In the California Current System, subthermocline, lenslike anticyclonic eddies generated within the California Undercurrent (CU) are one mechanism for lateral transport of the warm, saline waters of the CU. Garfield et al. established the name “Cuddies” for eddies of this type and hypothesized that they account for a significant fraction of the offshore transport of CU water. This study presents observations of subthermocline eddies collected from a time series of Seaglider surveys in the northern California Current System. Gliders made 46 crossings of subthermocline anticyclones and 17 crossings of subthermocline cyclones over 5.5 yr. Close inspection grouped these into 20 distinct anticyclones and 10 distinct cyclones. Water properties at the core of anticyclonic eddies were similar to those in the core of the CU over the continental slope; these anticyclones are examples of Cuddies. Anticyclonic (cyclonic) eddies had average radii of 20.4 (20.6) km, peak azimuthal current speeds of 0.25 (0.23) m s−1, and average core anomalies of potential vorticity 65% below (125% above) ambient values. Anticyclones contained an order of magnitude greater available heat and salt anomaly relative to background conditions than cyclones on average. Circumstantial evidence of eddy decay through lateral intrusions was found although this was not observed consistently. Observed eddy properties and the geometry of flow over the continental slope were consistent with eddy formation due to frictional torque acting on the CU. Loss of heat and salt from the CU due to subthermocline eddies is estimated to account for 44% of the freshening and cooling of the CU as it flows poleward.

Argo float profile data are used to analyze warm, salty, weakly stratified, subthermocline eddies of tropical origin in the eastern subtropical South Pacific Ocean. These eddies contain anomalous signatures of the equatorial Pacific “13°C Water” that is carried poleward within the Peru–Chile Undercurrent (PCU) as it flows along the west coast of South America. From their source along the Chilean coast between ∼29° and 39°S, the eddies spread westward and slightly northward, likely at least partly advected by the subtropical gyre. The eddy water properties contrast strongly with the colder, fresher, more strongly stratified waters of subantarctic origin being carried northward then westward by the gyre. Near the eddy source, about 6% of Argo profiles sample eddies that are above selected thresholds for both salinity and potential vorticity anomalies relative to maps of the mean distributions of these properties on and around the core isopycnal for the eddies. The proportion of such profiles diminishes to about 1% near the northwestern limit of the eddy range, near 15°S and 115°W. These eddies are anticyclonic, with a subsurface radial velocity maximum near the core isopycnal for water property anomalies, hence a reduced surface expression. Their geostrophic signature sometimes extends below 1000 dbar, suggesting the eddies may influence float subsurface trajectories. Radial transports around the eddy centers are estimated to be on the order of 2 × 106 m3 s−1 for the potential density layer 26.0 < σθ < 27.0 kg m−3, about the same magnitude as the mean poleward transport of the PCU.

Signaling through the Ror2 receptor tyrosine kinase promotes invadopodia formation for tumor invasion. Here, we identify intraflagellar transport 20 (IFT20) as a new target of this signaling in tumors that lack primary cilia, and find that IFT20 mediates the ability of Ror2 signaling to induce the invasiveness of these tumors. We also find that IFT20 regulates the nucleation of Golgi-derived microtubules by affecting the GM130-AKAP450 complex, which promotes Golgi ribbon formation in achieving polarized secretion for cell migration and invasion. Furthermore, IFT20 promotes the efficiency of transport through the Golgi complex. These findings shed new insights into how Ror2 signaling promotes tumor invasiveness, and also advance the understanding of how Golgi structure and transport can be regulated.

Seismic images and glider sections of the Gulf Stream front along the U.S. eastern seaboard capture deep, lens-shaped submesoscale features. These features have radii of 5-20 km, thicknesses of 150-300 m, and are located at depths greater than 500 m. These are typical signatures of anticyclonic submesoscale coherent vortices. A submesoscale-resolving realistic simulation, which reproduces submesoscale coherent vortices with the same characteristics, is used to analyze their generation mechanism. Submesoscale coherent vortices are primarily generated where the Gulf Stream meets the Charleston Bump, a deep topographic feature, due to the frictional effects and intense mixing in the wake of the topography. These submesoscale coherent vortices can transport waters from the Charleston Bump's thick bottom mixed layer over long distances and spread them within the subtropical gyre. Their net effect on heat and salt distribution remains to be quantified. Plain Language Summary The interior of the ocean is populated by small-scale coherent vortices, which redistribute water properties on the scale of basins. These structures are very difficult to observe. They have no surface signature and small dimensions, on the order of 1-50 km, such that they are missed by satellites and sampled only by chance. Furthermore, climate-scale ocean models do not resolve these type of motions and do not take into account their impacts for the large-scale transport and distribution of heat, nutrients, and other materials. Understanding and parameterizing these phenomena within models is critical for a better prediction of climate. Here we present new observations of submesoscale coherent vortices from seismic images and glider sections in the region of the Gulf Stream. We use a numerical model at very high resolution to reproduce vortices with the same characteristics and to analyze their generation mechanism. These vortices are generated where the Gulf Stream interacts with a deep topographic feature called the Charleston Bump due to frictional effects and intense mixing in the wake of the topography. These vortices transport waters from the Charleston Bump's thick bottom mixed layer and act to spread them all around the subtropical gyre.

An anticyclonic lens of water in the permanent thermocline off the Bahamas has water mass characteristics representing Mediterranean and eastern Atlantic central waters. This eddy's ability to translate across the Atlantic without losing its identity points to baroclinic eddies as a specific mechanism for large-scale mixing.

Episodic eddy-driven upwelling may supply a significant fraction of the nutrients required to sustain primary productivity of the subtropical ocean. New observations in the northwest Atlantic reveal that, although plankton blooms occur in both cyclones and mode-water eddies, the biological responses differ. Mode-water eddies can generate extraordinary diatom biomass and primary production at depth, relative to the time series near Bermuda. These blooms are sustained by eddy/wind interactions, which amplify the eddy-induced upwelling. In contrast, eddy/wind interactions dampen eddy-induced upwelling in cyclones. Carbon export inferred from oxygen anomalies in eddy cores is one to three times as much as annual new production for the region.

. Localized open-ocean low-oxygen “dead zones” in the eastern tropical North Atlantic are recently discovered ocean features that can develop in dynamically isolated water masses within cyclonic eddies (CE) and anticyclonic mode-water eddies (ACME). Analysis of a comprehensive oxygen dataset obtained from gliders, moorings, research vessels and Argo floats reveals that “dead-zone” eddies are found in surprisingly high numbers and in a large area from about 4 to 22° N, from the shelf at the eastern boundary to 38° W. In total, 173 profiles with oxygen concentrations below the minimum background concentration of 40 µmol kg−1 could be associated with 27 independent eddies (10 CEs; 17 ACMEs) over a period of 10 years. Lowest oxygen concentrations in CEs are less than 10 µmol kg−1 while in ACMEs even suboxic (< 1 µmol kg−1) levels are observed. The oxygen minimum in the eddies is located at shallow depth from 50 to 150 m with a mean depth of 80 m. Compared to the surrounding waters, the mean oxygen anomaly in the core depth range (50 and 150 m) for CEs (ACMEs) is −38 (−79) µmol kg−1. North of 12° N, the oxygen-depleted eddies carry anomalously low-salinity water of South Atlantic origin from the eastern boundary upwelling region into the open ocean. Here water mass properties and satellite eddy tracking both point to an eddy generation near the eastern boundary. In contrast, the oxygen-depleted eddies south of 12° N carry weak hydrographic anomalies in their cores and seem to be generated in the open ocean away from the boundary. In both regions a decrease in oxygen from east to west is identified supporting the en-route creation of the low-oxygen core through a combination of high productivity in the eddy surface waters and an isolation of the eddy cores with respect to lateral oxygen supply. Indeed, eddies of both types feature a cold sea surface temperature anomaly and enhanced chlorophyll concentrations in their center. The low-oxygen core depth in the eddies aligns with the depth of the shallow oxygen minimum zone of the eastern tropical North Atlantic. Averaged over the whole area an oxygen reduction of 7 µmol kg−1 in the depth range of 50 to 150 m (peak reduction is 16 µmol kg−1 at 100 m depth) can be associated with the dispersion of the eddies. Thus the locally increased oxygen consumption within the eddy cores enhances the total oxygen consumption in the open eastern tropical North Atlantic Ocean and seems to be an contributor to the formation of the shallow oxygen minimum zone.\n

Sporadic in situ observations have shown evidence that subthermocline eddies exist off the Mindanao coast. These subthermocline eddies are believed to play an important role in the heat, freshwater, and other ocean property transports of the region, but their characteristics and in particular their pathway and source of energy are poorly explored because of the lack of long-term observations. Analysis of results from an eddy-resolving general ocean circulation model has revealed that most subthermocline eddies off the Mindanao coast originate from the equatorial South Pacific Ocean to the west of the Ninigo Group. These eddies propagate northward along the New Guinea coast, cross the equator in the far western Pacific, and reach the Mindanao coast at a typical propagation speed of ~0.12 m s−1. The dominant time scales of these eddies range between 50 and 60 days.

Both sporadic observations and modelling studies suggest that subthermocline eddies (SEs) exist east of the Philippines, where interhemispheric waters meet. However, effects of SEs on water mass mixing have never been observed. Here, using data from mooring and buoy deployed in the frontal region of the interhemispheric water masses, we show for the first time that the SEs act as an “underwater mixer” of intermediate waters from north and south Pacific oceans. The SEs have typical swirl speeds of 0.1~0.4 m s−1 between 200 and 800 m depth with a dominant period of ~90 days. Variation in intermediate water salinity also had a period of ~90 days, lagging eddy speed by ~8 days. Horizontal eddy diffusivity representative of eddy mixing rate was quantified using a mixing-length framework. Horizontal eddy diffusivity had both surface and subthermocline maxima. The vertically varying eddy diffusivity can be used to improve parameterization of eddy stirring in the tropical Pacific by coarse-resolution ocean climate models. The effect of the SEs on mixing of intermediate water masses seems not resolved by available eddy-resolving ocean models typically used for this region.

Seasonal modulation of subthermocline eddy kinetic energy (EKE) east of the Philippines and its associated dynamics are studied, using mooring measurements and outputs from an eddy-resolving ocean general circulation model for the period from 2000 to 2017. Significantly high EKE appears below the thermocline in the latitude band between 5° and 14°N east of the Philippines. Separated by 10°N, the EKE in the northern and southern parts of the region shows nearly opposite seasonal cycles, with its magnitude reaching a maximum in early spring and minimum in summer in the northern part and reaching a maximum in summer and minimum in winter in the southern part of the region. Further investigation indicates that both baroclinic and barotropic instabilities are essential in generating the subthermocline eddies, but the seasonal variation of subthermocline EKE is mainly caused by the seasonal modulation of barotropic instability. The seasonal modulation of barotropic instability in the northern and southern part of the region is associated with the seasonal evolution of North Equatorial Undercurrent and Halmahera Eddy, respectively.

模态水在全球气候变化中有着重要作用。但是由于缺乏海洋次表层的高分辨率观测，对空间尺度为百公里的海洋中尺度涡旋如何影响空间尺度大于千公里的模态水的认识仍然欠缺。为了解决这一科学难题，在科技部的支持下，实施了一次成功的海上观测试验。系统梳理了基于该观测数据所发表的有关涡旋影响模态水潜沉和输运的主要研究成果：①捕捉并揭示了中尺度涡导致混合层水潜沉的过程和动力机制；②发现了中尺度涡携带模态水迁移的新路径；③阐明了模态水多核结构的形成机制。研究结果揭示了黑潮延伸体海域中尺度涡旋影响大尺度模态水的物理本质，为该海域多时空尺度海洋—大气相互作用作出了一定的贡献。通过对该次观测试验结果的分析和总结，得到了如下新的科学推论：海洋次中尺度过程对模态水的形成和耗散也具有重要影响。

<p>Mode Mode water is important for the climate system as memories of climate variability and by 'breathing in' anthropogenic carbon dioxide. Due to the lack of subsurface observations， many fundamental questions remain regarding how it is subducted and transported by mesoscale eddies.</p><sec><title>Results</title><p>from a field campaign from March 2014 that captured the eddy effects on mode water subduction and transport south of the Kuroshio Extension east of Japan are reviewed here. The experiment deployed 17 Argo floats in an Anticyclonic Eddy （AE） with enhanced daily sampling. Analysis of over 5 000 hydrographic profiles following the eddy reveals that： ①the eddy-induced North Pacific Subtropical Mode Water （STMW） subduction process is successfully captured for the first time， and the eddy subduction mechanism is revealed. We find potential vorticity and apparent oxygen utilization distributions are asymmetric outside the AE core， with enhanced subduction near the southeastern rim of the AE. There， the southward eddy flow advects newly ventilated mode water from the north into the main thermocline. Our results show that subduction by eddy lateral advection is comparable in magnitude to that by the mean flow—an effect that needs to be better represented in climate models. ②A new mode water transport pathway by anticyclonic eddies is found. AEs transport STMW westward across the Izu Ridge through a bathymetric gap between the Hachijojima and Bonin Islands， forming a cross-ridge pathway for STMW transport. Because of the eddy transport， the shallow STMW （&lt; 400 m） intrudes through the gap westward， which is also observed in Argo climatology. ③the formation mechanism of STMW multicore structure is clarified. We find that AEs formed east of 150°E could trap the local cold and dense STMW and migrate westward. Since sea surface temperatures increase toward the west， warmer and lighter STMWs are formed during the winter ventilation process as the AEs move westward. The newly formed STMW ride on the preexisting cold and dense STMW inside the eddy core， forming a multicore structure in the STMW. These findings update the traditional understanding of mode water. Mesoscale eddies are usually accompanied by submesoscale processes， whose effects on mode water seems to be considerably significant as well and need to be studied in the future.</p></sec>

Subthermocline eddies (STEs), also termed intrathermocline eddies or submesoscale coherent vortices, are lens-shaped eddies with anomalous water properties located in or below the thermocline. Although STEs have been discovered in many parts of the World Ocean, most of them were observed accidentally in hydrographic profiles, and direct velocity measurements are very rare. In this study, dynamic features of STEs in the Kuroshio Extension (KE) region are examined in detail using concurrent temperature/salinity and velocity measurements from mooring arrays. During the moored observation periods of 2004–06 and 2015–19, 11 single-core STEs, including 8 with warm/salty cores and 3 with cold/fresh cores, were captured. The thermohaline properties in their cores suggest that these STEs may originate from the subarctic front and the upstream Kuroshio south of Japan. The estimated radius of these STEs varied from 8 to 66 km with the mean value of ~30 km. The warm/salty STEs seemed to be larger and rotate faster than the cold/fresh ones. In addition to single-core STEs, a dual-core STE was observed in the KE recirculation region, which showed that the upper cold/fresh cores stacked vertically over the lower warm/salty cores. Based on the observed parameters of the STEs, their Rossby number and Burger number were further estimated, with values up to 0.5 and 1, respectively. Furthermore, a low Richardson number O (0.25) was found at the periphery of these STEs, suggesting that shear instability-induced turbulent mixing may be an erosion route for the STEs.

. Fixed nitrogen (N) loss to biogenic N2 in intense oceanic O2 minimum zones (OMZ) accounts for a large fraction of the global N sink and is an essential control on the ocean's N-budget. However, major uncertainties exist regarding microbial pathways as well as net impact on the magnitude of N-loss and the ocean's overall N-budget. Here we report the discovery of a N-loss hotspot in the Peru OMZ associated with a coastally trapped mesoscale eddy that is marked by an extreme N-deficit matched by biogenic N2 production, high NO2− levels, and the highest isotope enrichments observed so far in OMZ's for the residual NO3−. High sea surface chlorophyll in seaward flowing streamers provides evidence for offshore eddy transport of highly productive, inshore water. Resulting pulses in the downward flux of particles likely stimulated heterotrophic dissimilatory NO3− reduction and subsequent production of biogenic N2 within the OMZ. A shallower biogenic N2 maximum within the oxycline is likely a feature advected by the eddy streamer from the shelf. Eddy-associated temporal-spatial heterogeneity of N-loss, mediated by a local succession of microbial processes, may explain inconsistencies observed among prior studies. Similar transient enhancements of N-loss likely occur within all other major OMZ's exerting a major influence on global ocean N and N isotope budgets.

. Recent observations in the eastern tropical South Pacific (ETSP) have shown the key role of meso- and submesoscale processes (e.g. eddies) in shaping its hydrographic and biogeochemical properties. Off Peru, elevated primary production from coastal upwelling in combination with sluggish ventilation of subsurface waters fuels a prominent oxygen minimum zone (OMZ). Given that nitrous oxide (N2O) production–consumption processes in the water column are sensitive to oxygen (O2) concentrations, the ETSP is a region of particular interest to investigate its source–sink dynamics. To date, no detailed surveys linking mesoscale processes and N2O distributions as well as their relevance to nitrogen (N) cycling are available. In this study, we present the first measurements of N2O across three mesoscale eddies (two mode water or anticyclonic and one cyclonic) which were identified, tracked, and sampled during two surveys carried out in the ETSP in November–December 2012. A two-peak structure was observed for N2O, wherein the two maxima coincide with the upper and lower boundaries of the OMZ, indicating active nitrification and partial denitrification. This was further supported by the abundances of the key gene for nitrification, ammonium monooxygenase (amoA), and the gene marker for N2O production during denitrification, nitrite reductase (nirS). Conversely, we found strong N2O depletion in the core of the OMZ (O2 &lt; 5 µmol L−1) to be consistent with nitrite (NO2−) accumulation and low levels of nitrate (NO3−), thus suggesting active denitrification. N2O depletion within the OMZ's core was substantially higher in the centre of mode water eddies, supporting the view that eddy activity enhances N-loss processes off Peru, in particular near the shelf break where nutrient-rich, productive waters from upwelling are trapped before being transported offshore. Analysis of eddies during their propagation towards the open ocean showed that, in general, “ageing” of mesoscale eddies tends to decrease N2O concentrations through the water column in response to the reduced supply of material to fuel N loss, although hydrographic variability might also significantly impact the pace of the production–consumption pathways for N2O. Our results evidence the relevance of mode water eddies for N2O distribution, thereby improving our understanding of the N-cycling processes, which are of crucial importance in times of climate change and ocean deoxygenation.\n