Explore the vast range of titles available.

Understanding the mechanisms by which climate variability affects multiple trophic levels in food webs is essential for determining ecosystem responses to climate change. Here we use over two decades of data collected by the Palmer Long Term Ecological Research program (PAL-LTER) to determine how large-scale climate and local physical forcing affect phytoplankton, zooplankton and an apex predator along the West Antarctic Peninsula (WAP). We show that positive anomalies in chlorophyll- a (chl- a ) at Palmer Station, occurring every 4–6 years, are constrained by physical processes in the preceding winter/spring and a negative phase of the Southern Annular Mode (SAM). Favorable conditions for phytoplankton included increased winter ice extent and duration, reduced spring/summer winds, and increased water column stability via enhanced salinity-driven density gradients. Years of positive chl- a anomalies are associated with the initiation of a robust krill cohort the following summer, which is evident in Adélie penguin diets, thus demonstrating tight trophic coupling. Projected climate change in this region may have a significant, negative impact on phytoplankton biomass, krill recruitment and upper trophic level predators in this coastal Antarctic ecosystem. The Western Antarctic Peninsular is subject to climate change, including increased winter temperatures and melting sea ice. In this study, the authors demonstrate that climate change in this area effects bacteria and phytoplankton levels, which culminates in an altered diet for the apex predator, the Adélie penguin.

Summary A decade of research has shown that numerical weather prediction (NWP)‐modeled wind speeds can be highly sensitive to the inputs and setups within the NWP model. For wind resource characterization applications, this sensitivity is often addressed by constructing a range of setups and selecting the one that best validates against observations. However, this approach is not possible in areas that lack high‐quality hub height observations, especially offshore wind areas. In such cases, techniques to quantify and disseminate confidence in NWP‐modeled wind speeds in the absence of observations are needed. We address this need in the present study and propose best practices for quantifying the spread in NWP‐modeled wind speeds. We implement an ensemble approach in which we consider 24 different setups to the Weather Research and Forecasting (WRF) model. We construct the ensemble by considering variations in WRF version, WRF namelist, atmospheric forcing, and sea surface temperature (SST) forcing. Our analysis finds that the standard deviation produces more consistent estimates compared to the interquartile range and tends to be the more conservative estimator for ensemble variability. We further find that model spread increases closer to the surface and on shorter time scales. Finally, we explore methods to attribute total ensemble variability to the different ensemble components (e.g., atmospheric forcing and SST product) and find that contributions by components also vary depending on time scale. We anticipate that the methods and results presented in this paper will provide a reasonable foundation for further research into ensemble‐based wind resource data sets.

The Caribbean Through-Flow (CTF) provides a key pathway linking the North Atlantic Subtropical Gyre and the upper limb of the Atlantic Meridional Overturning Circulation. Yet, its internal structure and variability remain poorly resolved. Autonomous underwater gliders offer a unique capability to address this gap by collecting high-resolution hydrographic and velocity observations in regions where sampling is sparse. Here, data from a glider that operated for >90 d along 69° W in summer 2024 were analyzed to investigate mesoscale-driven variability in the CTF. Two consecutive occupations of this ∼600 km trans-Caribbean section revealed a sharp decline in zonal transport from −17.64 to −9.22 Sv, coinciding with a shift in mesoscale activity. Magnitude and variability in the vertical shear of the subsurface currents and dynamic height anomaly calculations from the glider data showed a shift from flow largely in geostrophic balance during Transect #1 to increased mesoscale influence during Transect #2. Satellite altimetry spanning the full deployment suggested this shift was driven by a cyclonic eddy that passed through the northern half of the section between the timing of the two transects. Despite the large changes in transport between transect occupations, water mass analysis showed that the relative contributions from North and South Atlantic water masses remained nearly constant. Direct sampling of an anticyclonic eddy during a partial Transect #3 revealed strong temperature and salinity anomalies in the upper 200 m. These findings highlight how glider observations can resolve key features and processes governing variability in this critical inter-basin pathway and improve understanding of mesoscale influences on large-scale circulation.

Offshore wind turbine monopiles extract momentum from ocean currents and generate turbulence that can modify stratification in the coastal ocean. As offshore wind development expands into seasonally stratified regions, these interactions become increasingly important. The U.S. Mid-Atlantic Bight is a strongly stratified shelf in summer with weak tidal currents, active offshore wind development, and a persistent Cold Pool—a bottom layer of cold water beneath a summer thermocline critical for regional fisheries. This study combines regional model output, glider observations, and an analytical model based on the turbulent kinetic energy budget to evaluate the timescales of mixing driven by monopile–flow interaction only. For a current velocity scale of order 0.1 m s -1 , corresponding to the most frequently occurring currents at the site, the estimated mixing timescale is on the order of years, far longer than the seasonal overturning timescale (~3 months). Even under cyclone-strength currents (~0.8 m s - ¹), full mixing of peak stratification would require ~10 days of sustained forcing, which is rare at the weather-band timescale. Projected monopile array density and weak shelf currents further constrain the area-averaged turbulent energy input relative to bottom friction and storm-driven mixing. Thus, large-scale Cold Pool destratification from offshore wind development appears unlikely in the Mid Atlantic Bight, though localized wake-driven turbulence and associated altered nutrient fluxes may still occur near individual turbines, motivating targeted high-resolution studies.

Strong physical disturbance from hurricanes can disrupt coral reef ecosystems and precipitate a regime shift toward algal dominance, particularly in the absence of grazing pressure to regulate algal growth post-storm. Here, we examine the influence of Hurricane Irma on a keystone grazer, Diadema antillarum, and the surrounding coral reef benthic community in the Florida Keys. D. antillarum densities and test diameters, as well as percent cover of coral reef benthic groups, were measured at 10 sites in the middle and upper Keys before and after Irma. Significant decreases in mean D. antillarum density and median test diameter were observed following the storm. There was a correlation between the magnitude of decline in D. antillarum density and the magnitude of sediment deposition on reefs, suggesting that abrasion or burial from sediment transport may have contributed to D. antillarum mortality. We detected significant decreases in the percent cover of sponges and hydrocorals following the storm, but no change in scleractinian coral cover, which was very low (3% mean cover) at the onset of the study. Macroalgal cover increased at sites in the upper Keys and decreased at sites in the middle Keys. There was no relationship between post-storm D. antillarum density and the change in percent cover of macroalgae or turf-algal-sediment matrix (TAS), likely due to low overall abundance of the grazer. We predict that coral reefs will remain in an algal-dominated ecosystem state due to, among other factors, increasing frequency of strong hurricanes that impact the D. antillarum population.

Cold wakes left behind by tropical cyclones (TCs) have been documented since the 1940s. Many questions remain, however, regarding the details of the processes creating these cold wakes and their in-storm feedbacks onto tropical cyclone intensity. This largely reflects a paucity of measurements within the ocean, especially during storms. Moreover, the bulk of TC research efforts have investigated deep ocean processes—where tropical cyclones spend the vast majority of their lifetimes—and very little attention has been paid to coastal ocean processes despite their critical importance to shoreline populations. Using Hurricane Irene (2011) as a case study, the impact of the cooling of a stratified coastal ocean on storm intensity, size, and structure is quantified. Significant ahead-of-eye-center cooling (at least 6°C) of the Mid-Atlantic Bight occurred as a result of coastal baroclinic processes, and operational satellite SST products and existing coupled ocean–atmosphere hurricane models did not capture this cooling. Irene’s sensitivity to the cooling is tested, and its intensity is found to be most sensitive to the cooling over all other tested WRF parameters. Further, including the cooling in atmospheric modeling mitigated the high storm intensity bias in predictions. Finally, it is shown that this cooling—not track, wind shear, or dry air intrusion—was the key missing contribution in modeling Irene’s rapid decay prior to New Jersey landfall. Rapid and significant intensity changes just before landfall can have substantial implications on storm impacts—wind damage, storm surge, and inland flooding—and thus, coastal ocean processes must be resolved in future hurricane models.

Climate change is driving an ongoing increase in tropical cyclone (TC) activity. While global economic losses are projected to double by 2100, there are no comparable predictions for TC impacts to coastal ecosystems that protect and sustain human lives and livelihoods. Here, rising North Atlantic TC (NATC) activity from 1970 to 2019, influenced by anthropogenic and natural climate forcing, is used to study the ecosystem impacts of intensifying TCs, potentially indicative of broader future climate change scenarios. Analysis of 97 NATC landfalls revealed 891 immediate post-storm impacts on ecosystems, with particularly detrimental effects on mangrove forests. Specifically, NATCs reduced the performance of individual species. Additionally, they altered community structure and processes through impacts on foundation species and their associated organisms. The severity of impacts was directly correlated with NATC landfall intensity (wind speed) for mangroves, whereas changes to waves, surge, sediments, and salinity caused most impacts on coral reefs, salt marshes, seagrass meadows, and oyster reefs (respectively), indicating complex intensity-damage interactions for many ecosystems. The analyses also revealed a positive correlation between very intense NATC activity and ecosystem damages. The research highlights a concerning trend of escalating impacts on coastal ecosystems under rising storm intensities, with the potential to challenge ecosystem resilience.

Tropical cyclones are one of the costliest and deadliest natural disasters globally, and impacts are currently expected to worsen with a changing climate. Hurricane Ida (2021) made landfall as a category 4 storm on the US Gulf coast after intensifying over a Loop Current eddy and a freshwater barrier layer. This freshwater layer extended from the coast to the open ocean waters south of the shelf-break of the northern Gulf of Mexico (GoM). An autonomous underwater glider sampled this ocean feature ahead of Hurricane Ida operated through a partnership between NOAA, Navy, and academic institutions. In this study we evaluate hurricane upper ocean metrics ahead of and during the storm as well as carry out 1-D shear driven mixed layer model simulations to investigate the sensitivity of the upper ocean mixing to a barrier layer during Ida’s intensification period. In our simulations we find that the freshwater barrier layer inhibited cooling by as much as 57% and resulted in enhanced enthalpy flux to the atmosphere by as much as 11% and an increase in dynamic potential intensity (DPI) of 5 m s -1 (~9.72 knots) in the 16 hours leading up to landfall. This highlights the utility of new ocean observing systems in identifying localized ocean features that may impact storm intensity ahead of landfall. It also emphasizes the northern Gulf of Mexico and the associated Mississippi River plume as a region and feature where the details of upper ocean metrics need to be carefully considered ahead of landfalling storms.

Coastal and ocean acidification can alter ocean biogeochemistry, with ecological consequences that may result in economic and cultural losses. Yet few time series and high resolution spatial and temporal measurements exist to track the existence and movement of water low in pH and/or carbonate saturation. Past acidification monitoring efforts have either low spatial resolution (mooring) or high cost and low temporal and spatial resolution (research cruises). We developed the first integrated glider platform and sensor system for sampling pH throughout the water column of the coastal ocean. A deep ISFET (Ion Sensitive Field Effect Transistor)-based pH sensor system was modified and integrated into a Slocum glider, tank tested in natural seawater to determine sensor conditioning time under different scenarios, and validated in situ during deployments in the U.S. Northeast Shelf (NES). Comparative results between glider pH and pH measured spectrophotometrically from discrete seawater samples indicate that the glider pH sensor is capable of accuracy of 0.011 pH units or better for several weeks throughout the water column in the coastal ocean, with a precision of 0.005 pH units or better. Furthermore, simultaneous measurements from multiple sensors on the same glider enabled salinity-based estimates of total alkalinity (AT) and aragonite saturation state (ΩArag). During the Spring 2018 Mid-Atlantic deployment, glider pH and derived AT/ ΩArag data along the cross-shelf transect revealed higher pH and ΩArag associated with the depth of chlorophyll and oxygen maxima and a warmer, saltier water mass. Lowest pH and ΩArag occurred in bottom waters of the middle shelf and slope, and nearshore following a period of heavy precipitation. Biofouling was revealed to be the primary limitation of this sensor during a summer deployment, whereby offsets in pH and AT increased dramatically. Advances in anti-fouling coatings and the ability to routinely clean and swap out sensors can address this challenge. The data presented here demonstrate the ability for gliders to routinely provide high resolution water column data on regional scales that can be applied to acidification monitoring efforts in other coastal regions.

Miles et al focus on uncrewed ocean gliders and saildrones support hurricane forecasting and research. Components of the sustained ocean observing system are useful for understanding the role of the ocean in hurricane intensity changes. Here, the authors provide a broad overview of the ongoing US hurricane glider project and details of a new effort with the Saildrone USV during the 2021 hurricane season. While this article focuses on the US East Coast, Gulf of Mexico, and Caribbean Sea, similar efforts are underway in Korea, the Philippines, Japan, and China, among other countries.