Category: Scientific Papers (Abstract & PDF)

Pre-Exposure to a Variable Temperature Treatment Improves the Response of Acropora Cervicornis to Acute Thermal Stress

DEMERLIS, A., A. Kirkland, M.L. Kaufman, A.B. MAYFIELD, N. FORMEL, G. KOLODZIEJ, D.P. Manzello, D. Lirman, N. Traylor-Knowles, and I.C. ENOCHS. Pre-exposure to a variable temperature treatment improves the response of Acropora cervicornis to acute thermal stress. Coral Reefs, 41(2):435-445 (https://doi.org/10.1007/s00338-022-02232-z) (2022). 

Abstract: Given that global warming is the greatest threat to coral reefs, coral restoration projects have expanded worldwide with the goal of replenishing habitats whose reef-building corals succumbed to various stressors. In many cases, however, these efforts will be futile if outplanted corals are unable to withstand warmer oceans and an increased frequency of extreme temperature events. Stress-hardening is one approach proposed to increase the thermal tolerance of coral genotypes currently grown for restoration…

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Projections of faster onset and slower decay of El Niño in the 21st century

Lopez, H., Lee, S. K., Kim, D., Wittenberg, A., & Yeh, S. W. (2021). Projected Increase in Fast-Growing and Slow-Dissipating El Niño Events in the 21st Century.

Abstract: Future changes in the seasonal evolution of El Niño – Southern Oscillation (ENSO) during the onset and decay phases have received little attention by the research community. This work investigates the projected changes in the spatio-temporal evolution of El Niño events in the 21st Century (21C) using a large ensemble simulation of a couple general circulation model under anthropogenic forcing. Here we show that El Niño is projected to (1) initiate sooner in boreal spring, (2) to grow at a faster rate, (3) to persist longer over the eastern and far eastern Pacific, and (4) to have a broader impact on remote teleconnections. Significant changes in the tropical Pacific mean state, dominant feedback processes, and a projected increase in stochastic westerly wind burst forcing largely explain the fast growing and slow dissipating El Niño in the late 21C. Important implications of these findings are that the global climate impacts are projected to become more significant and persistent, owing to the extended persistence of El Niño.

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Synergy of In Situ and Satellite Ocean Observations in Determining Meridional Heat Transport in the Atlantic Ocean

Dong, S., Goni, G., Domingues, R., Bringas, F., Goes, M., Christophersen, J., & Baringer, M. (2021). Synergy of In Situ and Satellite Ocean Observations in Determining Meridional Heat Transport in the Atlantic Ocean. Journal of Geophysical Research: Oceans, 126(4), e2020JC017073.

Abstract: The Atlantic meridional overturning circulation (AMOC) is an oceanic conveyor belt that transports large amounts of heat northwards throughout the Atlantic Ocean. Variations in the heat carried by the AMOC have pronounced impacts on regional and global extreme weather (hurricanes, heat waves, monsoons, etc.), climate, and sea level. Because of its importance, several efforts from the international community are underway to monitor the AMOC at a few latitudes based on in situ oceanographic instruments. The majority of these estimates, however, only span over relatively short and recent time periods…

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Remote Impact of the Equatorial Pacific on Florida Current Transport

Dong, S., Volkov, D. L., Goni, G., Pujiana, K., Tagklis, F., & Baringer, M. (2022). Remote Impact of the Equatorial Pacific on Florida Current Transport. Geophysical Research Letters, e2021GL096944.

Using in-situ and satellite observations, this study is the first to demonstrate that ENSO temperature anomalies in the equatorial Pacific force Florida Current transport (FCT) anomalies 3 months later.  The connection between FCT and ENSO is through ENSO’s impact on sea level on the eastern side of the Florida Straits, which is associated with anomalous oceanic convergence/divergence in the Caribbean region and the Bahamas forced by ENSO-induced wind stress curl changes. This established relationship gives some predictability of the Florida Current transport and coastal sea level changes with a 3-month lead time, which can benefit coastal communities, particularly during strong El Niño and La Niña events.

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Frontiers in Ocean Observing

Kappel, E.S., S.K. Juniper, S. Seeyave, E. Smith, and M. Visbeck, eds. 2021. Frontiers in Ocean Observing: Documenting Ecosystems, Understanding Environmental Changes, Forecasting Hazards. A Supplement to Oceanography 34(4), 102 pp., https://doi.org/10.5670/oceanog.2021.supplement.02.

Articles in this inaugural Frontiers in Ocean Observing supplement to Oceanography describe new technologies and reveal some exciting results that advance our understanding of the world ocean and its resources and support its sustainable use and management. Topics covered align with the priorities of the UN Decade of Ocean Science for Sustainable Development (2021–2030). Five articles in this Supplement were co-authored by AOML scientists and science support personnel: Climate-Relevant Ocean Transport Measurements in the Atlantic and Arctic Oceans, Monitoring Boundary Currents Using Ocean Observing Infrastructure, An Integrated Observing Effort for Sargassum Monitoring and Warning in the Caribbean Sea, Tropical Atlantic, and Gulf of Mexico, Uncrewed Ocean Gliders and Saildrones Support Hurricane Forecasting and Research, and The Technological, Scientific, and Sociological Revolution of Global Subsurface Ocean Observing.

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Revisiting the Recharge and Discharge Processes for Different Flavors of El Niño

Chakravorty, S., Perez, R. C., Gnanaseelan, C., & Anderson, B. T. (2021). Revisiting the recharge and discharge processes for different flavors of El Niño. Journal of Geophysical Research: Oceans, 126(11), e2020JC017075.

Plain Language Summary: The El Niño-Southern Oscillation (ENSO) is the largest source of year-to-year climate variability. ENSO has a pronounced influence on regional and global circulation and precipitation patterns and thus has considerable worldwide socio-economical impacts. El Niño, the warm phase of ENSO, exhibits modulation in the longitudinal location of its maximum warming, creating what is referred to as ENSO diversity. For conventional El Niño events, maximum surface warming is located in the eastern equatorial Pacific, for which subsurface warming along the tropical Pacific has proven to serve as a predictor several months in advance. Previous studies disagree on whether this subsurface warming is similarly essential for El Niño events that have peak surface warming in the central Pacific. The authors developed an improved method for identifying these two types of El Niño in an ocean reanalysis product. Using this improved method, they found no clear evidence of a subsurface warming precursor for the central Pacific El Niño events along the equator. This lack of a tropical subsurface precursor limits our ability to predict these types of El Niño events.

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Coral persistence despite extreme periodic pH fluctuations at a volcanically acidified Caribbean reef

Enochs, I. C., Formel, N., Manzello, D., Morris, J., Mayfield, A. B., Boyd, A., … & Hendee, J. (2020). Coral persistence despite extreme periodic pH fluctuations at a volcanically acidified Caribbean reef. Coral Reefs, 39(3), 523-528.

Abstract: Naturally acidified environments, such as those caused by volcanic CO2 venting, reveal how complex coral reef ecosystems may respond to future ocean acidification conditions. Few of these sites have been described worldwide, and only a single such site is known from the Caribbean. Herein, we have characterized an area of volcanic acidification at Mayreau Island, St. Vincent and the Grenadines. Despite localized CO2 enrichment and gas venting, the surrounding area has high hard and soft coral cover, as well as extensive carbonate frameworks. Twice daily extremes in acidification, in some cases leading to undersaturation of aragonite, are correlated with tidal fluctuations and are likely related to water flow. Corals persisting despite this periodic acidification can provide insights into mechanisms of resilience and the importance of natural pH variability on coral reefs.

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Global Oceans: Meridional Overturning Circulation and Heat Transport in the Atlantic Ocean

VOLKOV, D.L., S. DONG, M. Lankhorst, M. KERSALÉ, A. Sanchez-Franks, C. SCHMID, J. Herrford, R.C. PEREZ, B.I. Moat, P. Brandt, C.S. MEINEN, M.O. BARINGER, E. Frajka-Williams, and D.A. Smeed.  Global oceans:  Meridional overturning circulation and heat transport in the Atlantic Ocean. In State of the Climate in 2020, J. Blunden, and T. Boyer (eds.). Bulletin of the American Meteorological Society, 102(8):S176-S179 (https://doi.org/10.1175/BAMS-D-21-0083.1) (2021).

The zonally integrated component of surface and deep currents, known as the meridional overturning circulation (MOC), plays an important role in Earth’s climate because it provides a mechanism for ocean meridional heat transport (MHT). The observing system for the Atlantic MOC/MHT consists of several basin-wide moored arrays as well as the combination of satellite altimetry and in situ (mainly Argo and eXpendable BathyThermograph [XBT]) measurements (Fig. 3.21a; e.g., Frajka-Williams et al. 2019)…

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

Manzello, D. P., Kolodziej, G., Kirkland, A., Besemer, N., & Enochs, I. C. (2021). Increasing coral calcification in Orbicella faveolata and Pseudodiploria strigosa at Flower Garden Banks, Gulf of Mexico. Coral Reefs, 1-15.

Abstract: 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)…

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The Role of the Gulf of Mexico Ocean Conditions in the Intensification of Hurricane Michael (2018)

Le Hénaff, M., Domingues, R., Halliwell, G., Zhang, J. A., Kim, H. S., Aristizabal, M., … & Goni, G. The role of the Gulf of Mexico ocean conditions in the intensification of Hurricane Michael (2018). Journal of Geophysical Research: Oceans, e2020JC016969.

Abstract: Hurricane Michael formed on October 7, 2018, in the Northwestern Caribbean Sea, and quickly traveled northward through the Gulf of Mexico, making landfall on the Florida panhandle as a devastating Category 5 hurricane only 3 days later. Before landfall, Michael underwent rapid intensification, despite unfavorable atmospheric conditions. Using observations, we characterized the key ocean features encountered by Michael along its track, which are known for favoring hurricane intensification: high sea surface temperatures, upper ocean heat content and low salinity barrier layer conditions. Ocean observations were consistent with suppressed hurricane-induced upper ocean cooling, which could only be observed by underwater gliders, and showed that Hurricane Michael constantly experienced sea surface temperatures above 28°C…

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