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Intense aqueous alteration on C-type asteroids: Perspectives from giant fine-grained micrometeorites
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This study explores the petrology of five giant (>400 μm) hydrated fine-grained micrometeorites from the Transantarctic Mountain (TAM) micrometeorite collection. For the first time, the extent and mechanisms of aqueous alteration in unmelted cosmic dust are evaluated and quantified. We use a range of criteria, previously defined for use on hydrated chondrites, including phyllosilicate fraction, matrix geochemistry and micro textures. Collectively, these micrometeorites represent ∼2.22 mm2 of intensely altered hydrated chondritic matrix (with petrologic subtypes of <1.2 in the scheme of Howard et al. (2015)) and reveal a range of alteration styles. Two particles are found to contain pseudomorphic chondrules with thick fine-grained rims, while another micrometeorite contains several aqueously altered CAIs. Their outlines range from well-defined to indistinct, demonstrating that the advanced stages of aqueous alteration progressively remove evidence of coarse-grained components. The remaining two micrometeorites entirely lack coarse-grained components but are similarly altered. Thus, the combined chondrule-to-matrix ratio among these giant micrometeorites is extremely low (6.45 area%), and significantly below the average ratio found in typical CM or CR chondrites (∼20%, Weisberg et al., 2006). Our findings are consistent with previous analyses from smaller Antarctic micrometeorites, which suggest that chondrules (and CAIs) derived from hydrated carbonaceous chondrite parent bodies are underrepresented among the micrometeorite flux, even when considering contributions from coarse-grained micrometeorites. Therefore, to explain the relative paucity of anhydrous material, we propose that the flux of fine-grained micrometeorites is primarily derived from intensely aqueously altered, primitive C-type asteroids, which have lost the majority of their refractory coarse-grained components by replacement with secondary phyllosilicate minerals.
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RBINS Staff Publications 2019
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Inter and intra island introgression in a wolf spider radiation from the Galapagos and its implications for parallel evolution
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Parallel radiations within island systems are often assumed to follow a simple scenario in which single colonization events are followed by in situ adaptive divergence. However, subsequent gene exchange after the initial colonization and during the divergence process might have important evolutionary impacts on species radiations. Gene exchange among ecologically similar species from different islands may lead to introgression of adaptive genetic variation and influence the parallel divergence process. In this study, we estimate levels of gene exchange within a wolf spider radiation of the genus Hogna Simon, 1885, from the Galápagos, wherein habitat specialization into ‘high elevation’ and ‘coastal dry’ species apparently evolved repeatedly on two islands. By using a multilocus approach we show that low levels of inter-island and relatively higher levels of intra island introgression shaped genetic variation in this species complex. Using these estimates, we demonstrate by means of a coalescence simulation that under these inter- and intra-island migration rates parallel evolution most likely evolves by introgression of adaptive alleles among islands, rather than through independent mutations despite the close genetic relationship of species within islands. As species phylogenies within radiations are frequently used to infer the divergence pattern, even relatively low levels of interspecific gene flow should not be neglected when interpreting parallel trait evolution.
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RBINS Staff Publications
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Inter- and intraspecific variation in the surface pattern of the dermal bones of two sturgeon species
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Archaeological bone remains of sturgeon (Acipenser sturio/Acipenser oxyrinchus) from northwestern Europe are often identified to species on the basis of their surface morphology and then used to reconstruct the spatial distribution of the two species through time. The dermal bones of A. sturio are said to have an exterior surface pattern consisting of tubercles, while those of A. oxyrinchus are said to display alveoli. In the present paper, the validity of the surface pattern as a species-specific characteristic is critically assessed. To this purpose, dermal plates from modern, genetically identified museum specimens were studied and the surface morphology observed in a series of archaeological remains was compared with the genetic identifications obtained on these same remains. The analyses show that the surface pattern of dermal bones is related to the size of the individual, with the pattern of small A. oxyrinchus being similar to that of A. sturio. In addition, variations in the surface pattern among the bones of a single individual and within the same bone have been observed. These findings explain previous conflicting results between morphological and genetic identifications and allow the formulation of some recommendations for more accurate morphological identification of isolated archaeological sturgeon dermal bones.
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RBINS Staff Publications 2016
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Inter‐specific aggression generates ant mosaics in canopies of primary tropical rainforest
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RBINS Staff Publications 2017
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Intercontinental dispersal of mammals during the Paleocene new data from Europe
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The Paleocene in general and in Europe in particular, is generally considered as an epoch with high endemism and few intercontinental dispersals of mammals, although some faunal interchange is known between Asia and North America, mainly from the Tiffanian-Clarkforkian boundary. Up to now, however, faunal interchange between Europe and North America during the Paleocene has almost never been demonstrated. The study of the early Paleocene fauna of Hainin (Belgium) reveals high endemism in European mammals at the end of the Danian (early Paleocene). The age of the fauna of Walbeck (Germany) is reevaluated and is likely to be Selandian (middle Paleocene), significantly older than previously suggested. Therefore, Walbeck is closer in age to Hainin than to the typical late Paleocene fauna of Cernay (France). However, the faunas from Walbeck and Cernay share many common genera that are not present in Hainin, showing a faunal turnover around the Danian-Selandian boundary in Europe, marked by the first occurrence of Plesiadapis, Arctocyon and Adunator in Walbeck, and of neoplagiaulacid multituberculates and Dissacus in Cernay. The three genera present in Walbeck are abundant and diversified in North America from the beginning of the Tiffanian, i.e., older than the expected age of Walbeck. Therefore, it is inferred that these genera dispersed from North America to Europe around the Danian–Selandian boundary, corresponding roughly to the Torrejonian–Tiffanian boundary. The absence of multituberculates in the fauna of Walbeck does not allow the drawing of definite conclusions about the moment of their dispersal, but it is likely that it happened at the same time as Plesiadapis and Arctocyon, because neoplagiaulacids are abundant and diversified during the whole Paleocene in North America. Similarly, Dissacus is very rare in Cernay, and could also have dispersed at the same time as others, but remained unnoticed because of its rarity. The Clarkforkian in North America is marked by massive arrival of taxa from Asia, among which are rodents, carnivorans, and tillodonts. The recent discovery of the latest Paleocene fauna of Rivecourt (France), where typical Paleocene taxa cohabit with rodents and a carnivoran, indicates that the large-scale dispersal event marking the Paleocene–Eocene boundary began in Europe about at the same time as in North America, with the arrival of rodents and carnivorans. The morphology of the new carnivoran species suggests that this group dispersed separately from Asia to Europe and from Asia to North America.
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RBINS Staff Publications
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Interdisciplinary science to support North Sea marine management: lessons learned and future demands
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RBINS Staff Publications 2019
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Intermediate gastropod hosts of major feline cardiopulmonary nematodes in an area of wildcat and domestic cat sympatry in Greece
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RBINS Staff Publications 2020
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International assessment of priority environmental issues for land-based and offshore wind energy development
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Abstract Non-technical summary A substantial increase in wind energy deployment worldwide is required to help achieve international targets for decreasing global carbon emissions and limiting the impacts of climate change. In response to global concerns regarding the environmental effects of wind energy, the International Energy Agency Wind Technical Collaborative Program initiated Task 34 – Working Together to Resolve Environmental Effects of Wind Energy or WREN. As part of WREN, this study performed an international assessment with the global wind energy and environmental community to determine priority environmental issues over the next 5‒10 years and help support collaborative interactions among researchers, developers, regulators, and stakeholders. Technical summary A systematic assessment was performed using feedback from the international community to identify priority environmental issues for land-based and offshore wind energy development. Given the global nature of wind energy development, feedback was of interest from all countries where such development is underway or planned to help meet United Nations Intergovernmental Panel on Climate Change targets. The assessment prioritized environmental issues over the next 5–10 years associated with wind energy development and received a total of 294 responses from 28 countries. For land-based wind, the highest-ranked issues included turbine collision risk for volant species (birds and bats), cumulative effects on species and ecosystems, and indirect effects such as avoidance and displacement. For offshore wind, the highest-ranked issues included cumulative effects, turbine collision risk, underwater noise (e.g. marine mammals and fish), and displacement. Emerging considerations for these priorities include potential application to future technologies (e.g. larger turbines and floating turbines), new stressors and species in frontier regions, and cumulative effects for multiple projects at a regional scale. For both land-based and offshore wind, effectiveness of minimization measures (e.g. detection and deterrence technologies) and costs for monitoring, minimization, and mitigation were identified as overarching challenges. Social media summary Turbine collisions and cumulative effects among the international environmental priorities for wind energy development.
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RBINS Staff Publications 2022
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International maritime regulation decreases sulfur dioxide but increases nitrogen oxide emissions in the North and Baltic Sea.
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RBINS Staff Publications 2023
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International maritime regulation decreases sulfur dioxide but increases nitrogen oxide emissions in the North and Baltic Sea
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Sulfur dioxide and nitrogen oxide emissions from shipping have been regulated internationally for more than fifteen years. Emissions reduction from shipping provides benefits for human health and the environment, but the effectiveness of regulations in reducing ship emissions is less well understood. Here, we examine how the establishment of European Emission Control Areas and other international maritime regulations in the North and Baltic Seas affect sulfur dioxide and nitrogen oxide emissions in the region. We combine and analyze more than 110,000 ship plume measurements, inspection results, and satellite data from 2018 to 2022. We find that compliance rates for sulfur emissions are higher near ports than in open waters. However, the regulations did not affect the concentration of nitrogen oxide emissions, which increased in the past three years. These findings highlight the need for enhanced emission regulations that improve air quality.
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RBINS Staff Publications 2023