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Abstract The coastal plain of Santa Barbara County (SBC) is bounded by the cool waters of the Pacific Ocean to the south and the west–east-oriented Santa Ynez Mountains (SYM) to the north. Downslope windstorms with a typical onset after sunset are frequently observed on the lee slopes of the SYM. These northerly winds are known as Sundowner winds or simply Sundowners. The Sundowner Winds Experiment (SWEX), conducted between 1 April and 15 May 2022, aimed to unravel mechanisms responsible for the spatiotemporal variability of these winds. The present study examines data collected from lidar wind profilers, radiosondes, and surface stations during the 12–13 May 2022 intensive observation period (IOP). Gusty winds were observed on both the western and eastern slopes of the SYM. This event was associated with the second-largest observed mean sea level pressure difference between the Santa Barbara and Bakersfield airports during SWEX. However, horizontal wind speeds exceeding 20 m s⁻¹were recorded on the eastern slopes of the SYM hours before the most pronounced observed pressure differences. Furthermore, lidar measurements in the foothills of the eastern SYM exhibited positive vertical wind speeds of approximately 6 m s⁻¹. These ascending vertical motions were associated with the lifting of the lee-slope jet and a concurrent weakening of winds near ground level—a clear indication of mountain-wave activity influencing surface winds. While mesoscale numerical simulations with 1-km grid spacing captured the spatial patterns of the winds, their temporal variability was inadequately represented in highly turbulent regions. 

Transposable elements (TEs) are known to be major components of eukaryotic genomes and impact genome evolution and architecture, including in the speciose lineage of Insecta. Although new and increased efforts have allowed for more insect genomes to become available, our understanding of insect TE diversity across various lineages is poor. This lack of knowledge is especially true in the hyper-diverse Hymenoptera (including bees, ants, wasps, and sawflies) which includes some of the most beneficial insects, such as pollinators and parasitoid (parasitic) wasps. Here, we present the order-level TE composition and analyze its phylogenetic signal across the Braconidae (Hymenoptera), a very diverse lineage of parasitic wasps. Further we investigate the effect of TEs on genome size and note a positive relationship that has some distinct lineage specific differences. Despite phylogenetically conserved genome sizes within Braconidae, we found that TE abundance and diversity was not phylogenetically conserved and was highly variable across taxa, more so than what has been reported for other insect lineages. This represents the first comparative genomic analysis of TEs in a lineage of parasitic wasps and increases our understanding of the diversity of TE composition across related taxa. 

Abstract Applying full-waveform methods to image small-scale structures of geophysical interest buried within the Earth requires the computation of the seismic wavefield over large distances compared to the target wavelengths. This represents a considerable computational cost when using state-of-the-art numerical integration of the equations of motion in three-dimensional earth models. “Box Tomography” is a hybrid method that breaks up the wavefield computation into three parts, only one of which needs to be iterated for each model update, significantly saving computational time. To deploy this method in remote regions containing a fluid-solid boundary, one needs to construct artificial sources that confine the seismic wavefield within a small region that straddles this boundary. The difficulty arises from the need to combine the solid-fluid coupling with a hybrid numerical simulation in this region. Here, we report a reconciliation of different displacement potential expressions used for solving the acoustic wave equation and propose a unified framework for hybrid simulations. This represents a significant step towards applying ’Box Tomography’ in arbitrary regions inside the Earth, achieving a thousand-fold computational cost reduction compared to standard approaches without compromising accuracy. We also present examples of benchmarks of the hybrid simulations in the case of target regions at the ocean floor and the core-mantle boundary. 

Abstract The existence of highly productive coral reefs within oligotrophic gyres is in part due to intensive recycling of macronutrients and organic matter by microbes. Therefore, characterizing reef bacterioplankton communities is key for understanding reef metabolism and biogeochemical transformations. We performed a high‐resolution survey of waters surrounding Mo'orea (French Polynesia), coupling 16S metabarcoding with biogeochemical and physical measurements. Bacterioplankton communities differed markedly among reef ecosystems on three sides of the island, and within each system distinct communities emerged in forereef, backreef and reef pass habitats. The degree of habitat differentiation varied among the island sides according to current speeds inferred from wave power. Oceanic‐associated taxa were enriched in forereefs and throughout western reefs with highest wave power and lowest productivity. Reef‐associated taxa were enriched in backreef and pass habitats most strongly on northern reefs with lowest wave power and highest productivity. Our results offer insight into dynamics regulating reef microbial communities. 

Evidence of metamorphism at ultrahigh‐pressure (UHP) conditions is documented by the presence of coesite, diamond and/or majoritic garnet. However, the growth of UHP‐stable phases such as majoritic garnet is often volumetrically low, and overprinting during exhumation can obscure evidence of UHP growth, making it difficult to positively identify UHP rocks. In this study, we selected garnet‐kyanite schists from three microdiamond‐bearing localities within the Rhodope Metamorphic Complex, located in eastern Greece. Samples from Xanthi, Sidironero, and Kimi have similar bulk rock compositions, but the pressure–temperature (P–T) paths differ. Because the major phases record vanishingly little evidence of metamorphism at UHP conditions, we analyzed zircon grains with complex textures to evaluate if zircon preserves a record of UHP metamorphism. Zircon grains from all localities have cores and rims separated by a characteristic interface domain, as revealed by cathodoluminescence (CL) imaging. The detrital igneous cores range in age from c. 2.5 Ga to 220 Ma and exhibit a negative Eu* anomaly, a Yb/Gd of 10–100, and variable Th/U (0–1.2). Rims yield dates of 150–125 Ma with Yb/Gd of 0.1–10 and Th/U of 0–0.2. Interface domains yield dates 165–145 Ma with Yb/Gd ranging between 0–1000 and Th/U < 0.2. We interpret the distinctive CL textures and Yb/Gd of the interface domains as evidence of zircon that reacted at UHP. The interface domain in zircon from all petrographic contexts yields variable Yb/Gd ratios that are significantly higher than both cores and rims. We therefore interpret that zircon recrystallized via interface‐coupled dissolution–reprecipitation reaction; this process preferentially partitioned heavy rare earth elements within the interface domain, which explains the higher Yb/Gd ratios. The rim domains equilibrated with the matrix, producing a relatively homogeneous and low Yb/Gd ratio in these domains. The spatial extent and degree of preservation of interface domains are interpreted as a function of the P–T path and minor variations in bulk composition. Interface domains are best preserved in rocks from Xanthi and Sidironero; in these samples, thin, homogeneous, garnet‐stable rims only partially overprint and crosscut the interface domain. In contrast, rocks from Kimi followed a higher‐temperature trajectory and the zircon grains grew large rim domains that overprinted much of the interface domain and the detrital core. Zircon grains from plagioclase‐rich versus quartz‐rich domains within samples from Sidironero show differences in texture, which indicates that local bulk composition can affect what evidence of UHP metamorphism is preserved. Collectively, these samples provide a new, durable marker of metamorphism in UHP rocks and yield new insight about which factors affect the preservation of UHP textures.