and the United States Virgin Islands. NCRMP provides periodic, national-level assessments of the status of United States coral reef ecosystems and communities connected to them. In 2014, NCRMP partnered with the University of Maryland Center for Environmental Science on an unprecedented collaboration between federal and jurisdictional/state agencies, academia, and non-governmental organizations to synthesize NCRMP data into a reporting format designed to be accessible and relevant to the public and policy makers. The process involved multi-year data analyses of key benthic, fish, and climate indicators. In populated jurisdictions, socioeconomic data were integrated to assess public support for management actions, participation in pro-environmental behaviors, and awareness of threats to coral reefs. Jurisdictions were scored using a report-card scale (0–100%) by establishing references for each indicator using best-available historical data or expert opinion where historical data did not exist or were not statistically comparable. Despite overall ecosystem scores of Fair for all combined Atlantic (70%) and Pacific (74%) jurisdictions, the current trend is downward with a majority of United States coral reefs declining and vulnerable to further degradation. Remote, uninhabited reefs had an advantage with respect to reef fish population scores, i.e., Flower Garden Banks (85%) and Pacific Remote Islands (93%), when compared to populated location scores, i.e., Puerto Rico (63%) and Main Hawaiian Islands (66%). All coral reefs are highly impacted by climate change, and climate impacts were more pronounced than expected on remote reefs, i.e., the Northwestern Hawaiian Islands (58%). Presenting results in a report-card style facilitates communication to the public and policy makers, and provides a useful mechanism to garner support for management actions such as expanding protected areas; enforcing existing regulations; increasing climate change education; reducing land-based sources of pollution; and other actions to improve the trajectory of coral reef ecosystem conditions.

Key Life History Attributes and Removal Efforts of Invasive Lionfish (Pterois volitans) in the Flower Garden Banks National Marine Sanctuary, Northwestern Gulf of Mexico

Indo-Pacific lionfish (Pterois volitans and P. miles) are the first marine teleost to have successfully invaded and become established in the Western Atlantic Ocean of the United States, Gulf of Mexico (GoM), and Caribbean Sea. Pterois volitans were first reported in the Flower Garden Banks National Marine Sanctuary (FGBNMS), a protected coral reef system in the northwestern GoM, in 2011. Little is understood about the life history characteristics of lionfish in this ecosystem. This study assessed population characteristics (size, density, age and growth) and removal efforts of lionfish (n = 1,665) at two coral reef sites within FGBNMS for 2015, 2016, and 2018. The annual increment formation in sagittal otoliths was examined to assess the age and growth of lionfish collected in 2018 (n = 100). Lionfish ranged in size from 75 to 444 mm total length (TL) and 4–1,153 g in total weight (TW). Six hundred and ten fish were randomly dissected for sex determination (females = 256, males = 354), females ranged in size from 137 to 348 mm TL and 21–586 g, while males ranged from 118 to 444 mm TL and 18–1,153 g. Interannual variation in mean lionfish density ranged from 26.7 individuals per hectare (ind ha–1) in 2016 to 81.1 ind ha–1 in 2018, while removal effort significantly increased ranging from 1.92 to 5.42 kg diver h–1. Lionfish age ranged from 0 to 10 years, with a mean age of 3.9 years. The observed values of the asymptotic maximum total length (L∞) and Brody’s growth coefficient (K) were 345 mm and 0.30 for females and 415 mm and 0.18 for males. Results suggest lionfish from FGBNMS exhibit markedly lower mean densities, a lower L∞ and growth rate, but attain older ages than lionfish in the Caribbean Sea, Western Atlantic Ocean, and other ecoregions in the northern GoM. This study describes the first key life history parameters and removal efforts for lionfish in a protected, healthy coral reef system in the northwestern GoM that may provide insight into environmental population controls (e.g., ecological resilience). Metrics from this study could be integrated into mechanistic ecological models to determine if FGBNMS is in fact exhibiting natural resilience to the lionfish invasion.

Insights from barium variability in a Siderastrea siderea coral in the northwestern Gulf of Mexico

Coral Ba/Ca is a proxy for seawater barium concentration that varies with upwelling, terrigenous input, and marine productivity whereas coral Sr/Ca varies with temperature. We examine monthly coral Ba/Ca and Sr/Ca before and during offshore oil exploration in a Siderastrea siderea coral from West Flower Garden Bank located on the continental shelf edge in the Gulf of Mexico. Coral Ba/Ca variations lack pulses driven by upwelling or river outflow and are not in sync with coral Sr/Ca that exhibit a different seasonal pattern. Seasonal variations in chlorophyll-a concentration negatively correlate with coral Ba/Ca explaining 25% of that variability. A significant increase in mean coral Ba/Ca of 1.76 μmol/mol between 1931–1944 and 1976–2004 corresponds to the increase in the United States barite production and consumption primarily used in offshore oil drilling, which escalated in the 1970s, suggesting oil drilling operations are increasing seawater Ba concentration in the Gulf of Mexico.

Expanding coral reproductive knowledge using remotely operated vehicles (ROV): broadcast-spawning observations of mesophotic corals at the Flower Garden Banks

Expanding coral reproductive knowledge using remotely operated vehicles (ROV): broadcast-spawning observations of mesophotic corals at the Flower Garden Banks

Increasing coral calcification in Orbicella faveolata and Pseudodiploria strigosa at Flower Garden Banks, Gulf of Mexico

Coral reefs are globally in decline and western Atlantic reefs have experienced the greatest losses in live coral cover of any region. The Flower Garden Banks (FGB) in the Gulf of Mexico are high-latitude, remote reefs that are an outlier to this trend, as they have maintained coral cover ≥ 50% since at least 1989. Quantifying the long-term trends in coral growth of key reef-building coral species, and the underlying environmental drivers, leads to a better understanding of local sensitivities to past changes that will ultimately allow us to better predict the future of reef growth at FGB. We obtained coral cores and constructed growth records for two of the most abundant hermatypic coral species at FGB, Pseudodiploria strigosa and Orbicella faveolata. Our records cover 57 yrs of growth for P. strigosa (1957–2013) and 45 yrs for O. faveolata (1970–2014). Linear extension and calcification rates of both species have increased significantly, but skeletal density did not change over the respective time periods. Extension and calcification data of both species combined were negatively correlated with the discharge from the Atchafalaya River, but positively correlated with maximum sea surface temperatures (SST). These data provide evidence that runoff from the Atchafalaya River impacts FGB corals and is a major control on coral growth at FGB. The increase in growth at FGB can be attributed to the significant warming trend in maximum monthly SSTs. Given the warming trend and recent increase in severity of bleaching at FGB, the prognosis is that bleaching events will become more deleterious with time, which will lead to a breakdown in the positive relationship between coral growth and maximum SST. This study provides further evidence that some high-latitude, cooler reef sites have experienced a stimulation in coral growth with ocean warming.

Gene expression associated with disease resistance and long-term growth in a reef-building coral.

Rampant coral disease, exacerbated by climate change and other anthropogenic stressors, threatens reefs worldwide, especially in the Caribbean. Physically isolated yet genetically connected reefs such as Flower Garden Banks National Marine Sanctuary (FGBNMS) may serve as potential refugia for degraded Caribbean reefs. However, little is known about the mechanisms and trade-offs of pathogen resistance in reef-building corals. Here, we measure pathogen resistance in Montastraea cavernosa from FGBNMS. We identified individual colonies that demonstrated resistance or susceptibility to Vibrio spp. in a controlled laboratory environment. Long-term growth patterns suggest no trade-off between disease resistance and calcification. Predictive (pre-exposure) gene expression highlights subtle differences between resistant and susceptible genets, encouraging future coral disease studies to investigate associations between resistance and replicative age and immune cell populations. Predictive gene expression associated with long-term growth underscores the role of transmembrane proteins involved in cell adhesion and cell–cell interactions, contributing to the growing body of knowledge surrounding genes that influence calcification in reef-building corals. Together these results demonstrate that coral genets from isolated sanctuaries such as FGBNMS can withstand pathogen challenges and potentially aid restoration efforts in degraded reefs. Furthermore, gene expression signatures associated with resistance and long-term growth help inform strategic assessment of coral health parameters.

Oldest Indo-Pacific Lionfish (Pterois volitans/P. miles) Recorded From the Northwestern Gulf of Mexico

Indo-Pacific lionfish (Pterois volitans/miles) were first detected off the coast of Florida in the 1980s, with aquaria release being the most likely mechanism for introduction. Since then, lionfish have proliferated through the Western Atlantic Ocean, Caribbean Sea, and Gulf of Mexico (GOM). Here, we report the oldest lionfish aged on record in the Western Atlantic, removed from Flower Garden Banks National Marine Sanctuary (FGBNMS) in the GOM. In August 2018, a research expedition removed 745 lionfish from FGBNMS, of which a subset were retained for age and growth estimation. The oldest lionfish was a 10 y old male, with total length 375 mm and weight 805 g. The back-calculated birth date (2008) preceded the first observation of lionfish at FGBNMS by 3 years (2011). It is not well understood if lionfish are having negative impacts at FGBNMS, but this report signifies the importance of continued monitoring and removal efforts of this protected area.