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Sensitivity analysis of the dark spectrum fitting atmospheric correction for metre- and decametre-scale satellite imagery using autonomous hyperspectral radiometry
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The performance of the dark spectrum fitting (DSF) atmospheric correction algorithm is evaluated using matchups between metre- and decametre-scale satellite imagery as processed with ACOLITE and measurements from autonomous PANTHYR hyperspectral radiometer systems deployed in the Adriatic and North Sea. Imagery from the operational land imager (OLI) on Landsat 8, the multispectral instrument (MSI) on Sentinel-2 A and B, and the PlanetScope CubeSat constellation was processed for both sites using a fixed atmospheric path reflectance in a small region of interest around the system&\#x2019;s deployment location, using a number of processing settings, including a new sky reflectance correction. The mean absolute relative differences (MARD) between in situ and satellite measured reflectances reach <20&\#x0025; in the Blue and 11&\#x0025; in the Green bands around 490 and 560 nm for the best performing configuration for MSI and OLI. Higher relative errors are found for the shortest Blue bands around 440 nm (30&\#x2013;100&\#x0025; MARD), and in the Red-Edge and near-infrared bands (35&\#x2013;100&\#x0025; MARD), largely influenced by the lower absolute data range in the observations. Root mean squared differences (RMSD) increase from 0.005 in the NIR to about 0.015&\#x2013;0.020 in the Blue band, consistent with increasing atmospheric path reflectance. Validation of the Red-Edge and NIR bands on Sentinel-2 is presented, as well as for the first time, the Panchromatic band (17&\#x2013;26&\#x0025; MARD) on Landsat 8, and the derived Orange contra-band (8&\#x2013;33&\#x0025; MARD for waters in the algorithm domain, and around 40&\#x2013;80&\#x0025; MARD overall). For Sentinel-2, excluding the SWIR bands from the DSF gave better performances, likely due to calibration issues of MSI at longer wavelengths. Excluding the SWIR on Landsat 8 gave good performance as well, indicating robustness of the DSF to the available band set. The DSF performance was found to be rather insensitive to (1) the wavelength spacing in the lookup tables used for the atmospheric correction, (2) the use of default or ancillary information on gas concentration and atmospheric pressure, and (3) the size of the ROI over which the path reflectance is estimated. The performance of the PlanetScope constellation is found to be similar to previously published results, with the standard DSF giving the best results in the visible bands in terms of MARD (24&\#x2013;40&\#x0025; overall, and 18&\#x2013;29&\#x0025; for the turbid site). The new sky reflectance correction gave mixed results, although it reduced the mean biases for certain configurations and improved results for the processing excluding the SWIR bands, giving lower RMSD and MARD especially at longer wavelengths (>600 nm). The results presented in this article should serve as guidelines for general use of ACOLITE and the DSF.
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RBINS Staff Publications 2020
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Sequence stratigraphy and palaeontology of the upper Miocene Pisco Formation along the western side of the lower Ica Valley (Ica Desert, Peru)
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RBINS Staff Publications 2017
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Seven new species and two new genera of Physocypria sensu latu (Crustacea, Ostracoda) from Brazilian floodplains
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We describe seven new species in two new genera of the Physocypria sensu latu clade (Cyclocypridinae) from three of the main Brazilian floodplains. Brasilocypria pea gen. et spec. nov. and Brasilocypria ricardopintoi gen. et spec. nov. occur in the Upper Paraná River floodplain and the South Matogrossense Pantanal, Claudecypria mesquitai gen. et spec. nov., Brasilocypria alisonae gen. et spec. nov. and Claudecypria rochei gen. et spec. nov. were found in the South Matogrossense Pantanal, and Brasilocypria lordi gen. et spec. nov. and Brasilocypria namiotkoi gen. et spec. nov. occur in the Amazon River floodplain. All new species here described were found as sexual populations. Generally, they have a short and suboval carapace, with the left valve overlapping the right valve on all sides, except for the dorsal side in some species. The morphology of the hemipenis and the prehensile palps, together with the shape of the valves, were the most important characters to distinguish the species. Size differences between species can be substantial. Several characters, such as the absence in all new species of the short accompanying seta of the five natatory setae on the antenna; the presence in all new species of a long seta next to the two a-setae on the first thoracopod, and the presence/absence or differences in length of specific setae on the second and third thoracopod, are relevant for the generic diagnoses. We also redefine Keysercypria Karanovic, 2011.
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RBINS Staff Publications 2023
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Sex-Biased Dispersal at Different Geographical Scales in a Cooperative Breeder from Fragmented Rainforest
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RBINS Staff Publications
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Sexual dimorphism in the walrus mandible: comparative description and geometric morphometrics
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RBINS Staff Publications 2022
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Shaking the wings and preening feathers with the beak help a bird to recover its ruffled feather vane
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The feather of a bird consists of barbs which again comprise numerous barbules with micro-hooklets. This hierarchically organized feather structure provides a smooth vane to bear the load from the airflow; however, the feather vane is vulnerable to disruption by external pulling forces during collision with the branches of a tree and hitting some small obstacles in flight or strong turbulence. The feather is unable to carry the weight of the bird's body if the vane could not be recovered immediately. Here we discovered that the feather vane can be re-established easily by birds themselves. A bird can always recover its feather vane from ruffled state by shaking its wings and preening its feathers with its beak because of the cascaded geometries of barbs and barbules. This biophysical mechanism of self-healing suggests that the hierarchical vane structure can be used to design artificial feathers for a flapping robot.
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RBINS Staff Publications 2019
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Shallow benthic invertebrate communities in relation to substrate types in coastal environments of the sub-Antarctic Crozet archipelago.
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"The European weatherfish Misgurnus fossilis, once widespread across Eurasia, is now critically endangered in Flanders (Belgium), prompting the establishment of a captive breeding programme as part of conservation efforts. During rearing, juvenile weatherfish suffered heavy infections from the ectoparasitic flatworm Gyrodactylus fossilis, leading to mortality events. Although G. fossilis is a natural parasite of M. fossilis, high host densities in hatchery conditions facilitated pathological infection intensities, while adult fish maintained at lower densities showed no visible pathology. This suggests that husbandry practices strongly modulate dynamics of this host–parasite system in captivity. To place these observations in a historical context, we screened both captive-bred fish and archival material (1881–1973, i.e. prior to the anthropogenic introduction of Asian congeners in Misgurnus) for ectoparasites. Morphological and molecular characterisation revealed infections of three monopisthocotylan flatworms: G. fossilis, Gyrodactylus misgurni (Gyrodactylidae), and Actinocleidus cruciatus (Dactylogyridae). All represent new records for Belgium, with G. misgurni and A. cruciatus considered native due to their occurrence in historical material. Notably, these parasites’ abundance has declined compared to historical collections, raising concerns about their own conservation status. Since parasites contribute substantially to species-richness, ecosystem functioning, and even the health of their host individuals and populations (e.g., their immunological development and resilience) their co-decline alongside endangered hosts represents a hidden and meaningful dimension of biodiversity loss. Our findings highlight both risks and opportunities associated with parasite conservation in ex situ programmes focused on fishes or other vertebrate hosts. High juvenile stocking densities increased parasite burdens and mortality, while improved husbandry practices allowed stable co-existence of host and parasite populations. This indicates that carefully managed captive breeding facilities may act as refugia not only for M. fossilis but also for its specialist parasites, maintaining ecological interactions and genetic diversity that would otherwise be lost. While parasites are often overlooked or actively eliminated in wildlife management, they play essential roles in ecosystems and represent species of conservation concern in their own right. These results emphasise the possibility of including parasites in conservation planning. For the weatherfish and its parasites, ex situ conservation thus provides an experimental framework for developing integrated strategies that safeguard both host and parasite persistence. Future reintroduction initiatives should therefore consider whether to also re-establish native parasite populations, a decision that requires informed discussion among conservation stakeholders. By demonstrating the feasibility of host–parasite co-conservation, this study advances the idea that conservation programmes can optimise resource allocation while preserving the evolutionary and ecological relationships of multiple species simultaneously.
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RBINS Staff Publications 2025
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Shell chemistry of the Boreal Campanian bivalve Rastellum diluvianum (Linnaeus, 1767) reveals temperature seasonality, growth rates and life cycle of an extinct Cretaceous oyster.
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RBINS Staff Publications 2020
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Shell repurposing is an important consideration for the future sustainability of mollusc aquaculture
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RBINS Staff Publications 2016
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Shell thickness of Nucella lapillus in the North Sea increased over the last 130 years despite ocean acidification
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RBINS Staff Publications 2022
