The Annelid Community of a Natural Deep-sea Whale Fall off Eastern Australia

In the deep ocean, whale falls (deceased whales that sink to the seafloor) act as a boost of productivity in this otherwise generally food-limited setting, nourishing organisms from sharks to microbes during the various stages of their decomposition. Annelid worms are habitual colonizers of whale falls, with new species regularly reported from these settings and their systematics helping to resolve biogeographic patterns among deep-sea organic fall environments. During a 2017 expedition of the Australian research vessel RV Investigator to sample bathyal to abyssal communities off Australia’s east coast, a natural whale fall was opportunistically trawled at ~1000 m depth. In this study, we provide detailed taxonomic descriptions of the annelids associated with this whale-fall community, using both morphological and molecular techniques. From this material we describe nine new species from five families (Dorvilleidae: Ophryotrocha dahlgreni sp. nov. Ophryotrocha hanneloreae sp. nov., Ophryotrocha ravarae sp. nov.; Hesionidae: Vrijenhoekia timoharai sp. nov.; Nereididae: Neanthes adriangloveri sp. nov., Neanthes visicete sp. nov.; Orbiniidae: Orbiniella jamesi sp. nov.), including two belonging to the bone-eating genus Osedax (Siboglinidae: Osedax waadjum sp. nov., Osedax byronbayensis sp. nov.) that are the first to be described from Australian waters. We further provide systematic accounts for 10 taxa within the Ampharetidae, Amphinomidae, Microphthalmidae, Nereididae, Orbiniidae, Phyllodocidae, Protodrilidae, Sphaerodoridae and Phascolosomatidae. Our investigations uncover unique occurrences and for the first time enable the evaluation of biogeographic links between Australian whale falls and others in the western Pacific as well as worldwide.Marine Biodiversity Hub, supported through the Australian Government's National Environmental Science Program (NESP)UK Research & Innovation (UKRI) Natural Environment Research Council (NERC) NE/R000670/1Ifremer Postdoctoral FellowshipChadwick Biodiversity Fellowship from the Australian MuseumAustralian Biological Resources Study (ABRS) RG18-2

Sulfur isotopes of hydrothermal vent fossils and insights into microbial sulfur cycling within a lower Paleozoic (Ordovician‐early Silurian) vent community

This study was supported by a UK Natural Environment Research Council grant (NERC; number NE/R000670/1 to AG). MG is also grateful for support from an Ifremer Postdoctoral Fellowship. Alvinella samples were collected with the help of a NERC Small Grant (number NE/C000714/1 to CTSL). S isotopic analyses were undertaken under NERC Facility awards IP-1755-1117 and IMF672/1118.Symbioses between metazoans and microbes involved in sulfur cycling are integral to the ability of animals to thrive within deep‐sea hydrothermal vent environments; the development of such interactions is regarded as a key adaptation in enabling animals to successfully colonize vents. Microbes often colonize the surfaces of vent animals and, remarkably, these associations can also be observed intricately preserved by pyrite in the fossil record of vent environments, stretching back to the lower Paleozoic (Ordovician‐early Silurian). In non‐vent environments, sulfur isotopes are often employed to investigate the metabolic strategies of both modern and fossil organisms, as certain metabolic pathways of microbes, notably sulfate reduction, can produce large sulfur isotope fractionations. However, the sulfur isotopes of vent fossils, both ancient and recently mineralized, have seldom been explored, and it is not known if the pyrite‐preserved vent organisms might also preserve potential signatures of their metabolisms. Here, we use high‐resolution secondary ion mass spectrometry (SIMS) to investigate the sulfur isotopes of pyrites from recently mineralized and Ordovician‐early Silurian tubeworm fossils with associated microbial fossils. Our results demonstrate that pyrites containing microbial fossils consistently have significantly more negative δ34S values compared with nearby non‐fossiliferous pyrites, and thus represent the first indication that the presence of microbial sulfur‐cycling communities active at the time of pyrite formation influenced the sulfur isotope signatures of pyrite at hydrothermal vents. The observed depletions in δ34S are generally small in magnitude and are perhaps best explained by sulfur isotope fractionation through a combination of sulfur‐cycling processes carried out by vent microbes. These results highlight the potential for using sulfur isotopes to explore biological functional relationships within fossil vent communities, and to enhance understanding of how microbial and animal life has co‐evolved to colonize vents throughout geological time.Publisher PDFPeer reviewe

Microbial-tubeworm associations in a 440 million year old hydrothermal vent community

Microorganisms are the chief primary producers within present-day deep-sea hydrothermal vent ecosystems, and play a fundamental role in shaping the ecology of these environments. However, very little is known about the microbes that occurred within, and structured, ancient vent communities. The evolutionary history, diversity and the nature of interactions between ancient vent microorganisms and hydrothermal vent animals are largely undetermined. The oldest known hydrothermal vent community that includes metazoans is preserved within the Ordovician to early Silurian Yaman Kasy massive sulfide deposit, Ural Mountains, Russia. This deposit contains two types of tube fossil attributed to annelid worms. A re-examination of these fossils using a range of microscopy, chemical analysis and nano-tomography techniques reveals the preservation of filamentous microorganisms intimately associated with the tubes. The microfossils bear a strong resemblance to modern hydrothermal vent microbial filaments, including those preserved within the mineralized tubes of the extant vent polychaete genus Alvinella. The Yaman Kasy fossil filaments represent the oldest animal–microbial associations preserved within an ancient hydrothermal vent environment. They allude to a diverse microbial community, and also demonstrate that remarkable fine-scale microbial preservation can also be observed in ancient vent deposits, suggesting the possible existence of similar exceptionally preserved microfossils in even older vent environments

Identification of fossil worm tubes from Phanerozoic hydrothermal vents and cold seeps

One of the main limitations to understanding the evolutionary history of hydrothermal vent and cold seep communities is the identification of tube fossils from ancient deposits. Tube-dwelling annelids are some of the most conspicuous inhabitants of modern vent and seep ecosystems, and ancient vent and seep tubular fossils are usually considered to have been made by annelids. However, the taxonomic affinities of many tube fossils from vents and seeps are contentious, or have remained largely undetermined due to difficulties in identification. In this study, we make a detailed chemical (Fourier-transform infrared spectroscopy and pyrolysis gas-chromatography mass-spectrometry) and morphological assessment of modern annelid tubes from six families, and fossil tubes (seven tube types from the Cenozoic, 12 Mesozoic and four Palaeozoic) from hydrothermal vent and cold seep environments. Characters identified from these investigations were used to explore for the first time the systematics of ancient vent and seep tubes within a cladistic framework. Results reveal details of the compositions and ultrastructures of modern tubes, and also suggest that two types of tubes from ancient vent localities were made by the annelid family Siboglinidae, which often dominates modern vents and seeps. Our results also highlight that several vent and seep tube fossils formerly thought to have been made by annelids cannot be assigned an annelid affiliation with any certainty. The findings overall improve the level of quality control with regard to interpretations of fossil tubes, and, most importantly, suggest that siboglinids likely occupied Mesozoic vents and seeps, greatly increasing the minimum age of the clade relative to earlier molecular estimates

TOI-1268b: The youngest hot Saturn-mass transiting exoplanet

We report the discovery of TOI-1268b, a transiting Saturn-mass planet from the TESS space mission. With an age of less than 1 Gyr, derived from various age indicators, TOI-1268b is the youngest Saturn-mass planet known to date; it contributes to the small sample of well-characterised young planets. It has an orbital period of P = 8.1577080 \ub1 0.0000044 days, and transits an early K-dwarf star with a mass of M∗ = 0.96 \ub1 0.04 M+, a radius of R∗ = 0.92 \ub1 0.06 R+, an effective temperature of Teff = 5300 \ub1 100 K, and a metallicity of 0.36 \ub1 0.06 dex. By combining TESS photometry with high-resolution spectra acquired with the Tull spectrograph at the McDonald Observatory, and the high-resolution spectrographs at the Tautenburg and OndR ejov Observatories, we measured a planetary mass of Mp = 96.4 \ub1 8.3 Mp and a radius of Rp = 9.1 \ub1 0.6 Rp. TOI-1268 is an ideal system for studying the role of star-planet tidal interactions for non-inflated Saturn-mass planets. We used system parameters derived in this paper to constrain the planeta\u27s tidal quality factor to the range of 104.5-5.3. When compared with the sample of other non-inflated Saturn-mass planets, TOI-1268b is one of the best candidates for transmission spectroscopy studies

Ageing increases reliance on sensorimotor prediction through structural and functional differences in frontostriatal circuits

This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Nature Publishing Group.The control of voluntary movement changes markedly with age. A critical component of motor control is the integration of sensory information with predictions of the consequences of action, arising from internal models of movement. This leads to sensorimotor attenuation – a reduction in the perceived intensity of sensations from self-generated compared to external actions. Here we show that sensorimotor attenuation occurs in 98% of adults in a population-based cohort (n=325; 18-88 years; the Cambridge Centre for Ageing and Neuroscience). Importantly, attenuation increases with age, in proportion to reduced sensory sensitivity. This effect is associated with differences in the structure and functional connectivity of the pre-supplementary motor area (pre-SMA), assessed with magnetic resonance imaging. The results suggest that ageing alters the balance between the sensorium and predictive models, mediated by the pre-SMA and its connectivity in frontostriatal circuits. This shift may contribute to the motor and cognitive changes observed with age.Cam-CAN research was supported by the Biotechnology and Biological Sciences Research Council (BB/H008217/1). JBR and NW were supported by the James S. McDonnell Foundation 21st Century Science Initiative, Scholar Award in Understanding Human Cognition. JBR was also supported by Wellcome Trust [103838] and the Medical Research Council [MC-A060-5PQ30]. DMW was supported by the Wellcome Trust [097803], Human Frontier Science Program and the Royal Society Noreen Murray Professorship in Neurobiology. RNH was supported by the Medical Research Council [MC-A060-5PR10]. RAK was supported by a Sir Henry Wellcome Trust Postdoctoral Fellowship [107392]. LG was funded by a Rubicon grant from the Netherlands Organisation for Scientific Research (NWO)

Perceptual and conceptual processing of visual objects across the adult lifespan

Abstract: Making sense of the external world is vital for multiple domains of cognition, and so it is crucial that object recognition is maintained across the lifespan. We investigated age differences in perceptual and conceptual processing of visual objects in a population-derived sample of 85 healthy adults (24–87 years old) by relating measures of object processing to cognition across the lifespan. Magnetoencephalography (MEG) was recorded during a picture naming task to provide a direct measure of neural activity, that is not confounded by age-related vascular changes. Multiple linear regression was used to estimate neural responsivity for each individual, namely the capacity to represent visual or semantic information relating to the pictures. We find that the capacity to represent semantic information is linked to higher naming accuracy, a measure of task-specific performance. In mature adults, the capacity to represent semantic information also correlated with higher levels of fluid intelligence, reflecting domain-general performance. In contrast, the latency of visual processing did not relate to measures of cognition. These results indicate that neural responsivity measures relate to naming accuracy and fluid intelligence. We propose that maintaining neural responsivity in older age confers benefits in task-related and domain-general cognitive processes, supporting the brain maintenance view of healthy cognitive ageing

Distinct components of cardiovascular health are linked with age-related differences in cognitive abilities

Cardiovascular ageing contributes to cognitive impairment. However, the unique and synergistic contributions of multiple cardiovascular factors to cognitive function remain unclear because they are often condensed into a single composite score or examined in isolation. We hypothesized that vascular risk factors, electrocardiographic features and blood pressure indices reveal multiple latent vascular factors, with independent contributions to cognition. In a population-based deep-phenotyping study (n = 708, age 18–88), path analysis revealed three latent vascular factors dissociating the autonomic nervous system response from two components of blood pressure. These three factors made unique and additive contributions to the variability in crystallized and fluid intelligence. The discrepancy in fluid relative to crystallized intelligence, indicative of cognitive decline, was associated with a latent vascular factor predominantly expressing pulse pressure. This suggests that higher pulse pressure is associated with cognitive decline from expected performance. The effect was stronger in older adults. Controlling pulse pressure may help to preserve cognition, particularly in older adults. Our findings highlight the need to better understand the multifactorial nature of vascular aging

Poorer White Matter Microstructure Predicts Slower and More Variable Reaction Time Performance: Evidence for a Neural Noise Hypothesis in a Large Lifespan Cohort

Most prior research has focused on characterizing averages in cognition, brain characteristics, or behavior, and attempting to predict differences in these averages among individuals. However, this overwhelming focus on mean levels may leave us with an incomplete picture of what drives individual differences in behavioral phenotypes by ignoring the variability of behavior around an individual's mean. In particular, enhanced white matter (WM) structural microstructure has been hypothesized to support consistent behavioral performance by decreasing Gaussian noise in signal transfer. Conversely, lower indices of WM microstructure are associated with greater within-subject variance in the ability to deploy performance-related resources, especially in clinical populations. We tested a mechanistic account of the “neural noise” hypothesis in a large adult lifespan cohort (Cambridge Centre for Ageing and Neuroscience) with over 2500 adults (ages 18-102; 1508 female; 1173 male; 2681 behavioral sessions; 708 MRI scans) using WM fractional anisotropy to predict mean levels and variability in reaction time performance on a simple behavioral task using a dynamic structural equation model. By modeling robust and reliable individual differences in within-person variability, we found support for a neural noise hypothesis (Kail, 1997), with lower fractional anisotropy predicted individual differences in separable components of behavioral performance estimated using dynamic structural equation model, including slower mean responses and increased variability. These effects remained when including age, suggesting consistent effects of WM microstructure across the adult lifespan unique from concurrent effects of aging. Crucially, we show that variability can be reliably separated from mean performance using advanced modeling tools, enabling tests of distinct hypotheses for each component of performance