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Several early Oldowan localities are known from the Homa Peninsula, in southwestern Kenya, the oldest of which, Nyayanga (~3–2.6 Ma), preserves the earliest known evidence of Oldowan tool assemblages, long- distance raw material transport, and butchery. Here, we present a multi-proxy reconstruction of hominin environments at Nyayanga, using stratigraphy, particle size, phytoliths, and stable isotopes to reconstruct the site's sedimentary dynamics, depositional environment, and palaeovegetation. Four units have been identified from Nyayanga (NY-1 to NY-4); this study concentrates on NY-1 to NY-3. The site is interpreted as a former alluvial plain environment where deposition occurred through episodic hyperconcentrated flows and intermittent unconfined fluvial flows. During flow hiatus, secondary processes, including fluvial runoff and aeolian deposition, occurred, along with the development of a stable land surface. Climatic conditions at Nyayanga are characterized as moderately seasonal and well-watered. Isotopic analyses of fossil mammals and pedogenic carbonates, alongside phytolith taxonomic analyses, demonstrate that C3 vegetation is underrepresented throughout the sequence, whereas higher abundances of C4 plants could indicate a dense ground cover. Based on multi-proxy evidence, the landscape at Nyayanga becomes more stable through time, showing less frequent higher-energy, hyperconcentrated flows and less unconfined fluvial activity. Soil development increases and becomes more mature with varying levels of pedogenesis. 

Abstract Plants alter soil biotic and abiotic properties with consequences for plant community dynamics at local and global scales, but how plant–soil interactions are affected by other environmental and biotic interactions remains poorly understood. We performed a fully reciprocal plant–soil feedback (PSF) experiment between two herbaceous plants, Monarda fistulosa and Plantago lanceolata, and tested how PSFs were influenced by drought and foliar powdery mildew pathogen infection. We observed significant negative feedbacks between the two plant species, but only when plants were grown with live soil biota and infected with powdery mildew. The strongest feedback was observed under both foliar infection and drought. High-throughput sequencing of soil fungi and bacteria from the treatment groups with foliar infection and drought revealed that both fungal and bacterial community composition were influenced by soil condition (live versus sterile) and soil training (Monarda versus Plantago). Together, our results indicate that the observed negative PSF was driven by foliar pathogens and plant species-specific soil microbial communities and intensified by drought. Our study suggests that PSF can be sensitive to both aboveground plant–pathogen interactions and climatic factors, improving our understanding of microbial impacts on plant community dynamics. This article is part of the theme issue ‘Wild plant pathosystems’. 

We demonstrate a self-referenced and optically-stabilized Er:fiber frequency comb that does not require external amplification. The 100 MHz frequency comb operates with only 250 mW of optical pump power. This advance employs a low-noise polarization-maintaining mode-locked laser that outputs 100 pJ, 100 fs pulses to drive octave generation and self-referencing with integrated nanophotonics. Multi-day optical phase locking and outdoor operation in the Colorado mountains highlight the robustness required for future use on transportable and airborne platforms beyond the research lab, where power and space are at a premium. 

Background Albatrosses can commute long distances to feed during the breeding season by avoiding energetically costly flapping flight. Energy from both wind and waves can be used to sustain soaring and reduce flapping flight, yet most studies of albatross flight have focused solely on the influence of wind. Methods To examine how wind and waves allow albatrosses to reduce energetic costs by limiting flapping flight, we analyzed how the flap rates of five albatross species (370 individuals) across two ocean basins varied with wind speed and swell height. Results For all study species, soaring using both wind and waves resulted in an 89–93% reduction in the number of flaps per hour and thus more energetically efficient flight. We found notable differences in the relative importance of wind and waves for albatrosses breeding in the Southern Ocean and North Pacific. The flap rates of Southern Ocean species, black-browed (Thalassarche melanophris), grey-headed (T. chrysostoma), and wandering (Diomedea exulans) albatrosses, were better explained by variability in windspeed whereas those of North Pacific species, black-footed (Phoebastria nigripes) and Laysan (P. immutabilis) albatrosses, were better explained by variability in swell height. Conclusions Our results suggest that Southern Ocean species relied more on dynamic soaring by exploiting winds whereas North Pacific species relied more on wave-slope soaring using swells. This divergence in behavior is likely the result of differences in the regional winds and swells between the two ocean basins. Although windspeeds experienced by albatrosses in both oceans were similar, North Pacific species experienced greater swell heights, likely allowing them to extract more wind energy from waves than albatrosses in the Southern Ocean. Our research highlights the importance of both wind and waves for albatross movement and the need to better understand environmental impacts on physiological drivers of foraging energetics to assess responses of seabirds to a rapidly changing climate. 

Abstract Let $$T$$ be a satellite knot, link, or spatial graph in a 3-manifold $$M$$ that is either $S^3$ or a lens space. Let $$\b_0$$ and $$\b_1$$ denote genus 0 and genus 1 bridge number, respectively. Suppose that $$T$$ has a companion knot $$K$$ (necessarily not the unknot) and wrapping number $$\omega$$ with respect to $$K$$. When $$K$$ is not a torus knot, we show that $$\b_1(T)\geq \omega \b_1(K)$$. There are previously known counter-examples if $$K$$ is a torus knot. Along the way, we generalize and give a new proof of Schubert's result that $$\b_0(T) \geq \omega \b_0(K)$$. We also prove versions of the theorem applicable to when $$T$$ is a "lensed satellite" and when there is a torus separating components of $$T$$. 

Extreme event attribution (EEA) research increasingly studies how the impacts of specific disasters can be linked to climate change. We use a multi-hazard, high resolution, and temporally dynamic framework to study these impacts for Hurricane Ida (2021) in Louisiana. This framework begins with hurricane wind modeling that produces wind fields at warming levels set at 30 year averages for 1971 (i.e. the storm that could have been), 2021 (i.e. the storm that was), and 2071 (i.e. the storm that could be). We then connect these wind fields to storm surge flood models as well to damage functions for both storm surge and wind impacts. Total damages from Hurricane Ida were 19% higher in 2021 than they would have been in 1971 due to historical climate change, and could be 76% higher in 2071 compared to 2021 under projected warming. Damage characteristics vary considerably by hazard (e.g. wind impacts increase at a higher rate than storm surge), time (e.g. greater future increases), space (e.g. climate change’s imprint is higher in the areas with severe or moderate impacts), and by number of affected structures and structure type (e.g. residential structures increase at a higher rate for storm surge). Our findings demonstrate the value of a contextualized, multi-dimensional framework for EEA.