Over the past few years, hurricanes in the Gulf of Mexico have broken records for their intensity and the speed at which they have evolved from tropical storms into major cyclones. Hurricane Beryl, for example, strengthened quickly in early July 2024 to become the earliest category 5 hurricane on record. A few months later, in October, Hurricane Milton set a record for intensifying from a tropical depression to a category 5 hurricane in a little over 2 days.
Ocean currents that circulate warm water, including the Loop Current, are well-documented contributors to conditions around the Gulf today.
A wealth of scientific research has implicated anomalously warm seas as the primary cause for intensifying storms in the region [e.g., Liu et al., 2025]. Ocean currents that circulate warm water, including the Loop Current, which transports water from the tropics to latitudes farther north, are also well-documented contributors to conditions around the Gulf today.
But how these currents have behaved in the past and how they are responding to climate change, which may have significant implications for coastal and inland communities adversely affected by cyclones, are not entirely clear. An interdisciplinary group of scientists from Mexico and the United States has been collaborating in recent years to find out.
Why the Loop Current Matters
The Loop Current (Figure 1), which enters the Gulf of Mexico from the Caribbean by way of the Yucatán Channel between the Campeche Peninsula and Cuba, is a major pathway for water flowing from the tropics to the high-latitude North Atlantic. It is a key component of global thermohaline circulation (currents driven by differences in temperature and salinity), providing roughly 85% of the Gulf Stream as it flows through the Straits of Florida, up the U.S. East Coast, and across the North Atlantic. This warm, salty water substantially influences the Gulf’s hydrography, as well as North American and European climate.
Recent research has shed light on concerning trends in the Gulf, the Loop Current, and the broader system of ocean currents. For example, warming upper layer waters in the Gulf appear to be exacerbating rising sea levels there [Thirion et al., 2024], and warm-core eddies shed from the Loop Current have been shown to be an important factor in the rapid intensification of recent Gulf hurricanes [Liu et al., 2025] (Figure 1).
Fig. 1. Eddies shed by the Loop Current into the Gulf’s central basin on 21 July 2018 are evident in this depiction of water velocity measurements (U.S. Navy model). These eddies can have either warm or cool cores. They fundamentally influence environmental conditions in the Gulf, from the temperature balance to biological diversity. The presence of warm-core eddies is now being implicated as a cause of rapid hurricane intensification [
Liu et al., 2025] and accelerated sea level rise [
Thirion et al., 2024].
Slowing of the Atlantic Meridional Overturning Circulation could have far-reaching consequences for the habitability and sustainability of communities all around the Atlantic.
The Loop Current and Gulf Stream together also form an important part of the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is a fundamental component of Earth’s climate system, circulating water north and south through the Atlantic—and from the surface to ocean depths—while also distributing heat and nutrients. With the recently documented slowing of the Gulf Stream [Piecuch and Beal, 2023], concern is growing that a similar change in AMOC, perhaps in response to a warming planet, will upset the global heat balance in the Northern Hemisphere. This sort of change could have far-reaching consequences—from cooling temperatures in northern Europe to rapidly rising sea levels along the U.S. East Coast—for the habitability and sustainability of communities all around the Atlantic.
Since 2017, researchers at the University of Texas Institute for Geophysics (UTIG) and Universidad Nacional Autónoma de México (UNAM) have been collaborating to study the paleoceanographic (i.e., deep-time) history of the Loop Current. Among its activities, this team has gone to sea to acquire high-resolution subseafloor seismic images [Lowery et al., 2024] (Figure 2), generate high-precision seafloor maps, and collect samples from the seafloor.
A broad international effort is also ongoing to understand the Loop Current’s modern complexity [National Academies of Sciences, Engineering, and Medicine (NASEM), 2018], using data from moored instruments, glider measurements across multiple transects in the Yucatán Channel, and modeling (Figure 3). This effort has focused primarily on characterizing today’s Loop Current in the region between eastern Mexico and Cuba, where historical data are limited.
Delving into the Current’s History
A current has been flowing through the Gulf of Mexico since at least the Late Cretaceous (~100 million years ago), and like ocean circulation generally, that current has probably strengthened gradually since then. However, hypotheses about when a current of roughly the size and strength of the modern Loop Current first developed are still debated. Understanding this timing is important because it will implicate either a climatic or nonclimatic (i.e., tectonic) driver for its onset and could therefore inform ideas about whether and how the current will respond to climate change. Whereas this region is now relatively stable tectonically, the state of climate is changing rapidly.
Fig. 2. High-resolution seismic profiles (top) crossing the flank of Campeche Bank/Yucatán Platform, on the west flank of the Yucatán Channel, were collected during a 2022 research cruise. Shown here is profile 1005. The associated line drawing (middle) shows the drifts (i.e., offlapping sediment wedges) that will be targeted for coring (red arrows indicate prospective coring locations), as well as other labeled geologic features [
Lowery et al., 2024]. Biostratigraphic analyses of cores will help researchers deduce the history of the Loop Current. Locations of the seismic profiles collected in 2022, including line 1005, are shown on the map (bottom), along with the locations of moored instrument arrays in the Yucatán Strait used by
Candela et al. [2019] and of the Deep Sea Drilling Project’s (DSDP) Site 95, where cores were collected in 1970. (H = horizon; MS = marine sequence). Click image for larger version. Credit: Adapted from
Lowery et al. [2024]
Building on previous seismic and coring expeditions, the U.S.-Mexico team collected high-frequency, multichannel seismic profiles, multibeam bathymetry, and surficial seafloor sediments (i.e., grab samples) in the Yucatán Channel in 2022 and 2024 (Figure 2) while aboard the UNAM vessel Justo Sierra. The primary imaging target was a series of offlapping sediment drift deposits laid down by the interaction of the Loop Current with the seafloor over millions of years.
Drift deposits are lens-shaped accumulations elongated along the axis of prominent boundary flows like the Loop Current and are promising archives for precision samplings (i.e., piston coring and drilling) and dating. Their fine-grained compositions and rich concentrations of microfossil skeletal remains of benthic (bottom-dwelling) and calcareous planktonic (floating) foraminifera provide valuable chronological markers and proxy records of ocean temperature and salinity, important for reconstructing past oceanographic and climatic conditions. Preliminary observations from samples collected confirm that these skeletal remains are diverse and excellently preserved.
The at-sea data acquisition in the Gulf led to two follow-on workshops. The first, held in Mexico City in August 2023, brought together international investigators to examine the new seismic data from the Yucatán Channel and begin to identify potential sites to propose for future drilling (Figure 2). The second, held in Austin, Texas, in September 2024, focused on integrating the paleoceanographic perspectives of the Loop Current with knowledge of its modern physical oceanography.
As illuminated during discussions at the Austin workshop, physical oceanographic measurements collected across the Yucatán Channel from 2012 to 2016 using moored instrument arrays (Figure 2) established the modern Loop Current’s temporal complexity for the first time [Candela et al., 2019]. The current varied, both spatially and in strength, across that 4-year observation period. Tides play an important role in influencing the current, with both semidiurnal and diurnal components; the strength of transport in the current varies by 5%–10%.
Fig. 3. Temperature (top; yellow is warmer, red to blue is cooler) and salinity (bottom; bluer is more saline, yellower is less saline) data were collected in the Yucatán Channel from 18 January to 20 March 2024 during MASTR, the Mini-Adaptive Sampling Test Run. Credit: Courtesy of A. Knap, Geochemical and Environmental Research Group, Texas A&M University
This work has led to a multiyear set of studies of the Yucatán Channel, coordinated by the U.S. National Academies of Sciences, Engineering, and Medicine [NASEM, 2018], to characterize further modern conditions in the Loop Current. The 2024 portion of this study, called the Mini-Adaptive Sampling Test Run (MASTR), applied enhanced observation capacities, combining near-real-time surface and subsurface data from a simultaneous deployment of instrumented gliders and drifters with background observations from Argo floats and modeling. MASTR observations confirmed the Loop Current’s short-term complexity over short timescales, and they improved the performance of numerical models, including NOAA’s Real-Time Ocean Forecast System, in representing the current’s vertical hydrographic structure [DiMarco et al., 2024] (Figure 3).
Linking the Loop’s Past to Its Present
A key overlap, as revealed by recent research [Lowery et al., 2024], between modern and ancient oceanography in this region involves the seafloor. Current strength plays a vital role in our knowledge of past and present Loop Current conditions because it moves the grains that eventually become the current’s sedimentary archive. Seafloor topography also drives turbulent mixing of seawater in the Gulf, influencing both current flow and eddy formation. It is clear that more work and collaboration are needed to link our understanding of the long-term evolution of the Yucatán Channel seafloor with the Loop Current and its history.
An important, and thus far understudied, question is how the Loop Current responded to past warm climate events.
An important, and thus far understudied, question is how the Loop Current responded to past warm climate events, such as the Middle Miocene Climatic Optimum (~17.5–14.5 million years ago) [e.g., Steinthorsdottir et al., 2021]. Thoroughly addressing that question will require scientific ocean drilling to sample and date key buried sediment layers (i.e., seismic reflectors) in the Yucatán Channel to build a picture of Loop Current history. Planning for this work is underway, with support potentially coming from the U.S. National Science Foundation (NSF), the Scientific Ocean Drilling Coordination Office (which NSF has just established), and the current International Ocean Discovery Programme (IODP3), a partnership among Japan, Europe, and Australia and New Zealand.
Another issue on the minds of researchers studying the Loop Current is how anthropogenically driven changes in the current might negatively affect coastal resiliency and estuarine health along the entire Gulf Coast. Emerging problems include risks from sea level rise [Thirion et al., 2024] and strengthening hurricanes, both of which are directly affected by Loop Current flow.
Community organizations such as the Galveston Bay Foundation in Texas are leading efforts to adapt to changes in coastal environments brought by storms and sea level rise by, for example, building terraces and bulkheads, developing “living shorelines,” and restoring coastal prairie and by communicating with the public. As the global climate continues to warm, more effort is required to enhance coastal resilience. Scientists must partner with community organizations to build public awareness of ongoing, human-induced climate change and to train students, the future leaders in environmental mitigation efforts.
In addition to coastal ecosystems, millions of people around the Gulf region are affected by the Loop Current and its influences on weather and sea level rise. Studying these effects requires active participation and collaboration among researchers and various entities in Mexico and the United States. Indeed, the studies noted here could not have been attempted or completed without such participation—and continued collaboration is essential to continuing to collect crucial data. Unfortunately, despite ongoing efforts from all parties to involve representatives from Cuba in these initiatives, meaningful engagement has yet to be achieved.
Our long-term goal is to continue the tradition of international collaboration in the study of the Loop Current, which demands intensified, sustained scrutiny, considering the enormous stakes as human-induced climate change continues.
Acknowledgments
The August 2023 workshop was funded by the U.S. Science Support Program of the International Ocean Discovery Program. The September 2024 workshop was funded by the Jackson School of Geosciences and the Teresa Lozano Long Institute for Latin American Studies, both at the University of Texas at Austin. We also thank the officers and crew of the Justo Sierra.
References
Candela, J., et al. (2019), The flow through the Gulf of Mexico, J. Phys. Oceanogr., 49(6), 1,381–1,401, https://doi.org/10.1175/JPO-D-18-0189.1.
DiMarco, S. F., et al. (2024), Results of the Mini-Adaptive Sampling Test Run (MASTR) experiment: Autonomous vehicles, drifters, floats, ROCIS, and HF-radar, to improve Loop Current system dynamics and forecasts in the deepwater Gulf of México, paper presented at the Offshore Technology Conference, Houston, Texas, 6–9 May, https://doi.org/10.4043/35072-MS.
Liu, Y., et al. (2025), Rapid intensification of Hurricane Ian in relation to anomalously warm subsurface water on the wide continental shelf, Geophys. Res. Lett., 52(1), e2024GL113192, https://doi.org/10.1029/2024GL113192.
Lowery, C. M., et al. (2024), Seismic stratigraphy of contourite drift deposits associated with the Loop Current on the eastern Campeche Bank, Gulf of Mexico, Paleoceanogr. Paleoclimatol., 39(3), e2023PA004701, https://doi.org/10.1029/2023PA004701.
National Academies of Sciences, Engineering, and Medicine (NASEM) (2018), Understanding and Predicting the Gulf of Mexico Loop Current: Critical Gaps and Recommendations, 116 pp., Natl. Acad. Press, Washington, D.C., https://doi.org/10.17226/24823.
Piecuch, C. G., and L. M. Beal (2023), Robust weakening of the Gulf Stream during the past four decades observed in the Florida Straits, Geophys. Res. Lett., 50(18), e2023GL105170, https://doi.org/10.1029/2023GL105170.
Steinthorsdottir, M., et al. (2021), The Miocene: The future of the past, Paleoceanogr. Paleoclimatol., 36(4), e2020PA004037, https://doi.org/10.1029/2020PA004037.
Thirion, G., F. Birol, and J. Jouanno (2024), Loop Current eddies as a possible cause of the rapid sea level rise in the Gulf of Mexico, J. Geophys. Res. Oceans, 129(3), e2023JC019764, https://doi.org/10.1029/2023JC019764.
Author Information
James A. Austin Jr. (jamie@ig.utexas.edu) and Christopher Lowery, Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin; Ligia Pérez-Cruz and Jaime Urrutia-Fucugauchi, Universidad Nacional Autónoma de México, Mexico City; and Anthony H. Knap, Geochemical and Environmental Research Group, Texas A&M University, College Station
Citation: Austin, J. A., Jr., C. Lowery, L. Pérez-Cruz, J. Urrutia-Fucugauchi, and A. H. Knap (2025), Ocean current affairs in the Gulf of Mexico,
Eos, 106, https://doi.org/10.1029/2025EO250190. Published on 19 May 2025.
Text © 2025. The authors.
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